Open Mind

Wiggles

December 16, 2007 · 311 Comments

I started working on a post about feedbacks, an interesting and important topic recently raised in reader comments. But I’ve been sidetracked by the revival of one of the favorite false claims of denialists, one of those pieces of garbage that never dies. Occasionally I look at the stats provided by wordpress, and I noticed I was getting a lot of hits from the science blog Deltoid. That’s because Deltoid commented on an open letter in the National Post signed by a collection of scientists which includes many, if not most, of the usual list of denialists. The open letter has some rather outrageous claims; possibly the most egregious (and most easily proved false) is this:


Consistent with this, and despite computer projections of temperature rises, there has been no net global warming since 1998. That the current temperature plateau follows a late 20th-century period of warming is consistent with the continuation today of natural multi-decadal or millennial climate cycling.

Regarding the claim that there hasn’t been any global warming since 1998, I’ve already posted about it, the claim is demostrably false. What’s really surprising (well, maybe it isn’t so surprising) is that some of the signatories to this drivel are trained in statistics, including Ross McKitrick and Edward Wegman.

But why, you may wonder, does this claim (in one form or another) keep rearing its ugly head? Whether it’s “global warming stopped in 1998″ or “the satellite trend is flat over the last 13 years” or “this year’s hurricane season was a dud,” I keep hearing so-called “statistics” that are touted as evidence against the reality of global warming. The reason lies in the fact that there are two things which contribute to data: the signal and the noise.

Noise is the “random” part of the data. It may be measurement error, or a random physical process, or even a deterministic physical process which mimics a random process. But it’s there. For the layman, it’s often unexpected; if global warming is real, how can global temperature fail to rise enough to break the 1998 record for hottest year ever (according to HadCRU data — according to NASA GISS data the hottest year is 2005)? But in the real world, noise is unavoidable. If I were to see temperature data which didn’t have noise in it, I’d be immediately suspicious that the data were faulty. Still — how can it be that we haven’t broken the 1998 record yet (according to HadCRU, because according to GISS we broke it in 2005)? It’s been nearly 10 years! Doesn’t that cast some doubt on global warming?

The “modern global warming era” is from about 1975 to the present. If you study the yearly global average temperature 1975-now, you’ll find that it shows a statistically significant upward trend, the planet getting hotter by about 0.018 deg.C/yr. You’ll also find that in addition to this signal, there’s noise which has a root-mean-square value (a “standard deviation”) of about 0.1 deg.C.

Is global temperature data really indistinguishable from a steady trend with random fluctuations? Is a steady trend with random fluctuations really indistinguishable from global temperature data? To get some perspective I decided to generate artificial data to mimic this, so I created a time series of 100 years length which is the sum of a signal plus noise: the signal consists of a steady trend at a rate of 0.018 deg.C/yr, the noise is random numbers with standard deviation 0.1 deg.C. Then I chose one of the values that had a particularly large positive random part and called that the year “1998″ in order to match the record-setting temperature actually observed on earth in 1998. Finally I shifted all the values by a constant, so the data would be on the same scale as actual temperature data. Using this artificial data, here’s what the modern global warming era looks like:

art1.jpg

Just like real temperature data, it shows a distinct (and statistically significant) rise. Linear regression indicates the rate of increase is 0.014 +/- 0.004 deg.C/yr, so the error range includes the true value.

What if we looked only at data from the 1998 peak to the present? Now it looks like this:

art2.jpg

Oh my God!!! Suddenly we have “no global warming since 1998″!!! Linear regression actually indicates cooling at a rate of -0.007 deg.C/yr!!!

But we know, without any doubt whatsoever, that the signal is still increasing, at a rate of exactly 0.018 deg.C/yr. It’s the noise that shows cooling — and for such a short time span, the cooling in the noise overwhelms the warming in the signal.

What does the future hold for this artificial temperature data? Here’s the data from the start of the global warming era, to 28 years from now:

art3.jpg

It looks like we’ve got some serious warming on the way. Linear regression indicates that for this data, the rate of warming is 0.018 +/- 0.002 deg.C/yr. But of course, we already know that the warming rate is exactly 0.018 deg.C/yr — the artificial data is designed that way.

Noise exists. Anyone who tells you different isn’t just selling something, they’re lying. The noise we observe in annual global average temperature is big enough that it’s easy to get an entire decade which will give a cooling trend. And I didn’t have to work hard to make this happen; I didn’t generate lots of 100-year signal+noise series until I found one that made my point, I only generated a single series, and there it was. But the cooling trend so determined will not be statistically significant. The warming trend in longer time spans is statistically significant.

The right approach is to look for the trends, not the wiggles, and to apply statistical significance testing to determine whether they’re real changes in the system or just accidental fluctuations. There’s always noise mixed in with the signal, and disentangling the two can be very tricky. But it can be done.

Another way to get a better picture of actual trends is by taking averages, not over very brief 1-year periods, but over longer stretches of time. Here’s the actual global average temperature (from NASA GISS) averaged over each 5-year interval (the last average is incomplete, since we haven’t yet finished the 2005-2010 interval):

5yrave.jpg

Now we see a much more steady progression. That’s because taking longer-term averages actually reduces the effect of the noise without affecting the trend. But there’s still noise! By taking averages over longer time spans we don’t eliminate the noise, we just make it smaller.

Global average temperature isn’t the only global-warming related variable which shows wiggles. In fact, just about all measured quantities show wiggles similar to what is seen in global temperature. Because of this, we can expect that there will always be several climate variables which are wiggling in a direction opposite to the long-term trend. Hence there will always be one or more measures which are — momentarily — going the “wrong way” according to global warming. And because of that, we will continue to hear about them from denialists. 2007 wasn’t as hot as 2005; Argentina had a colder winter this year than last; arctic sea ice anomaly isn’t as negative as it was this summer; hurricane activity this year was less than predicted; etc., etc., etc. As long as physical variables show wiggles — and they always will — there will be plenty of fodder for denialists. They’ll never run out of something that they can spin to make it look like global warming isn’t happening.

As long as there’s noise, denialists will exploit it to paint a false picture of the changes earth’s climate is experiencing. And there will always be noise — both in climate data, and from denialists.

UPDATE UPDATE UPDATE

The issue has arisen, are not the fluctuations seen in global temperature data since 1998 below the preceding trend? Is such deviation statistically significant?

The answers are, no and no. Let’s take GISS global temperature data, and use only the data from 1975 through 1998 to estimate the trend. By ending with 1998, we’ll get an especially high trend rate, so the following data will have a high trend to “live up to.”

We can then extend that trend line to the present, to see whether or not the most recent data depart from that trend. Here’s the result:

It’s rather clear that the data after 1998 are well in accord with the trend before 1998. We can also compute residuals, the difference between the observed data and what the value would have been if it followed the 1975-1998 trend exactly:

trend2.jpg

We see that the data since 2001 are actually a little warmer than what we would have expected from the 1975-1998 trend. But the deviations are not statistically significant.

UPDATE #2 UPDATE #2 UPDATE #2

Here’s the surface temperature record according the GISS and HadCRU, smoothed on a 5-year time scale:

gisscru.jpg

Categories: Global Warming · climate change

311 responses so far ↓

  • dhogaza // December 16, 2007 at 6:04 pm

    Just to make clear to readers that there’s no way that Wegman can be ignorant of the fact that cherry-picking a starting point like 1998 …

    As part of [Wegman's] duties at the Office of Naval Research, [he] coined the phrase, computational statistics, and developed a high profile research area around this concept. The idea was to focus on techniques and methodologies which could not be achieved without the capabilities of modern computing resources. This program led to a revolution in contemporary statistical graphics.

    There’s more from his CV but you get the idea…

  • dhogaza // December 16, 2007 at 6:05 pm

    should’ve said “the wrongness of cherry-picking” …

  • KenH // December 16, 2007 at 6:35 pm

    The 2007 Arctic ocean ice extent may present a new cherry picking opportunity for denialists. If the minimum ice extent doesn’t match the 2007 extent for several years, they’ll be able to claim (like 1998 temperature) that “the ice extent was a minimum in 2007 and has been increasing ever since”.

  • tonylee6032 // December 16, 2007 at 6:37 pm

    Great post, Tamino. Very accessible for us non-scientists. I have a question and a comment.

    The question: Which dataset is preferred: HadCRU or GISS? I know the GISS includes estimates for the polar regions, which HadCRU doesn’t, but media reports almost always refer to HadCRU. Why is that?

    The comment: While it’s clear to me from what you’ve laid out that the temperature is increasing despite short-term noise, surely a denialist can simply claim that the current trend is just as indicative of a plateau before a drop. After all, if you believe current warming is just a natural cycle and that there is no link between human-emitted CO2 and warming, then the entire warming period from 1975 is just a deviation from the baseline. Which of course, just proves your point about the hardiness of denialist dog whistles.

  • Timothy Chase // December 16, 2007 at 6:40 pm

    From the essay:

    But I’ve been sidetracked by the revival of one of the favorite false claims of denialists, one of those pieces of garbage than never dies.

    Typo? I presume “than” should be “that.”

    Still reading the essay.

    [Response: Fixed!]

  • EliRabett // December 16, 2007 at 7:16 pm

    How about writing to Wegman and asking him what he meant?

  • vixt // December 16, 2007 at 7:20 pm

    This blog seems to be less about science these days and more about attacking others. Me thinks you should change the name to “anti-denialist mind”.

    Your argument is hypocritical. Anybody could pick any starting point and find a different trend. You picked one yourself when you said “The “modern global warming era” is from about 1975 to the present. ”

    [Response: I didn't pick 1975 out of a hat, nor did I choose it because it makes my case look good. There are objective mathematical reasons to choose 1975 as the "turning point" at which the rapid upward trend begins. Look a the graph of 5-year averages; it gives a good visual impression of the change that happened at that time. Running the numbers, rather than choosing randomly or cherry-picking what you want, indicates 1975.

    And that's the *real* difference between denialists and not. Those who claim that global warming is real and caused by human activity, do so on the basis of what the numbers say. Those who claim the opposite, trumpet only the numbers that appear to support what they say.]

    Anybody could just as easily say “the modern cooling trend began in 1998″. The difference is, you don’t like that, so you rant about it.

    [Response: "Cooling since 1998" FAILS statistical significance tests, while "warming since 1975" PASSES. Temperature since 1998 is perfectly consistent with a continued warming signal plus random noise. In fact, because of the existence of noise it's impossible NOT to get periods of apparent cooling. That's the point of the post.

    Do you believe there's no noise in the data? Do you dispute the validity of statistical significance testing?]

    In another post you wrote “13 years isn’t long enough to establish a trend”.

    Ok agreed, but 30 years is? It seems just as arbitrary to me. Climate seems to have longer cycles than that.

    [Response: Again -- it's called "statistical significance." It's how we tell the difference between actual trends in the signal and apparent trends due to the noise.]

    So it’s getting warmer since 1975. You promote that. But when some other scientist says “cooling since 1998″ you say it can’t be so and accuse using the old tired “cherry picking” argument.

    [Response: When someone trained in statistics, like McKitrick or Wegman, claims cooling based a data which are *easily* shown to be too brief for a signal to rise above the noise, they should know better -- I think they *do* know better. In your case maybe it's just ignorance. But for McKitrick and Wegman, it's cherry-picking.]

    I see cherry picking on both sides. Nobody is innocent. It’s all getting tiring. It’s like watching arguments in congress.

    [Response: False. In fact you've given us another favorite denialist argument: everybody is wrong, so nobody is any more right than anybody else. The AGW side rarely engages in cherry-picking, and the leading scientists supporting it don't do it at all.]

    The way I see it, a little warmer is a good thing. We can manage that, if sea levels rise like Gore claims, we move inland, we adapt. Been there done that. Humans adapt well. But if the ice comes, there’s no way in hell you can get out of the way of a glacier. Everything north of about 40-45, including Toronto, Montreal, New York, Boston, Portland gets ground up to a coarse gravel.

    Then there’s the massive agricultural failures in colder climates and the famines that follow. Crops grow better in warm climates with extra CO2.

    Warm is easier to manage. I like to think of Co2 based global warming as terraforming to our advantage. An ice age would be a true disaster.

    I’m sure you’ll all tell me how stupid and wrongheaded my view is. Flail away.

  • Timothy Chase // December 16, 2007 at 7:28 pm

    I didn’t know that Ross McKitrick had signed the recent letter about the plateau, but judging from what I found by doing a little search on his history, it really doesn’t surprise me. What is difficult for me to understand is how he or anyone like him could expect to be treated in a civil manner by any competent climatologist after having signed such a document — let alone coauthored some of the papers which have borne his name. But if I spend too much time thinking about that, something inside me is likely to short-circuit.

    Out of curiosity, have you looked into the spectral density which is associated with temperature series? Is it roughly constant? I assume there are measurable differences era to era.

    Anyway, one of the points that I remember we have bumped into in the past is the detection of regime change in the presence of red noise. One example would of course be in the case of temperatures (the temperature trend of the stratosphere seems to be rather step-wise, particularly in comparison to surface temperatures) but another would be with respect to hurricanes. (Quick question: I assume that internal to a given regime, there may nevertheless be a linear trend?)

    With this in mind, I thought I might bring to your attention something I found a little while ago which might be of interest — assuming you hadn’t already seen it:

    The Problem of Red Noise in Climate Regime Shift Detection
    Sergei N. Rodionov
    http://www.beringclimate.noaa.gov/regimes/Red_noise_paper_v3_with_figures.pdf

    Regime shift detection (Excel-based software)
    http://www.beringclimate.noaa.gov/regimes/

    Both are a little beyond me at this point, but at least the physical location is convenient: Sergei is at the University of Washington.

  • Aaron Lewis // December 16, 2007 at 7:30 pm

    You illustrate the point that we do not teach our young people enough math so that they can intelligently consume statistics.

    It is a problem we have had since Mark Twain said, “Figures don’t lie, but liars figure.”

    Excellent!

  • Hank Roberts // December 16, 2007 at 7:31 pm

    > writing to Wegman

    He ought to be interested in the subject:
    # Statistical Graphics and Visualization
    Wegman, E. J. and Carr, D. B..in Rao (1993) Handbook of Statistics, Elsevier
    # Statistical Image Processing and Graphics
    Wegman, E. J. and DePriest, D. J.. Marcel Dekker; New York, NY. 1986.

  • Timothy Chase // December 16, 2007 at 7:50 pm

    tonylee6032 wrote:

    The question: Which dataset is preferred: HadCRU or GISS? I know the GISS includes estimates for the polar regions, which HadCRU doesn’t, but media reports almost always refer to HadCRU. Why is that?

    I suspect both are valuable — as long as you know what each is refering to. As to why media reports might be focusing on HadCRU, I suspect it is either because it isn’t showing as much of a trend at this point as GISS, or because what happens north of the Arctic Circle can’t possibly affect all that much given how remote it is. However, when people bring it up, it might be a good opening for discussing the differences and what is going on north of that circle, or perhaps even the good work that is coming out of Hadley. I mean if they like the temperature series, undoubtedly they will find some of the other data from Hadley of value as well.

    tonylee6032 wrote:

    After all, if you believe current warming is just a natural cycle and that there is no link between human-emitted CO2 and warming, then the entire warming period from 1975 is just a deviation from the baseline. Which of course, just proves your point about the hardiness of denialist dog whistles.

    Sounds more like metaphysics than climatology, but I suppose that at least in terms of popular perception, this is precisely what they are trying to make it out to be. A bit like the “infinitely recurring cosmic cycles.” Then again, they a great deal of what they are doing reminds me of a Humean approach to causality and epistemology, too.

  • dhogaza // December 16, 2007 at 9:48 pm

    The way I see it, a little warmer is a good thing. We can manage that, if sea levels rise like Gore claims, we move inland, we adapt. Been there done that.

    Ah, we have years of evolution of the denialist argument compressed into a single post. First, “it’s not true”, then “it’s a good thing”. Actually, you left out the interim step, “it won’t be so bad”.

    You claim “been there, done that”, as though it’s not big deal. The dislocation of a couple of hundred thousand people from New Orleans serves as an example countering your “not a big deal” hand-wave. Yes, adaptation won’t have to happen overnight as it did in New Orleans. However, the number of people living in coastal urban areas is huge, and that migration will be anything than “ho-hum” if it becomes necessary.

    And this is precious…

    if the ice comes, there’s no way in hell you can get out of the way of a glacier.

    So, ignore warming issues in the next century because the next ice age, which will kick off in thousands of years, might be a bummer.

    That’s sorta like saying “I’ll jump off this 50 story building today because I’ll die of old age anyway 50 years from now”.

    But it’s interesting, because the Carter letter says essentially the same thing. Not explicity, because it’s so bone-headedly stupid, but implicitly, with its talk of investing to adapt to future natural changes (by which they mean “worry about cooling as much as warming”).

    Looks like the talking points broadcast center is working effectively, with the high and the low picking up the message and spreading it through the blogosphere.

    Then there’s the massive agricultural failures in colder climates and the famines that follow. Crops grow better in warm climates with extra CO2.

    The great breadbaskets of the world are in the northern hemisphere’s temperate regions, the plains of the US, the Steppes of eastern Europe, etc.

    The “extra CO2″ canard assumes that crop growth is currently limited by the amount of CO2 in the atmosphere.

    Tell that to farmers who spend millions on fertilizer, who rotate crops like wheat with nitrogen-fixing legumes, etc.

    The “extra CO2 means more growth” argument comes from research done in enclosed environments (like greenhouses) where other plant needs were provided to the point where CO2 was the limiting factor. Not a real-world experiment.

  • John Mashey // December 16, 2007 at 10:27 pm

    1) Absent human effects, we would normally have expected the glaciers to have been slowly growing again. [See William Ruddiman's Plows, Plagues, Petroleum.]

    2) We didn’t use to have ice caps on Earth. We could return to that state, to all intents permanently [>further lifetime of human species is long enough.]
    After all, Milankovitch ice-cap cycles didn’t appear until CO2 got low enough, i.e., we are already overriding the usual orbital cycles.

    3) And, if in some faroff future, it’s starting to get cold, stepping up CFC production takes care of lower CO2. I.e., it’s a *lot* easier to keep the planet warm than it is to cool it…

  • Steve Bloom // December 16, 2007 at 10:54 pm

    vixt wries: “But if the ice comes, there’s no way in hell you can get out of the way of a glacier.”

    Actually intentionally spreading black soot on glaciers would be a very effective way of getting rid of them. Given the ease of application, I suspect a glaciation could be fought off to a significant degree using such a method.

    However, just now we have the opposite problem. As Tamino is in the process of detailing in his “Wobbles” posts, glaciations come and go based on orbital changes that happen to be predictable with great precision. Conveniently, it’s possible to validate the likely future relationship between those changes and the glaciations by looking at the traces left by the many past glacial cycles that have taken place over the last two million years. IIRC current thinking is that we are in a very long interglacial, probably on the order of 30-40,000 years; i.e. without any anthropogenic influences it would be at least another 20,000 years until the next glaciation starts. With anthropogenic influences added in, I think it’s fair to say that we have nothing to worry about.

    One other thing you might want to bear in mind is that the geologic record shows that ice sheets form very slowly and melt very quickly. Another is that the climate scientists who study the past tend to be the most worried of all about the near future. This is because the last time GHG levels were anything like they are now we had a much warmer climate with much-reduced ice sheets, sea levels at least 25 meters higher than present, different rainfall patterns, etc., etc.

    If you want to learn more about all of this, you could start with the Wikipedia paleoclimate article and follow the references.

  • Fielding Mellish // December 17, 2007 at 5:00 am

    Vixt wrote:
    “This blog seems to be less about science these days and more about attacking others.”

    Your post certainly provides a self-proving example.

    “We can manage that, if sea levels rise like Gore claims, we move inland, we adapt.”

    To focus on the purely human costs of that, never mind the tragic impact on other species, can you conceive of the widespread bankruptcies that coastal areas would experience? Let alone the incredible task of moving enough infrastructure to support 150 million people, including reconstructing the entire power and transportation grid (into the exact area where you hope food will be grown). Lest this be so America-centric, consider how the rest of the world would fare. By the way, it isn’t ‘Gore’s claim,’ but thanks anyway for the lame perjorative.

    “Been there done that.”

    Never before. Not with 150 million+ residents, plus refugees, in this country alone.

    “Crops grow better in warm climates with extra CO2.”

    This would be a good place for you to toss in some of that science you think there is not enough of here. A frank examination of the state of our current food production coupled with growing conditions under a fully engaged AGW scenario ought to sober you up straight away. Besides other things, such as the fact that sunlight and soil quality restrains the northward move of North American cropping areas, the prospect of the Ogallala aquifer’s running dry about the time AGW snicks into third gear should have an effect rivaling that of the best contraceptives that Not At All Naughty Chemists, Ltd. has to offer. The tenor of your post suggests that you don’t know much about food production, so it might be a good idea to gauge AGW’s impact on the developing countries from where a lot of what you likely now eat originates. As you consider that, remember to exclude seafood from the food supply budget, owing to a collapsed marine food chain. AGW is bad enough on its own, but we also have a nice array of co-morbidity factors to consider.

    “Warm is easier to manage.”

    What about bloody hot? And when did the “either too hot/or too cold” strawman enter the conversation? On the bright side, we do figure that tropical diseases will waltz into latitudes heretofore hostile to them, so you have going for your view.

    “I’m sure you’ll all tell me how stupid and wrongheaded my view is.”

    Your post leaves little to embellish on that point. In fairness, it’s obvious that you did not generate your post from serious research, but rather from the consumption of propaganda designed and purveyed to maintain the purveyors’ profit. In the AGW conversation as in baking, chaff makes for very poor crumpets and a downright evil legacy.

  • Fielding Mellish // December 17, 2007 at 5:02 am

    edit: “On the bright side, we do figure that tropical diseases will waltz into latitudes heretofore hostile to them, so you have THAT going for your view.”

  • vixt // December 17, 2007 at 5:03 am

    You folks are wonderfully predictable. Are you 100% sure of everything or just in denial of alternate ways of looking at things? There’s not a curious one in the lot.

    Tamino - Thank you but I don’t need a statistical test to see trend lines, from the temp graphs I’ve seen there there’s a slight downturn since 1998. Run tests all you want, but that won’t change that perception.

    [Response: You *really* don't get it! Yes you *do* need statistical tests, unless you want to keep seeing trend lines where there's just noise. That's how we tell the difference; the eye is not good enough.]

    “been there, done that” I was referring to the fact that I once lived on the eastern seaboard. We had a beach erosion (probably due to catastrophic sea level rise y’all keep talking about) that forced me to abandon a beach home.

    Yes, I’ve “been there, done that”. I didn’t “dismiss it with a wave of the hand” I got busy and worked my butt off to save what I could. I’m still alive, so is the town. The beachfront is now back further. The point is that these changes are slow motion compared to human adaptability. Ice will be just as slow motion, but crop failures from an ice age will reach in the Canadian wheat-lands and upper US breadbasket. And that’s not something you can fix with a snowblower. Then there’s the cities like Minneapolis that will be uninhabitable. People will pack up and move just like in the Grapes of Wrath. Comparing that which will happen over years to Katrina which was 2 days notice is just stupid.

    For Mr. Hogaza, thank you but here is a story about CO2 and tree growth patterns. It looks like there IS an effect outside of the greenhouse. It seems reasonably “real world” to me.

    http://www.breitbart.com/article.php?id=paLeaves_Tue_10_CO2_impact&show_article=1

    I like a warmer world, so does agriculture. It seems our existence is owed to it because if we were still in the last Ice Age we’d still be chasing caribou. A warming world helped our transition from hunter-gatherers to agrarians, so bring it on! Sorry but I just can’t get too worried over the claims of impending doom having personally survived a few of nature’s trials myself.

    I just started up a blog. It’s not much. This makes good practice. I’ll send an invite when I’m ready.

    Flail away, lads.

  • nanny_govt_sucks // December 17, 2007 at 5:04 am

    But doesn’t noise work both ways? If we had just entered a climate cooling phase, might not the noise in the data possibly give a false impression of warming?

  • bill // December 17, 2007 at 5:10 am

    Interesting post. Could you expand more on your choice of 1975? Mauna Loa goes back to 1959, and the annual CO2 increment is positive over that range. I ask because forecasts using an autoregression will depend on your starting point. For example, using the entire hadley annual series forecast a decrease over the next decade (big C.I. though), while the 1975+ series forecasts a nice steady increase. (forecasts using SAS’ Forecast procedure)

    Also, what does your change-point algorithm (SCUMSUM) say? The claim is about a change-point.

  • jonathan // December 17, 2007 at 5:27 am

    Your outrage about the cherry picking and outright exaggeration in a political process should be directed within your own scientific community. I dare you to have the same critical analysis on Mann’s infamous hockey stick. Take away the bristlecone proxies and the convoluted statistic manipulations which make white noise show a hockey stick and what do we have?

    I happen to believe that humanity should drastically lower its carbon footprint (esp coal!) but I am disgusted how scientists have gotten so sloppy once their “consensus” is determined

  • bill // December 17, 2007 at 5:34 am

    My change-point algorithm (Hawkins, D.M. (2001) Comp.Stat.Data.anal) insists on putting a change-point right on 1997, and none after. It only fits constants between the change-points, though. I haven’t coded up the regression-tree yet.

  • Marion Delgado // December 17, 2007 at 10:10 am

    I can’t speak for anyone else, but vixt is well below my response line. So no flailing. just killfile.

  • Petro // December 17, 2007 at 2:29 pm

    One aspect of denialism is certainly a failure to understand basic statistics. That is not suprising by itself, since many times much easier natural facts are not grasped there.

    Lack of scientific education can be corrected by curious mind. Lack of curiosity cannot be corrected.

  • bill // December 17, 2007 at 4:00 pm

    To your point on 1975, CART in regression mode puts its first break point at 1977 (and its third at 1997. ) Its still fitting means within the intervals.

  • Hank Roberts // December 17, 2007 at 4:41 pm

    vixt:
    >beach
    North Carolina?
    http://www.questia.com/library/book/the-beaches-are-moving-the-drowning-of-americas-shoreline-by-wallace-kaufman-orrin-h-pilkey-jr.jsp

    >’hockey stick’ …what do you have left?
    You might as well imagine you’re undercutting current stem cell research by referring to what we know that Darwin or Wallace or Mendel didn’t, or undercutting microbiology by pointing out that Leewenhoek thought there were six kinds of bacteria.

    You’re right. Without statistics, all you get is what you see. Thrash on.

  • george // December 17, 2007 at 5:22 pm

    Isn’t it possible to actually estimate the magnitude of the temperature change induced by “noise” (which includes the effect of El Nino) in 1998?

    Doesn’t a least squares line fit to the decades preceding and including 1998 (or over all of the past 3 decades, for that matter) actually give us a pretty good idea what the temperature increase would look like without the “noise” over that period?

    Isn’t that one of the primary points of doing a linear regression?

    If that is the case, isn’t the difference between the ordinate for 1998 for that (several decade) trend line and the actual 1998 temperature a gauge of the magnitude of the noise (including El Nino) for that year?

    If the “noise” over that entire period has a root-mean-square value of about 0.1 deg.C, as you indicate, that would mean that the actual temperature for 1998 lies more than a couple standard deviations above the trend line at that point in time, would it not?

    Which begs the question about the validity of using 1998 as a comparison for later years, of course.

  • luminous beauty // December 17, 2007 at 6:49 pm

    Statistics applied without an understanding of underlying physical constraints is just noise.

    GHGs do warm the planet. Tree ring growth is effected by temperature.

    The slowing down of global temperatures since 1998 (anomalous in it’s own right as being a strong El Niño year) is consistent with known internal variability in the climate system. What is different about this particular fluctuation is that there is no downward trend after the warming trend, but global temperatures have continued to trend upwards, in spite of lowering solar insolation over this period of approx 0.15Wm^-2.

  • Pat Trombly // December 17, 2007 at 11:01 pm

    Signal = data that supports your theory

    Noise = data that doesn’t….

    …..Besides, the point isn’t limited to the fact that there still hasn’t been a year warmer than 1998 - the point is also that you folks predicted that by now there would be years warmer than 1998. As early as December 2006 we heard that 2007 was going to be warmer than 1998. Then as the year has progressed the predictions have come down, to second, third, and as of late November, sixth - though it’s been a cold December so far so 2007 could fall out of the top 10 - - starting to look like BC football’s BCS ranking….

    Yeah, I know - El Nino stopped way earlier than expected.

    But that’s the point - - - if you cannot predict a regional phenomenon a few weeks in advance, how can we place value on your longer-term predictions?

    And predictions are all you have - there is no tangible evidence of causation; every time anyone asks for evidence, you start talking about models - which haven’t predicted squat.

    What if 2008, 2009, 2010 pass and 1998 is still the record - will you guys commit to a date after which, if 1998 is still the ‘warmest year on record’ you’ll admit you were wrong? Or will there be some excuse? Will you claim that solar radiation has dropped temporarily, that mother nature is “giving us a second chance?”

    [Response: I differentiate between signal and noise based on sound statistical analysis. Only. Denialists do the opposite. So I'll ask you the same questions I asked vixt:

    1. Do you believe that noise doesn't exist? Because if it does, then it's impossible NOT to get apparent cooling trends which don't reflect the signal, just the noise.

    2. Do you not accept the validity of statistical significance tests? Because if you do, then there's not only no basis to claim a cooling trend, there's no basis to deny a warming trend.

    When a cooling trend in global average temperature passes statistical significance tests, I'll readily admit that global warming isn't happening. What will it take for YOU to admit you're wrong?]

  • cce // December 18, 2007 at 12:31 am

    I suppose it’s inconsequential that NASA puts 2005 warmer than 1998, and 2007 will probably be warmer also. As long as the other temperature analyses don’t address the poles, they will under count the amount of warming that is really going on, especially compared to 1998 which wasn’t particularly warm at the poles (at least, not compared to recent years).

    Go to the GISTEMP website, click on the “Global Maps” link. Specify 1998-1998 as the base year, and 2005 or 2007 as the time interval (for 2007, you can specify the Dec-Nov mean period). Look at where the strongest anomalies are.

  • luminous beauty // December 18, 2007 at 2:25 am

    “…will you guys commit to a date after which, if 1998 is still the ‘warmest year on record’ you’ll admit you were wrong?”

    Yes. 2005.

    If you’ll spot 1998 -0.2C for being an exceptionally strong El Niño year, then 2001. Even according to Hadley.

  • Boris // December 18, 2007 at 3:22 am

    “And predictions are all you have - there is no tangible evidence of causation; every time anyone asks for evidence, you start talking about models - which haven’t predicted squat.”

    There is tangible evidence of causation, evidence from theory–CO2 DOES cause warming. The question of how much has been estimated by models, but also by observational evidence, which suggests a range similar to models, though a range that has a wider uncertainty.

    Also, keep in mind that models generally don’t make predictions. Models simulate the climate and give us a good idea of what happens when CO2 doubles.

    But it a myth and absolutely false that models are the only evidence for what will happen if CO2 continues to rise.

  • nanny_govt_sucks // December 18, 2007 at 4:33 am

    GHGs do warm the planet.

    Well, Water Vapor in the form of a cloud, by reflecting incoming solar radiation, can have a cooling effect on the climate, so your statement is not 100% true.

    Tree ring growth is effected by temperature.

    But is this relationship linear?

  • luminous beauty // December 18, 2007 at 5:07 am

    nags,

    The reflective component of a cloud is tiny droplets of liquid water, not water vapor.

  • nanny_govt_sucks // December 18, 2007 at 5:26 am

    If you’ll spot 1998 -0.2C for being an exceptionally strong El Niño year,

    Since when have El Ninos been considered to be less than an integral part of the climate?

  • nanny_govt_sucks // December 18, 2007 at 5:34 am

    The reflective component of a cloud is tiny droplets of liquid water, not water vapor.

    OK, point taken. But water vapor has other cooling properties. Ex. Transport of heat from the lower atmosphere to the upper atmosphere where some of it is released to space on condensation.

  • elspi // December 18, 2007 at 5:57 am

    Wow ngs, you really outdid yourself.

    So an El Nino, which is just a transfer of cold to the ocean depths rather than an actual increase in the average temp of the entire planet, should not be adjusted for when looking for global warming.

    Kind of like where Karl Rove said that it was the democrats who were pushing for a vote on the war resolution before the 2002 elections.

    You ngs have a future in politics (in the worst possible way).

  • Hank Roberts // December 18, 2007 at 6:00 am

    > Since when have El Ninos been
    > considered to be less than
    > an integral part of the climate

    Nan’s got that right. An El Nino year is part of the climate for long enough to do trend calculations:

    http://geology.geoscienceworld.org/cgi/content/abstract/28/11/1007

    “significant periodicities of 3.1 and 8.4 yr in the terrigenous series; these are indistinguishable, within the frequency resolution of the spectra, from significant periodicities of 3.5 and 7.6 yr in the diatomaceous series. The 3.1 and 3.5 yr periodicities record El Niño modulation of coastal runoff and marine production; the 8.4 and 7.6 yr periodicities are consistent with modulation by strong to very strong El Niño events. …. terrigenous and diatomaceous records …. reveal inverse or antiphase relationships at 3.5 and 7.6 yr. Our work adds to a body of evidence that suggests that El Niño has been a persistent feature of late Quaternary climate variability.”

    So that’s clear — don’t cherry pick an El Nino year, pick the long span of climate records of which it is an integral part to see what trend exists.

    To look at any trends that’s happened during recent human fossil fuel use, you can’t fixate on an El Nino year — it’s a persistent feature that comes and goes, and you have to take the longterm trend to avoid getting misled by focusing on one El Nino temperature.

    Good point, Nan. Thank you.

  • RB // December 18, 2007 at 7:18 am

    I would just like to thank you for this and the garbage-never-dies threads. I was able to download GISTEMP data and run the same analysis.

    Trust but verify.

    It shames me that Dr. Gray’s name is on that denialist letter. I am embarrassed for my alma mata.

  • fred // December 18, 2007 at 7:57 am

    Still working on the troposphere and the stratosphere, but in the meantime, Pielke offers as the key signature of AGW, ocean heating. The link is here:

    http://climatesci.colorado.edu/2007/04/04/a-litmus-test-for-global-warming-a-much-overdue-requirement/

    And the suggested parameters are half way down the page.

    No idea what this indicator shows at the moment, and I’m aware of the measurement deficiencies in Willis’ cited paper.

    However, do you agree this is what Pielke calls a litmus test?

    This is not, please, about what the test shows now, or about whether Pielke is an estimable fellow. Just about whether the cited measure really is fit for purpose as a litmus test of the occurence of AGW. Or GW at least.

  • firebird // December 18, 2007 at 8:36 am

    nags,

    The reflective component of a cloud is tiny droplets of liquid water, not water vapor.

  • firebird // December 18, 2007 at 8:36 am

    Well, Water Vapor in the form of a cloud, by reflecting incoming solar radiation, can have a cooling effect on the climate, so your statement is not 100% true.

  • dhogaza // December 18, 2007 at 9:14 am

    Nags, nags, nags …

    If you’ll spot 1998 -0.2C for being an exceptionally strong El Niño year,

    Since when have El Ninos been considered to be less than an integral part of the climate?

    As was pointed out in the post, 2005 is the warmest year on record if you don’t discount for El Niño. 2001 if you do.

    The point was that the post being responded to claims that 1998 is the warmest year on record, which is incorrect, if you look at global temps (my guess is that the poster making the claim is one of those who thinks the lower 48 is the world, something my european friends complain constantly about when talking about the American view of life).

    But it a myth and absolutely false that models are the only evidence for what will happen if CO2 continues to rise.

    Absolutely false, yes. Myth, no. The truth is less flattering.

  • Chris O'Neill // December 18, 2007 at 1:48 pm

    will you guys commit to a date after which, if 1998 is still the ‘warmest year on record’ you’ll admit you were wrong?

    Ignoring polar areas (yes I know it’s an ignorant thing to do) we could use the HadCRU figures which, I think, give 1998 as being about 0.25 deg C higher than the trend level for that year. The warming rate is under 0.2 deg C/decade (lower if you leave out the polar areas) so we should expect it to take something more than 12.5 years after 1998 for the HadCRU trend to reach the temperature of 1998. i.e. it’s probably unlikely for HadCRU to be cooler than 1998 in 2011 and beyond.

  • Hank Roberts // December 18, 2007 at 3:59 pm

    Fred, here’s some reading on Pielke’s “litmus” test — if he were talking about ocean pH, he’d be closer to the mark. The buoy system (Argo) is producing data now and should inform this sort of discussion within the next few years.

    http://www.google.com/search?q=%2Bstoat+%2B%22litmus+test%22+%2Bocean+%2Btemperature+%2Bprometheus

  • Hank Roberts // December 18, 2007 at 4:19 pm

    Fred, the first link in the search above (if Google hasn’t changed, hah) is to John Fleck’s page, for discussion of the Pielke “litmus” paper. For convenience, this link gets you the paper discussed there, among many others on the subject:
    http://www.gfdl.gov/reference/bibliography/authors/stouffer.html

  • Rob // December 19, 2007 at 12:15 pm

    A bit of topic…(but not noice)

    Why aren’t we talking about the real cause of the problem of our times; overpopulation? Why care about warming or cooling when in the end it’s a resource problem; land, food, etc.?

    If we blend some sci-fi into the mix one could argue that mother nature is trying to kill us off (warming, earthquakes, flooding, diseases etc.) to survive her self?

    /Br. Rob

  • HJ // December 19, 2007 at 1:47 pm

    Your trend graph stretching to 2035 is about 300% off the scale since you have not included the most recent findings re. climate sensitivity:
    http://www.agu.org/pubs/crossref/2007/2007JD008740.shtml

    Also when extrapolating trends, why not also use HadAT2, MSU or UAH for the lower troposphere, all of which show considerably less warming than GISS and HadCRU? Surely surface warming alone from potentially UHI-biased data will not yield an accurate trend estimation?

  • Hank Roberts // December 19, 2007 at 4:32 pm

    >Chylek

    Hmmm.
    http://tamino.wordpress.com/2007/08/29/polar-ice/#comment-4603
    and
    http://julesandjames.blogspot.com/2007/11/kooks-corner.html

    I’ll wait til someone who can read the full paper, not just the publicly available abstract, can comment.

  • dhogaza // December 19, 2007 at 7:52 pm

    Why aren’t we talking about the real cause of the problem of our times; overpopulation? Why care about warming or cooling when in the end it’s a resource problem; land, food, etc.?

    Even if we cut the world’s population by 50%, if the developing world were to adopt a first-world lifestyle complete with profligate burning of fossil fuels, we would still have a problem.

    Population is an issue and at some point humanity has to reach zero growth or perish (unless science fiction dreams of planetary-scale emigration comes true), but it’s certainly not the only issue, and we can slow global warming without addressing population growth.

  • Ian Rae // December 19, 2007 at 8:56 pm

    I’m a skeptic, but I ignore any statement that includes the phrase “since 1998″. It was a strange year. Besides, ten years is not a climate trend; both sides, in their zeal, keep forgetting that.

  • Michael Smith // December 19, 2007 at 8:59 pm

    The author of this post said:

    “But we know, without any doubt whatsoever, that the signal is still increasing, at a rate of exactly 0.018 deg.C/yr. It’s the noise that shows cooling — and for such a short time span, the cooling in the noise overwhelms the warming in the signal.”

    This is the logical fallacy of “begging the question”. It consists of assuming the truth of what you wish to prove and then using that assumption as a premise in that proof.

    The fact that you can create a data series that combines a signal with noise and evenually find a set of data points that contradicts the trend only proves that such a contradiction MAY be the sole result of the noise. It is a useful exercise to demonstrate a POSSIBILITY — but it is not a proof that this is what has happened since 1998.

    You may BELIEVE “without any doubt whatsoever” that the signal is increasing, but you have not proven such to be the case. The fact of the matter is that you do not know whether the signal continued or stopped in 1998. The data — particularly the tropospheric temperature data — are inconclusive at this point in time. (And this would apply to any claims of cooling since 1998 as well — such a claim is simply not supported by the data.)

    AGW theory says that tropospheric warming should exceed surface warming — and the data does not indicate that this is happening.

    [Response: Isn't it obvious -- even to you -- that what you quote refers to the artificial data? Since the artificial data are signal+noise, and the signal is *defined* as a steady increase at exactly 0.018 deg.C/yr, we do indeed know without doubt that the signal is still increasing.

    The point of this post is to show that given a signal plus noise, with the signal steadily increasing, it's not only *possible* to have intervals which seem to contradict the trend, it's impossible NOT to. The only way to have no episodes of inconclusive trends, some even having an *apparent* countertrend, is to have zero noise. But we know, without any doubt whatsoever, that there is noise.

    As for the *apparent* contradiction between tropospheric and surface data, read this.]

  • nanny_govt_sucks // December 19, 2007 at 9:08 pm

    Why care about warming or cooling when in the end it’s a resource problem; land, food, etc.?

    Well, cooling leads to crop failures and large areas of land covered by ice, so these exacerbate resource problems. Warming leads to more livable land area, and warmth+CO2 leads to increased food production which should ease population pressures. But even as the Earth is now it can handle a much larger population, the problem is distributing the food and that comes down to politics and international trade policies.

  • Hank Roberts // December 20, 2007 at 2:18 am

    Nan, each time I ask you for your sources you go to CO2science or something. Please, try Google Scholar for each of those statements, just copy and paste into the search box everything between commas, limit to recent, and read. It’s a boatload.

  • Dano // December 20, 2007 at 4:15 am

    Oh, look: na_gs is back with his increased food production BS. The interval between his latest assertion and the refutation and his return with the same old refuted line is 49 days.

    The last time was 56 days, the time before that was 46 days., before that 55 days.

    There’s been no warming since 1998!

    Best,

    D

  • nanny_govt_sucks // December 20, 2007 at 4:18 am

    Hank, when have I ever referenced CO2science?

    What kind of a reference do you need to show that crops don’t grow on ice, that warmth melts ice, or that warmth and CO2 are good for plants? I thought these ideas were pretty well known.

  • JesusChristHimself // December 20, 2007 at 6:26 am

    I don’t know if you have ever farmed, but the difference between a crop and a bunch of crispy stalks can be just a little warmth and dryness above normal. What a farmer needs is lots of normal. He’s used to that, and he knows what to do with it.

  • nanny_govt_sucks // December 20, 2007 at 7:18 am

    I don’t know if you have ever farmed, but the difference between a crop and a bunch of crispy stalks can be just a little warmth and dryness above normal.

    Well it’s a good thing then that we have higher CO2 concentrations nowadays to help crops deal with dryer conditions. But I thought that predictions wer for a warmer, wetter global climate overall? It would seem that would favor farming. Not to mention more arable land and higher CO2!

  • ErikS // December 20, 2007 at 8:01 am

    Hank Roberts, I´ve read the Chylek et al. paper. To me it seems that there is a fundamental flaw in the way they treat the ocean uptake of heat. They state that it should be propotional to the temperature increase (deltaT) during the last ten years, which is kinda odd. They refer to a Raper et al. paper where deltaT is the difference to the unpertubed state.

  • Gary // December 20, 2007 at 10:30 am

    The reason that so many “denialists” use 1998 as a starting point is because it was used by so many as proof that things were getting bad very quickly. The temperature of 1998 was not described as an outlier in 1999 but was used as proof that GW was speeding up and at the time a 25 year trend from an artificially chosen low point was fine for those claiming that the rate of global warming was was increasing. We were told that we had hit or passed a tipping point.

    Now there is a 10 year trend showing that these claims were premature. GW is happening at rates similar to what it was prior to significant human CO2 production and at constant rates not at accelerating rates.

    All of this talk is rather ridiculous because discussing any climate trend without looking at the trends within the last 10,000 or even 100,000 years silly. We are still within the normal bounds of an interglacial warming period.

    [Response: Warming per se is not a problem, even if the planet heats up 3 deg.C or more this century. But that much warming in ONLY ONE CENTURY is a HUGE problem. There's abolutely nothing even close to it in the last several million years at least.]

    But the point is that when GW alamists used 1998 to “prove” that things are getting bad very quickly, at an accelarating rate then they have to be willing to let the “deniers” throw it back at them when their predictions of rapidly increasing temperatures in the next few years don’t come true.

    [Response: Name names: who used 1998 to "prove that things are getting bad very quickly"? Either back up this claim with citations, or don't expect to be believed.]

    The trend since 1998 shows temperatures going up at about the same rate as they were since we have been recording temperatures and those trends fit within longer term patterns and trends over 1000’s, 10,000’s and 100,000’s of years.

    [Response: Not so.]

  • dhogaza // December 20, 2007 at 10:34 am

    What kind of a reference do you need to show that crops don’t grow on ice, that warmth melts ice, or that warmth and CO2 are good for plants? I thought these ideas were pretty well known.

    The great breadbaskets of the world, such as the north american plains and the eastern european steppes, aren’t covered in ice.

    Wheat doesn’t grow in the sea, either, melting the artic icecap isn’t going to cause farmers to move to the north pole.

    Wheat doesn’t grow well in poor soil, either. Warming isn’t going to lead to flourishing crops in what is now boreal forest, either.

    But, as was pointed out above, your assertion has been refuted many times, and you come back over and over with the same crap at an interval of about one and a half months, on average.

    Typical science denialist tactic. You’re shown that available science doesn’t back up your assertion, you disappear awhile, then you pop up again. Climate science denialists use this technique. Creationsists use this technique. HIV denialists do. On and on.

  • fred // December 20, 2007 at 3:25 pm

    Well, its delightful to find someone else (Michael Smith) who shares my confusion about the troposphere. Maybe he would help out in the struggle by telling us if he has references for the idea that AGW predicts a warming troposphere? Help wanted on this one.

    But now there seem to be two additional candidates for litmus tests. The first is the heat absorption of the oceans. Not whether its happening or not, but were it to happen. It seems to be a candidate. Don’t think the papers referenced tend to show that it is not a test. They reflect more on whether its happening, which for now is a different issue.

    Its hard to see that CO2 absorption would be a litmus test for global warming. Why would that be? Any references?

    The second new one can be found on Pielke’s site. That is, water vapour in the atmosphere should be rising if the feedback loop CO2 - water vapour - warming were to be happening. Not commenting on whether water vapour is rising or falling, but this is right, yes? If we were to find water vapour falling with rising CO2, this would blow a hole in AGW? By contrast, measured rising levels of water vapour correlating with CO2 rises would support AGW?

    [Response: The oceans do appear to be warming appreciably, and the temperature rise has been used to estimate the net planetary energy imbalance (Hansen et al. 2005, "Earth’s Energy Imbalance: Confirmation and Implications", Science, 308, 1431). Atmospheric water vapor also appears to be rising, so as to maintain reasonably stable *relative* humidity (i.e., it's rising in step with temperature, according to the Clausius-Clapeyron equation). For a much better perspective on predictions and observations of tropospheric warming, and the uncertainties associated with them, see this.

    I'd say it's important to appreciate that despite reliability of the conclusion that greenhouse-gas increases are primarily responsible for modern warming, there's still a lot we don't know about climate. So, it's actually quite difficult to point to a single phenomenon and say it's a sure-fire litmus test for AGW. However, it's a common denialist tactic to *claim* certain phenomena as a litmus test, so that if they don't come to pass they can then claim that AGW has been disproved. Don't believe every claim that "if such-and-such doesn't happen, then AGW is disproved."]

  • Dean P // December 20, 2007 at 3:37 pm

    To “name names” on who used 1998 as the crux of the AGW argument, look no further than the IPCC and their report: “Climate Change 2001 Synthesis Report, Summary for Policymakers”, Q2.7

    “Globally it is very likely that the 1990s was the warmest decade, and 1998 the
    warmest year, in the instrumental record (1861–2000) (see Box SPM-1). The increase
    in surface temperature over the 20th century for the Northern Hemisphere is likely to have been
    greater than that for any other century in the last thousand years (see Table SPM-1). Insufficient
    data are available prior to the year 1860 in the Southern Hemisphere to compare the recent warming with changes over the last 1,000 years. Temperature changes have not been uniform globally but have varied over regions and different parts of the lower atmosphere.”

    We now know that the 1990s were NOT the warmest decade, that was the 1930s. We also know that 1998 was not the warmest year, that was 1934. But the 2001 IPCC report made the case that things were getting worse and would only stop when the world cut CO2 emissions.

    [Response: You're being ridiculous; just because the IPCC 2001 report states that 1998 was the warmest year in the instrumental record, it doesn't follow that it's the "crux of the AGW argument." The claim that AGW advocates have trumpeted 1998 was, and is, just plain false.

    And for your information, the 1990s *are* the warmest decade in the instrumental record (as of 2001), and 1998 *was* the warmest year (as of 2001). You're just repeating denialist propaganda when you say it was 1934; that applies only to the lower 48 states of the U.S. (less than 1.5% of the globe), not the planet as a whole (see this post), but denialist propaganda repeatedly omits to mention that. As of now, the hottest year in the instrumental record is 1998 (according to HadCRU) or 2005 (according to GISS).

    Why is it that people who haven't even looked at the evidence enough to know that the "1934 is hottest" claim applies only to the lower-48 U.S. states, nonetheless feel qualified to discredit modern climate science? You need an IMMENSE amount of education before you'll even be qualified to comment on the issue without making yourself look like an idiot.]

  • Dean P // December 20, 2007 at 4:23 pm

    I may have misspoke about the warmest decade. I can’t remember whether the temperature adjustment made over the summer dropped the 90s below the 30s for the world or just for the US. Likewise 1998 being the warmest. Regardless, IPCC 2001 clearly uses the 90s and 1998 as the basis for their argument that something has to be done now…

    [Response: Repeating garbage doesn't make it true.]

  • dhogaza // December 20, 2007 at 4:40 pm

    I can’t remember whether the temperature adjustment made over the summer dropped the 90s below the 30s for the world or just for the US.

    Perhaps you don’t remember which it is, because both are false.

    Likewise 1998 being the warmest.

    It’s the old “I don’t know what I’m talking about, but I’m right anyway” argument.

    In other news, Fred makes another valiant try:

    The second new one can be found on Pielke’s site. That is, water vapour in the atmosphere should be rising if the feedback loop CO2 - water vapour - warming were to be happening. Not commenting on whether water vapour is rising or falling, but this is right, yes? If we were to find water vapour falling with rising CO2, this would blow a hole in AGW? By contrast, measured rising levels of water vapour correlating with CO2 rises would support AGW?

    Warmer temps mean more water vapor in the atmosphere. This helps explain why morning fogs “burn off”, and why afternoon thunderstorms are frequent in Arizona in the monsoon season (well, the latter is due to the inverse of warming).

    This has nothing to do with “correlation with CO2 concentrations”.

    I imagine Pielke’s trying to argue that this is a way to show that global warming isn’t happening, AGW or otherwise.

  • Dean P // December 20, 2007 at 4:59 pm

    You have to love “ad hominem” attacks.

    To go back to the point. IF the 1990s weren’t the warmest on record, then the IPCC summary from 2001 would be moot. IF there was no warming trend in the 90s, the AWG argument would die. That’s plain and simple. TO say that the IPCC doesn’t use the 90s and 1998 to show that something has to be done is simply blinding oneself to the entire purpose of the 2001 report. It’s a report to POLICYMAKERS so that POILICYMAKERS are informed enough to make POLICY.

    If the trends seen over the last 10 years were actually the trends seen over the last 20, would that then refute AWG? If not, at what point would that trend refute AWG? At some point, a lack of warming would actually indicate a lack of warming and not just noise obscuring the trend.

  • Chris O'Neill // December 20, 2007 at 5:34 pm

    “You have to love “ad hominem” attacks.”

    Pointing out the mistakes in an argument is not an ad hominem attack. Saying an argument is wrong because the arguer is an idiot is an ad hominem attack. Please try to understand the difference.

  • elspi // December 20, 2007 at 5:38 pm

    Dean P
    Not only don’t you know anything about global warming, but you don’t even know what “ad hominem” means.

    That at least I can teach you.

    1. “You are an idiot therefore you are wrong when you say that 2+2=4” is an ad hominem.

    2.“You just claimed that 2+2 =17 therefore you are an idiot” is a logical deduction.

    You see the difference right?

    In the first the argument is dismissed because of the source

    In the second the source is dismissed because of the argument.

  • Dean P // December 20, 2007 at 5:48 pm

    Ok, independent of my being a total idiot, no one has given me a clear reason why the IPCC 2001 report did not use the records from the 1990s and 1998 to indicate that something needed to be done now. It did.

    As for my being an idiot, it really is immaterial. The question was posed to supply a reference to someone that used 1998 as an indication that something had to be done. I did. The IPCC 2001 report.

    Assume that i am an idiot. Now, if i say that 2+2=4, does that then imply it doesn’t? No, it means that even an idiot can be right upon occasion.

    The problem is that there was no need in the first place to call names. Calling people names NEVER advances one’s argument.

    [Response: Of course IPCC 2001 mentions that the hottest year so far was 1998. What's false is Gary's implication that it "was used by so many as proof that things were getting bad very quickly." All you've been able to show is that it was mentioned, and you have furthered his implication by arguing that it is somehow a crucial talking point, which is foolish.]

  • Barton Paul Levenson // December 20, 2007 at 6:54 pm

    nanny posts:

    [[Water Vapor in the form of a cloud, by reflecting incoming solar radiation, can have a cooling effect on the climate, so your statement is not 100% true.]]

    nanny, water vapor can’t be in the form of a cloud. Clouds are collections of drops of liquid or solid water (or some other volatile material).

    The relationship between water vapor in the air and clouds is unknown. Lindzen proposed that greater cloud formation with higher temperatures would provide an “iris” to control global warming, but satellite observations shot that down. Apparently the relationship is not that strong in either direction. So clouds ain’t gonna save us.

  • Barton Paul Levenson // December 20, 2007 at 7:02 pm

    nanny writes:

    [[Warming leads to more livable land area, and warmth+CO2 leads to increased food production which should ease population pressures.]]

    CO2 can only lead to increased food production in an environment where CO2 is the limiting factor. Do you know of such a place? You might want to google “Liebig’s Law of the Minimum.”

    Also, as the world warms, agricultural growing belts shift toward the poles — which means they get smaller. Area decreases with latitude on a (1 - sin theta) curve, where theta is the latitude.

  • nanny_govt_sucks // December 20, 2007 at 7:38 pm

    CO2 can only lead to increased food production in an environment where CO2 is the limiting factor.

    Sounds good to me. The fewer limiting factors, the better, no?

    Also, CO2 increases a plant’s ability to deal with drought by causing stomate to close up, allowing the plant to retain precious moisture. Another plus.

    Also, as the world warms, agricultural growing belts shift toward the poles — which means they get smaller.

    The shapes of the continents also play a role. North America and Asia get wider as you go North and will have vast areas of land that will open up for farming as the climate warms.

  • dhogaza // December 20, 2007 at 8:08 pm

    Also, as the world warms, agricultural growing belts shift toward the poles — which means they get smaller. Area decreases with latitude on a (1 - sin theta) curve, where theta is the latitude.

    Oh, come on! Mercator disproved that myth centuries ago!!!!

    CO2 can only lead to increased food production in an environment where CO2 is the limiting factor.

    Sounds good to me. The fewer limiting factors, the better, no?

    If you’re joking, there’s hope for you. If not … I really don’t know what to say. You do realize that if growth is limited by nitrogen (”fertilizer”), more CO2 isn’t going to increase growth, right?

    North America and Asia get wider as you go North and will have vast areas of land that will open up for farming as the climate warms.

    Re-read what I wrote above about poor soils and today’s boreal forests.

  • fred // December 20, 2007 at 8:11 pm

    dhogaza, if I am making valiant efforts, it is to understand what exactly counts as evidence for and against the AGW proposition. Not whether there is such evidence. No, just what would count as evidence, should we find it. I will worry about finding it later.

    Pielke, well, you have to read the site, and its worthwhile, but no, he is not trying to argue that global warming is not happening. Pielke can speak for himself, but I think a quick and dirty summary might be, there are lots of ways in which humans affect climate and CO2 emissions are among them, but not the most important. He gives greater importance to land use changes and to particulates. I do not know what he thinks of how much warming there is, it doesn’t seem to be a particular focus of his. He is quite interested, like me, in litmus tests, feedback mechanisms, evidence for them. Pielke is worth reading even if you don’t agree at the end of reading him. Perhaps especially then.

    With some irritation, let me also point out that trying to find out what would confirm or falsify a theory is not being a ‘denialist’ in relation to it. It is being interested in its truth or falsity. The idea that we should stop trying to find what are the observations which would confirm or deny this particular theory, or any scientific theory, is anti-scientific and anti-rational. I am not going to be stopped from doing this by being called silly names, and doubt Pielke is either.

  • Michael Smith // December 20, 2007 at 8:27 pm

    You responded to my post yesterday with this:

    “The point of this post is to show that given a signal plus noise, with the signal steadily increasing, it’s not only *possible* to have intervals which seem to contradict the trend, it’s impossible NOT to. The only way to have no episodes of inconclusive trends, some even having an *apparent* countertrend, is to have zero noise. But we know, without any doubt whatsoever, that there is noise.”

    I believe the point of the post was to demonstrate why the claim of “no net global warming since 1998″ is “garbage”.

    [Response: No, that was the point of this post.]

    You have demonstrated that the data since 1998 MAY be the result of noise. You have raised that as a possibility. However, this does not prove that global warming has continued and it does not refute the claim in the letter of “no net global warming since 1998″.

    At this point, the claim, “it is just noise, and the warming has not stopped” and the claim, “no net global warming since 1998″ are BOTH possibilities. The temperature data does not allow us to rule either one in or out.

    [Response: In fact it does allow us to rule out the possibility that warming stopped in 1998; as the above-linked post shows, the data since 1998 do *not* show an ambiguous result which may be due to noise. It actually shows a significant warming trend.

    GISS data shows a statistically significant warming, even if you start from 1998, and even allowing for the red-noise character of the data. HadCRU shows a trend which appears to be significant, and again it's warming, but when one compensates for the red-noise character of the data the result is actually inconclusive (but still consistent with the long-term warming rate of 0.018 deg.C/yr). However, starting from 1999 rather than 1998 returns a statistically significant warming even for HadCRU data, even accounting for red noise. The data actually do contradict the "no warming since 1998" claim.

    So not only is there no evidence to support the "no global warming since 1998" claim, it really can be refuted. Nobody who is both trained in statistics, and honest, can support such a claim.]

    You also wrote:

    “As for the *apparent* contradiction between tropospheric and surface data, read this.”

    I have indeed read that article and noted the revised +/-2sigma bars around the model results. The new bars show that model outputs even include outputs showing as little as .01 -.02 degC/dec warming up to 200mb and actual COOLING above that.

    Thus, we have arrived at a situation in which the models are offered as proof of upcoming catastrophic AGW — while at the same time they are defended as being not inconsistent with little tropospheric heating or even cooling.

    With that range of possibilities coming from the models, I see no way to claim that “the science is settled”.

    [Response: The models are not offered as proof of upcoming catastrophic AGW, they are used to obtain the best possible numerical estimates of climate sensitivity and regional response. Basic physical arguments are sufficient to show that sensitivity is high enough that we can expect severe harm from continued warming unless greenhouse-gas emissions are reduced.]

  • nanny_govt_sucks // December 20, 2007 at 8:31 pm

    Also, as the world warms, agricultural growing belts shift toward the poles — which means they get smaller.

    Actually, growing experiences a poleward expansion which is different from a shift towards the poles. People are still farming at the equator, you know.

  • Michael Smith // December 20, 2007 at 8:37 pm

    Fred asked:

    “Well, its delightful to find someone else (Michael Smith) who shares my confusion about the troposphere. Maybe he would help out in the struggle by telling us if he has references for the idea that AGW predicts a warming troposphere? Help wanted on this one.”

    See the link that I was referred to here: http://www.realclimate.org/index.php/archives/2007/12/tropical-troposphere-trends/#more-509

    Note that , according to that article, increased tropospheric heating, greater than surface heating, is considered intrinsic to any global warming, regardless of the source of the forcing.

  • elspi // December 20, 2007 at 9:16 pm

    “The shapes of the continents also play a role. North America and Asia get wider as you go North and will have vast areas of land that will open up for farming as the climate warms.”

    Nanny
    It turns out that the world is not flat, ie
    that flat map you are looking at is not actually the way the world is. The area that is improving in terms of agriculture is smaller than the area where it is getting worse. In the southern hemisphere this is catastrophic, while in the northern hemisphere it is merely disastrous. Add to this the fact that the areas improving are so far from the equator that the amount of sunlight becomes the real issue (Hint: not changing).

  • P. Lewis // December 20, 2007 at 9:47 pm

    nanny_govt_sucks says

    Sounds good to me. The fewer limiting factors, the better, no?

    Also, CO2 increases a plant’s ability to deal with drought by causing stomate to close up, allowing the plant to retain precious moisture. Another plus.

    The shapes of the continents also play a role. North America and Asia get wider as you go North and will have vast areas of land that will open up for farming as the climate warms.

    Ah! Yes, just move the agricultural production!

    Agriculture occurs where it has over the last few hundred to a few thousand years because the climate and soils were/are suitable for growing the crops that were/are grown.

    I can’t imagine the permafrost wastes of Canada and Siberia being much good for agriculture when they’re no longer frozen (or no longer frozen all year).

    Also, the further north you go, the shorter the growing season is. And the greater the altitude, the shorter the growing season is. If there are suitable soils further north, then are they at acceptable latitudes and altitudes before spring/autumn frosts and light levels become a problem for achieving suitable yields?

    So, do you know whether the soils (other than the no-longer permafrost soils) further north are suitable? If perchance the US grain belt can theoretically and practicably move north (into Canada presumably), are you (I’m presuming a US citizen) prepared to become a net grain importer?

    IIRC, Australia might be in a bit of a pickle with regard to wheat (or was it corn?) and rice if continued global warming occurs for this very reason (though there it is presumably a progression further south that is an issue), i.e. that the soils and water are not available elsewhere (or not in sufficient quantities) on the continent to sustain the current levels of agricultural output.

    Are you prepared to foot the bill for modifying the soils as necessary by, say, increased irrigation, reducing possible aluminium toxicity, modifying cation-exchange capacity and modifying other deficiencies and fixation efficiencies? Are you prepared for the necessary land use changes required (perhaps conversion of pristine forests and wooded habitats to agriculture; or resettlement of coastal populations inland on possibly good agricultural land; …)?

    Since I know next to nothing about this particular subject (but perhaps someone can enlighten us all), the questions posed (without little thought, off the top of my head) may already have perfectly acceptable answers and there is consequently no reason to worry. But, I have the notion that thinking you can just shift agriculture to follow the climate is a pipedream, at least in the short term. Minor changes to chemistry and processing variables in my materials research days (let alone major changes to the same) took many months to years to work through into saleable products. I daresay the same/similar is true of any scientific endeavour and practical agricultural endeavours.

    I have the notion that anyone thinking agriculture/food production can just simply shift with the climate (which it must, of course, eventually do) has not engaged the requisite number of little grey cells.

    Food production can generally get through the odd year’s decimated or poor harvest without too much dislocation to normal life (at least in the first world), but real hardships occur when that may carry over into subsequent years. Are you prepared for that possible dislocation to the food supply?

    Do you expect to wait until global warming stabilises and then move your agriculture, or do you propose to move it every 5 years or so? Will the farmers just swap the no-longer-suitable agricultural land on their southern borders for suitable agricultural land on their northern borders? How would this be achieved (and what happens when you cross a national border)? Will governments have to nationalise the land and food production to ensure that food can be produced when and where it needs to be produced? (Jeez, I hope not. It didn’t work for the Soviets.)

    Just move the agriculture? In your dreams! Prepare for the nightmare more like.

    Past civilisations have fallen on past climate changes’ effects on agriculture. Just because we’re technologically and scientifically better off than past civilisations doesn’t make us immune to those effects. Thinking that we will be is just pure arrogant nonsense.

  • Hank Roberts // December 20, 2007 at 10:37 pm

    > The fewer limiting factors,
    > the better, no?

    Free market botany? Hmmmm…

  • erikv // December 21, 2007 at 2:17 am

    >1. Do you believe that noise doesn’t exist? Because if it does, then it’s impossible NOT to get apparent cooling trends which don’t reflect the signal, just the noise.

    What do you mean by noise? Those blips on the temp graph are weather, right? They represent the sweater I need to wear today or the A/C I had to run in July.

    To an engineer, “noise” is random fluctuations in a electrical signal, caused by the statistics of thermal processes. (That why you cool your sensor to reduce “noise” ;)

    Are you saying that the earth really has warmed, we just can’t see it because of measurement noise? Or are you saying that is has not warmed, but only because of short timescale processes which we have reason to believe will be reversed soon.

    Maybe if you define how you are using the word “noise” I can understand better.

    [Response: Noise is the part of the data that is random. It can be measurement error (so it's only an artifact of imperfect measurement) or it can be a physical process that is truly random (like the decay of a radioactive atomic nucleus, or the thermal fluctuations of an electrical signal). The terme "noise" is also used to refer to deterministic physical processes that are unpredictable either due to insufficient understanding of the system, or the chaotic nature of the dynamics. The essence of noise is that it can't be predicted and follows no pattern.

    Global average temperature exhibits noise, because there are fluctuations which are unpredictable and show no pattern. Perhaps someday we'll have such an advanced understanding of weather and climate that we'll be able to predict, or show the pattern of, part of the fluctuations that are now called noise -- just as someday we may have a sufficiently advanced understanding (and computing power) to predict, or show the pattern of, part of the fluctuations due to thermal processes in electrical signals.]

  • Chris O'Neill // December 21, 2007 at 3:58 am

    ngsucks:

    North America and Asia get wider as you go North and will have vast areas of land that will open up for farming as the climate warms.

    Try living on the south coast of Australia.

  • Heretic // December 21, 2007 at 7:35 am

    NGS is at it again relaying CO2Science “message.”
    Maybe you should look at a globe instead of a Mercator projection. Soil composition will not necessarily follow your wishes. It’s not because the polar circle regions will become warmer that they won’t get 6 months of night, NGS. Talk about limiting factors. I guess we could try mushrooms as alternate crops, they grow in the dark, don’t they? Could that be genetic memory from the time there was no light?

  • Andrew Dodds // December 21, 2007 at 8:34 am

    NGS -

    People may farm at the equator, but they don’t in the sahara.

    In any case, current farming is adapted to the current climate - and this is non trivial, since soil types vary strongly with latitude - most of our best farmland happens to be in the temperate zones where the outwash from the last glaciation was. This produced vast amounts of excellent and fertile soil; as you go north you go into the zones that were scraped clean of soil by the glaciation.

    At best this means that whole new varieties of crops will be required; at worst we’ll be finding that we can’t grow anything useful.

    But still, at least you seem to think that this will be happening now..

  • henry // December 21, 2007 at 8:39 am

    [As of now, the hottest year in the instrumental record is 1998 (according to HadCRU) or 2005 (according to GISS).]

    Have you done, or could you do a post on the reasons the two measurment systems are so far off?

    [Response: The only thing I know about the difference is that GISS attempts to estimate the temperature over the arctic region (by interpolation) while HadCRU doesn't. That's probably the reason GISS shows more warming over the last decade than HadCRU; the arctic region seems to be the fastest-warming part of the planet. That's the main reason I prefer to use GISS data, considering it more representative of the planet as a whole.

    The GISS data and processing procedures are an open book; the data are available for download from the web, the procedures are documented in the peer-reviewed literature, even their computer code is available. As far as I know this is not true for HadCRU, so I'm not sure how detailed a comparison would be possible.]

  • JamesG // December 21, 2007 at 10:43 am

    “CO2 can only lead to increased food production in an environment where CO2 is the limiting factor”
    “You do realize that if growth is limited by nitrogen (”fertilizer”), more CO2 isn’t going to increase growth, right?”

    There are lots of experiments proving that increasing only CO2 can increase plant growth spectacularly. It’s not even controversial, it is established fact. Do you guys just make up the first thing that comes into your heads?

  • fred // December 21, 2007 at 10:55 am

    The RC piece on the troposphere, Michael S.

    Yes, I think we’re reading it the same way - they do seem to be saying that if there is warming, then the trop. must warm faster than the ground. They also say, which is interesting “They differ most clearly in the stratosphere (the part above 100mb) where CO2 causes cooling while solar causes warming.” So what people said here seems to be right: we do have a potential falsifier. If the stratosphere doesn’t cool, CO2 warming will be falsified.

    McKittrick should have based his CO2 tax on stratospheric cooling rather than tropospheric warming then? Is that the conclusion? The problem with his tax as specified right now is that it would tax CO2 emissions in the presence of GW, even if that GW were not caused by that CO2. Whereas what he wanted was a tax on something that could only be seen if CO2 was causing warming. Well, he probably would be amenable to amending the details.

  • Gary // December 21, 2007 at 11:08 am

    Regarding people using 1998 as evidence of an increasing rate of global warming: Use the following google search:

    http://news.google.com/archivesearch?q=1998+accelerate+%22global+warming%22&as_ldate=1999&as_hdate=2000&hl=en&um=1&sa=N&start=10

    and you will find plenty of articles like this:

    http://nl.newsbank.com/nl-search/we/Archives?p_product=ST&s_site=dfw&p_multi=ST&p_theme=realcities&p_action=search&p_maxdocs=200&p_topdoc=1&p_text_direct-0=0EAF91DC72F70021&p_field_direct-0=document_id&p_perpage=10&p_sort=YMD_date:D&s_trackval=GooglePM

    and this:

    http://select.nytimes.com/gst/abstract.html?res=F30C1FFF355D0C758CDDAE0894D8404482

    and this:

    http://www.highbeam.com/doc/1P2-510679.html

    There are a lot more there. It is kind of hard for me to believe that you don’t remember this and that it has to be demonstrated. When the Hockey stick graph came out in 1998 along with the hottest year on record data, I remember stories just about every day stating that we were at a tipping point.

  • Gary // December 21, 2007 at 12:01 pm

    Also, you responded to my statement that when talking about the Earth’s climate 25 years or even 100 years was way too short to demonstrate a trend by stating:

    [Response: Warming per se is not a problem, even if the planet heats up 3 deg.C or more this century. But that much warming in ONLY ONE CENTURY is a HUGE problem. There’s abolutely nothing even close to it in the last several million years at least.]

    First, I have no idea where you get 3 deg. per century. Your extrapolation of a 30 year trend to a century only comes up with about 1.6 degrees.

    Second, it ignores the fact that the recorded data show cycles of about 30 years so it is unreasonable to assume that the last 30 years will continue for 100 years.

    Third, you do not respond to my statement that measuring climate change in such short time frames as 25 years or 100 years is even relevent in geological terms.

    Fourth, you offer no evidence that even a 3 deg. change (which is unsupported and unreasonable to begin with) would cause a problem.

    The graph below shows that there is no reason to panic about a 25 year trend or a hundred year trend or even a 3 degree change. We are within a normal variation and there seems to be a maximum temperature that the earth reaches before natural feedbacks kick in and cool it off.

    http://www.seed.slb.com/en/scictr/watch/climate_change/images/global_temp2.jpg

    [Response: There are two things you should know about the temperature estimates from the Vostok ice core (which is the graph you link to). First -- just so you know -- those are estimates of local (Antarctic) temperature; global temperature variations are only about half as large.

    Second -- and quite important -- is the time scale. Have you looked at the time axis, or at this data in time detail? Those "very rapid" temperature increases (10 deg.C or more in Antarctica, 5 or 6 deg.C globally) take 5000 years or more! The sustained warming rate during a reasonably *rapid* deglaciation is around 0.001 deg.C/yr. We're now experiencing 0.018 deg.C/yr, and over this century we're expected to get 2 to 3 deg.C warming (according to model projections -- and it really depends on emissions scenarios) in a mere century -- 20 to 30 times faster than a rapid deglaciation.

    That's what I mean when I say the danger is the *rapidity* of warming. There's nothing catastrophic about 3 deg.C warming, IF it happens slowly enough for ecosystems to adapt. But a single century isn't enough time.]

  • Dano // December 21, 2007 at 1:56 pm

    Folks,

    you are refuting na_gs’ arguments the same way people have been refuting them 2 months ago, then again 7 months ago when he brought up the same argument, and again 13 months ago, 17 months ago, 21 months ago, same stuff 24 months ago, 29 months ago, 34 months ago…

    You get the picture. FUD must be purveyed, whether it is “pure” belief, duty, or employ - it matters not. FUD must be purveyed.

    Best,

    D

  • Dean P // December 21, 2007 at 2:22 pm

    One thing to note with respect to the rapidity of the warming and comparing HadCRU to GISS:

    Looking at the 20th century, there are two major warming periods: 1910-1940 (30 years) and 1979-present (28 years). If you use the HadCRUT3 data smoothed with a 5 year, center weighted average, the difference in the temperature rise is almost nil (0.02°C). the difference in rate between the two time periods is similarly very small (a difference of 0.0006°C/yr between the two time periods). The HadCRUT3 data shows a warming rate of 0.013°C/year.

    The GISS data has about a 0.2°C difference (out of 0.6°C total), so the rate is quite a bit higher. We know that the GISS data tries to account for the temperature at the poles, so this could account for the difference (and could make comparing the two difficult).

    It does raise the question of how GISS accounted for the temperature at the poles in the early 20th century. Does anyone know?

  • JesusChristHimself // December 21, 2007 at 3:10 pm

    “There are lots of experiments proving that increasing only CO2 can increase plant growth spectacularly. It’s not even controversial, it is established fact. Do you guys just make up the first thing that comes into your heads?” … JamesG

    I noticed that several of them were done with CO2 at 550ppm. The assumption of benefit is based upon a stable agricultural situation like the one that has existed for thousands of years. At 550ppm, that stability may be gone. I would speculate there will be several altered variables effecting plant growth, some of which may be harmful to plants.

    Farmers thrive on normal weather. Abnormal weather events in a stable climate often cripple farming efforts. At 550ppm I think there may no longer be a stable climate, so farming efforts would be up against both abnormal weather events and an unstable climate. People who have never farmed can hold hands and skip blithely into that future, but I can’t imagine anybody who has farmed being so sanguine about it.

    In the area where I used to farm they recently had abnormally high precipitation for several years in a row. One river valley lost almost all of its trees. Fertile fields became lakes, and they produced nothing. Other fields were so wet in the spring that farm equipment could not operate in them. Nothing was planted. Lately things have returned to normal. The lakes are gone now, and the fields are back in production.

    Will there be a normal in a 550ppm world?

  • cce // December 21, 2007 at 3:39 pm

    Take a corn field. Double the CO2, but take away the fertilizer. Let’s see how great the crop yields are.

  • george // December 21, 2007 at 4:13 pm

    It seems that those who question the reality of human influence on the climate — or at least its magnitude relative to “natural causes” — usually focus on one piece of evidence (eg, the global mean surface temp anomaly) at a time, instead of all the evidence collectively.

    As you show above, over a given period of time, there is a certain probability that any one particular record (the global mean temperature anomaly) may show a downward trend due to “noise” (natural variation, or whatever you wish to call it).

    But it seems that what is most important in the case at hand is really the probability that all the different trends would behave as they have simultaneously merely based on “natural variation”.

    For example, suppose that the recent (last few decades) downward trends in both sea ice cover and thickness are not due to human-induced global warming but instead due to some other “natural variation”.

    Perhaps the question is unanswerable (depending as it does on assigning definite probabilities to various trends and perhaps on assumptions about dependence or indpendence of the various trends), but perhaps it might be possible to make a rough estimate nonetheless:

    What is the probability that all the various measures — sea ice cover, sea ice thickness, global mean surface temp anomaly, stratosphere temp, troposphere temp, tropopause height, global glacial mass balance, Greenland ice mass balance, etc — would show the trends that they have in recent decades based merely on “natural variation”?

    At the very least (even if one can not assign a definite probability to the latter), it would seem that if any of the above individual probabilities is close to zero, that would imply that the entire probability would also be close to zero.

  • Dean P // December 21, 2007 at 5:43 pm

    Maybe someone can enlighten me…

    isn’t it a misnomer to label the variation in data in the temperature recreations as “noise”?

    Isn’t noise, by definition, a random signal that has no impact on the trend. But if the ‘noise” in these datasets are consistently to one side of the trend, then does that not change the trend and therefore the variations are not truly “noise”?

    Is it wrong/too simplistic to label the “noise” as weather? And doesn’t “weather” when averaged over a period of time become “climate”?

    IF these are the cases, then how can this “noise” be considered “random”?

    [Response: If you can show, with statistical significance, that a set of variations are *consistently* to one side of a purported trend, then you will have successfuly established the existence of a pattern. If you can establish a pattern then it is indeed part of the signal, not the noise.

    The catch, of course, is the "statistically significant" part. The observed variations in global average temperature over the last decade do not show statistically significant deviation from the purported trend of 0.018 deg.C/yr increase. But they do show statistically significant increase; whatever trend may be operating over the last decade, it is neither cooling nor stability, but definitely warming. The trend over the last decade may indeed be less than that of the preceding 20 years (or it may be higher), but there's no evidence of that.]

  • Barton Paul Levenson // December 21, 2007 at 5:52 pm

    nanny writes:

    [[Also, as the world warms, agricultural growing belts shift toward the poles — which means they get smaller.

    Actually, growing experiences a poleward expansion which is different from a shift towards the poles. People are still farming at the equator, you know.]]

    So we’ll all just switch from wheat and corn to manioc and rice? You seem to think massive change can be accommodated without cost. Think again.

  • Barton Paul Levenson // December 21, 2007 at 5:56 pm

    JamesG posts:

    [[There are lots of experiments proving that increasing only CO2 can increase plant growth spectacularly. It’s not even controversial, it is established fact. Do you guys just make up the first thing that comes into your heads?]]

    No, we actually read the papers. The experiments you’re talking about allowed the plants all the water and nutrients they needed besides adding CO2. They were not good models of plants in the wild or under cultivation.

  • luminous beauty // December 21, 2007 at 6:00 pm

    Another characteristic of the argument that historical GW could be a natural variation is that it is a purely statistical argument. A poorly framed one that assumes the least likely extremes of uncertainty in one direction are what is of interest. It ignores the equal possibility that estimated projections of temperature may be greater than the mean. It ignores the physics of radiative transfer. It’s all correlation and zero causality.

    These are but two reasons why these folks are up a certain river in Egypt without a paddle.

  • JesusChristHimself // December 21, 2007 at 7:00 pm

    In some of them they did drought stress the plants. The one I remember said 9 days.

    9 days is a picnic drought. It indicates something positive in the plants’ reaction, but it does not indicate the plants would not have died in a real drought.

  • tamino // December 21, 2007 at 7:38 pm

    Dean P asks

    But if the ‘noise” in these datasets are consistently to one side of the trend, then does that not change the trend and therefore the variations are not truly “noise”?

    The real question of course is, are the variations consistently to one side of the trend? See the UPDATE to this post.

  • nanny_govt_sucks // December 21, 2007 at 8:06 pm

    So we’ll all just switch from wheat and corn to manioc and rice? You seem to think massive change can be accommodated without cost. Think again.

    This is a familiar meme, so I’ll address it. No, I didn’t say there would be no cost. Of course there will be a cost to the farmer to switch crops should he need to. But you should also understand that there is marginal land under cultivation at the poleward extent of the farmer’s land that will see a boost in productivity as the climate warms. Virtually no additional cost will be incurred there.

    And should additional costs outweigh the benefits of increased productivity of marginal lands, and CO2 fertilization, then of course the farmer will have to charge more for his products, and that cost will get passed along to consumers. But this is nothing new, it’s how a market works. We deal with this kind of thing everyday, such as when a cold snap ruins orange crops in Florida and the price of OJ jumps. But it’s not the end of the world, and prices don’t stay high for long.

  • JesusChristHimself // December 21, 2007 at 9:19 pm

    The agricultural market has never had to deal with an unstable climate. It has dealt with the costs and benefits of weather in a stable climate.

  • Hank Roberts // December 21, 2007 at 9:38 pm

    Citations, please?

  • Michael Smith // December 21, 2007 at 9:54 pm

    You wrote:

    “GISS data shows a statistically significant warming, even if you start from 1998, and even allowing for the red-noise character of the data.”

    1) What test are you using to assess statistical significance of this data?

    2) Does this data measure tropospheric temperatures? As best I can tell, it does not, yet those are the temperatures that should show the most warming, according to what RC says about AGW.

    You also wrote:

    [Response: The models are not offered as proof of upcoming catastrophic AGW, they are used to obtain the best possible numerical estimates of climate sensitivity and regional response. Basic physical arguments are sufficient to show that sensitivity is high enough that we can expect severe harm from continued warming unless greenhouse-gas emissions are reduced.]

    What are the purely “physical arguments’ — i.e. the arguments that do not make use of the models or any of the model’s output — that justify the IPCC’s claim of 3 deg C for climate sensitivity?

    And what are the “physical arguments” for the notion that we face “severe harm” unless emissions are reduced?

  • Eli Rabett // December 21, 2007 at 10:07 pm

    1. Surface temperature measurements are exactly that.

    2. The models are physical arguments.

    So the question is why are you selling red herrings out of a barrel?

  • luminous beauty // December 22, 2007 at 12:33 am

    “What are the purely “physical arguments’ — i.e. the arguments that do not make use of the models or any of the model’s output — that justify the IPCC’s claim of 3 deg C for climate sensitivity?”

    HERE.

    “And what are the “physical arguments” for the notion that we face “severe harm” unless emissions are reduced?”

    HERE.

  • luminous beauty // December 22, 2007 at 1:50 am

    Aackk! 404 Alert!

    Try this…

    http://julesandjames.blogspot.com/2006/03/climate-sensitivity-is-3c.html

  • Hank Roberts // December 22, 2007 at 2:07 am

    That second “HERE” is a collision of two different URLs; could be edited perhaps.

  • dhogaza // December 22, 2007 at 6:57 am

    And should additional costs outweigh the benefits of increased productivity of marginal lands, and CO2 fertilization

    NGS giving further proof that he refuses to learn.

    Once again, NGS, “CO2 fertilization” is a myth. In the real world, it is not CO2 that limits growth. Farmers spend large sums of money on fertilizer (or rotate crops, or both, or perhaps both + other things) for a reason.

  • henry // December 22, 2007 at 10:20 am

    [Response: The only thing I know about the difference is that GISS *attempts to estimate* the temperature over the arctic region (by interpolation) while HadCRU doesn’t. That’s probably the reason GISS shows more warming over the last decade than HadCRU; the arctic region seems to be the fastest-warming part of the planet. That’s the main reason I prefer to use GISS data, considering it more representative of the planet as a whole.]

    I could understand it if the two methods were off by an order of degrees in the same year (eg, one hotter than the other in 1998), but that doesn’t explain them having different “hottest” years.

  • Dean P // December 22, 2007 at 2:06 pm

    Henry,

    I am not real surprised that they’d have two different peaks, especially if the two peak temperatures are close together.

    The bigger question which I’ve not seen addressed is how GISS dealt with polar warming for the timeperiod 1910-1940? Did it account for it at all (seeing as temperature measurments at the poles were much more scarce than they are today).

    It’s beens shown that the HadCRU data doesn’t show this warming period to be larger than the one in the early 20th century. The GISS data does, but there’s a suspicion on my part that the GISS data isn’t able to apply it’s method accurately to both timeperiods. Therefore, the reliability of the method is in question when comparing the two timeperiods. This seems to be somewhat born out when you compare the error bars on the GISS data from the following website:

    http://data.giss.nasa.gov/gistemp/graphs/Fig.A2.lrg.gif

    In 1880, the error bar was about 0.2C, in the late 40s it was 0.15C, now it’s less than 0.1C.

    Does this invalidate the data? No. But it does mean you have to be careful when comparing the two timeperiods. It also means that there’s not unanimous agreement in the datasets on the rise nor the rate of rise being ‘unprecedented’.

  • Dean P // December 22, 2007 at 2:12 pm

    Tamino,

    I think you missed the point about my question on the ‘noise’ (probably due to my not explaining it well).

    By definition, noise is random and has no effect on the trend (as your example clearly shows). But in the temperature reconstructions, the variations we see (what you call noise) are what becomes the trend when averaged. Therefore I still say it’s improper to call this noise (because it directly affects the trend).

  • Bob // December 22, 2007 at 3:00 pm

    CO2 fertilization is a fact. Farmers spend large sums of money on fertilizer (or rotate crops, or both, or perhaps both + other things) to increase yield. Farmers have no control over atmospheric concentrations of CO2.

  • dhogaza // December 22, 2007 at 3:06 pm

    It also means that there’s not unanimous agreement in the datasets on the rise nor the rate of rise being ‘unprecedented’.

    Since this last point seems to have been missed by working climate scientists, perhaps you’d like to explain exactly why you think this is true, rather than just assert it?

    Call me old-fashioned, but as poor as “scientific consensus” might be, I’m unconvinced that random, unknown, uncredentialed people writing on the internet are more likely to be right than the professionals in the field.

  • Michael Smith // December 22, 2007 at 3:21 pm

    luminous beauty,

    Thank you for the link to Jame’s Empty Blog. I will study his paper regarding the 3 deg climate sensitivity estimate.

    But what is the evidence for the “severe harm” that we supposedly face if we do not curtail emissions?

    I am also waiting to hear what tests were used to prove that the GISS temperature data since 1998 shows “statistically significant” warming.

  • Dean P // December 22, 2007 at 4:33 pm

    Dhogaza

    The “consensus” is that the current warming is at a greater rate than ever before. But that’s only the case if you use the GISS data. The HadCRU data shows no such trend. In fact, the warming from 1910-1940 time (30 years) is within 0.02C of the warming from 1977-2007 (also 30 years). Now, if you want to argue that 0.02C over 30 years is statistically significant, then be my guess.

  • tamino // December 22, 2007 at 5:52 pm

    Michael Smith:

    To test for statistical significance of the 1998-present trend I applied an F-test to monthly global temperature anomaly from GISS, compensating for red noise by modelling the data as an AR1 process, using the Yule-Walker estimate of autocorrelation, and applying the complete formula for the impact of autoregression on linear regression (Lee & Lund 2004, Revisiting simple linear regression with autocorrelated errors, Biometrika, 91, 240–245).

    Dean P:

    For monthly data from HadCRU, I get a trend rate of 0.0152 deg.C/yr from 1910-1940, and 0.0172 deg.C/yr from 1977 to 2007. Over 30 years the difference would be 0.06 deg.C, not 0.02. Using annual averages instead gives the same rate from 1977-present, but 0.0156 deg.C/yr from 1910-1940, which over 30 years would be 0.05 deg.C

  • tamino // December 22, 2007 at 6:44 pm

    Dean P:

    It’s not true that noise has “no effect on the trend.” It introduces an error into the trend estimate; essentially, the trend estimate has noise too. Statistics enables us to estimate the uncertainty of a trend, i.e., to estimate the size of the noise in the trend itself. The variations we see which have no demonstrable pattern are what determine the size of this uncertainty.

    Until you can establish a pattern to the variations, it’s not proper to call them anything *but* noise. Look again at the update to this post (just before the comments begin); is there any demonstrable pattern to the variations of the last decade?

  • Hank Roberts // December 22, 2007 at 7:22 pm

    Bob, you need a source other than “CO2Science” before you can credit the idea that CO2 is a fertilizer at the level of the world climate.

    Ever see yellow spots on your lawn, where it’s been fertilized by passing dogs? That’s nitrogen, also a fertilizer.

    You can overdo anything.

    Increasing the amount worldwide in the atmosphere isn’t a good way to fertilize _anything_, let alone _everything_.

    C’mon. Be skeptical of this stuff.

    And cite your sources. Tell us where you get what you believe and why you consider your source credible — after you’ve read _their_ cites and checked whether they’re representing them correctly.

  • Dean P // December 22, 2007 at 11:27 pm

    Tamino,

    Are you saying that 0.05C over 30 years is significant? It’s 25% of what the GISS data shows and I’d be hesitant to say that such a measurement is statistically significant.

    I’ll chalk the difference we have (0.02 vs. 0.05 over the period) to the exact starting points we chose. I’ll even grant that the 0.05C is accurate for what the HadCRUT3 data shows. What I won’t concede is that such a small difference allows one to say with any real confidence to proclaim that what we’re seeing now is “unprecedented”.

    And since we’re looking at the HadCRUT3 data, look at the temperature change between 1942 & 1948. There’s a -0.25C change in the average temperature over 6 years. That change in temperature is much larger than anything we’re talking about (-0.04C/yr vs 0.02C/yr using the GISS or 0.015/17C/yr for the HadCRUT3 data). Likewise, from 1898 to 1910, there’s a -0.25C delta (-0.0208C/yr). To say that what we have is ‘unprecedented’ is (again in my opinion) overstating the results.

  • Hank Roberts // December 23, 2007 at 12:54 am

    > between 1942 & 1948

    Try computing the trend, as was done here
    http://scienceblogs.com/stoat/2007/05/the_significance_of_5_year_tre.php#

    Done for you from the Hadley data for the period since 1970, as an example of how to think.

    Quoting:

    “5 year trends from surface temperature are not very significant and are a bad measure of anything. As everyone should know. But it seems that some people don’t. So in tedious detail…. [click link to see the result]
    (black lines data, thicker black same but smoothed, thin straight lines non-sig trends; thick straight blue lines sig trends)
    “… 5 year trends are not useful with this level of natural variability. They tell you nothing about the long-term change.”

  • dhogaza // December 23, 2007 at 10:08 am

    Are you saying that 0.05C over 30 years is significant? It’s 25% of what the GISS data shows and I’d be hesitant to say that such a measurement is statistically significant.

    But I’ll bet my sweet bippy that you’ve done nothing other than make this assertion from personal incredulity. Science doesn’t work this way. It is up to you to show analytically that such a rise isn’t statistically significant.

    What I won’t concede is that such a small difference allows one to say with any real confidence to proclaim that what we’re seeing now is “unprecedented”.

    Again, we have nothing here other than a statement from personal authority.

    “I won’t concede this”. No wiggle-room (bad news on the wiggles thread). So, not even if God strikes a bush with lightning and leaves you a stone tablet with the words “concede, turkey” inscribed on it?

    Unshakable faith that science is wrong, no matter what level of evidence is provided, is an interesting position.

  • dhogaza // December 23, 2007 at 10:15 am

    Another data point indicating that warming is real, and if you care for human health, significant, An outbreak of chikungunya in Italy.

    The epidemic proved that tropical viruses are now able to spread in new areas, far north of their previous range. The tiger mosquito, which first arrived in Ravenna three years ago, is thriving across southern Europe and even in France and Switzerland.

    And if chikungunya can spread to Castiglione — “a place not special in any way,” Dr. Angelini said — there is no reason why it cannot go to other Italian villages. There is no reason why dengue, an even more debilitating tropical disease, cannot as well.

    Many species have been extending their range north. In the Northern Hemisphere, data shows that many species are migrating earlier in spring, later in fall. And for species that show mixed patterns of migratory behavior and year-round residency in various places, we’re seeing expansion of year-round residency northwards, too.

    Most of this goes unnoticed outside of biological circles.

    Until such a northward expansion of range happens with a disease vector, as in this case. Then people sit up and take notice (unless the disease kills them first, of course).

  • Bob // December 23, 2007 at 3:28 pm

    Hank Roberts

    I did not source CO2 Science.

    I did not say increasing CO2 levels was a good way to fertilize the planet.

    You say too much fertilizer can kill grass. Show me a source indicating projected CO2 levels will harm vegetation on any kind of a wide spread basis.

    Encyclopedia Britannica:

    Included among the rate-limiting steps of the dark stage of photosynthesis are the chemical reactions by which organic compounds are formed using carbon dioxide as a carbon source. The rates of these reactions can be increased somewhat by increasing the carbon dioxide concentration. During the past century, the level of carbon dioxide in the atmosphere has been rising due to the extensive combustion of fossil fuels. The atmospheric level of carbon dioxide climbed from about 0.028 percent in 1860 to 0.0315 percent by 1958 (when improved measurements began), and to 0.034 percent by 1981. This increase in carbon dioxide directly increases plant photosynthesis, but the size of the increase depends on the species and physiological condition of the plant.

    From Brookhaven National Laboratory:
    The atmospheric carbon dioxide concentration ([CO2]) has risen by 35% since the start of the industrial revolution, it is higher now than at any time in the past 25 million years and is predicted to increase an additional 50% by 2050 (IPCC). Plants respond to rising [CO2] through increased photosynthesis and reduced transpiration. Photosynthesis removes CO2 from the atmosphere and respiration by plants and heterotrophs add it back.

    Therefore, the terrestrial biosphere is not just a passive respondent to rising [CO2] but can play a fundamental role in determining the rate of global change. Before FACE, much of what we knew about plant and ecosystem responses to rising [CO2] came from studies conducted in enclosures where the response of plants is modified by their growth conditions. FACE was developed as a means to grow plants in the field at a controlled elevation of [CO2] under fully open-air conditions. Results from FACE experiments provide perhaps the best estimate of how plants and ecosystems will respond in a future high CO2 world.

  • Dean P // December 23, 2007 at 3:30 pm

    Hank,

    The link showed 5, 10 & 15 year trends from 1970. But let’s go back to 1900 and look at these trends. Each averaging technique shows breaks during the following time periods (give or take a few years due to the averaging): 1900-1910, 1910-1940, 1940-1950, 1950-1075, 1975-present. In each of these breaks, we can get a relatively accurate linear trend to the data. In 5 & 10 year cases, the steepest line (either positive or negative slope) is from 1940-1950. in the 15 year case, it’s not as clear that this time period is the steepest, but then the 15 year trend seems to break the 1910-1950 time period into 3 sections instead of two as is the case with the 5 & 10 year averages (1910-1932, 1933-1945 & 1945-1952). the third section does exhibit a very steep slope.

    Another interesting thing to note is that in the 5 & 10 year averages, there’s a downturn for the last 2-3 years. The 15 year averaged doesn’t show this downturn as of yet.

    Another interesting point about the 15 year averaging is that the peaks are significantly reduced (the current anomaly for the 15 year trend is only 0.35 whereas the 5 & 10 year trends show anomalies of 0.45 & 0.41 respectively.

    So I disagree that 5 & 10 year averages are useless. they’re quite useful as long as we know what we’re dealing with

  • Dean P // December 23, 2007 at 3:50 pm

    dhogaza,

    Except that the GISS dataset plots show an error bar of about 0.1C . To me, that means that the difference is bordering on the accuracy of the data (+/-0.05C) and therefore could easily just be noise .

    I do not know what the error bar on the HadCRUT3 data set is (one plot of global temperature has error bars of 0.2C). If it is 0.2C, then my comment about it being statistically of questionable meaning holds.

    As for your final comment, unshakable faith in a position is wrong when confronted with data that supports other views. All I’ve done here is raise an issue about interpreting the data and claims made from that interpretation. I’ve made no assumptions about whether the data is flawed, but only that the given interpretation that we’re in an ‘unprecedented’ warming period depends on using the GISS dataset and not the HadCRUT3 dataset. i’ve also shown that for the HadCRUT3 dataset, the time period with the steepest trendlines are 1940-1950 & 1898-1910.

  • tamino // December 23, 2007 at 4:13 pm

    If we take the GISS and HadCRU temperature data and smooth them on a 5-year time scale, we get the result shown in UPDATE #2 to this post.

    Both show an increase of about 0.6 deg.C from 1975 to the present. For the period 1910-1940, GISS indicates a warming of about 0.45 deg.C but HadCRU indicates more, about 0.6 deg.C (roughly the same as that since 1975). I don’t think it’s possible to say with confidence which is more correct. So, according to HadCRU, the 0.6 deg.C warming since 1975 is indeed not unprecedented, it’s happened before — in fact it happened twice in the last 100 years.

    If we compare this to credible paleoclimate reconstructions smoothed on the same time scale, there is a range of possibilities. Using Mann & Jones 2003, both modern warming episodes are unprecedented. But using Moberg et al. 2005, there have been periods of 0.6 or 0.7 deg.C warming in comparable periods of time during the last 2,000 years. So according to Mann & Jones both modern warming episodes are unprecedented, while according to Moberg et al. they are not. I’ve seen credible arguments to support the claim that the Mann & Jones reconstruction is more correct, but I don’t know the details of this and as far as I can tell, it’s not possible to say with confidence which is closer to the truth.

    But this much is clear: the last 100 years has witnessed not one but two warmings of the order of half a degree C or more, hot on the heels of each other. The warming since 1910 is, according to GISS, about 0.9 deg.C and according to HadCRU over a full deg.C. No credible paleoclimate reconstruction shows such an increase at any other time in the last 2,000 years. In this sense the temperature change in last 100 years is indeed unprecedented.

    Another important consideration, in my opinion, is that there’s no natural explanation for the modern warming. The roughly 0.5 deg.C coolings/warmings of the preceding 2,000 years can be associated with the cooling effect of large volcanic eruptions and the recovery from those events. Only a fraction of the early-20th-century warming, and none of the late-20th-early-21st century warming, can be attributed to the unusual lull in volcanic activity and possible slight increase of solar output of the early 20th century.

    It’s not unlike seeing rises and falls in a person’s blood pressure; previous events coincide with physical exercise or meditative rest but the recent rise cannot be attributed to such natural events. A rise in blood pressure which is greater than any other observed over a long period of time, and which has no apparent natural cause but does have a clear man-made cause, is cause for serious concern.

    Worst of all, the clear-cut physics of greenhouse-gas warming combined with the continued dumping of large quantities of greenhouse gases into the atmosphere gives us every reason to believe that the rapid warming experienced in the last 100 years will continue, will in fact be even greater in the next 100 years. A 2-deg.C warming this century will surely be both unprecedented for the last several million years, and cause for extreme concern.

  • Hank Roberts // December 23, 2007 at 4:57 pm

    Bob, you can find this yourself with almost no effort just by looking.

    For example, one of hundreds Google Scholar turned up in a single search for damage to plants from increased CO2:
    http://www.springerlink.com/content/32370807846477k5/

    Seriously, man, I’m asking you to be skeptical of what you claim, tell us where you are finding your beliefs so we can help you read the source material and check what’s claimed against published science.

    You can look this stuff up.

  • Michael Smith // December 23, 2007 at 7:53 pm

    Tamin0, thank you for responding.

    Since AGW theory predicts the most heating will occur in the troposphere, will you run the same analysis that you did on the GISS data on UAG MSU middle troposphere data?

    [Response: I'll look at that data (when time permits, which probably won't be too long) and report the results.

    But a correction is necessary: it's not "AGW theory" that predicts enhanced warming of the tropical troposphere. It's computer models of climate in general that predict enhanced tropospheric warming in the tropics when the surface warms, *whatever* the reason. As the first graphic in this post shows, computer models predict enhanced tropical tropospheric warming whether surface warming is due to greenhouse gases, increased solar output, or whatever.]

  • Ian Forrester // December 23, 2007 at 8:45 pm

    Bob said: “Show me a source indicating projected CO2 levels will harm vegetation on any kind of a wide spread basis”.

    If you are going to talk about the biochemistry of CO2 fixation it would pay to get a little more up to date before making statements which can be shown to be wrong.

    Many AGW deniers quote old work.The older studies showed that the enzymatic activity of isolated RUBISCO (the enzyme responsible for the fixing of CO2 into organic metabolites) was increased at higher temperatures and higher CO2 concentrations. They argued that this would be good for agriculture since it would allow for higher yields (forget about water and available nitrogen for now). However, there were always problems in getting reproducible levels of RUBISCO activity (preparations had to be aged and/or treated to give maximum activity).

    Later research has shown that there is another layer of regulation affecting RUBISCO activity (as is common with many enzyme system). A new enzyme, RUBISCO activase, was found to be responsible for converting “inactive” to “active” RUBISCO. And, surprise surprise, this new enzyme was found to be inhibited by higher temperatures and also inhibited by higher CO2 concentrations. Thus increasing CO2 concentrations and increasing temperatures will result in lower levels of active RUBISCO which will not be good for agriculture.

    Here are a couple of papers describing the role of RUBISCO activase:

    http://www.ars.usda.gov/is/AR/archive/nov02/plant1102.htm

    http://www.pnas.org/cgi/content/abstract/97/24/13430

    People should always be aware of the old saying “a little knowledge is a dangerous thing”. It would not surprise me to find that there is also a RUBISCO deactivase. It would be interesting to find out its CO2 and temperature sensitivities (if it exists).

  • Hank Roberts // December 23, 2007 at 10:30 pm

    Thanks, Ian, it’s always wonderful when someone who actually knows this stuff comments. Your first link has this rather interesting bit about the mechanism — which seems likely to be a general one. Almost everything alive runs on ATP.

    “… In the lab experiments, higher-than-normal carbon dioxide makes ADP more plentiful than ATP. …”

    Spooky thought.

  • Bob // December 23, 2007 at 10:37 pm

    Hank,

    No papers showing widespread damage in the range of doubling of CO2 levels to 560 ppm. AR4 Section 7.3.3.1.2 indicates most outdoor experiments show a positive response to smaller increases in CO2. No mention in AR4 of any damage caused by CO2 levels in the projected doubling range.

  • henry // December 23, 2007 at 11:49 pm

    Dean P said:

    “I am not real surprised that they’d have two different peaks, especially if the two peak temperatures are close together. ”

    Definition of “close”? Again, they are 1998 (according to HadCRU) and 2005 (according to GISS).

    7 years apart?

  • henry // December 23, 2007 at 11:59 pm

    Two questions on update 2:

    1. That’s global and not US, right? It appears that both “warmest” years are after 2000.

    2. What time frame was used for the average? I think HadCRU and GISS use different averaging periods. Could the charts be done using 2000 as the end of the averaging period for both?

  • EliRabett // December 24, 2007 at 12:08 am

    Ah, is that why the CO2 effect is saturating in the FACE studies (field studies done outdoors)

  • Hank Roberts // December 24, 2007 at 12:24 am

    Bob, cite please. Where are you reading this? If you’re looking at a web page, copy the URL and paste it in here.

    Did you get that from one of the links Google finds?

    http://www.google.com/search?q=AR4+Section+7.3.3.1.2

    I looked at the first one — read that paragraph — and didn’t find support for what you said.

    Where are you reading what you’re writing?

  • WhiteBeard // December 24, 2007 at 3:27 am

    Barton, Nanny,

    From: Navin Ramankutty, Jonathan A. Foley, John Norman, Kevin McSweeney (2002)

    The global distribution of cultivable lands: current patterns and sensitivity to possible climate change in Global Ecology and Biogeography 11 (5), 377–392.

    “We estimate that climate change, as simulated by global climate models, will expand cropland suitability by an additional 16%, mainly in the Northern Hemisphere high latitudes. However, the tropics (mainly Africa, northern South America, Mexico and Central America and Oceania) will experience a small decrease in suitability due to climate change.”

    This is taken from the abstract as the article is behind Blackwell’s $wall. I don’t have any reason to question them, at least on the basis of solid geometry. Much of the difference in land distribution between the northern and southern hemispheres is rather poleward and not as congenial to our agracultural systems as they evolved. Without access to the paper, it’s difficult to see if sufficent account is taken of relevant factors. Their listed affiliation is with the Center for Sustainability and the Global Environment at the University of Wisconsin.

    On it’s face, I’d think the tropical reduction is the saliant observation in the larger frame of feeding the worlds future population.

    Bob,

    “CO2 fertilization is a fact. Farmers spend large sums of money on fertilizer (or rotate crops, or both, or perhaps both + other things) to increase yield. Farmers have no control over atmospheric concentrations of CO2.”

    When not a reader and occasional commentor, I operate a commercial greenhouse just above 61 degrees North Latitude. The trade journals I read show there is an economically significant advantage to CO2 enhancement under some conditions in closed systems where plant CO2 assimilation is the limiting factor in very high input, high value crops. The econimic growing period here is limited to March through October, because solar iradience (over which I have no control) is insufficient to produce anything, even when there is no other check to plant growth.

    Farmers fertilize with Nitrogen (mostly) and irrigate because those are the LIMITING FACTORS on productivity. Adding CO2 gains very, very, very little to nothing until all other growth factors are satisfied. Additionally, most agricultural isn’t much of a carbon sink as the CO2 turns over very quickly.

    Results from FACE would be interesting but it seems they’re looking for effects on existing “natural” vegitation.

  • Bob // December 24, 2007 at 4:38 am

    Hank - Sorry about the confusion. You had the correct section. I would have copied and pasted it here, but my copy of AR4 is in pdf format and I can’t seem to copy it. The section concludes that CO2 fertilization effects are real, but it is difficult to say how strong the effects are due to nutrient limitations and saturation.

    Eli - Nice web site.

    From your link the bottom line is:
    - no fertilization in C4 plants. Agreed, but 95 of plant species are C3.
    - FACE shows current ag models overestimate CO2 fertilization for crop. Agreed, but they also confirm some fertilization, which is all I was saying.
    - C3 crop fertilization saturates somewhere between 600 and 800 ppm. OK, we agree on crop fertilization. The saturation occurs after the doubling of pre-industrial levels of CO2.
    -Crop breeders should work on strains that benefit from higher CO2 concentrations. Here here.

    I got involved in this thread when dhogaza stated “Once again, NGS, “CO2 fertilization” is a myth. In the real world, it is not CO2 that limits growth. ” Hank then added “Bob, you need a source other than “CO2Science” before you can credit the idea that CO2 is a fertilizer at the level of the world climate.” OK, so now we IPCC AR4 on record as saying CO2 fertilization is real. This is further supported by Eli Rabett of the Rabett Run Blog.

  • fred // December 24, 2007 at 8:02 am

    tamino -

    Strong argument there on one of the critical issues. Were the current warming unprecedented in 2,000 years, that would be sobering and thought provoking. However, how sure are you that proxy reconstructions and the surface temp records are comparable? One is measuring annually or less frequently with lots of processing to reconstruct temps, the other daily with pretty much direct readings (and adjustments of course). How sure are you that you can look at them side by side and compare apples with apples?

  • tamino // December 24, 2007 at 1:37 pm

    Fred,

    Indeed a proxy reconstruction is not identical to an instrumental record, and I’d say certainly not as reliable. But not only is it the best we’ve got, I think there’s reason to believe it’s indicative of reality.

    After all, proxies are calibrated by using a period of overlap with the instrumental record and determining thereby the relationship between the proxy and the surface temperature as measured by thermometers. Also, it seems an unlikely coincidence that the biggest swings in the proxy reconstructions coincide with known climate-changing events, large volcanic eruptions (which we can determine, and date, with confidence because they leave a signature of debris in ice-core and other records). It’s also cause for concern that some of these events and their consequent climate changes are implicated in extreme stress on past civilizations; even mild climate change affects food and water supplies.

    Nonetheless there’s far more uncertainty about proxy reconstructions than the instrumental record! In my opinion, the extent of geographic coverage is problematic and probably constitutes the largest degree of uncertainty. But before (yet another!) firestorm ignites over the reliability of proxy reconstructions (which has been done to death here, and mainly on other sites), let readers be warned I don’t want the discussion to go there.

    I think the current warming being unprecedented is not really that important. After all, the climate change we’ve seen in the last 100 years certainly hasn’t been any great burden on civilization. What worries me is that there really is good reason to expect twice as much temperature change to happen in the next 100 years. That would certainly be unprecedented, and since we’re already at a high-temperature point the probable changes are so disturbing that it seems to me to be imprudent not to do what we reasonably can to reduce the impact. It’s also worrisome that CO2 in particular has effects other than on climate; the acidification of the oceans doesn’t bode well for marine life.

    I’m not a doomsayer, in fact for most of my life I tended to scoff at those who are. Just three years ago I saw evidence which caused me to doubt that global warming was even real! That’s when I decided to investigate this issue in detail. It’s because of this that I’m now convinced it’s real, it’s caused by human activity, and it’s very dangerous.

    I’m also convinced that those who argue against its reality, cause, or danger, have an extremely strong tendency to use extremely underhanded methods of persuasion — I’ve come not only to disbelieve the opposition, but to distrust them. Unfortunately, many like yourself who are genuinely skeptical (rather than “denialist” ;) are lumped in with those who are intransigent, and sometimes treated with less than perfect courtesy when they ask probing questions in a sincere effort to get closer to the elusive truth.

  • Barton Paul Levenson // December 24, 2007 at 3:25 pm

    nanny posts:

    [[But you should also understand that there is marginal land under cultivation at the poleward extent of the farmer’s land that will see a boost in productivity as the climate warms. Virtually no additional cost will be incurred there.]]

    Not as much new land as old land will be lost. The Earth being a sphere and all.

    And should additional costs outweigh the benefits of increased productivity of marginal lands, and CO2 fertilization, then of course the farmer will have to charge more for his products, and that cost will get passed along to consumers. But this is nothing new, it’s how a market works. We deal with this kind of thing everyday, such as when a cold snap ruins orange crops in Florida and the price of OJ jumps. But it’s not the end of the world, and prices don’t stay high for long.]]

    And if half of humanity is wiped out, and demand for coffins is sky-high, undertakers will simply increase their prices to match the demand. That’s how a market works, too. But most people would want to avoid having half of humanity wiped out. Similarly, the gigantic costs of global warming to humanity are better avoided as much as possible than dealt with later, by free-market means or otherwise.

  • Barton Paul Levenson // December 24, 2007 at 3:28 pm

    Michael Smith writes:

    [[What are the purely “physical arguments’ — i.e. the arguments that do not make use of the models or any of the model’s output — that justify the IPCC’s claim of 3 deg C for climate sensitivity?]]

    Without using a global climate model, you can calculate the radiative forcing from increased CO2, apply a sensitivity factor to the RF, calculate the new temperature, figure the increased water vapor from the Clausius-Clapeyron law, apply radiative forcing to that, etc. You could do it with a radiative-convective model (much less complicated than a GCM), or you could be a masochist and write out the calculations by hand.

  • Barton Paul Levenson // December 24, 2007 at 3:30 pm

    [[And what are the “physical arguments” for the notion that we face “severe harm” unless emissions are reduced?]]

    Our agriculture and economy are heavily dependent on the climate we have enjoyed for the last 10,000 years. Global warming will caused increased drought in continental interiors, increased violent weather along coastlines, and eventually, submerging a lot of coastal cities and infrastructure. Read the IPCC AR4 for more detailed arguments.

  • Dean P // December 24, 2007 at 5:20 pm

    Tamino,

    Unfortunately, the proxy story is one of the main tenets to the AGW story and therefore for any claims to be valid, the proxies must be validated.

    Some proxies show a much warmer MWP that others and even warmer than our current temperature. If those are accurate, then once again the ‘unprecedented’ claims fall flat. A recent paper showed vegitation uncovered in Greenland that dated between 800 & 1000 AD. So that seems to indicate that at least Greenland was warmer then than it is now. Here’s the reference:

    “Organic Remains from the Istorvet Ice Cap, Liverpool Land, East Greenland: A Record of Late Holocene Climate Change” by Lowell, T V, Kelly, M A, Hall, B., Smith, C A, Garhart, K,: Travis, S, and Denton, G H

    Doesn’t this fly in the face of “warmer now than ever before”?

    The claim is (by the pro-AWG crowd) is that the warming during the MWP was only localized and not global. That may be, but then isn’t what we’re now seeing also localized? The antarctic is certainly not warming at anywhere near the rate of the north pole (if it’s warming at all).

    as for the ‘denialists’ and the ’skeptics’, all we have to do is look at the approach taken by ICECAP & JunkScience versus ClimateAudit. ICECAP/JunkScience are clearly denialist, ClimateAudit is much more aligned with being critical of the science. The latter is much more likely to result in a better overall story.

    [Response: There is considerable disagreement between credible proxy reconstructions as to the size of the MPW/LIA. But there is no *credible* global or hemispheric reconstruction which shows temperatures in the MWP to be anywhere near what they are today.

    I agree that discussion of proxy reconstructions is important, but there are *plenty* of places to do that, this is not one of them. Others attempting to raise the issue will note that their comments do not appear.]

  • luminous beauty // December 24, 2007 at 7:25 pm

    “Unfortunately, the proxy story is one of the main tenets to the AGW story and therefore for any claims to be valid, the proxies must be validated.

    Unfortunately for the skeptics, this is a non sequitur. The real usefulness of paleoclimate reconstructions is as one of a number of empirical tests of climate sensitivity. If natural fluctuations in the past are indeed greater than what we’ve seen in the 20th century, then climate sensitivity is likely at the high end of estimates and future warming more likely to be at the high end or above IPCC projections.

    The basic tenets of AGW, simply put, are that humans have modified the climate since the Industrial Revolution by increasing the concentration of greenhouse gasses in the atmosphere and that further increasing those concentrations will lead to dramatic and potentially harmful changes in the biosphere.

    Nothing predicated on past climate.

    [Response: While you have an important point, I really intend to avoid the "can of worms" which is all discussion of proxy reconstructions; it inevitably turns into pointless (and hostile) argument. So let's let it go.]

  • cce // December 24, 2007 at 10:04 pm

    Tamino,

    You could do a post on the data that caused you to doubt AGW, and what changed your mind. That would be interesting.

    There seems to be this notion that AGW won over everyone with no actual scientific debate. We always hear about people “switching to the other side,” that is, from “believers” to “skeptics,” but the truth of the matter is that science has followed the exact opposite trend.

    What is your personal story?

  • Mike D // December 25, 2007 at 3:13 am

    Barton: You need to get your facts straight. during the last 10,000 years the temp,s have been both warmer and colder than now. Trees under the glaciers in the swiss alps and other locations in the Nothern hemisphere that have been dated indicated that 12 times during the last 10,000 years the temp’s have been higher and for at least 5000 yrs they have been colder. Are you people denying that we came came out of a little ice age in the 1800’s and denying the natural varibatity of climate that has been going on for that long. Are you even considering the effect of the sun. IF you deny the sun you will be in for an interesting future. We live in interesting times.

  • Hank Roberts // December 25, 2007 at 6:10 am

    “higher” than when? Mid-20th century, yes. 2004, not too likely from the sources I have.

    What are your sources, MikeD? Where do you find what you consider “facts straight” that you’re quoting from?
    http://www.globalwarmingart.com/wiki/Image:2000_Year_Temperature_Comparison_png
    http://www.globalwarmingart.com/wiki/Image:Holocene_Temperature_Variations_Rev_png

  • dhogaza // December 25, 2007 at 11:56 am

    Are you even considering the effect of the sun.

    Got us! Thousands of climate scientists have been unaware of the effect of the sun until you, just now, pointed it out!

    (smacks forehead)

    Damn, how could they miss something so obvious for an entire century?

  • dhogaza // December 25, 2007 at 12:09 pm

    ClimateAudit is much more aligned with being critical of the science. The latter is much more likely to result in a better overall story.

    The CA thesis is that mainstream climate science is fradulent, and that folks like Mann are guilty of scientific misconduct. I fail to see the difference in their view than that held by Milloy of Junkscience, etc.

  • Mike D // December 25, 2007 at 11:29 pm

    Hank: I was talking about the fact that trees have grown at locations where they have not been growing under our climate conditions not someones version of climate reconstruction.
    dhogaza: Listen to what the SOLAR people are saying I think they have a better hold on that than some self made climate climate gurus

  • Mike D // December 26, 2007 at 12:38 am

    If natural fluctuations in the past are indeed greater than what we’ve seen in the 20th century, then climate sensitivity is likely at the high end of estimates and future warming more likely to be at the high end or above IPCC projections.

    If it gets hotter you have proved your case. If it gets colder you have proved your case.
    If it gets drier you have proved your case.
    If it gets wetter you have proved your case.

    I think this is CRANIAL MYOPIA.

  • Hank Roberts // December 26, 2007 at 12:49 am

    Mike, no problem. Ruddiman’s work for example points out that human activity came along well after the peak temperature at the end of the last glacial cycle, which was followed by the beginning of a typical long slow cooling trend. Nobody disagrees with that, although the various reconstructions from different sites come up with different estimates. I’d expect the tree stumps you refer to are in one or more of those reconstructions. Have you looked?

  • cce // December 26, 2007 at 1:03 am

    I agree that we should ignore the opinions of “self made climate gurus,” which is why we should listen to actual experts like the NRC and IPCC. For starters, between the TAR and AR4, the “solar people” substantially cut the estimated solar influence.

  • Dean P // December 26, 2007 at 1:41 am

    CA is not just a “denial” website, it’s pointing out bad science and especially bad statistics. If the statistics that are behind the science are bad, then the science is dubious (not necessarily wrong, but certainly not proven). And THAT is what CA points out.

    And I challenge anyone to show where the CA statistical analysis is incorrect. I’m sure that CA would love to see it too! They openly publish their information with the full expectation that they’ll be corrected when in error. That they have little time or use for people who hide their data is NOT a reason to dismiss their site.

  • Heretic // December 26, 2007 at 2:39 am

    Good point Dean.

    However, there are other reasons to distrust their site. The half disguised accusations of fraud and misconduct flourishing there are one.

    Another is the fact that the underlying mission is not to understand climate better but to find any possible critic (relevant or not) of the AGW/CO2 hypothesis, while at the same time showing a strange complacency for anything opposing it.

    Yet another reason for distrusting it is that, when their own effort does not lead where they expect (and they always expect it to go a certain way), they stop talking about it, as in the funny surface stations adventure. That one was a major source of accusations of fraud and even conspiracy. Rather funny in retrospect.

    Am I impressed? Hell no. Critic is easy. When are the CA folks going to come up with some original results? Where is the meat? Where is the drive to understand? Where are the novative ideas?

    The biggest problem that opponents of the CO2 driven GW face is the lack of an equally viable alternative. Where is it to be found? Not on CA (nowhere so far). All there is there is a bunch of people who dislike the AGW/CO2 idea so much that they put out an enormous organized effort to discredit it, regardless of its actual merit, which they postulate from the start to be zero in spite of the physics supporting it. Of course, in the process, some valid critics occasionally arise. Big deal.

    Meanwhile, thousands of real scientists, like those recently gathered at the AGU meeting, are working hard to better understand reality. I’d rather listen to that kind of people.

  • henry // December 26, 2007 at 4:02 am

    Just a few comments:

    1. The surface stations project is the work of Anthony Watts, not CA. The project has not been “forgotten”. With only half of the US surface stations surveyed, about 70% fall into the “bad” listing (those having an error of more than 1C).

    2. Anthony Watts is also in the middle of an experiment testing the paint being used on the stevenson screens. Early results show warming induced into the readings because of paint used.

    3. I agree that accusations of fraud should be tempered on both sides. The recent post at CA talks about a post at RC, in which Raymond Pierrehumbert mocks another set of French authors, accusing them of a variety of sins.

    RC agrees with him, but sees it strange that he is silent on similar or more serious problems on papers written by fellow RC coauthors or the IPCC.

    “Meanwhile, thousands of real scientists, like those recently gathered at the AGU meeting, are working hard to better understand reality. I’d rather listen to that kind of people.”

    P.S., Steve and Anthony were both there, along with Lonnie Thompson (who still won’t release his Bona-Churchill data).

  • Mike D // December 26, 2007 at 5:09 am

    Hank I located a report the other day regarding trees found under the glaciers in the alps and ond regarding tree trunks north of the current tree line in Canada where it is still too cold for them. The Swiss report after dating the tree stated that there were 12 periods that had been warm enough for those trees to establish and grow during the last 9000 years where there are glaciers now.
    cce: Pick which ever group you feel are promoting the theory you want to belive. I am looking for the facts not some made up statistics that prove sombodys theory. I will take carbon dating and biological evidence such as the flora located under the Greenland glaciers anyday over GCM computer games that try to prove Al Gore et al. theorys. I picked up the computer game theory from a solar scientest.

  • Phil. // December 26, 2007 at 6:38 am

    Dean it would appear that at least some of the time ‘good science’ plays second fiddle to getting digs in at the opposition and defending bad science in the interest of the party-line?

    http://www.climateaudit.org/?p=2522
    The Comedy of the Chevaliers: a French Farce
    By Steve McIntyre

  • J. Peden // December 26, 2007 at 6:59 am

    Heretic: http://www.surfacestations.org/

    Take a deep breath - the rest of your 2:39 am. assertions are also fatally flawed.

  • dhogaza // December 26, 2007 at 7:51 am

    So many ill-informed posts, so little time …

    CA is not just a “denial” website, it’s pointing out bad science and especially bad statistics. If the statistics that are behind the science are bad, then the science is dubious (not necessarily wrong, but certainly not proven). And THAT is what CA points out.

    If you’re referring to the hockey stick, your statement is false. CA won’t tell you this. They continue selling their claim despite real working scientists having shown WHY their claims are false.

    This is just one reason why objective people don’t trust the CA people.

    You can, for instance, find information on “how Wegman exploded the hockey stick”, without ever learning that applying the analysis recommended by Wegman leads to … the same hockey stick.

    Why do they make their claim without explaining that a reanalysis shows that whatever error in analysis Mann made doesn’t change the conclusion in any significant way?

    Honesty? That would be the motivation for hiding this fact?

    The recent post at CA talks about a post at RC, in which Raymond Pierrehumbert mocks another set of French authors, accusing them of a variety of sins.

    Sins which they do appear to be guilty of. If you have evidence to the contrary, feel free to post it here, and RC won’t stop you from posting there, either.

    The problem isn’t in the claim that errors, even fraud, have occurred. Both do happen in science, after all.

    The problem is in

    1. backing up the claim

    2. if the claim is shown to be based on false assumptions, errors, or analysis, having the good grace to admit it, apologize and move on. CA’s claims have been shown to be bullshit by so many people trying to keep them straight will make your head spin. But CA keeps parroting away with outright lies like “the NAS as exploded the hockey stick and chastised Mann”, or “Wegman exploded the hockey stick”, etc etc.

    And they keep suggesting that Mann and other climate scientists practice fraud and are guilty of scientific misconduct without following up with specific claims or taking action.

    The posts at RC you dislike document in extreme detail the errors that have been made.

    Again, if you believe Raypierre’s wrong, be specific and show us where he is wrong.

    The fact that occasionally an innocent person is indicted for a crime they didn’t commit doesn’t mean we should stop indicting criminals. It means we should scrutinizes the available evidence before accepting the truth of such an indictment.

    Same in science. Claim Mann is guilty of scientific misconduct all you want, BUT BACK IT UP WITH FACTS.

  • Hank Roberts // December 26, 2007 at 9:21 am

    No argument with such a Swiss report, though I’d like to see it, do you remember where you read this? A name, date, or web link would help find it.

    Has the person you know as a “solar scientist” published? I’d like to read his or her work, what’s the person’s name and where is the work published?

    It’s rather an odd idea to call a theory, might be more of a political opinion, but I can’t tell for sure without reading it.

    Most important, be skeptical of what people tell you second hand — insist on cites to the published paper. You can probably read almost anything, with help from a decent reference librarian to search for the original work, once you know what to look for.

  • cce // December 26, 2007 at 9:27 am

    A few facts that you may want to note:

    1) The IPCC represents many, many “solar scientists.”
    2) There has been no appreciable increase in solar irradiance in 50 years.
    3) The stratosophere is cooling. That is the result of an enhanced greenhouse effect and is incompatible with an increase in solar output.
    4) Greenland and Europe are not the world.

  • Dean P // December 26, 2007 at 2:54 pm

    Hank,

    While it’s not the Swiss study, here’s a recent paper on Greenland which dates vegitation under the glaciers to 800-1000 AD

    “Organic Remains from the Istorvet Ice Cap, Liverpool Land, East Greenland: A Record of Late Holocene Climate Change” by Lowell, T V, Kelly, M A, Hall, B., Smith, C A, Garhart, K,: Travis, S, and Denton, G H

    If abundant vegitation is being uncovered by retreating glaciers and that vegitation is dated to the end of the first millenium AD, I find it difficult to believe that it’s not been warmer than it is right now.

  • Barton Paul Levenson // December 26, 2007 at 3:22 pm

    Mike D writes:

    [[Barton: You need to get your facts straight.]]

    I’m trying…

    [[ during the last 10,000 years the temp,s have been both warmer and colder than now. ]]

    If you’re talking about the mean global annual surface temperature, I don’t think that’s correct. Colder, certainly.

    [[Trees under the glaciers in the swiss alps and other locations in the Nothern hemisphere that have been dated indicated that 12 times during the last 10,000 years the temp’s have been higher and for at least 5000 yrs they have been colder.]]

    Source, please.

    [[ Are you people denying that we came came out of a little ice age in the 1800’s and denying the natural varibatity of climate that has been going on for that long.]]

    Nope.

    [[ Are you even considering the effect of the sun. IF you deny the sun you will be in for an interesting future. We live in interesting times.]]

    The sun obviously has a profound influence on climate. But it can’t be causing the present global warming, for the following four main reasons:

    1. The solar constant hasn’t risen or dipped significantly in the past 50 years. Global warming turned up sharply in the last 30.

    2. Increased sunlight would warm the stratosphere first. Instead, the stratosphere is cooling, as climate scientists predicted from the effects of increased greenhouse gases.

    3. Increased sunlight would warm the equator more than the poles (Lambert’s cosine law). Instead we’re seeing “polar amplification,” which again was predicted by the climate models.

    4. Increased sunlight would affect daytime temperatures more than nighttime temperatures (think about it). Instead, nights are warming more than days. That’s consistent with increased IR opacity of the atmosphere due to increased greenhouse gases, but not to increased sunlight.

  • Barton Paul Levenson // December 26, 2007 at 3:27 pm

    henry writes:

    [[With only half of the US surface stations surveyed, about 70% fall into the “bad” listing (those having an error of more than 1C).]]

    Henry, do you understand the difference between a high temperature and a rising temperature?

  • Dean P // December 26, 2007 at 3:39 pm

    As for Europe and Greenland not being the ‘world’, that is true… and currently the north pole and Greenland aren’t Antartica, which has had a remarkably constant average temperature since the mid-50s.

    One of the big areas of disagreement in the current debate is reconstructing past temperature records. Tamino has asked that proxy discussions not take place and i accept that. Let’s just say that there are some significant issues that need to be resolved before anyone can say we have a thorough and accurate temperature profile for the last 2000 years.

    One of my favorite movie quotes comes from Men In Black, and its something we all need to remember:

    “A person is smart. People are dumb, panicky dangerous animals and you know it. Everything they’ve ever “known” has been proven to be wrong. A thousand years ago everybody knew as a fact, that the earth was the center of the universe. Five hundred years ago, everybody knew that the Earth was flat, and fifteen minutes ago, you knew that humans were alone on it. Imagine what you’ll know tomorrow.”

    To say we “know everything” we need to know about climate science is in itself a dubious claim.

  • Mike D // December 26, 2007 at 5:03 pm

    Hank off the top of my head I do not recall the papers . But do your self a favor and ask a botonist or arborist how to determine the temp. from tree rings. I did locate the information on the web while searching for information about high latitudes and high elevation areas of the globe. That is where temp. variations will be the greatest. Look at ENSO and PDO and the other ocean areas as changes to those will affect large areas of climate. Of course must of what you will find about the ocean is still theory as not enough observation has been done yet. maybe in 20 or 30 years we will have a better understanding of all the factors related to climate. Then we will not have statments based on best guess estimates.

  • luminous beauty // December 26, 2007 at 5:11 pm

    (1) The Holocene Maximum is generally held to have occurred 8-12 thousand yrs BP . Though glaciers advance and retreat over annual, decadal, and centennial periods, it is reasonable to assume that on average, glaciers world-wide have been advancing since that time. That there are trees buried in that general advance over any of that time period is not evidence that there were periods then warmer than now, but evidence conditions have, on a millenial scale, grown cooler since the Holocene Maximum.

    (2) One location does not make a global average. There are very wide regional variations of climate that swing way beyond global averages. The 30’s dust bowl, for example. In the natural order of things these swings pretty much cancel each other out as the planetary climatic circulation systems quickly, slowly or somewhere in between, react to significant astronomical variations, very slight changes in solar radiance and the occasional massive explosive volcanic eruption. So, yes, it can be warmer or colder in any particular place and time without affecting the over-all trend.

    What is unprecedented about the wide spread, non-localized global warming we are unequivocally experiencing in the present is a massive increase of GHGs into the atmosphere directly through the activities of Homo sapiens (not so) sapiens.

    Also indisputable, if we continue on this course we will, rapidly and catastrophically in terms of geological time, alter the planet’s climate in ways that haven’t been seen in the paleontological record for millions of years.

  • Phil. // December 26, 2007 at 6:02 pm

    Dean there’s a problem in relying on statements made in movies:
    “Everything they’ve ever “known” has been proven to be wrong. A thousand years ago everybody knew as a fact, that the earth was the center of the universe. Five hundred years ago, everybody knew that the Earth was flat, and fifteen minutes ago, you knew that humans were alone on it. ”

    All three of those statements are incorrect!

  • luminous beauty // December 26, 2007 at 6:07 pm

    Mike D,

    Interesting that you should bring up ENSO. The 1998 El Niño is one of the first successes of general circulation models to accurately predict a regional feature of the climate:

    http://www.nationalgeographic.com/elnino/mainpage.html

    While it is true that our knowledge of climate is incomplete in many areas and uncertainties will undoubtedly always persist to some degree, that is no good reason to deny what significant things that we do know with a fair degree of certainty.

  • Barton Paul Levenson // December 26, 2007 at 6:28 pm

    Dean P writes:

    [[To say we “know everything” we need to know about climate science is in itself a dubious claim.]]

    To say anything was saying we “know everything” we need to know about climate science is an even more dubious claim. In fact, it’s a straw man argument.

    But we don’t have to know everything to know enough to draw some conclusions.

    BTW, J was wrong. Educated people 500 years ago did not think the Earth was flat. In fact, no educated person has believed that since Eratosthenes estimated its size around 300 BC.

  • Heretic // December 26, 2007 at 6:33 pm

    Fatally flawed? Oh, that sounds so impressive. I recall very precisely the results obtained by John V plotting temperature records from the supposedly “good” stations, and they matched GISSTEMP the best. Give me a link to a new different graph if you have one. I have little interest in the S.S. website itself, have seen before the cherry-picked photos of stations, still not impressed.

  • luminous beauty // December 26, 2007 at 6:58 pm

    One thing we know for certain is that the physics of average warming or cooling of global temperatures is not controlled by the chaotic fluctuations of the troposphere and oceans, but by radiative transfer in the earth’s thermodynamic equilibrium between incoming solar radiation and the net negative radiative capacity of empty space. This radiative balancing act physically occurs mainly in the stratosphere. The climate below responds, in its chaotic and imperfectly understood (but, as a consequence of intensive research, progressively better understood) manner to changes in the dynamic radiative equilibrium caused by changes in concentration of GHGs as well as very slight changes in TSI. To imagine otherwise is to invert cause and effect.

  • Hank Roberts // December 26, 2007 at 8:19 pm

    > ask a botonist or arborist
    > how to determine the temp.
    > from tree rings

    Eh? That’s like asking someone with a bug collection how to determine the temperature from cricket chirps. You get opinions that way, not sources.

    Seriously, this is how science works — cite your sources. If you can’t find what you think you recollect, suspect your memory, and find a new good source for the information.

    I’m familiar as an amateur reader with the dendrochronology literature; it’s a complicated subject, and requires a lot of cross-subject work to correlate events from any particular site. There’s no one simple general answer.

    It’s always safer to find actual published references, not just ask somebody their opinion.

    You really can look this stuff up. Only you know what search terms you used; your browser history might help you find what you’re recollecting.

    You need to know what tree, or cricket, you’re using as your thermometer.

    http://www.srh.noaa.gov/elp/wxcalc/cricketconvert.shtml

  • Dean P // December 26, 2007 at 9:17 pm

    While some have found issues with the quote i used, what i really like about it is that it demands that we stay humble to exactly what we ‘know’. And while we know much more today than we did a hundred years ago, it’s not at all clear that we know a lot…

    And where this ties into climate science is when we have some nobel laureates claiming that “the science is settled”, which to most people means that we can stop looking for answers because we know them all..

    Sorry, we don’t. To claim otherwise is to deny just how little we know.

  • Eli Rabett // December 26, 2007 at 10:05 pm

    Just for giggles, how has surface stations dealt with the shaded sites that are cooler than the surrounding areas or does Eli have to start his site of the day series again (The comments ain’t bad either)

  • Lee // December 26, 2007 at 10:28 pm

    Several claims have been made in this thread that since glacial retreat is uncovering organic remains from ~1000 years ago, it must have been warmer then.

    Well, no - that claim does not follow from the observation. What does follow is that it is warm enough now, for long enough, to uncover a spot that was warm enough for long enough to have been uncovered then.

    It is entirely consistent with the idea that temps have recently gotten much warmer than it was then, and the rapidly retreating ice front is just now moving back past that location as it retreats to a new front much upstream.

    It is also consistent that it is colder now, but has nonetheless been just warm enough to melt ice for long enough, that the ice front is uncovering just now - although this seems unlikely given that it is warming rapidly, and ice fronts worldwide are responding to that warming quite rapidly.

    The simple observation, by itself, does not tell us the relative temperatures.

    The relative position of the equilibrium ice fronts might tell us something about relative temps - but these ice fronts are not in equilibrium, they are retreating rapidly.

  • Mike D // December 26, 2007 at 10:50 pm

    Well lets put it this way. I have been living my adult life for the last 40 years doing what I thought was right. I spent 37 years at one job and retired. I bought 57 acres of trees to keep the from being subdived and made into a housing area. I went from driving 38 miles a day to about 40 a week. I went from 200 a month power bills to less than 80. Now you want to mess with me with your so called the world is going to end B.S. I want to tell you to remove your heads from the dark place and look at what is really going on. I can get better information from an Astrologer or the lady with a CRYSTAL BALL than the information you are all falling all over yourselves trying to defend.
    I will take this time to appoligize as it is none of my buisness what you choose to belive. But if your nearsightedness affects my way of life then I will fight back as will others.

  • henry // December 26, 2007 at 10:57 pm

    Barton Paul Levenson writes:

    “Henry, do you understand the difference between a high temperature and a rising temperature?”

    Yes, but I’d also expect a doctor to make a diagnosis using an accurate thermometer, not one with a margin of error of 5 degrees…

  • luminous beauty // December 27, 2007 at 1:01 am

    henry,

    What gives you the idea that the thermometers used in weather stations are only accurate to 5 degrees?

    Mike D,

    It sounds to me you’ve made some admirable decisions to reduce your own carbon footprint. Would you deny the opportunity to give others affordable incentives to make similar decisions?

    Consider that if you are right and global warming is nothing but a fairy tale. If we nonetheless facilitate the transformation of the world’s energy infrastructure toward renewable and endogenously available sources and away from fossil fuels, then we have shown the foresight to accomplish what will ultimately be necessary anyway when the limited resources of petroleum, natural gas and coal are, not too far in the future, exhausted, while simulteneously reducing the global political tensions control over those limited supplies already are exacerbating.

    Win/win.

    And if you’re wrong?

  • Hank Roberts // December 27, 2007 at 1:35 am

    Mike, someone’s trying to scare you.

    It’s not me. Your story’s a lot like mine.

    Except I use the reference desk at the library to check what people tell me.

    Who is telling you the things you’re worried about?

    We can’t help you look this stuff up, if you can’t say where you’re hearing about it.

    This is not a political thing.
    This is a librarian thing.

  • henry // December 27, 2007 at 4:13 am

    luminous beauty said:

    “What gives you the idea that the thermometers used in weather stations are only accurate to 5 degrees?”

    I’m sure that, when manufactured, the accuracy is checked. How they’re installed is another story.

    The error of some 14% of the surveyed stations (so far 460 out of 1221), have a possible error greater than 5 degrees. Another 55% have a possible error of greater than 2 degrees.With the RISE in surface temps being only .8 degrees, it looks like the possible error could swamp the rise.

    For those who aren’t sure about this discussion, check here:

    http://wattsupwiththat.wordpress.com/2007/12/06/ushcn-national-weather-station-quality-plot/

    As far as the “cherry-picking” of bad sites (to Heretic): When you consider that, so far, only 4% of the 460 sites (about 1 8) fall into the “CRN1″ category, the “bad” outweigh the “good”.

    If you really want to disprove his theory, go to your local USHCN site and see what category it falls in. If it’s good, I’m sure they’d like to know…

  • tamino // December 27, 2007 at 6:07 am

    The effort to discredit the thermometer record is a total red herring. There are so many evidences of notable global warming quite apart from the surface thermometer record, including the disappearance of glaciers, the startling decrease of the polar ice cap, atmospheric temperature measurements from satellites, sea level rise, migration of species, earlier flowering of plants in springtime, earlier melting of ice in rivers and lakes, earlier arrival of snowmelt runoff pulse in river flow, lengthening of the wildfire season, decline in global snow cover, etc., etc., etc., etc., etc., that even if the thermometer had never been invented there would still be no doubt that the globe is warming. Anyone who actually questions the reality of planetary warming is either seriously deluded or utterly dishonest.

    Such talk as that about “5 degrees error” is ludicrous. The important point is not to determine absolute temperature but temperature change, and I’ve seen no evidence whatsoever that there’s any significant error in the data which invalidates estimates of temperature change. Furthermore, the surfacestations defiition of what’s good and what’s not utterly fails to impress me, and independent analysis has shown that the trend determined by the stations classified “good” doesn’t substantively differ from that determined by the stations labelled “bad.”

    There are some genuine skeptics in the world, who sincerely want to get a better handle on the truth and understand what the future is likely to bring with greater confidence. Those who are attempting to discredit global warming by suggesting that the thermometer record is unrealistic, are not among them.

  • fred // December 27, 2007 at 7:27 am

    luminous says:

    “Unfortunately for the skeptics, this is a non sequitur. The real usefulness of paleoclimate reconstructions is as one of a number of empirical tests of climate sensitivity. If natural fluctuations in the past are indeed greater than what we’ve seen in the 20th century, then climate sensitivity is likely at the high end of estimates and future warming more likely to be at the high end or above IPCC projections.”

    This is logically fallacious. Sensitivity to what? It does not follow from the fact that there have been previous natural fluctuations whose cause we do not know, that there is sensitivity at any level to rising CO2.

    I am not saying there is not. Just that this is a fallacious argument for it.

    Should it, for instance, turn out that MWP was actually a full degree warmer than today, it does not follow that the climate is more sensitive to CO2 than we think. Its a non sequitur to argue that.

    You can see this readily because it proves the opposite equally well. Do dramatic cooling episodes in the past prove that a new ice age is likely to be caused by negative feedback loops provoked by CO2 rises? Of course not, those episodes are simply irrelevant to the CO2 proposition.

  • fred // December 27, 2007 at 7:35 am

    “You can, for instance, find information on “how Wegman exploded the hockey stick”, without ever learning that applying the analysis recommended by Wegman leads to … the same hockey stick.”

    Citation please! Or you will incur the wrath of Hank R. He will, won’t he?

  • Barton Paul Levenson // December 27, 2007 at 2:05 pm

    henry writes:

    [[The error of some 14% of the surveyed stations (so far 460 out of 1221), have a possible error greater than 5 degrees. Another 55% have a possible error of greater than 2 degrees.With the RISE in surface temps being only .8 degrees, it looks like the possible error could swamp the rise.]]

    It only looks that way if you don’t understand statistics. Henry, one thermometer with a 5 degree uncertainty has a five degree uncertainty. The mean of two or more thermometers, each with a five degree uncertainty, is less than five degrees, and for large numbers, considerably less. Want the math?

  • Barton Paul Levenson // December 27, 2007 at 2:42 pm

    For those who like coding, here’s a Basic-language program to examine why many stations are usually better than one, even if they all have large errors:

    ‘=====
    ‘ Monte does Monte Carlo simulations of multiple temperature stations.
    ‘=====

    while 1 = 1
    randomize 0.7
    sumT = 0

    print
    input “N? =>”; N
    if N < 0 then exit while

    for i = 1 to N
    T = 9.0 + 10.0 * rnd(i)
    delta = T - 14.0
    sumT = sumT + T
    next i

    meanT = sumT / N
    delta = abs(meanT - 14.0)

    print
    print “mean T = “;
    print using(”##.###”, meanT)

    print “|dT| = “;
    print using(”##.###”, delta)
    wend

    print
    print “RUN ENDS.”
    end

    Note what I’m doing here. I assume the true temperature is 14.0 degrees C. exactly. I then create N temperature stations which read anywhere from 9.0 to 19.0 degrees C. at random. Here’s what I got for different numbers of stations, using as output the absolute difference between the mean reading and the true reading:

    1 1.441
    10 0.599
    100 0.025
    1,000 0.118
    10,000 0.029
    100,000 0.005

    Remember, they all had a 5.0 degree C. uncertainty.


    ‘ 1 1.441
    ‘ 10 0.599
    ‘ 100 0.025
    ‘ 1,000 0.118
    ‘ 10,000 0.029
    ‘ 100,000 0.005

  • Barton Paul Levenson // December 27, 2007 at 2:44 pm

    I seem to have lost the indentation there, and repeated my error table. Sorry for the confusion.

  • Null // December 27, 2007 at 4:38 pm

    Thanks for the info BPL.

    Can I see the analysis for the case of systematic deviation of the readings from the true value. All readings are 5.0 larger that the true mean, for example.

    And does your table for the random case indicate that well over 1000 readings would be needed in order to get clear correctness in the first decimal place?

    And does that mean that over 1000 estimates of the same physical quantity, measured under the exact same circumstances, and having only random deviations from the true mean would be necessary?

    Thanks again.

  • fred // December 27, 2007 at 6:31 pm

    BPL, yes, understand the stats, but what is being alleged, rightly or wrongly, is systematic bias. You have supposed they are varying randomly about a mean. What surfacestations is alleging is that the errors will probably not, given the errors in siting, be random, but will have an upward bias.

    I don’t myself get what the problem is that the warmers have with surfacestations. Should we not insist that the stations conform to the quality requirements of the operator? Is it not perfectly reasonable to go look at them and see if they do? Is it not somewhat amazing that it took a bunch of amateurs to think of doing it?

    Surely, the right response is not to attack them for ‘denialism’ but to agree this is not the way this ought to be run, and *get it run better*. What possible excuse can there be for just ignoring your own quality standards wholesale? None. Defending this stuff and minimizing its significance gives AGW a bad name.

    [Response: If the goal of the surfacestations project were to "get it run better," then I'd be all for it and so would the vast majority of those interested in climate science. But it's my belief that the *goal* is, as you put it, to "give AGW a bad name." For example: you seem to think that the network of observing stations has ignored its own quality standards. But those quality standards were only developed recently, they were not "ignored" in collecting and analyzing the data, and one thing that's just plain impossible is to go back in time in order to enforce modern standards on historical data. What we can do is to examine the data intensely in order to determine how reliable it is, what the probable errors are, and how they can best be compensated. That is exactly what has been done.

    But in my opinion, the main motive of the surfacestations project is to discredit the data and analysis which exists presently, in order to give AGW a bad name. I posted on the topic here.]

  • Hank Roberts // December 27, 2007 at 6:33 pm

    Fred, of all things you could ask me to find for you, Wegman’s report is one of the silliest. You really can look this stuff up.

    Don’t miss the high point of the transcript:

    —–excerpt—–
    MS. SCHAKOWSKY. I also had said earlier that in my question to Dr. North and that most scientists agree that in large part or for your purposes I will say in some part attributable to human activity. Would you agree with that?
    DR. WEGMAN. I don’t know that for a fact.
    MS. SCHAKOWSKY. Okay. You don’t know that.
    DR. WEGMAN. Again, it is the connection between carbon dioxide and temperature increase. Now, Mr. Inslee pointed out that he thinks there is a physical explanation based on a blanket of carbon dioxide in the reflection. Carbon dioxide is heavier than air. Where it sits in the atmospheric profile, I don’t know. I am not an atmospheric scientist to know that but presumably if the atmospheric– if the carbon dioxide is close to the surface of the Earth, it is not reflecting a lot of infrared back.
    MS. SCHAKOWSKY. Okay. But are you not really qualified to–
    DR. WEGMAN. No, of course not.
    ——end excerpt———

    Let me know if you really need help finding the rest of it. I think Tamino posted on it earlier, try looking here first.

  • henry // December 27, 2007 at 10:29 pm

    And if the GISS temp and HadCRU charts:

    1. Listed their “zero” as “zero=x”,

    2. Stated that their anomaly had an error +/- x degrees, and

    3. Both used the same standard, i.e., the averaging period 71 - 2000.

    From Barton Paul Levenson’s post, he proved that there WILL be an error. Simply post it with the charts, and don’t assume that all the world’s thermometers have absolute accuracy.

  • henry // December 28, 2007 at 12:14 am

    To Fred:

    “In 1999, a U.S. National Research Council panel was commissioned to study the state of the U.S. climate observing systems and issued a report entitled: “Adequacy of Climate Observing Systems”. (National Academy Press).

    The panel was chaired by Dr. Tom Karl, director of the National Climatic Center, and Dr. James Hansen, lead climate researcher at NASA GISS. That panel concluded:

    “The 1997 Conference on the World Climate Research Programme to the Third Conference of the Parties of the United Nations Framework Convention on Climate Change concluded that the ability to monitor the global climate was inadequate and deteriorating.”

    Yet, ten years later, even the most basic beginning of a recovery program has not been started. No online photographic database existed of the USHCN stations.”

    [For example: you seem to think that the network of observing stations has ignored its own quality standards. But those quality standards were only developed recently]

    Dec 2002, to be exact.

    http://www1.ncdc.noaa.gov/pub/data/uscrn/documentation/program/X030FullDocumentD0.pdf

    Starting at section 2.2.1.

    [What we can do is to examine the data intensely in order to determine how reliable it is, what the probable errors are, and how they can best be compensated.]

    So once again, what is the error for the GISS anomaly chart (+/-)? I can’t seem to find it anywhere…

    [Response: It took me about a minute to find this in the abstract of Hansen et al. 2001, J. Geophys. Res., 106, 23947-23963:

    There are inherent uncertainties in the long-term temperature change at least of the order of 0.1°C for both the U.S. mean and the global mean.

    With several hours investment I could probably find even more detailed delineation of the probable error, not only in long-term temperature change but in the monthly global estimates themselves. It's overwhelmingly likely that they're of the same order of magnitude as the probable error in HadCRU temperature, which is estimated for each month in their basic data files and included with the downloadable data, and considerably less than the 0.1 estimated uncertainty in long-term temperature change.

    So here's my guess: you "can't" find it because you'd rather whine than search in earnest.]

  • Hank Roberts // December 28, 2007 at 12:18 am

    Okay, Fred, I always do find new-to-me and better info when I do the homework help thing, and I didn’t want to leave your question hanging over the long holiday weekend while mostly offline

    Got an hour? Watch this seminar,
    FROM: Andrew Dessler’s site, where he writes:

    Monday, September 04, 2006
    North on the hockey stick
    My colleague Jerry North was the chair of the National Academy panel that investigated the hockey stick. Last week he gave an interesting seminar to our department about the experience. You can view the seminar here.

    http://www.met.tamu.edu/people/faculty/dessler/NorthH264.mp4

    [Techincal details: it's a 40 MB file, so it'll take some bandwidth. It's in mp4 format --- if you have a recent version of quicktime on your computer, you should be able to view this. It runs just over an hour, so grab some popcorn and enjoy!]

  • Horatio Algeranon // December 28, 2007 at 12:19 am

    Tamino says:

    “The effort to discredit the thermometer record is a total red herring.”

    Horatio Algeranon says:

    We’ve heard conversations,
    Of surface stations,
    “Quite worthless, without reservations.”

    “The tennis courts,
    We must report,
    Have made thermometers jump and snort.”

    ….

    from
    A Tale of Two Surface Stations

  • Deech56 // December 28, 2007 at 12:43 am

    Fred, as long as you are checking out the surfacestations.org and the ClimateAudit play-by-play, I hope you see the analysis done by John V and posted on CA (referenced by Eli: http://rabett.blogspot.com/2007/09/and-so-it-goes.html). As Tamino pointed out, the effort sounds worthy, but something about it tickles the spidey sense. And henry, please remember that measurements are subject to error (in a statistical sense), but there are ways to determine whether a signal exists and whether it is significant.

  • Heretic // December 28, 2007 at 1:22 am

    The allegation by surfacestations that the bias is all one sided is the one thing that does not add up. Why would that be? There is no established reason for that bias to be one sided, nor do they hypothesize any convincing one.
    Furthermore, the analysis done by John V showed that it seemd to actually be the opposite happening, proving that GISS methodology and corrections are adequate.
    I don’t care about people taking pics of stations. Knock yourself out with all the ASOS you can go to if you have nothing better to do. I do care about telling fables about the significance of it. Put the pics in your pocket and crunch some data instead, like John V did, and then we’ll have something to look at.
    This is nothing but a red herring and distraction. Just like CA set out with the specific goal to discredit the idea of AGW, not to understand climate better or “filter the bad science,” the surface stations distraction has for only goal to cast unwarranted doubt on trends that are seen not only from thermometers, but from satellites, boreholes and a multitude of other proxies. The “effort” is so eager to do that that it essentially exaggerate the significance of the temp record itself, which does not exist in a vacuum. There are many other aspects of warming that correlate with the surf temp record and indicate that, more likely than not, this record accurately reflects a reality. For those really trying to understand what’s going on in nature, it is a total waste of time to pay any attention to it.

  • nanny_govt_sucks // December 28, 2007 at 5:17 am

    The allegation by surfacestations that the bias is all one sided is the one thing that does not add up.

    Can you provide a reference for this allegation, please? I can’t seem to find it at surfacestations.org

  • fred // December 28, 2007 at 8:21 am

    Of course I have read Wegman, several times, and have a copy of both the report and the reply to questions on my hard drive. Certainly did not mean to ask for help finding that. Very sorry if this wrong impression is my fault. Not an idiot!

  • fred // December 28, 2007 at 12:38 pm

    Heretic, this is not sensible. The reason for thinking there may be systematic bias upwards is to be found in the pictures of the stations and in the ways they differ from the specifications, which mostly concern making sure the stations are not exposed to artificial heat sources. It is a documented fact that many of them are more exposed to such heat sources than the specifications say is permitted.

    But, whether or not there is any reason to think there is an upside bias, and I am aware of John V’s work, there can be no reason whatever to object to scrutiny of the stations. Whatever the motivations of the scrutineers. If they were looking for bias and could find none, this would advance our knowledge. If they were looking for bias and found it, this would do so too.

    It is certainly true that even so, it need not invalidate the measurement of trends by these stations. Suppose there were an upward bias and it had remained identical through the life of the time series. Fine, even if the values could not be trusted, the trend would be valid. But having found an upward absolute bias, one has to start scrutinizing in some detail exactly when and how it happened - in short, do we have an homogenous series?

    There is nothing evil about having an agenda. Most scientific work is guided by an agenda. It is useful. It provokes ideas. I see nothing whatever wrong with trying to find evidence for or against AGW. What would be wrong would be to refuse to make available the results of such efforts.

    What Luminous needs to do by the way (separate issue) is quote some passage someplace in which it is proven that “applying the analysis recommended by Wegman leads to … the same hockey stick.”

    Where exactly has that been done and by who? Is that what Wegman says? Lets see a quote. I think what Wegman said was that the M&M criticisms were correct and had been replicated by Wegman’s group. But hey, show me I am wrong.

  • Barton Paul Levenson // December 28, 2007 at 1:53 pm

    Fred,

    You still don’t seem to understand the difference between a high temperature and a rising temperature. Thermometers may well read hot and yet not show an upward trend. I’ve seen nothing from surfacestations.org that indicates they have shown a bias toward rising temperatures in the surface stations.

  • luminous beauty // December 28, 2007 at 5:07 pm

    fred,

    Why me?

    http://tinyurl.com/yqhr3b

    You can google, can’t you?

  • luminous beauty // December 28, 2007 at 5:12 pm

    fred,

    You seem quite well read when it comes to denialist assertions, but infinitely naive concerning the science upon which they throw their poo.

    Why is that?

    [Response: I'll hazard a guess. Fred heard about global warming through mainstream media, which for the most part (with notable exceptions) portrays it according to IPCC but tends to be extremely short on scientific details. He then heard denialist propaganda, which is expertly designed to discredit the concensus view and give the impression of scientific sophistication. Unwilling to accept either point of view on faith, he's trying to find out what's true, what's reliable, and hard evidence about how much confidence we can assign to claims about the likely future of earth's climate and how it depends on human activity.

    Denialists are eager to package misinformation with a veneer of scientific detail, but if you want depth and details of the concensus view you have to work for it. Personally, I'm glad there are people like Fred who are willing.

    I could be mistaken.]

  • Heretic // December 28, 2007 at 5:32 pm

    NGS: Fred’s post 12/27 @ 06.31 pm: “What surfacestations is alleging is that the errors will probably not, given the errors in siting, be random, but will have an upward bias. ”

    I took his word for it, assuming he was more knowledgeable about surface stations than I.
    Perhaps that was a mistake, but he seems pretty sure that’s what the all idea is, as repeated in his 12/28 post.

    Fred, a nice size sample was used by John V, the results indicate to me that any more effort in that direction is likely enough to be a waste of time. If some want to go that way, more power to them, but, as a layman with a job and a life, there is only so much attention I can devote to it (i.e. zero).

    Furthermore, I still stand by my conviction (formed by listening to their supprters’ message and comments) that the goal of surface stations is not to provoke ideas or discover anything, but to cast doubt on existing data and promote ideas that are not adequately supported by data. I’ll let you choose whatever word you deem appropriate (evil has too much of a religious connotation to me), but I still won’t waste my time with that nonsense.

  • Hank Roberts // December 28, 2007 at 5:58 pm

    Fred, look at that video of North’s presentation describing the hearings.

    Or here’s a short transcript from a session not long after that video.

    Chronicle of Higher Education
    Live Chat with Gerald North

    http://chronicle.com/live/2006/09/hockey_stick/

    ——excerpt—–
    Greetings Dr. North: I am curious what you thought of the primary part of the Wegman Report, that dealing with the statistical issues in Mann, et al. Specifically, the statement (or similar), “Incorrect mathematics + correct result = bad science.” I must say that the NAS Report appeared, to me, to find fault with the Mann methodology but then went on to seemingly endorse the result. The later was the media’s take, anyway. TIA

    Gerald North:
    There is a long history of making an inference from data using pretty crude methods and coming up with the right answer. Most of the great discoveries have been made this way. The Mann et al., results were not ‘wrong’ and the science was not ‘bad’. They simply made choices in their analysis which were not precisely the ones we (in hindsight) might have made. It turns out that their choices led them to essentially the right answer (at least as compared with later studies which used perhaps better choices).

    —–end excerpt——-

  • Hank Roberts // December 28, 2007 at 6:13 pm

    Oh, and Wegman:

    —–excerpt—–
    We do agree with Dr. Mann on one key point: that MBH98/99 were not the only evidence of global warming. As we said in our report, “In a real sense the paleoclimate results of MBH98/99 are essentially irrelevant to the consensus on climate change. The instrumented temperature record since 1850 clearly indicates an increase in temperature.” We certainly agree that modern global warming is real. We have never disputed this point. We think it is time to put the ‘hockey stick’ controversy behind us and move on.
    ——–end excerpt——

    Those who keep bringing Wegman up always leave this part out.

    Eh?
    —–end excerpt——

  • Hank Roberts // December 28, 2007 at 6:14 pm

    The Wegman quote is from:
    http://republicans.energycommerce.house.gov/108/hearings/07272006Hearing2001/Wegman.pdf

  • Mike D // December 29, 2007 at 2:40 am

    Hank:
    Abstract
    Rapid climate change events can have devastating impacts upon agricultural production and human society. Advances in spatial
    and temporal resolution of palaeoenvironmental and archaeological data enable detailed examination of the nature of human–
    environment interactions. Recent studies have shown that throughout the Holocene human populations responded to rapid climate
    change events by existing subsistence strategies adopting to novel environmental conditions. In the case of agriculturalists in New
    Guinea and hunter-gatherers in northern Australia, climate change set in motion a range of biological and demographic possibilities
    and restrictions that had long-term consequences for each region. The early Holocene climatic and ensuing environmental
    transformations heightened natural biomass production and population increases. Consequently, later rapid changes in climate
    centred around 6000 and 3500 cal yr BP, resulted in the adoption of innovative technologies and diverse subsistence strategies
    throughout the region that reduced the vulnerability of people in an environment of increasing unpredictable climate variability

  • Mike D // December 29, 2007 at 2:44 am

    Hank:
    The aggregate distribution of driftwood dates from the Arctic Ocean coast of Ellesmere Island resembles that for the Baffin Bay region (cf. Figs. 3 and 4). However, this similarity is largely due to the effort applied to dating wood behind the ice shelves. When only samples from areas without ice shelves are considered, important differences appear between the records of the two regions. For example, the decline of wood abundance during the late Holocene, a prominent feature of the Baffin Bay record, is not apparent here (cf. Figs. 3 and 4). This part of the archipelago is nearest to wood sources, and the two oldest dated wood samples from the entire archipelago are from here, both from 8.9 ka B.P. (Stewart and England, 1983; Bednarski, 1986; Lemmen, 1988). Driftwood arrived in only moderate abundance until 6.75 ka B.P., when it increased coincidentally with its increase in Jones Sound. Prominent modes of driftwood arrival date from 6 to 5.75 ka B.P. and from 4.75 to 4.5 ka B.P. The strong mode in Jones Sound between 5.25 and 5 ka B.P. correlates with a minimum in the northern Ellesmere record (cf. Figs. 3 and 4).

    Driftwood arrived sparsely between 8.6 and 6 ka B.P. when it suddenly, but briefly, increased to one of two middle Holocene maxima, between 6 and 5.75 ka B.P. This modal abundance correlates exactly with the mode for the northern coast of Ellesmere Island (cf. Figs. 4 and 6). Thus this brief event of abundant wood arrival is widely recorded. Similarly, both records display driftwood minima between 5.25 and 5 ka B.P. that, in turn, correlate with the modal abundance in the Baffin Bay region (cf. Figs. 4 and 6 with 3). The mode between 4.75 and 4.25 ka B.P. in the central Arctic appears to be represented in both the northern Ellesmere and the Baffin Bay records. The strong central Arctic mode between 3.75 and 3.5 ka B.P. corresponds with the sharp decline in wood abundance in the Baffin Bay region.

  • Mike D // December 29, 2007 at 3:38 am

    I do not deny that there are man made problems on our planet.
    The denial I see is a group that is refusing to admit that there have been a wide range of natural climate variabilities and trying to scare the world into hurrying up and make some major change .
    I visited so. Cal in the 60s and70s I now wht polution is.
    I lived in so. Nevada from 1953 until 2006.
    I know what uncontrolled growth can do to and area.
    Yes we are killing the planet.
    Yes we should have done something a long time ago.
    From where I sit a 60 years I see another wrong headed attempt at loving our planet to DEATH.
    what you advocate will cause more troubles that you can even dream of.
    There is a better chance that we will see in the next ten years a major cooling than a continued warming.
    Are you ready for that. You need to spend a little time studing history.
    When we forget history we repeat the mistakes of the past.
    Learn every thing you can about the last 2000 thousand years then you might have an idea what we could be looking at except worse.

  • JesusChristHimself // December 29, 2007 at 5:41 am

    Climate scientists are well aware of natural variability. They study it every day. So your contention that they refuse to admit there is natural variability is wrong. Read the University of Washington website. It appears all of the climate scientists who work there think man is causing global warming. A group of them just recently published a paper that found natural variability, not AGW, is responsible for some of the changes in the arctic. The conservative media trumpeted the study as a sort of nail in the coffin of AGW.

    They’re not zealots. They go where the evidence and observation goes. Many of them thought the changes they were seeing were being caused by AGW, but the trail went elsewhere, and they published that finding.

    What would cause this cooling you’re predicting? Aerosols?

  • Hank Roberts // December 29, 2007 at 6:00 am

    I found a source for the driftwood quote; the first Google hit is
    http://www.climateaudit.org/?p=1015

    Have you read the original paper, its refereces and papers citing it? Got a cite to the source?

    I don’t find your source for your odds on gobal cooling. Have you placed your bet? http://www.jamstec.go.jp/frsgc/research/d5/jdannan/betting.html

  • Hank Roberts // December 29, 2007 at 6:12 am

    Driftwood? Your point?
    Likely it was warmer at the end of the ice age, albeit briefly, than it’s been up through the 20th Century. Lots of references on that, e.g.

    “The warmest point of the last interglacial period, around 125,000 years ago, was about 1°C warmer than the present global average temperature for only a few centuries, yet saw an average sea level 4 to 6 meters higher than at present….”
    http://www.csis.org/component/option,com_csis_pubs/task,view/id,4154/type,1/
    at p.43

    Was that the point about how the driftwood got up to that high stand? Guessing without reading the original paper and its cites.

  • fred // December 29, 2007 at 7:44 am

    Guys, only an idiot would fail to understand the difference between higher and rising temps, that is between temperature and trend.

    My view is that if surfacestations shows an upward bias in measured temps today, this is the start of an interesting and difficult question. That question is, was the bias identical throughout the station’s history?

    If not, we have bias in the trend as well as the measurement.

    I do not know what the answer is, but what I know for sure is that if you were designing a network for the next 100 years, you would not have siting guidelines which permitted what we have seen in the way of photos and docs from surfacestations.

    I don’t give a damn about their motivation. What I am interested in is the facts.

    Yes, John V’s work was interesting. It did indeed tend to show that the bias was in absolute measures as opposed to trends of temps. It will be interesting to see if its confirmed by the whole surfacestations project.

    My judgement remains that it is a blot on the record of climate science that this was not done until amateurs started, and that once started, what should have been basic quality control by station operators was greeted with hostility and ridicule.

  • fred // December 29, 2007 at 8:03 am

    “applying the analysis recommended by Wegman leads to … the same hockey stick”

    No it don’t. Eliminate decentered PCA, eliminate BCP, and you don’t got no hockey stick.

  • dman // December 29, 2007 at 9:20 am

    All this leads to the questions, “What should we do?” I keep hearing of all the things we should do to “FIGHT” global warming. If we stop ALL CO2 emissions, will that stop global warming? NO so I don’t think reducing will have any great affect either.

  • Barton Paul Levenson // December 29, 2007 at 12:47 pm

    Mike D posts:

    [[There is a better chance that we will see in the next ten years a major cooling than a continued warming.]]

    Care to place a small bet on that?

  • luminous beauty // December 29, 2007 at 2:37 pm

    fred,

    “Eliminate decentered PCA, eliminate BCP, and you don’t got no hockey stick.”

    Did you read the links Hank and I provided?

    Rather than acting like a turtle by reasserting this unfounded assertion, held almost exclusively by CA fanatics, why don’t you respond to the findings that the hockey stick does persist when calculated with PC centering according to M&M’s criticism and eliminating the tree rings they object to or even without PCA or any tree rings?

  • Dean P // December 29, 2007 at 3:19 pm

    With respect to the Gerald North quotes…

    Sorry, that’s just plain stupid. If a poor method is shown to be used, then whatever the ‘result’ of that method shows, the only thing we know is that the result is wrong. We know nothing about the science behind it. It’s troubling that a professor would say otherwise…

    In this case, the Mann results overinflate the magnitude of the hockey stick (according to M&M). That result was used specifically by AIT to solicit the need to implement dramatic changes in CO2 output. If the magnitude of the hockey stick is half of what Mann shows, how well does AIT convince people that we need to do something?

    In science, the ends NEVER justify the means…

  • JesusChristHimself // December 29, 2007 at 3:51 pm

    With China and India, etc., spewing aerosols at the rates they are, why is it so implausible that temporary cooling could happen?

  • Ian Forrester // December 29, 2007 at 4:01 pm

    Fred said: “No it don’t. Eliminate decentered PCA, eliminate BCP, and you don’t got no hockey stick”.

    Have you read the North Report? Have you read peer reviewed research papers on the subject? If you had you would have seen that what you said is just not true.

    Care to cite your sources?

  • Hank Roberts // December 29, 2007 at 4:26 pm

    Fred, what’s your basis for disagreeing with Dr. North and the National Academy on this point?

    “No it don’t” is an opinion. Yours?

    Tell us where you are reading what you are quoting, and why you consider this a more reliable source than the National Academy’s report, eh?

  • Wolfgang Flamme // December 29, 2007 at 6:19 pm

    Choose your Trend:
    http://i171.photobucket.com/albums/u304/wflamme/CRU-ARIMA1-0-1.png

  • Mike B // December 29, 2007 at 10:04 pm

    And then compare the different forcing during the two trends.

    First half of the century: postive volcanic, postive Solar, postive GHG

    1975+: negative volcanic, neutral solar, negative anthropogenic aerosol, highly positive GHG

  • nanny_govt_sucks // December 30, 2007 at 12:58 am

    With China and India, etc., spewing aerosols at the rates they are, why is it so implausible that temporary cooling could happen?

    Because warming is occuring in China contrary to the belief that aerosols can only cause cooling.

  • EliRabett // December 30, 2007 at 4:44 am

    Any idea what the response to Leif Svalgaard’s presentation at AGU was??

  • Hank Roberts // December 30, 2007 at 5:35 am

    > can only cause cooling

    Nonsense.
    Believed only by the flat earth society.

    You can look this stuff up, instead of taking canned beliefs.

    Try this start, follow the cites and related documents forward in time from this one, for example.

    http://www.sciencemag.org/cgi/content/abstract/294/5549/2119

    You don’t have to believe.
    You can read instead.
    It’s good for you.
    Try it.

  • fred // December 30, 2007 at 7:31 am

    I am relying for understanding of the PC/BCP issue on the papers of McIntyre and McKittrick, which can be found on CA, and in particular, for a non-technical explanation, on McKittrick’s paper in APEC Study Group, Australia April 4, 2005.

    Please refrain in this context from immediately explaining to me how McKittrick is in the pay of X Y Z and is also a thoroughly nasty man. I am not interested.

    Next, for an independent validation of this, I rely on Wegman, the report and the reply to Stupak, and in particular the remarks on Wahl and Amman in the reply to Stupak. As to North, I note that there is said by North and Wegman to be agreement between them.

    Now, to the point. I think you are claiming that someone, somewhere, has done a study that does not use decentered PCA (perhaps even does not use PCAat all), and does not use BCP proxies, and that this study shows the characteristic hockey stick of roughly the same shape and dimensions as MBH98.

    I read the links you offer me, and have not found a link to a study which does this. A simple note of the name and date and publication will do. I have seen studies which do not use PCA and BCP. Moberg in particular. I do not see the characteristic Hockey Stick in them.

    However, here is another way of looking at it. Will you accept a study which I will do, under the following conditions. First, I get to select the interval whose mean I use when doing PCA, and which will not be the mean of the whole series. Second, I don’t have to reveal my algorithm. Third, I am allowed to use proxies which are generally agreed by specialists not to measure temperature. Fourth, I get to add back in lower order principal components in the manner done by Wahl and Amman.

    Be careful what you wish for. I could end up proving some very strange things.

  • Hank Roberts // December 30, 2007 at 2:45 pm

    Historical re-enactment is valid recreation but not useful science, and staying fixed on 1988 puts you in a very small group of people who turn only in one direction. Consider if it’s truly the best use of your time here on Earth. It’s not mine to do much more, now that you’re clear you’re mining your info from the few people really stuck on what North and Wegman and others have advised them to let go.

    North’s reply to McIntyre on the exact question you repeat, Fred, is clear:

    “Gerald North:
    This is a difficult question (you always pose difficult questions!). My own view (not necessarily the committee’s) is that the verification period is misleading. I do not think there is enough data in that period to really nail down the matter. There are also the questions about using the mean (low frequency) versus the variations (higher frequency) parts in the verification procedure. Personally, I like the way Mann did it better than the others, because it is the long term stuff we want to check on. But this is a personal opinion. The fact is, there is no one way to do this — especially when we have so little data. That is why the committee was reluctant to put error bars on the early part of the record (or even the late part).”

    Focus on this, it’s what McIntyre never has understood, and why he’s still standing in 1988 waving his army and telling the climate science field they’re all wrong. But he’s alone there, as a scientist, focused on how to make the past over. It’s never going to work.

    “The fact is, there is no one way to do this — especially when we have so little data.” — Gerald North

    ” The Mann et al., results were not ‘wrong’ and the science was not ‘bad’. They simply made choices in their analysis which were not precisely the ones we (in hindsight) might have made. It turns out that their choices led them to essentially the right answer (at least as compared with later studies which used perhaps better choices).” — Gerald North

    “As we said in our report, ‘In a real sense the paleoclimate results of MBH98/99 are essentially irrelevant to the consensus on climate change. The instrumented temperature record since 1850 clearly indicates an increase in temperature.’ We certainly agree that modern global warming is real. We have never disputed this point. We think it is time to put the ‘hockey stick’ controversy behind us and move on.” — G. Wegman

    I’m done. Good luck with it.

  • JamesG // December 30, 2007 at 5:14 pm

    Hank
    If the IPCC would drop the MBH98/99 graph then it would be possible for everyone to “move on”. However it’s still there. In France, in fact, it is exclusively used (even spliced onto the instrument record) by the GIEC (IPCC) to “prove” in FAQ’s that recent warming is unprecedented - specifically to discredit the skeptic arguments. I’m sure you’d agree with me that ignoring all the other reconstructions in this way is plain dishonesty. So tell the IPCC they are stuck in the past, not McIntyre! Clearly Wegman has since changed his mind about “modern global warming” anyway since he signed Bob Carter’s letter saying the globe has stopped warming up.

    Tamino
    Of course if you use a spline fit and make the end gradient flat - it fits the temperature data perfectly, and shows temperature “plateauing”. Or you can easily present two flat lines with a significant temperature shift around 1998 - based on the satellite data. So the way you present the graph depends entirely on your prior assumptions, ie bias. In fact if you are stuck on straight lines you could also show the sunspot increase since 1850 as showing enough of a linear trend to be a good alternative theory for warming. (see NASA observatory FAQ for these graphs). That’s stats for you: You can prove anything depending on your prior assumptions about the end points and the smoothing. And it’s very convenient to say the bits that don’t fit are “noise”. I’ve seen this type of argument a lot.

    [Response: What a crock! Of course if you include a ridiculously large number of degrees of freedom in your model you can fit the data perfectly. All you'll have done is comit the cardinal sin of overfitting; I see that kind of crap argument a lot.

    The data clearly show that the model with the fewest degrees of freedom which is statistically significant is a linear fit, and the addition of further degrees of freedom gives no statistically significant improvement in the fit. So any OTHER model is an example of bias, which is exactly what you are guilty of.]

  • Ian Forrester // December 30, 2007 at 5:59 pm

    Fred said: “I am relying for understanding of the PC/BCP issue on the papers of McIntyre and McKittrick, which can be found on CA”.

    Are we to assume that when you need to get information concerning the lump in your neck (or elsewhere) you get advice from your local plumber?

    here is a very good quote from the North report:

    “However, the higher-variance variables tend to make correspondingly higher contributions to the principal components, so the decision whether to equalize variances or not should be based on the scientific considerations of the climate information represented in each of the proxies”.

    What this says is that to properly chose a statistical method one has to understand the underlying science, some thing that M, M and W are completely ignorant of.

    Here is another quote from the North report which shows that you have not read it (perhaps only the cherry picked sentences from CA?):

    “As part of their statistical methods, Mann et al. used a type of principal component analysis that tends to bias the shape of the reconstructions. A description of this effect is given in Chapter 9. In practice, this method, though not recommended, does not appear to unduly influence reconstructions of hemispheric mean temperature; reconstructions performed without using principal component analysis are qualitatively similar to the original curves presented by Mann et al. (Crowley and Lowery 2000, Huybers 2005, D’Arrigo et al. 2006, Hegerl et al. 2006, Wahl and Ammann in press)”.

  • nanny_govt_sucks // December 30, 2007 at 7:33 pm

    > can only cause cooling

    Nonsense.

    I agree, but it is consistently “aerosols” that are blamed for mid-century cooling regardless of the apparent absence of an aerosol cooling effect in China over the last 20 years or so.

  • Hank Roberts // December 30, 2007 at 8:36 pm

    And, you may ask, is there any known difference in behavior of emissions, comparing mid-20th century coal plants in the USA, and turn-of-the-century coal plants in India and China?

    And, if you do ask, you may be glad you did, because indeed there are several known differences, observed and modeled, and you can view the territory instead of some old map, so to speak, and know what’s where.

    One difference, of course, is the obvious — in the mid-2oth century, the background level of CO2 was still close to the baseline. The second _half_ of the fossil fuel burned was burned since 1970. The first half was burned between 1970 and the end of the last ice age. (We’re working on the ‘third’ half now.)

    So, that’s easy to understand. Small increase in CO2, which acts over decades and centuries to increase warming. Huge increase in sulfates, which act over days and weeks.

    Now, the next part depends on realizing the planet is a sphere — seriously!

    Photochemistry. Emissions in middle latitudes receive considerably less sunlight. You’ll recall this from the discussions of farming, as you go farther from the equator, sunlight is spread out more.

    So we have China’s emissions, at the turn of the century, happening against the background of all the fossil fuel burned — both the half before 1970 and the half since. The background effect of the CO2 is well established and warming is progressing, unlike the mid-century situation.

    And was there a Clean Air Act in China requiring tall smokestacks and emission at high speed and height to get the pollution away from the plants? Why, no, there wasn’t, so it’s happening much closer to the ground.

    And — latitude. On the spherical planet, China’s emissions are closer to the equator, in more intense sunlight.

    And you know how to look up aerosol photochemistry, so don’t take my word that it’s a different chemistry problem happening now. Read about it.

    Always nice to help you update the rhetorical questions. I’ve done this one with you three or four times at several different sites. I hope the explanations are getting clearer.

  • JesusChristHimself // December 30, 2007 at 8:42 pm

    CO2 is much higher now; China did not exceed the USA rate that existed before environmental controls were instituted until just recently.

  • cce // December 30, 2007 at 8:52 pm

    The cooling trend over the NH began around 1940 and ended in the ’70s, when CO2 concentration (and that of other GHGs) was lower .

  • Hank Roberts // December 30, 2007 at 9:13 pm

    >Bob Carter, Wegman
    Yep.

    Was he under oath, at the hearings? I forget.

    http://scienceblogs.com/deltoid/2007/12/a_picture_is_worth_a_thousand_2.php

  • Hank Roberts // December 30, 2007 at 10:52 pm

    Fred, how about citing _exactly_ to your source?

    I tried.

    I’m guessing you may have gotten what you believe from the four supposed quotations at the top of this thread, or from one of the very many places Google finds them repeated unskeptically:

    http://www.climateaudit.org/?p=756

    They are all lies.

    Read down into the discussion, or take the words in quotation marks, attributed to Wegmant, and actually search on them.

    _They_are_lies_.

    You can’t trust some sources. You have to take everything skeptically, and actually check.

    In this case, that page is what I found on trying to figure out where, exactly, in that site you were getting what you believe.

    If you have another source, please cite to it. Precisely. With a link or reference. So I can check it.

    So_you_ can check it.

    Don’t trust. Verify.

    Once a site’s known to maintain false claims, verify several times elsewhere, and check the originals, not secondary sources.

    So much of what people read is just repeated copies, but if you trace them back, you can find out if they’re lies.

    Those four statements there are lies.

    And they pop up in searches on Google, on the first page — so they’re looked for often in the searches.

    They could have been corrected right there, so people finding them wouldn’t be at the risk of believing them.

    They could have been explained, if there were an explanation. Isn’t one.

    Okay? This is why people worry about the sources for what you believe.

    Experience, trying to verify such stuff.

  • nanny_govt_sucks // December 30, 2007 at 11:01 pm

    Hank, I’m not really seeing that big of a difference in latitude between the US and areas of the most warming in China. If you look at fig d. :

    http://www.grida.no/climate/ipcc_tar/wg1/fig2-9.htm

    … you’ll see that the areas of China that have warmed the most are at about the same latitude as the USA.

    But didn’t you agree with me earlier that aerosols don’t always cause cooling? What happened? I’m sure you know about the brown clouds over Asia that have been implicated in warming:

    http://environment.newscientist.com/article/mg19526154.300.html

    “”We found that the brown cloud (produced by wood and coal fires, and car exhaust) enhanced lower atmospheric solar heating by around 50 per cent,” says Ramanathan, whose results are published in Nature (DOI: 10.1038/nature06019). ”

    And warming is indeed what we see over Asia.

  • Heretic // December 31, 2007 at 1:25 am

    NGS, isn’ t it possible that aerosols will have different effects, depending on the chemical composition, altitude etc…?

  • Hank Roberts // December 31, 2007 at 2:31 am

    > not that big a difference

    What map or list are you looking at, that you don’t see that much difference between the latitudes of the old coal cities and the new ones?

    They barely overlap at all.

    Not much difference? In latitude? What cities are you looking at? I think it’s safe to assume most of the coal is burned near the major cities.

    This is why they’re describing different photochemistry — emissions at lower latitude nowadays, closer to the equator, sun’s higher in the sky.

    City Latitude deg/min
    Beijing, China 39 55
    Bombay, India 19 0
    Calcutta, India 22 34
    Chongqing, China 29 46
    Hong Kong, China 22 20
    Mexico City, Mexico 19 26
    Shanghai, China 31 10

    Atlanta, Ga. 33 45
    Fort Worth, Tex. 32 43
    Los Angeles, Calif. 34 3
    Indianapolis, Ind. 39 46
    Bristol, England 51 28
    Chicago, Ill. 41 50
    Edinburgh, Scot. 55 55
    London, England 51 32
    Venice, Italy 45 26
    Buffalo, N.Y. 42 55
    Detroit, Mich. 42 20
    New York, N.Y. 40 47
    Richmond, Va. 37 33
    Chicago, Ill. 41 50

  • nanny_govt_sucks // December 31, 2007 at 6:28 am

    NGS, isn’ t it possible that aerosols will have different effects, depending on the chemical composition, altitude etc…?

    Certainly. So why is it always assumed by AGW credulists that aerosols cause cooling?

    What map or list are you looking at, that you don’t see that much difference between the latitudes of the old coal cities and the new ones?

    I never mentioned “coal cities”. Look at where the aerosols ARE (see http://www.grida.no/climate/ipcc_tar/wg1/fig5-2.htm) and look at where the warming IS: (see fig. d: http://www.grida.no/climate/ipcc_tar/wg1/fig2-9.htm)

    The most warming in Asia is found in Northern China (and Siberia - different issue) which is around the same latitude as the USA.

    With regard to your photochemical argument, are you saying that aerosols nearer to the equator will have LESS cooling properties? If so, then Southern China should show MORE warming than Northern China. But it does not. See fig d. above.

  • fred // December 31, 2007 at 7:57 am

    It is really not very helpful to speculate on where I got my material from. Its either right or wrong. The first time I saw those quotes, if that is what they are, was on following your link.

    Anyway, here is a source for the assertion made in the first one, Wegman p 4: (I hope Tamino will be patient with this extended quoting).

    “The controversy of Mann’s methods lies in that the proxies are centered on the mean of the period 1902-1995, rather than on the whole time period. This mean is, thus, actually decentered low, which will cause it to exhibit a larger variance, giving it preference for being selected as the first principal component. The net effect of this decentering using the proxy data in MBH98 and MBH99 is to produce a “hockey stick” shape. Centering the mean is a critical factor in using the principal component methodology properly. It is not clear that Mann and associates realized the error in their methodology at the time of publication. Because of the lack of full documentation of their data and computer code, we have not been able to reproduce their research. We did, however, successfully recapture similar results to those of MM. This recreation supports the critique of the MBH98 methods, as the offset of the mean value creates an artificially large deviation from the desired mean value of zero.”

    Its not what was implied in your ref to be quoted, which is not my present subject. But this is my source for thinking that Mann’s methods have been confirmed by Wegman to preferentially produce hockey sticks.

    The HS debate matters for two reasons. One is that it is not a key ingredient in the argument for AGW today. So it is a touchstone. If the AGW advocates cannot bring themselves to abandon studies which are not vital to their central argument, and also are discredited, that tells us a great deal about the movement. MBH98 seems to have become part of the canon. I don’t see why, you don’t need it, and the fact that it has does matter.

    The second reason is if there have been episodes of warming similar to today’s in the past but not caused by CO2, that shows warming can happen without it. It does not show todays *is* happening without it, it does not show CO2 does not have the effects which AGW asserts, but it does destroy the argument from necessity - the line that goes, CO2 is the only thing that could explain it. If it did happen before without CO2 rises, this argument goes.

    I don’t any longer think the loss of this argument is particularly critical to the case, which makes it even more puzzling that people hang onto the HS.

  • fred // December 31, 2007 at 8:52 am

    The first post was my source for believing Wegman endorses M&M’s claim that decentering selectively produces hockey sticks.

    This note goes to the evidence that decentering actually does that. On p 32 of Wegman, there are two charts. One is with centered and one with decentered PCA. One shows a HS, the other doesn’t.

    Based on M&M’s papers, and this replication of their work by Wegman, I believe that decentered PCA as done by Mann and co will produce HSs where there are none in the original series. Now, I haven’t done the work with R myself, having work to do and water vapor and the troposphere to investigate also….

    But this is about standards for belief. If two sets of people, one a national stats expert in Congressional committee mode, agree on the result of a statistical procedure, and their account makes sense, I don’t really see I need to replicate it to believe them. The error is not terribly difficult to see once pointed out. I don’t suppose anyone on this board has replicated it either.

    The point seems to have been confirmed on p33 of Wegman where the original multi charts of M&M are reproduced with the comment that they are compelling. These charts appeared to show HSs produced from trendless data series by use of decentering. I take this use of ‘compelling’ to be endorsement.

    HankR, I think your constant injunctions to verify are somewhat partial. Why are you not urging us to get Mann’s code and verify it?

  • fred // December 31, 2007 at 9:17 am

    “What are the principal scientific criticisms of their work and how significant are they?
    Ans: Our perception is that principal components (statistical) analysis was used incorrectly and, based on this, unsupportable inferences were drawn about the current magnitude of global warming relative to the historical past. We hasten to repeat that the Earth is getting warmer. What does not appear to be true is that the process mechanism is as well understood as some scholars would have us believe. In addition the use of some proxies does not appear to be as carefully managed as we might like.
    Has the information needed to replicate their work been available?
    Ans: In our opinion, the answer is no. As mentioned earlier, there were gaps in MBH98.

    ___________________________

    Wegman p 66. Hank, do you apply the same reasoning to the unreproducible results in MBH? Should we draw the same conclusions and distrust the authors from here on in?

  • Barton Paul Levenson // December 31, 2007 at 11:53 am

    fred writes:

    [[I am relying for understanding of the PC/BCP issue on the papers of McIntyre and McKittrick]]

    Well, that pretty much says it all.

  • Barton Paul Levenson // December 31, 2007 at 11:57 am

    nanny writes:

    [[I agree, but it is consistently “aerosols” that are blamed for mid-century cooling regardless of the apparent absence of an aerosol cooling effect in China over the last 20 years or so.]]

    To oversimplify greatly: Aerosols high up cool, aerosols low down warm. Light-colored aerosols cool, dark aerosols warm. Can you think of a way the Asian brown smog differs from the industrial smoke of the 1940s?

  • Barton Paul Levenson // December 31, 2007 at 1:51 pm

    nanny writes, in his typical, endearing manner:

    [[Certainly. So why is it always assumed by AGW credulists that aerosols cause cooling?]]

    Aerosols have different effects depending on altitude, latitude of emission, the absorption and scattering coefficients of the particles making them up, and the size distribution of the said particles. The aerosols emitted by industry, mostly in the US, Europe and USSR, from 1940 to 1970, had the overall effect of cooling. Not all aerosols do (see above).

  • Barton Paul Levenson // December 31, 2007 at 2:44 pm

    fred posts:

    [[The second reason is if there have been episodes of warming similar to today’s in the past but not caused by CO2, that shows warming can happen without it.]]

    No kidding. Was anybody disputing that?

    [[ It does not show todays *is* happening without it, it does not show CO2 does not have the effects which AGW asserts, but it does destroy the argument from necessity - the line that goes, CO2 is the only thing that could explain it. If it did happen before without CO2 rises, this argument goes.]]

    Adding in ALL known factors, you can’t explain the recent warming without taking account of CO2. The idea that climate modelers are ignoring everything else in a mad rush to pin the blame on carbon dioxide is a caricature at best, character assassination at worst.

  • Dean P // December 31, 2007 at 3:26 pm

    BPL,

    You emphasized the wrong word… you should have written it like this:

    Adding in all KNOWN factors, you can’t explain the recent warming without taking account of CO2.

    The issue is whether we know enough to be certain. M&M (despite the desires of several here) have shown that there are significant statistical issues with the hockey stick. These issues have been replicated by others. That people here don’t like it is immaterial.

    We have assumptions on solar output, on thermal inertia, on circulatory patterns, etc… Many of these are based upon the underlying science, but just how well they replicate the real world is up to debate.

    And using incorrect statistical methodologies do NOT prove the science, no matter what anyone says.

  • Hank Roberts // December 31, 2007 at 4:25 pm

    Photochemical Researches.–Part IV. [Abstract]
    Robert W. Bunsen, Henry Enfield Roscoe
    Proceedings of the Royal Society of London, Vol. 10, 1859 - 1860 (1859 - 1860), pp. 39-49
    http://links.jstor.org/sici?sici=0370-1662%281859%2F1860%2910%3C39%3APRI%5B%3E2.0.CO%3B2-F&size=LARGE&origin=JSTOR-enlargePage
    http://www.jstor.org/jstor/gifcvtdir/ar000614/03701662/ap000004/00a00180_l.1.gif?config=jstor&K=user@user_response/81mAWqQEBn5p441y40/40/4kkrEIc0/303701662.ap000004.00a00180.0/28OQWDGUb.xcgro8DmzusW

  • nanny_govt_sucks // December 31, 2007 at 6:31 pm

    Hank, BPL, enough with the hand waving. Why did aerosols supposedly cool parts of the globe from 1940-1975 but apparently warm parts of the globe from around 1980 onwards? Why does Northern China (which is about the same latitude as the USA) show more warming than Southern China over the last 20 years or so if aerosols at USA-latitude are supposed to cause cooling? Specific s please.

  • Heretic // December 31, 2007 at 7:21 pm

    What I meant was that aerosols in the stratosphere (where volcanic events send them) likely will do something different than aerosols in the troposphere, released close to the ground. Of course, those travel and they may end up doing different things at different times of their lives. Just thniking. Perhaps this is more complex than it seems. And, ngs, consdering what little you think of AGW “credulists” I wonder why you pay any attention to what they say. There is plenty of science out there that you can look into, isn’t there?

  • Barton Paul Levenson // December 31, 2007 at 8:09 pm

    Dean P writes:

    [[M&M (despite the desires of several here) have shown that there are significant statistical issues with the hockey stick. These issues have been replicated by others. That people here don’t like it is immaterial. ]]

    You forgot to say “Nyah-nyah-na-nyah-nyah!”

    M&M found minor errors in an essentially sound paper. 14 other studies since then have essentially replicated that paper’s findings. The goal was to knock out global warming; M&M haven’t done that.

    [[We have assumptions on solar output, on thermal inertia, on circulatory patterns, etc… Many of these are based upon the underlying science, but just how well they replicate the real world is up to debate. ]]

    They replicate it well enough to make some decisions.

    [[And using incorrect statistical methodologies do NOT prove the science, no matter what anyone says.]]

    You are misapplying a binary choice between correct and incorrect. Most real-world scientific studies are somewhere in between. When people thought the world was flat, they were wrong. When they thought it was a sphere, they were still wrong. But if you think they were both equally wrong, you’re wronger than both of them. [Paraphrase of a passage from an Asimov essay.]

  • nanny_govt_sucks // December 31, 2007 at 10:15 pm

    And, ngs, consdering what little you think of AGW “credulists” I wonder why you pay any attention to what they say.

    Wow. Are you kidding me? AGW credulists are trying to change the very way we live, and alter economies around the world sending millions below the poverty line, and keeping milliions more from ever having a chance to rise above it. Before this happens, I believe that the credulist arguments should be subjected to a fine degree of scrutiny.

  • nanny_govt_sucks // December 31, 2007 at 10:40 pm

    What I meant was that aerosols in the stratosphere (where volcanic events send them) likely will do something different than aerosols in the troposphere, released close to the ground.

    I agree, and a global cooling effect from volcanic aerosols is apparent in the temperature data. But we’re not talking about volcanic aerosols when it comes to the subject of mid-century cooling and the dubious climate effect of aerosols over China in the last 20 years or so.

  • tamino // January 1, 2008 at 12:06 am

    I surveyed some stations from China, and found an average warming rate there about 0.033 deg.C/yr. But the world-wide rate for northern-hemisphere land stations in the same latitude band (from NASA GISS) is 0.036 deg.C/yr. From this data, there doesn’t appear to be any warming trend in China above that which the rest of the world is experiencing — in fact it appears to be warming a little more slowly, although the difference is not statistically significant.

  • dhogaza // January 1, 2008 at 9:16 am

    M&M found minor errors in an essentially sound paper. 14 other studies since then have essentially replicated that paper’s findings.

    BPL, really, we must give up on these people. They believe what they want to believe, and no amount of science will dissuade them.

    It’s no different than those that believe that Dembski has proven mathematically that evolution can’t account for the observed complexity of life on earth. It doesn’t matter that the very creator of the No Free Lunch theorem he misapplies has said “Dembski doesn’t understand my work”. Nor that other mathematicians guffaw at the misapplication of NFL. The believers believe. They only read what they want to believe and ignore rebuttals, no matter how sound.

    Same is true with M&M.

    And then we have crappola like this from NGS:

    AGW credulists are trying to change the very way we live

    True.

    …and alter economies around the world sending millions below the poverty line

    false

    …and keeping milliions more from ever having a chance to rise above it.

    I have to wonder, though, why you think “changing the way we live” is such a bad idea. How strongly do you resist change? Are you sorry that we developed stone age technology? Bronze? Iron? Modern transporation? Computers?

    Our way of life changes constantly, some benefit, some suffer in the short-term, but long-term, I believe humankind at large benefits.

    What is it about improved energy technology that you find so distasteful?

  • cce // January 1, 2008 at 9:32 am

    I have a suggestion for anyone who are still obsessing over the Hockey Stick.

    Listen to the NAS press conference. Listen to what they say, and tune out the noise:
    http://video.nationalacademies.org/ramgen/news/isbn/0309102561.rm

    And if we return to the topic at hand for a moment, this thread concerns the claim that “global warming stopped in 1998,” a belief that both McKitrick and Wegman endorse. Now, if the auditors were so concerned with rigorous standards, they should turn their attention to an absurd pronouncement such as that, which is a thousand times more incompetent than anything in the MBH paper.

  • fred // January 1, 2008 at 9:35 am

    BPL, no, that my first source was M&M, and that I then relied on Wegman in the quotes cited to have independently confirmed the criticisms proves nothing. What matters is are they right or not.

    Too many people on this forum spend too much time worrying about what started us thinking something. They also spend too much time dismissing arguments because of who made them. They’d do a lot better to focus on whether what we think is correct and whether the arguments are valid.

    Now, you say that the MBH papers, and I think you’re saying the methods too, were right in essentials.

    Simple question then: is decentered PCA as used by MBH a legitimate and trustworthy statistical technique? Wegman says it is not. Is he wrong? Or, maybe I got Wegman wrong, maybe he is saying that it is correct?

    And, in keeping with the spirit of Hank R (who seems to look over my shoulder now all the time as I write!) - lets see a reference from some statistics guy showing that it is, and why. If Wegman says its all right, lets see a quote.

    Its not, you know, one law for me when I think something, and another for the rest. You want me to go to rigorous standards of citation and verification, fine, go there with me.

  • Barton Paul Levenson // January 1, 2008 at 12:32 pm

    nanny writes:

    [[AGW credulists are trying to change the very way we live, and alter economies around the world sending millions below the poverty line, and keeping milliions more from ever having a chance to rise above it. ]]

    You’re right, Nanny. It’s a plot, and everyone on this blog but you is in on it. Soon we’ll be sending the Men In Black after you. Then you’ll be sorry!

  • JesusChristHimself // January 1, 2008 at 3:09 pm

    The fact is the quality of life, at the turn of the 19th century, wasn’t all that bad. They lived in mansions; they had fabulous wealth; they had the finest things.

    Modern medicine and modern plumbing aren’t going to go away in an AGW-mitigated world. It’s not going to hurt 1/10th as bad as NGS thunks.

  • dhogaza // January 1, 2008 at 3:45 pm

    BPL, no, that my first source was M&M, and that I then relied on Wegman in the quotes cited to have independently confirmed the criticisms proves nothing. What matters is are they right or not.

    They also spend too much time dismissing arguments because of who made them.

    And you spend too little time (zero, AFAICT), looking into the rebuttals of those arguments by climate science professionals.

    You take them as gospel, unskeptically, from all appearances.

    You could, for instance, read this, and tell us exactly how Von Storch goofed when he looked into Wegman’s claims.

  • ChrisC // January 2, 2008 at 6:47 am

    Fred,

    Before I answer your stats questions, have a look at the raw calibrated MBH1998 data on RC :

    http://www.realclimate.org/FalseClaimsMcIntyreMcKitrick_html_7955bc86.png

    This is the proxy data that has been calibrated, but from which no PCA analysis has been conducted.

    As for PCA (and its cousin singular value decomposition) are pretty standard statistical methods, used in all sorts of applications (I used PCA to build a statistical “model” of aircraft motion back when I was an undergrad). Like any statistical method, it has its strengths and weaknesses. Have a look at:

    http://en.wikipedia.org/wiki/Principal_component_analysis#Properties_and_Limitations_of_PCA

    If you’ve got some time, I recommend this tutorial, which is a less technical explanation:
    http://www.umetrics.com/default.asp/pagename/methods_MVA_intro/c/1

    You’ll find PCA and SVD in most advanced level stats text books. Popular software packages like MATLAB/OCTAVE, STATSOFT, S-PLUS and R have routines for PCA built in. In short, PCA is a standard technique, and is probably used the most in pattern recognition.

    This doesn’t mean that it is error free and it certainly can be performed incorrectly. But when used properly it can be very useful, and its popularity in the scientific comunity.

    My reaction to the M&M paper was not that they thought that that PCA itself was bad. It was that they thought that components were incorrectly selected. In the 10 years since that paper has written, further work (such as Wahl and Amman (2006, the NRC panel and others) have shown the M&M critique to be far less important than its author’s state.

  • JamesG // January 2, 2008 at 6:19 pm

    Tamino
    You must be the first person to argue that a spline fit is “overfitting”. Usually when a straight line doesn’t fit, a spline is the next obvious choice - especially when that non-fitting part is at the end of the series and especially in a non-linear system. But fine, stick with those linear fits, and if you get a chance maybe you can check out that sunspot plot at the NASA site with your linear regression. If I was to produce a linear fit from say the year 1900, and of course the last 20 years were a wee bit low, how would you react if I said, “well clearly that’s just noise”? Thought so! But it’s exactly the same argument as you are pushing.

    [Response: I see you've decided to donate another crock of ****. For the temperature data from 1975 to the present, it's not possible to establish any more degrees of freedom with statistical signficance than a linear fit. So including more -- such as with a spline fit -- is overfitting, i.e., including more degrees of freedom than are justified by the data; the wiggles you get from a spline fit are simply not justified, except of course by your desire to replace what the data say with what you want to hear. The "argument," which it seems you really don't get, is that statistical significance tests pass a linear fit and NO MORE degrees of freedom, however strongly you wish to insert them so as to make it look like global warming stopped in 1998. And in fact the residuals from the linear fit 1975-present are, on average, ABOVE zero not below -- although the difference is not statistically signficant.

    As for a linear fit from 1900 to the present, it's trivially easy to establish that including further degrees of freedom passes statistical significance tests. So again, YOUR argument that the rest is just "noise" is a crock.

    It's almost always possible to choose enough degrees of freedom of the right kind to make the "fit" look like what you want it to. Without statistical justification it's just personal bias at work. If you really don't get this, then frankly there's no hope for you.]

    Hank
    Perhaps Wegman just changed his mind after further consideration. People do that you know! It doesn’t make him a liar. I’m sure many on that list have changed their minds after an apparent downturn in the temperature trend. Anyway if you want to polarize conservatives as intrinsically evil then you’re losing 50% of the voting public. You need to take Michael Moore’s advice - tell them how it’s going to make them money.

    Of course it might be quite nice to live like the Amish. Has anyone tried it? Is anyone going to? Or is this just another bunch of glaring hypocrisy? Pretending to be more moral than the rest of us doesn’t cut the mustard, you have to actually do something!

  • Hank Roberts // January 2, 2008 at 7:23 pm

    Yes, those are feedback problems too.

  • dhogaza // January 2, 2008 at 8:32 pm

    Perhaps Wegman just changed his mind after further consideration. People do that you know! It doesn’t make him a liar.

    However, it does call into question his vaunted expertise as a statistician, or at least his objectivity in applying that objectivity to the issue of global warming.

    Because no statistician is being honest if they sign a statement claiming that “global warming stopped in 1998″. Which he just did.

    Of course it might be quite nice to live like the Amish. Has anyone tried it? Is anyone going to? Or is this just another bunch of glaring hypocrisy?

    Of course if policy makers were arguing that we need to live like the Amish in order to solve the problem, you might have a point.

    But of course nothing like that is necessary, which means you’ve raised and demolished a strawman.

    Tch, tch, as they say.

  • dhogaza // January 2, 2008 at 8:33 pm

    …”in applying that expertise”, sigh. Shouldn’t post while watching news video of that volcano going off in Chile …

  • JesusChristHimself // January 2, 2008 at 11:24 pm

    Well, you had a lava on your mind.

    I’m reading a history of ExxonMobil. At the turn of the 19th century the Amish-like Exxonites were shipping large quantities of product all over the world in these really cool tankers that were powered by sail power. There were no automobiles, and yet, they were a fully globalized company. They had mansions and servants and wore fancy suits to work and went to clubs and just generally appear to have had a filthy rich lifestyle.

  • luminous beauty // January 3, 2008 at 4:03 am

    I’d like to point out that the Amish have quite successfully tried to live like the Amish, and to all appearances, seem determined to continue to try to live like the Amish.

  • JamesG // January 3, 2008 at 4:27 pm

    LB/dhogaza
    I’m not knocking the Amish at all. But if any of you guys believe in the CO2 cuts in the open letter signed in Bali by those 200 scientists then you must believe we all have to go back to that lifestyle. If we stop building coal plants as Hansen wants and we cut back on fuel to the extent necessary, I don’t see an immediate alternative. Incidentally I have managed to live without using a car for much of the last 8 years. You should try it! This issue has, after all, been current for the last 25 years - have any of you actually tried to become more carbon free in that time, or are you still waiting for those mandated carbon taxes?

    dhogaza
    I like that comment about Wegman’s objectivity. What about Mann’s objectivity? It’s either tit for tat or stick strictly to the maths. It’s indeed very possible that studying the stats in Mann’s work was enough to make him more skeptical.

    Tamino
    I see your new year resolution was to be less polite. A shame. In fact, a cubic spline fit would have only one wiggle and cubic spline fits are far more common than linear, statistical significance or not, because not much in life, unfortunately, is linear. Your analysis is no less biased than mine, because you know a cubic spline fit would actually increase the statistical significance. The other linear fit I was talking about was with the sunspot data from 1900 - did you notice - and yes, using your own criteria - probably a linear fit would be statistically significant. Which means, if you are being consistent, then you should agree that the rise in sunspots from 1900 is a valid alternative theory for the warming.

    [Response: One of my resolutions, made long before New Year's, is not to bend over for fools. Your statement that "a cubic spline fit would actually increase the statistical significance" removes all doubt that you belong in that category. If you fit a cubic spline to random noise, you get wiggles -- and every one of them is just as meaningless as your entire line of argument.]

  • dhogaza // January 3, 2008 at 5:57 pm

    I like that comment about Wegman’s objectivity. What about Mann’s objectivity? It’s either tit for tat or stick strictly to the maths.

    Let’s see …

    The statement that “global warming stopped in 1998″ is incorrect. Simple trend analysis shows it is incorrect. Wegman is a statistician, and either 1) knows it is incorrect or 2) signed the statement without paying attention.

    And you compare this to Mann’s using a standard statistical technique in a way that “isn’t recommended but doesn’t materially affect the result”?

    Really?

    It’s indeed very possible that studying the stats in Mann’s work was enough to make him more skeptical.

    Doesn’t excuse him for signing a statement that contains a falsehood like “global warming stopped in 1998″.

  • Barton Paul Levenson // January 3, 2008 at 6:07 pm

    JamesG posts:

    [[I’m not knocking the Amish at all. But if any of you guys believe in the CO2 cuts in the open letter signed in Bali by those 200 scientists then you must believe we all have to go back to that lifestyle. ]]

    Non sequitur. I think we can manage the transition by a massive switch to renewable energy sources. Lifestyle adjustment would be minimal. No need to go to an Amish lifestyle.

  • Hank Roberts // January 3, 2008 at 7:47 pm

    Global warming is slow.
    Ocean chemistry is changing fast.
    End of this century, predictable disaster
    Nobody’s arguing this isn’t happening.
    And it’s caused by excess CO2.

    If you forget completely about warming, you still ought to know enough basic chemistry –ever do a titration? — to understand why increasing CO2 is changing the oceans beyond safe limits.

    This has become my ‘litmus test’ for whether people have any science at all, or are just flogging political opinions.

  • EliRabett // January 4, 2008 at 3:33 am

    Simon Donner has an elevator graphic

    [Response: And Eli has a pretty good elevator speech!]

  • luminous beauty // January 4, 2008 at 4:54 pm

    JamesG,

    My personal lifestyle would make the typical Amish look positively extravagant. Though I try to live by the Friend’s motto of “live simply, that others may simply live”, I do not believe in forcing my personal ethical and moral standards on others, but I will do what I can to persuade them to live up to their own. I am a pacifist, but not a passivist.

    The ‘back to the stone age’ meme is another in the denialist arsenal of strawmen and red herrings.

    The potential of enhanced geothermal energy alone is capable of supplying multiple times the world’s energy needs from now until the sun turns into a red giant.

    No new technologies needed, just a concerted effort of implementation.

  • Nelson // January 5, 2008 at 2:32 am

    This might be a late entrant to the thread, but hopefully it’s of some interest to someone and perhaps I might learn a little.

    One story recently circulating in the blogosphere was an article in New Statesman, in which the author confidently states that global warming has stopped:

    http://www.newstatesman.com/200712190004

    I linked to this post to show that trend analysis is more complex than eyeballing data and that noise can obscure a warming trend, all of which was beautifully explained by tamino. This site is one of those precious reserves on the web.

    Anyway, another poster linked to me his fit of some temperature data:

    http://preview.tinyurl.com/396alz

    My instinct tells me the data set is inadequate and the fit arbitrary - it looks like statistical butchery. But can someone more qualified explain exactly why?

  • Barton Paul Levenson // January 5, 2008 at 2:27 pm

    Nelson posts:

    [[My instinct tells me the data set is inadequate and the fit arbitrary - it looks like statistical butchery. But can someone more qualified explain exactly why?]]

    The guy has NO POINTS on the declining part of the graph! All he’s done is superimpose part of a quadratic on the actual points. There’s no evidence he even derived the quadratic from the points on the graph, and I’d bet almost anything he didn’t. It’s as if he graphed the upward trend, then added a line for the future which headed straight down. It’s completely bogus.

  • JamesG // January 5, 2008 at 4:16 pm

    Tamino
    I now see that you’ve never done much cubic spline fitting or you’d know you can limit the wiggles such that the data from 1975 could have just one bend. In fact I do have to separate signal from noise in Finite Element results but my criterion is accuracy. If I was to assume linear fits because a higher fit “isn’t justified” then I would be settling for poor accuracy. In fact I’ve found the best fit for accuracy is “least squares”, which probably you never use either. Linear regression is a useful tool but only if you know the underlying data is linear. Any linear trend line on curvy data is just a useful indicator, not a true “fit” at all. I urge your readers to find that out for themselves - if it doesn’t fit most people don’t force it. I’d also urge them to read the wikipedia entry on statistical significance to realize just what it means and how it can be abused. Your insults are rather childish. I was probably more annoying last year but you didn’t stoop to that level.

    [Response: I'm thoroughly familiar with cubic splines and I use least squares all the time. Statistical significance testing (have you heard of it?) shows that ANY wiggles, even just one, are not justified by the data. The wiggle is a response to the noise, not the signal; what you have done is precisely to "force it" where it doesn't fit. Perhaps you regard the cubic spline fit as statistically justifiable because you don't know the difference between white noise and red noise.

    I make my living as a mathematician, my specialty is the statistical analysis of time series. I can tell from your comments that when it comes to time series analysis, you have only enough knowledge to be dangerous. Your obstinate refusal to accdept the reality of your own ignorance about these matters shows that not only are you shooting in the dark, you're too arrogant to be in the right frame of mind actually to *learn* something from someone who know a helluva lot more about the subject than you do. Goodbye.]

    LB , BPS
    Well said. Yes probably the Amish thing was going too far. I hope one day we can concentrate on the real energy issues, which I believe even conservatives support, rather than keep discussing irrelevant wiggles on graphs - which we likely have no understanding of whatsoever.

    dhogaza
    You guys are awfully quick to say someone is lying but it is possible to have a different view of the same short dataset. We’ll see in time who is correct. It really comes down to whether you are optimistic or pessimistic. Anyway, it was “net warming” that they signed up to, ie any small rise or fall in trends is within the standard error of the measurements and of course you can get a fall or rise depending on where you start - no net warming sounds fair to many people, including many climate scientists. Wegman didn’t agree with Mann’s methods so presumably that quote isn’t his.

  • stewart // January 5, 2008 at 4:16 pm

    Nelson:
    The statistically appropriate way to analyze such data is to do a linear trend, evaluate significance, add a second-order trend and evaluate for change in significance. The graph as presented indicates the author knows the future (and yet, isn’t releasing the data, dammit!). One side of a quadratic trend is generally not distinguishable from a simple linear trend.

  • Martin // January 6, 2008 at 1:32 pm

    Tamino the graph you produced showing artificial data up to 2035 is very interesting. If I am reading correctly it appears that the first two artificial points show quite significant increases over 2007, taking 2009 to a record high. One can understand that in order to show a continuing linear trend higher points are needed quite soon in the future time series.

    [Response: Yes the first two points after 2007 in the *artificial* series show increases as 2009 is a record high. But of course these are artificial data!

    However you're correct that in order to be consistent with a continuing roughly-linear trend higher points must come, and sooner rather than later. Unfortunately "sooner" may be three or four, or even a few more, years rather than months. This makes it easy for denialists to persuade the statistically naive that global warming has reversed itself.

    There is a "prediction" from the Hadley Centre (although it's clearly speculative rather than firm) than 2008 will continue the warm-but-not-record-breaking pattern of the 2000's, but 2009 will break their 1998 record. This is based on computer models (no cringing in the peanut gallery please) which include the exchange of energy between atmosphere and ocean.]

    The Hadley Centre prediction for 2008 is that it will be the coolest year since 2000. As an expert statistician can you calculate how many years with global temperatures well below those generated by your model it would take before we can sensibly question whether the trend has changed?

    All the artificial points are above 0.5. How many years of HadCRU temperature anomaly below 0.5 would it take for you to say that something statistically significant had happened to the trend?

    [Response: The artificial data and HadCRU data are not on the same scale! The "scale" for the artifical data is set roughly to match GISS data, which are consistently about 0.1 deg.C higher than HadCRU data because they use a different reference period for computing anomalies. So, HadCRU data exceeding 0.5 is roughly equivalent to GISS data and/or the artificial data exceeding 0.6.

    The real test of whether the trend has changed is probably to transform raw temperature anomaly to residuals from the trend generated by 1975-1998 data (as was done in this graph), or maybe residuals from the trend computed from 1975-2000 data (just to use round numbers). When these residuals show a statistically significant departure from being "flat," then I'd conclude that we've departed from that trend -- which departure may be either up or down. Another good indicator is to monitor the 5-year averages; if they should go down, or even fail to rise, I'll be testing those residuals.

    And of course there are physically relevant caveats: if we have a Mt. Pinatubo-scale volcanic eruption, then temperatures *will* fall well below the present trend, but that will not be valid evidence of a cessation of global warming (although denialists will probably claim it is), and if we have a 1998-scale el Nino then temperatures *will* break the record but that will be not be valid "proof" of global warming (although some advocates will probably claim it is, to their shame).

    I haven't done any detailed calculations (that might make an interesting post), but I'd expect the record to be broken (even in HadCRU data) by 2010, and if it doesn't happen by 2013 I'll be extremely surprised. But as I say, the real litmus test would be the residuals from the present trend. As the aforelinked graph shows, so far those residuals show no sign whatsoever of departure from the extrapolated trend.]

  • ChrisC // January 6, 2008 at 11:12 pm

    Tamino,

    It’s obvious in responding to James G’s queriesthat you haven’t even thought of using a 60th degree polynomial. After all, if you have a few wiggles in the data, the best way to fit to them is just whack in the biggest, largest polynomial you canuntil the problem is overconstrained.

    If you did this, you’d prove not only are temperatures going down, but also that cosmic rays cause global warming. You and Al Gore are quite clearly trying to hide the truth with your “statistical significance” testing.

  • henry // January 7, 2008 at 2:38 pm

    [There is a “prediction” from the Hadley Centre (although it’s clearly speculative rather than firm) than 2008 will continue the warm-but-not-record-breaking pattern of the 2000’s, but 2009 will break their 1998 record. ]

    There was also a “prediction” at the beginning of ‘07 that 2007 would be the warmest ever. Didn’t come true.

    [The “scale” for the artifical data is set roughly to match GISS data, which are consistently about 0.1 deg.C higher than HadCRU data because they use a different reference period for computing anomalies. So, HadCRU data exceeding 0.5 is roughly equivalent to GISS data and/or the artificial data exceeding 0.6.]

    Can you think of any statistical reason for GISS to use an earlier reference period than HadCRU? Most sciences will create charts that use the end of the latest decade as their “end” point for their averaging period (GISS uses 1980).

    [Response: As a reference period for computing anomalies, GISS uses 1951 to 1980, HadCRU uses 1961 to 1990, and NCDC uses the 20th century. When investigating whether or not the planet is warming, it makes no difference. Choosing a different reference period changes all anomalies by the same amount, hence it has no effect whatsoever on trends or on temperature changes over time. There's no statistical reason to prefer any particular choice of reference period.]

  • henry // January 7, 2008 at 5:54 pm

    [Choosing a different reference period changes all anomalies by the same amount, hence it has no effect whatsoever on trends or on temperature changes over time. There’s no statistical reason to prefer any particular choice of reference period.]

    I understand that the TREND doesn’t change.

    But if there’s no statistical reason for using a different averaging period, it must be for visual purposes, that is, .6 over zero looks worse than .5 over zero.

    It would also change the point where the line crosses zero, thereby changing the “warming since” date.

    The expression “a picture is worth a thousand words” is real.

    I believe that more people use the GISS because it “looks” worse. I’ve even seen temp anomaly charts printed over a shaded background, with the positive portion using a deepening shade of red at the top of the chart. No statistical reason there, either.

  • Barton Paul Levenson // January 8, 2008 at 1:16 pm

    henry posts:

    [[I believe that more people use the GISS because it “looks” worse. ]]

    How about more people use the GISS because it covers the poles, whereas the CRU doesn’t?

  • henry // January 8, 2008 at 3:02 pm

    Barton Paul Levenson said:

    [[I believe that more people use the GISS because it “looks” worse. ]]

    How about more people use the GISS because it covers the poles, whereas the CRU doesn’t?

    Which comes back around to the central premise: If GISS data and processing is better, covers more of the earth’s surface, and is more accurate, why the reluctance to use a later averaging period?

    Again, the choice of averaging period only affects the APPEARANCE of the chart, not the data or trends shown.

    In Tamino’s Update #2, the two charts (GISS and HadCRU) are showing the same trends, but using different zeros; zeros that were chosen simply because of the averaging periods.

    The majority of current charts use averages based on 71 t0 2000 EXCEPT FOR the temp chart still based on 51-80.

    As Tamino said, there is no statistical reason NOT to use newer reference periods. Can you think of a legitimate reason to use older reference periods?

  • luminous beauty // January 8, 2008 at 3:27 pm

    “I’ve even seen temp anomaly charts printed over a shaded background, with the positive portion using a deepening shade of red at the top of the chart. No statistical reason there, either.”

    Of course not. The reason is to draw the viewer’s attention to the point of interest. It’s the artistic side of graphic design.

  • Martin // January 8, 2008 at 4:26 pm

    Tamino thank you for your comments on my post. I am learning a lot from this site.

    Barton Paul Levenson: I have seen it suggested (on sceptics’ websites) that GISS gets data for the whole north pole region by extrapolating from just one or two coastal weather stations what the temperature is over 1000km away. Is that correct - or is a sceptic’s version of the truth (i.e. a lie)?

    On the other hand if that criticism is basically true, and it is “dodgy” data extrapolated for the poles that is responsible for the higher GISS temperatures then that would be an argument for preferring the HadCRU results.

  • henry // January 8, 2008 at 5:29 pm

    To Tamino:

    In my previous post, after re-reading it, I realize that the improper use of quotes would make it appear that BPL made the “GISS looks worse comment”.

    For the record, that comment was mine, and BPL’s comment concerned the “GISS covers the poles”. Every thing after that is mine.

    I’m used to other blogs that have a “block quote” function, and the lines got away from me.

    Please adjust the quotes for proper attribution.

    Thank you.

  • JesusChristHimself // January 8, 2008 at 5:46 pm

    Why does CRU not cover the poles? What’s up with that?

  • P. Lewis // January 8, 2008 at 7:17 pm

    Tamino

    Argh! It worked in preview mode on another site. Please delete my previous message (7:16 GMT), or amend it.

    [Response: There didn't seem to be anything to amend. I think you'll just need to re-submit the comment.]

  • Hank Roberts // January 8, 2008 at 7:33 pm

    I think CRU’s dataset is point measurements, not satellites, not sure.
    http://www.cru.uea.ac.uk/ may have info.

  • Mike B. // January 8, 2008 at 8:25 pm

    “As Tamino said, there is no statistical reason NOT to use newer reference periods. Can you think of a legitimate reason to use older reference periods?”

    The mean global temperature for 1951-1980 is also the mean global temperature for the 20th century, it’s not a bad base range.

    What does it really matter, all you are changing is the position of zero on the anomaly scale.

  • henry // January 8, 2008 at 8:27 pm

    JesusChristHimself said:

    “Why does CRU not cover the poles? What’s up with that?”

    In the chart that Tamino made for update #4, there doesn’t appear to be much of a difference if the poles are included: other than the mis-match of zeros caused by the arbitrary selection of the reference period (which makes GISS appear hotter), the two seem to be tracking each other quite well.

    Martin said:

    “On the other hand if that criticism is basically true, and it is “dodgy” data extrapolated for the poles that is responsible for the higher GISS temperatures then that would be an argument for preferring the HadCRU results.”

    As I’ve been saying, the reason GISS appears hotter is the use of the arbitrarily selected reference period. As Tamino said:

    [As a reference period for computing anomalies, GISS uses 1951 to 1980, HadCRU uses 1961 to 1990, and NCDC uses the 20th century.]

  • Martin // January 8, 2008 at 8:56 pm

    JCH asks why CRU does not cover the poles.

    I am only a beginner at all this, but as far as I can see from the information in the paper by Brohan et al. “Uncertainty estimates in regional and global observed temperature changes” 2005, CRU get data from 4349 stations. They use these readings to estimate the mean temperature for the grids where the stations are located, but do not extrapolate for regions where they do not have any stations. It seems that GISS has a way of calculating the temperature readings of places that are up to 1200km from the nearest weather station. This obviously gives them greater coverage, and could be very important. For example they estimate that the anomaly for the most northerly latitudes is over 2 degrees.

  • P. Lewis // January 9, 2008 at 1:22 am

    Re my Argh!

    I’d attempted to show Henry that block quotes are possible. I interspersed asterisks in the tags. This worked in a previewer, but when the message went up for moderation they’d disappeared, leaving what would appear as trash, basically.

    The easiest way to show you Henry (and you can see how links, etc. are done, too) is to view the page source on this “Wiggles” web page. Don’t know about IE or Opera, but it’s under View/Page Source in FF (or hit Ctrl+U). (You can omit the paragraph (p) tags.)

  • Martin // January 9, 2008 at 10:45 am

    Henry, the point of my point of my post about the difference between CRU and GISS was that for the last few years CRU has not shown a warming trend, wheras GISS has. Tamino has demonstrated that we cannot take any significance from the CRU figures, but global warming sceptics have used them to argue that global warming has stopped.

    I suppose that in a few years we will have a better idea of whether the CRU figures underestimated recent global warming by missing out the poles.

  • henry // January 9, 2008 at 5:07 pm

    I’m really not arguing that GISS is better than HadCRU which is better than NCDC which is better than…

    I’m just saying that charts are created to paint a picture. Choice of an arbitrary zero paints the +/- change from “normal”, while the choice of scale can change a near straight line to a cross-section of the Alps.

    How the data is collected and processed can be an individual scientific process. How the results are displayed should have some consistancy from agency to agency (or even have the same standard within an agency). Some of the charts produced by GISS use later averaging periods, only the temp anomaly doesn’t. Why?

    In the word of GISS (reply to an e-mail sent):

    “Dear {henry}

    You are right. The trend does not depend on a base period. In order to report the temperature anomaly results for decades, we think it is better to have a fixed base period. (We don’t have to remind the readers that we changed the base period every time we do, and the comparisons with old data sets are easier, etc.) We have been using 1951-1980 as a base period since our first publication of the global temperature.

    Sincerely,

    Makiko Sato”

    So they use 1951-1980 because they’ve always used 1951-1980. Good reason?

  • dhogaza // January 9, 2008 at 6:30 pm

    So they use 1951-1980 because they’ve always used 1951-1980. Good reason?

    Yes, and I think their explanation is clear and sensible.

    Moreover, I’m having a hard time understanding why this is even an issue.

  • henry // January 10, 2008 at 1:58 pm

    1. Does selection of a reference period change the data or trend? NO.

    2. “In order to report the temperature anomaly results for decades, we think it is better to have a fixed base period.” AGREED.

    3. If any 30-year fixed base period is suitable for use as a reference period, why not pick one during the LIA? NOT LOGICAL (although the current trend wouldn’t change, a chart would show a larger rise above average than current charts).

    If someone was to re-create a chart of current temp anomalies using a time period referenced during the “MWP”, people would question their choice (although since the trend wouldn’t change, it would be acceptable, right?)

    dhogaza said:

    “Moreover, I’m having a hard time understanding why this is even an issue.”

    Look again at Update #4. Which zero is correct (and why that one)? Are we actually .6 or .5 above “normal”?

  • P. Lewis // January 10, 2008 at 4:01 pm

    3. If any 30-year fixed base period is suitable for use as a reference period, why not pick one during the LIA? NOT LOGICAL (although the current trend wouldn’t change, a chart would show a larger rise above average than current charts).

    If someone was to re-create a chart of current temp anomalies using a time period referenced during the “MWP”, people would question their choice (although since the trend wouldn’t change, it would be acceptable, right?)

    Well you are right that it is not logical. It would also not be a very good idea. In large measure the LIA data are proxy based (apart from some CET data presumably) and the MWP are all proxy data with wide error bands. I can imagine the sceptics having a field day with the error ranges with a base period encompassing those years. Jeez, we’d only just be above the noise level (though statistically significant likely. Check!) based on an MWP basis, and there likely would not have been an LIA (all normal variation chaps). The baseline has to be in the period of “modern” observational data collection.

    Hadley has (in parts at least) a greater observation network density than GISS (IIRC, since this is from way-back memory). GISS has a sparser network over a wider range, taking in the polar region(s). The datasets are quite complementary. There is statistically no difference in their trends (IIRC). As long as you quote which dataset you are using, there is no problem. The Hadley dataset baseline is also the WMO standard baseline. It makes no sense for Hadley to change, since it is in step with the WMO standard climatology base period. And I seem to recall (a “couple” of years ago) that there was talk of the WMO changing the baseline at some point, so there is no point in either organisation changing their base periods now.

    There is no overwhelming science reason for aligning or updating the two dataset bases. If there were, then they’d do it. (And it has a financial cost attached.) They are what they are. No one of any note (professionally speaking) seems to give a fig over this “issue”. This is a complete nonissue.

  • Mike B // January 10, 2008 at 4:29 pm

    2. “In order to report the temperature anomaly results for decades, we think it is better to have a fixed base period.” AGREED.

    So you agree it is better to have a fixed base period but yet you say it is better to keep using newer reference periods. Which means you’d keep changing it.

    “3. If any 30-year fixed base period is suitable for use as a reference period, why not pick one during the LIA? NOT LOGICAL (although the current trend wouldn’t change, a chart would show a larger rise above average than current charts).”

    It’s also not logical because we don’t have an instrument record for the LIA unlike we do for 1951-1980. GISS also does regional anomally comparisons which would be even more inaccurate if you used a reconstruction.

    “If someone was to re-create a chart of current temp anomalies using a time period referenced during the “MWP”, people would question their choice (although since the trend wouldn’t change, it would be acceptable, right?)”

    Again there is no temperature record for the MWP, just reconstructions.

    Why is this an issue?

  • henry // January 10, 2008 at 5:19 pm

    1. “The baseline has to be in the period of “modern” observational data collection.” O.K, both are. No problem.

    2. “The Hadley dataset baseline is also the WMO standard baseline. It makes no sense for Hadley to change, since it is in step with the WMO standard climatology base period.” Which means that GISS is NOT in step with WMO standards. Problem? Not as far as the TREND is concerned.

    The issue is not the data, or trends. All seem to be tracking nicely. To me, the issue is with the presentation of those facts.

    One could state, correctly, that HadCRU shows a -.1 degree difference compared to GISS.

    Is HadCRU under-reporting the anomaly, or is GISS over-reporting the anomaly? A standard period would negate that difference.

  • Hank Roberts // January 10, 2008 at 5:31 pm

    Don’t confuse the pretty pictures with the data sets.

    You can draw a line differently on a picture if you want to, for yourself, as long as you tell people what you did.

    Look at globalwarmingart — some people had trouble reading the standard paleo charts, which put “zero” time at the left side, and _some_ of which assume that 1950 is the zero or present year because it was, when they were done.

    You can mirror-image a chart for the convenience of people who want the past on their left and the future on their right.

    You can’t arbitrarily move the zero to 2007, because that isn’t what the data set has in it.

    What follows is a wild-ass guess: I’d think that when baseline information is calculated, those numbers come with an error range tied to the known instruments _then_in_use_.

    If that’s right, you can’t arbitrarily change the baseline period — because a different and more accurate set of instruments was likely added to the mix by that time, so the error range of the baseline would also be different.

    And a lot of work is done based on published references — which can’t be changed later without endless confusion.

    Only reason to push this kind of fiddling is to confuse people outside the area. Like the arguments saying we should throw away all the old data because it’s not as good as the new data. Duh ….

  • Hank Roberts // January 10, 2008 at 6:22 pm

    Basic knowledge, not common, teachable. Thanks to
    http://scienceblogs.com/evolgen/2008/01/teaching_the_importance_of_sto.php
    this:
    http://biology.plosjournals.org/perlserv/?request=get-document&doi=10.1371%2Fjournal.pbio.0060003&ct=1
    basic understanding of randomness — not easy, but teachable.

  • tamino // January 10, 2008 at 6:31 pm

    The choice of zero point for anomalies (which is defined by the choice of baseline) is truly irrelevant. Choosing a different zero point won’t change the graph a wit — only the numbers on the left-hand axis will change. What’s important are the temperature differences from one time to another, and these are unaffected by the choice of zero point. And it’s not true to suggest that HadCRU anomalies are 0.1 deg.C “colder” than GISS — they’re simply on a different scale.

    However! While the choice of zero point makes no difference to the temperature anomaly graphs (except the labelling of the y-axis), the choice of baseline period does make a difference. That’s because the baseline data determine more than just the zero point; they also determine the shape of the average annual cycle. If the shape of the average annual cycle is different between two competing reference periods, then switching from one to the other will cause a change in the temperature plot.

    Yet this change affects only the annual cycle, not the annual average — so graphs like the ones in this post, of annual average temperature, won’t change. But if one studies the monthly data one will note that there’s a significant annual cycle in data before or after the reference period, but not during the reference period. That’s because the annual cycle computed from the 1951-1980 baseline period (for GISS data) cancels it out during the baseline period, but the average annual cycle has changed since then, and what we see in more mondern monthly anomaly is the difference between the annual cycle now and then.

    Anomalies are now (on average) lower in summer and higher in winter. That’s because the annual cycle is dominated by the northern hemisphere (thermal inertia of the oceans makes southern-hemisphere temperature more stable than northern), and in the northern hemisphere winter has warmed more than summer.

  • jacob l // January 13, 2008 at 9:31 am

    re Martin // January 8, 2008 at 8:56 pm
    try checking out http://data.giss.nasa.gov/gistemp/station_data/
    I found only 2 within 1200 km of the north pole
    that end in 2007
    Eureka,N.W.T. and Ostrov Vize
    how ever I found 10 north of 70 degree’s that have a 2007 date on them
    “tamino sorry about the late post”

  • Global Warming - Page 54 - Volconvo Debate Forums // January 17, 2008 at 9:49 pm

    [...] case, the noise results from the enormously wide natural variability of year to year temperatures. Here’s an excellent discussion of noise and why the "no warming since 1998" argument is false. [...]

  • KH // February 13, 2008 at 3:03 am

    This thread seems dead, but I’d like to offer an idea. I tried a linear fit to the data in the second graph (Temperature anomaly since 199 8) using an L1 norm instead of an L2 norm. Then the slope is positive – about +.0077 . The L1 norm can be useful for finding the trend in the presence of data outliers. I used an iteratively reweighted least squares algorithm to calculate the L1 norm.

  • Mike Donald // March 19, 2008 at 8:02 pm

    Many thanks Tamino. Even after a few glasses of wine I got the jist.

  • DonShmon // April 16, 2008 at 4:10 am

    Thanks for the post, your explanations are incredibly helpful.

    In dispelling the stastical significance of the supposed cooling trend, the post seems to give a lot of weight to the importance of temperature data only.

    In the absence of other considerations, is the trend by itself significant and worthy of not?

    Or is it only significant when considered in the context of being something we expected based on our understanding of the ramifications of increased CO2?

    IF there had been (or lets say in the next 8 years there is) a statistically significant moderate cooling trend, then would we have to say AGW theories are on their ear or expect to find other forcings that explained the anomaly?

    I assume we consider this extremely unlikely considering our understanding of the influence of CO2 on global temperature, but not impossible.

  • DonShmon // April 16, 2008 at 4:12 am

    follow-up: In the paragraph

    “In the absence of other considerations, is the trend by itself significant and worthy of note”

    I should have stated that I am asking about your emphasis on the statistical significance of the 30-yr trend, not the 1998-now trend.

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