Open Mind

Bjorn Lomborg: How did you get those numbers?

October 14, 2008 · 144 Comments

Some of you might wonder why I make so many posts about the impact of noise on trend analysis, and how it can not only lead to mistaken conclusions about temperature trends, it can be abused by those who wish deliberately to mislead readers. The reason is that this is still a common tactic by denialists to confuse and confound the public.


Case in point: Bjorn Lomborg has written an article for the British newspaper The Guardian in which he attempts to persuade readers that climate data indicate conditions are much better than expected. Here’s a excerpt:


The most obvious point about global warming is that the planet is heating up. It has warmed about 1C (1.8F) over the past century, and is predicted by the United Nations’ climate panel (IPCC) to warm between 1.6-3.8C (2.9-6.8F) during this century, mainly owing to increased CO2. An average of all 38 available standard runs from the IPCC shows that models expect a temperature increase in this decade of about 0.2C.

But this is not at all what we have seen. And this is true for all surface temperature measures, and even more so for both satellite measures. Temperatures in this decade have not been worse than expected; in fact, they have not even been increasing. They have actually decreased by between 0.01 and 0.1C per decade. On the most important indicator of global warming, temperature development, we ought to hear that the data are actually much better than expected.

Lomborg doesn’t say exactly what he means by “this decade,” nor does he state exactly what data set(s) lead him to his conclusions. But it’s a pretty safe bet that by “both satellite measures” he refers to the RSS and UAH estimates of TLT (lower-troposphere temperature). The most natural meaning of “this decade” is — well, this decade, i.e., the 2000’s. So I computed the trend and its uncertainty (in deg.C/decade) for three data sets: NASA GISS, RSS TLT, and UAH TLT, using data from 2000 to the present. To estimate the uncertainties, I modelled the noise as an ARMA(1,1) process. Here are the results:

Data Rate
(deg.C/decade)
Uncertainty
(2-sigma)
GISS +0.11 0.28
RSS +0.03 0.40
UAH +0.05 0.42

All three of these show warming during “this decade,” although for none of them is the result statistically significant.

Maybe by “this decade” he’s referring to the last 10 years. Let’s make the same calculation for the same data sets, using the last 10 years of data, from October 1998 through September 2008:

Data Rate
(deg.C/decade)
Uncertainty
(2-sigma)
GISS +0.18 0.23
RSS +0.10 0.34
UAH +0.11 0.35

Once again all three data sets indicate warming but none of the results is statistically significant.

Maybe, by “this decade,” he’s referring to data since 1998? But that would be the worst cherry-picking possible, extending “this decade” to more than 10 years ago just so he could get the most out of the giant el Nino of 1998. We all know that would be cheating, right? Let’s make the same calculation using data from January 1998 to the present:

Data Rate
(deg.C/decade)
Uncertainty
(2-sigma)
GISS +0.10 0.22
RSS -0.07 0.38
UAH -0.05 0.38

Finally one can obtain negative trend rates, but only for 2 of the 3 data sets. But again, none of the results is statistically significant. Even allowing this dreadfully dishonest cherry-picked start date, the most favorable case for Lomborg’s claim indicates that the trend rate could be as high as +0.31 deg.C/decade. That’s right, based on these data the trend rate could well be 50% higher than the IPCC “projection” of “about” 0.2 deg.C/decade.

How, then, does Lomborg arrive at his figures? Only God and Bjorn can be sure. But here’s my guess: he took the results from 1998, computed the uncertainty based on assuming that the data are a linear trend plus white noise (which we know, without doubt, is a terribly mistaken assumption), then computed his “range” by using only +/- one sigma. That would, in fact, give a range from -0.01 to -0.1 deg.C/decade.

What do you have to do to make this happen?

  • 1. Start at the beginning of 1998, more than 10 years ago, but call it “this decade.”
  • 2. Compute the probable error using a white-noise assumption, which is known without doubt to be wrong.
  • 3. Compute a confidence interval using only +/- one sigma, when we know that a normal random variable has about a 32% chance to fall outside the +/- 1 sigma range.

    One of these might be considered an honest mistake. If you’re woefully ignorant of statistics, you may not know that the noise in global temperature isn’t white.

    But the others are outright dishonest. Computing a confidence interval using only 1 sigma is bound to be wrong nearly one third of the time. And starting with the beginning of 1998, referring to “this decade” as starting more than 10 years ago, is cherry-picking taken to the extreme.

    I’ve previously said “Those who point to 10-year “trends,” or 7-year “trends,” to claim that global warming has come to a halt, or even slowed, are fooling themselves.” I may have been mistaken; is Lomborg fooling himself, or does he know exactly what he’s doing?

    So, Mr. Lomborg, we’re all very curious: how did you get those numbers?

  • Categories: Global Warming
    Tagged:

    144 responses so far ↓

    • Mark Hadfield // October 14, 2008 at 11:17 pm

      But surely he wouldn’t have made such a claim without citing a peer-reviewed paper in which the methods and results are described in detail?

    • David B. Benson // October 14, 2008 at 11:22 pm

      Tamino — I am sure that God is confused and questioning as well…

    • Brian D // October 15, 2008 at 12:49 am

      Mark Hadfield: You’d imagine so, but there aren’t any citations. There’s quotes from the Associated Press and the BBC, but that’s it.

      Tamino, have you considered sending this to the Guardian as a rebuttal (perhaps through an intermediary, if you’d prefer to remain anonymous as usual)? Lomborg, if he is fooling himself, isn’t going to be convinced by mere facts, but at least points like this can prevent others from being fooled themselves.

    • Ray Ladbury // October 15, 2008 at 1:13 am

      I’m SHOCKED!!! SHOCKED!!! to find Lomborg playing fast and loose with statistics. (where are my winnings)

      [Response: I think this is the beginning of a beautiful friendship.]

    • François GM // October 15, 2008 at 1:47 am

      What are you talking about ?? Confidence intervals are estimate intervals of a true endpoint, which could be human population parameters, distance to the moon or temperature trends. You don’t apply confidence intervals on the true endpoint but on proxies or measures to estimate the true endpoint. A - 0.1 temp trend from 2001 to 2008 is a -0.1 temp trend from 2001 to 2008 - period. There are NO confidence intervals. It is the true final endpoint, if you define it that way. You may argue that a short-term trend from 2001- 2008 is not a proper TRUE endpoint. Fine. You may then apply statistics (but which ones ??? good luck) to determine the confidence intervals to estimate the TRUE endpoint. But tell us - what is the TRUE endpoint ? Temperature trend from 1980 to 2030 ? From 2000 to 2099 ? Up to you to cherry pick but PELEASE DO NOT apply confidence intervals on the true endpoint.

      [Response: My opinion: there's no hope for you.]

    • Geoff Larsen // October 15, 2008 at 2:01 am

      Tamino

      I suggest Lomborg’s figures refer to since Jan01 & he may have got them from here (to Jul 08-scroll down to charts): -

      http://rankexploits.com/musings/2008/ipcc-central-tendency-of-2ccentury-still-rejected/

      or possibly from here (to Aug08-again scroll down to chart):-

      http://rankexploits.com/musings/2008/result-of-hypothesis-tests-very-low-confidence-2ccentury-correct/

      [Response: I doubt it. He'd have done a better (but not necessarily correct) job.]

    • george // October 15, 2008 at 2:12 am

      It is a well-established fact that Lomborg does not hold up well to close scrutiny, so it is no real surprise that he is again mistaken.

      And as far as knowing just how Lomborg got his numbers, I, for one would prefer to remain ignorant of Lomborg’s own ignorance.

      I seriously doubt there is anything worthwhile to be learned from it — other than perhaps how NOT to do statistics.

      I actually find it more than a little depressing that someone like Lomborg keeps getting public exposure for his opinions, which seem to require almost continual debunking by real scientists.

      Harvard biologist Edward O Wilson included Lomborg among what he termed “the parasite load on scholars who earn success through the slow process of peer review and approval.”

      http://www.grist.org/advice/books/2001/12/12/point/

      Based on what I have seen (eg. Lombog’s book and the response of several scientists to specific claims made in the book made in Scientific American and elsewhere), I have to say that I believe that to be a fairly accurate assessment.

    • Bob North // October 15, 2008 at 2:32 am

      Tamino -
      Another possibility you didn’t examine is that Lomborg is referring to the period from Jan 2001 to the present (i.e., part of the first decade of the first decade of the 21st century). This would probably result in a much lower “trend” but I don’t know what it would do to the uncertainty values. Using the period from Jan 2001 would be consistent with his statement that IPCC expected “about 0.2C” for this decade since the IPCC did expect about 0.2C for the first two decades of this century.

    • Duane Johnson // October 15, 2008 at 3:43 am

      None of the decade choices Tamino offers show a warming as large as 0.2C per decade.The degree to which natural variation can explain away this fact depends upon the statistical model that is used, as well as the method of measurement, as well as the method processing the measurements to arrive at the result. Since there hasn’t been a significant volcanic eruption in the period in question, and Tamino’s natural variation includes such effects, the odds are getting slim that the first two decades of the 21st century will in fact have warming as large as 0.2C/decade, whether you start in Jan 2000 0r Jan 2001 or 1998. If a significant volcano should occur, the odds are slimmer still.

      I’m pleased to see that Lomborg is questioning IPCC projections. In the past, he has been content to mostly accept their conclusions on temperature while exposing the absurdity of the economic conclusions (e.g. Stern report).

      [Response: The statistical analysis is both sound and robust, but it appears we have yet another person who will deny it mainly because he doesn't like the outcome.

      I'm no expert in economics, but Stern's credentials are vastly superior to Lomborg's, and what I hear from those who do know the subject is that Lomborg's economics is every bit as bogus as his statistics.]

    • Philip Machanick // October 15, 2008 at 4:32 am

      I suspect some on this page are making the mistake of accepting the claim that Lomborg is a “statistician”. I have yet to track down anything to support this claim. His primary qualifications are in political science (in which he has published at least 2 papers, which makes him hardly more of an authority than me) and though he has worked as a statistics associate prof, I strongly suspect it was in a role of teaching stats to social sciences, as he was working in a political science department at the time. He certainly has not published anything of significance in statistics (or for that matter on climate change, but he has at least written books and copious newspaper articles in that field).

      The man is a certifiable bogon and I don’t know why anyone pays attention to him. Just shows how gullible the commercial media are.

    • Former Skeptic // October 15, 2008 at 5:16 am

      That was good analysis on Lomborg’s cherry picking.

      I’m actually more interest in Bjorn’s other comment:

      “…Likewise, and arguably much more importantly, the heat content of the world’s oceans has been dropping for the past four years where we have measurements. Whereas energy in terms of temperature can disappear relatively easily from the light atmosphere, it is unclear where the heat from global warming should have gone – and certainly this is again much better than expected.”

      I assume BL is taking information from Pielke Sr. where Ol’ Roger makes the rather brazen claim that “…global warming has actually halted, for now.” (see http://climatesci.org/2008/09/19/comment-on-the-september-13-2008-article-in-the-economist-adapt-or-die/)

      If you click on the relevant link in RPSr.’s post, it brings you to another post that details the source i.e. OHC data from Josh Willis. I’m pretty sure that there’s something wrong with using only 7.5 yrs of upper ocean heat content data to make the conclusion that GW is stopped since 2004. But then again, making such huge leaps of logic has not stopped RPSr in the past (re: The butterfly effect debacle, upper troposphere T, his crazed insistence the UHI seriously contaminates the overall surface T increase…)

      PS: A bit off topic, but could this be the moment that Pielke Sr. jumped the shark?

    • Patrick Hadley // October 15, 2008 at 12:27 pm

      One of the good features of this site is the way that Tamino always uses clear illustrations to demonstrate his points.

      Why has Tamino not simply shown us graphs of the data from the last decade so that we can see for ourselves what the trend has been?

      Surely this is a post that is crying out for some graphs.

    • void{} // October 15, 2008 at 1:45 pm

      Former Skeptic // October 15, 2008 at 5:16 am

      Where can I find info re:

      “The butterfly effect debacle, …”

      Thanks

    • Ray Ladbury // October 15, 2008 at 2:47 pm

      Patrick Hadley, your use of the word “trend” and decade is pretty much inconsistent unless you are interested in trends in the noise. Now you’ve been around here long enough to know this, so one wonders what the point of your post is.

    • george // October 15, 2008 at 3:03 pm

      Patrick asks

      Why has Tamino not simply shown us graphs of the data from the last decade so that we can see for ourselves what the trend has been?

      There is a significant irony in that statement.

      An important (if not central) theme in Tamino’s posts (as I see it, anyway) is that your eyes can fool you.

      While graphs are certainly useful in many cases, they can also lead you astray.

      “Eyeballing” is simply not a reliable way of determining trends.

      That is particularly true for short spans of time, for which any “underlying” trend (due to CO2 increases, for example) can easily be buried in the noise.

      Statistics — including the error bar on the calculated trend — is the only way that you can reliably approach the issue.

      Unfortunately, for short time spans, it is simply impossible to say what the “actual” trend is with precision because the error bar is large relative to the calculated trend and encompasses a fairly broad range of possible trend values.

      That’s precisely why Tamino says above that

      the most favorable case for Lomborg’s claim indicates that the trend rate could be as high as +0.31 deg.C/decade. That’s right, based on these data the trend rate could well be 50% higher than the IPCC “projection” of “about” 0.2 deg.C/decade.

      [Response: A good summary of the situation. Thanks.]

    • Former Skeptic // October 15, 2008 at 3:50 pm

      Hi void{}:

      The relevant thread is here: http://www.realclimate.org/index.php/archives/2008/04/butterflies-tornadoes-and-climate-modelling/langswitch_lang/sp

      IMO it’s best read with a steaming cup of java. Ike Solem’s post (#53) is perhaps the best one explaining RPsr’s confusion. Hope that helps!

    • Patrick Hadley // October 15, 2008 at 4:29 pm

      Nobody is going to argue that graphs are on their own sufficient, the fact that Tamino seems to have made the decision that his argument might not be helped by showing us the data on a graph is rather telling.

      Perhaps if our eyeballs were shown the data points gradually trending south our brains might not be so receptive to an argument that there is really a trend in the other direction.

      [Response: You want graphs? Try this.

      Clearly your brain is very receptive to excuses to deny the truth.]

    • Thomas Huxley // October 15, 2008 at 5:13 pm

      Danish Biologist Kåre Foggood exposes Lomborg’s errors in great depth.

    • David B. Benson // October 15, 2008 at 7:26 pm

      Patrick Hadley // October 15, 2008 at 12:27 pm — After reading Tamino’s ‘this’, consider the five and ten year averages from the HadCRUTv3 global surface temperature product:

      http://tamino.files.wordpress.com/2007/12/5yrave.jpg

      http://tamino.files.wordpress.com/2008/04/10yave.jpg

    • Gavin's Pussycat // October 15, 2008 at 7:30 pm

      Patrick, you can create your own graphs — both those that you like and those that you hate — here.

    • Cthulhu // October 15, 2008 at 8:53 pm

      I’ve noticed that the 10 year window is moving past the 97/98 el nino peak now. Either they’ll switch to using “last 11 years” or “6 years”

      September 1998 - September 2008 with trend

      http://www.woodfortrees.org/plot/uah/from:1998.6/plot/uah/from:1998.6/trend

      And using UAH for the benefit of paranoids.

    • Steve Bloom // October 15, 2008 at 9:30 pm

      Former Skeptic wrote: “(C)ould this be the moment that Pielke Sr. jumped the shark?”

      No, but there has been a fairly steady slide downhill since the start of his blog. I suspect the underlying motivation is his perception that the larger climate science world has failed to acknowledge his peculiar (note not denialist as such) views. I suspect there was some major professional disappointment (loss of funding for his RCM?) around the time he began the blog, which was also roughly the same time he retired. He went off the reservation quite abruptly, the details of which are documented in the first six months or so of his blog.

    • John Mashey // October 15, 2008 at 10:49 pm

      Regarding Lomborg being a statistician:

      I have a copy of The Skeptical Environmentalist, and both American & British versions of Cool It!

      I can’t recall actually seeing any real *statistical* analysis, i.e., the sort of stuff that tamino does so well, or folks from my old place of work like Tukey & Kruskal.

      Can anyone point at any real statistical analyses in those books? Perhaps it’s there and I just missed it.
      [Note: I don't count just selecting & graphing data as statistical analysis.]

    • Ray Ladbury // October 16, 2008 at 12:25 am

      Hi John, Lomborg’s statistics and analysis always bring to mind some quotes by Andrew Lang:

      “He uses statistics as a drunken man uses lampposts - for support rather than illumination”

      and

      “He missed an invaluable opportunity to hold his tongue.”

    • John C // October 16, 2008 at 2:22 pm

      But isn’t Lomborg actually right ? The decade has been “better than expected” in terms of not having warmed up as much as the IPCC models predicted. I showed the monthly GISS graph graph to my 8 year old son and asked him if he saw it going up, going down or was flat. He said it looked pretty flat. I agree. All the fancy statistics is kind of missing Lomborgs point. Clearly it’s “better than expected”.

      And for those of you who think Lomborg is wrong, misguided, stupid or whatever. Maybe you’re right …. but his views certaintly aren’t irrelevant. I guarantee you that more people read the Guardian than read this blog.

      [Response: Take a step back, and consider this: I base my characterization of temperature trends on state-of-the-art statistical analysis. You base yours on "I showed the monthly GISS graph graph [sic] to my 8 year old son and asked him…”

      Seriously: do you not see a problem with your approach?

      In fact you just might have hit the bulls-eye when it comes to characterizing the naivete and folly of Lomborg’s approach. It’s no more sophisticated than what you’ve done.

      Furthermore, this post is about the actual numbers Lomborg quotes. Those numbers are bogus, and not just because of naivete — it sure looks to me like Lomborg had to cheat to get ‘em. Your son may not have any knowledge or experience with statistics, but at least he’s being honest.

      If your boy had cancer, and the doctors told you that the disease was progressing rapidly but at least he’d been feeling a little better than expected since a week ago Monday, would you rejoice? Would you cancel the scheduled treatment on the basis that ruining the family’s economy was a greater threat? When the doctors protested that it’s expected that he’ll have better days and worse days because of random fluctuations in patient condition, that his ten-day “feeling better” episode was absolutely zero evidence of a change in the underlying trend, and that if you stop treatment he’ll never see his 9th birthday — would you go to his best 8-yr-old friend to get a second opinion?]

    • Dano // October 16, 2008 at 5:44 pm

      Tamino, RE your reply to John C, it depends upon whether he chooses to deny the advice of experts.

      Best,

      D

    • Ray Ladbury // October 16, 2008 at 7:25 pm

      John C., I think the key words in your post are “than expected”. Expectation implies we have some sort of model. It implies that we know how it is likely to behave. In the case of climate, an inherent feature is noise. So as long as the behavior is not well outside of what we would expect given known trends + noise, then the behavior is as expected. Now contrast this with a model that assumes noise alone without anthropogenic warming and see how out of the norm the past 30 years are.

      [Response: Excellent point; the "apparent flat trend" is most certainly NOT outside expectation. That's the theme of this post.]

    • Anna Haynes // October 16, 2008 at 8:04 pm

      I’ve emailed the following to Dr. Lomborg’s personal assistant:
      _______

      Greetings Zsuzsa Horvath -

      Questions have arisen at the climate blog Open Mind, here -
      http://tamino.wordpress.com/2008/10/14/bjorn-lomborg-how-did-you-get-those-numbers
      … as to what dataset(s) Dr. Lomborg drew his conclusions from, for his recent Guardian article, that
      “[It] is true for all surface temperature measures, and even more so for both satellite measures [that] Temperatures in this decade have not been worse than expected; in fact, they have not even been increasing. They have actually decreased by between 0.01 and 0.1C per decade. ”

      Could you please check with Dr. Lomborg and let me know what dataset he used and how he arrived at this conclusion, and/or post the answer as a comment to the Open Mind blog post?

      _______

    • Dave A // October 16, 2008 at 10:51 pm

      Ray,

      Your faith in climate models is truly, truly touching. If only everyone could have such belief!

    • JCH // October 16, 2008 at 11:07 pm

      Oh boy, this going to be precious.

    • Ray Ladbury // October 17, 2008 at 12:25 am

      Gee, Dave, maybe that’s because I actually understand them to some extent.

      Look, Dave, two types of people come to blogs like this–people who are trying to understand the science and pudknockers. Want to learn some science? Great. Join the rest of us. Want to revolutionize climate science. That’s great, too. Publish something in a peer reviewed journal that actually furthers undestanding of climate. Otherwise…enjoy your solitary activity.

    • Charles // October 17, 2008 at 11:16 am

      Tamino, I very much enjoyed and appreciated the analogy you used in replying to John C. I suspect that analogy will make the rounds. Thanks.

    • John C // October 17, 2008 at 12:59 pm

      I agree that the two approaches (’eye ball’ and ’state of the art’ statistics) are clearly different .. but the result is the same. However you want to look at it … the last decade has not seen a 0.2 degree rise - so ‘better than expected’.

      [Response: Wrong. If the underlying trend is 0.2 deg.C per decade, then we do NOT expect exactly 0.2 deg.C rise in a single decade -- what we expect is somewhere within a range of values centered on 0.2. And that's the point: the observed value is within expectation.

      Your argument is like saying that if you flip a fair coin 100 times we expect to get 50 heads and 50 tails, so if we only got 49 heads then the result is outside "expectation." NOT TRUE. What we expect from 100 coin flips is somewhere between 40 and 60 heads. The observed result is well within expectation.]

      Your point that this may be irrelevant in the big scheme of things is, course, true …… the charming cancer analogy ….. but that wasn’t the point of Lomborgs article. And indeed, in answer to Ray Ladbury, on the issue of trend and noise, and a flat period being ‘not unexpected’ …. all true. Which is why it’s such a SHAME that the flat period falls outside the entire uncertainty range of the IPCC 2001 models (p34 of the Sum. for Policy Makers). I guess they never EXPECTED that there MIGHT ever be a flat period. How did that happen with so many modelling experts ? Hence the truth of Dave A.’s comment. I think they must now recognise their error as they have significantly increased the uncertainty range in the 2007 report.

      It think Lomborg made an error in quoting some numbers because they are irrlevant and only result in him being correctly criticised for not stating where they came from. It detracts the main thrust of his article - he didn’t need to do it. Maybe Anna Haynes will get an answer

      [Response: Lomborg did more than make an error. He cheated. And the numbers are not irrelevant because he's deliberately shrunk the range to make it seem that observation is outside that range.

      As for the "charming" analogy, maybe that's what it takes to get you to take this seriously. After all, this is a problem that unfolds on time scales of decades, not years; your son is at far greater risk from global warming than you or I. His health and happiness, even his life, could be at stake: THAT'S HOW SERIOUS THIS IS. I'm sure you care deeply about his future -- so for his sake, stop getting suckered by con artists.]

    • Ray Ladbury // October 17, 2008 at 2:27 pm

      John C., Let me guess, you’re one of those whose stock strategy is buy high and sell low, right? If all you look at is the current short-term trend, ignoring the long-term rise since 1750, the physics , the dramatic rise since 1975, the paleoclimate, etc., then I’d have a hard time imagining you looking at long-term stock trends.

      Produce one quote by the IPCC that precludes the sort of trend we’ve seen.

    • Anna Haynes // October 17, 2008 at 3:39 pm

      Response from Lomborg’s personal assistant Zsuzsa Horvath, re source of L’s statement on temperatures “They have actually decreased by between 0.01 and 0.1C per decade”:
      ———–
      The temperature measurements from Jan 2001 to Aug 2008 from http://rankexploits.com/musings/2008/result-of-hypothesis-tests-very-low-confidence-2ccentury-correct/
      ———–

      [Response: Does anyone else consider it outright dishonesty for Lomborg to base his "better than expected" claim on a blog post which states outright that a 0.2 deg.C/decade trend is NOT contradicted by statistical tests?]

    • Hank Roberts // October 17, 2008 at 4:00 pm

      As though “actually” meant something real. D’oh.

    • boulderSolar // October 17, 2008 at 5:28 pm

      Tamino,

      So Lomberg uses as his reference a reasonably respected website that matches the numbers he uses in his article. Furthermore the website author, an astute and competent statistician, makes the conclusion that there is a “very low confidence” (<10% chance) that the .2 deg/decade projection is correct. Now you accuse him of being dishonest because the probability is not less than 5%. Lomborg never states that the projection is statistically falsified, rather he is pointing out the recent temperature trend is better than expected. He has a good (and correct!) point in that recent temperature trends are better than expected; to the level that the IPCC projection is getting darn close to be statistically falsified. Are you meeting your standard of honesty that you are imposing on others?

      [Response: Lomborg states that the trend is declining at between 0.1 and 0.01 deg.C/decade. This is based on the range exhibited by different data sets; it takes absolutely NO account of the uncertainty in any one of the estimates, which is quite a bit larger than the range between the different data sets (which are not independent data sets).

      As to "darn close to be statistically falsified," even that result, dependent on a specific cherry-choice of starting time, only manages to come close. Choosing a start time which favors one's own hypothesis (and Lucia has tried darn hard to falsify the IPCC projection) alters the statistics of the result even further -- but neither Lucia nor anyone else I can find has taken that into account.

      And again: you are WRONG: recent trends are NOT outside expectation, they are well within the expected range given the size and character of the noise. Considering that even a cherry-picked starting date fails to contradict a trend of 0.2/decade, that's a very strong denial of the thesis that the trend is less.

      There's one clear conclusion from all this: those who want to believe what's false will not be swayed by reason.]

    • george // October 17, 2008 at 5:58 pm

      The fact that Lomborg went to such (short) lengths to get a trend to his liking basically says it all.

    • Hank Roberts // October 17, 2008 at 7:56 pm

      george wrote:

      > went to such (short) lengths
      > to get a trend to his liking

      Devastating, funny, terse. Good sharp point.

    • David B. Benson // October 17, 2008 at 9:07 pm

      What Hank Roberts just wrote.

    • Dave A // October 17, 2008 at 9:22 pm

      Ray,

      Believe me I am trying to understand the science - its just that there are all these holes everywhere.

      Not hailing from your neck of the woods I can still probably guess what you mean by “pudknocker”. If I was that it still might be better than being a” true believer”

    • tamino // October 17, 2008 at 9:25 pm

      After considering the source of Lomborg’s numbers, I’ve concluded that he might not have been deliberately misleading in his atrociously wrong statement. He might actually believe he’s correct.

      Which raises a very important point. Lomborg titles his article, “Let the data speak for itself.” The problem is, the data are numbers, and that’s a language that most people, frankly, don’t understand very well. It’s like saying “let the accused speak for himself” in a criminal trial, when the accused speaks only Chinese but the judge, jury, and attorneys don’t understand a word of it and no interpreter is available.

      So if he wants to let the data speak for itself, then he needs to find a competent interpreter. If Lomborg isn’t being deliberatly misleading, then he’s sufficiently innumerate that he’s the wrong spokesman for the data.

    • Ray Ladbury // October 17, 2008 at 9:35 pm

      boulderSolar, Now take a minute and step back to think about what you are defending: Lomborg took cherry-picked dates designed to give the absolute lowest trend he could and still it only ALMOST statistically falsified. Is that really what you consider a defensible position: “well, he almost wasn’t lying. “

    • Lazar // October 17, 2008 at 9:52 pm

      Tamino,

      After considering the source of Lomborg’s numbers, I’ve concluded that he might not have been deliberately misleading in his atrociously wrong statement.

      It seems he’s taken the exact slope from the NOAA data and the exact slope from HadCRUT as the minumum and maximum of his range. Also, that lucia has used those slopes as exact figures and put the observational error on the 2 degC/century purportedly estimated from GCMs. It appears there is no estimate of GCM error variance.

    • Ray Ladbury // October 17, 2008 at 9:54 pm

      Dave A., what I am is a scientist. That means that when it comes to what I believe, I have to side with the preponderance of the evidence–and virtually all the evidence (as well as the physics) supports anthropogenic causation. If you want to understand scientific belief, then I urge you to read:

      http://ptonline.aip.org/getpdf/servlet/GetPDFServlet?filetype=pdf&id=PHTOAD000060000001000008000001&idtype=cvips
      See, unlike you, I can’t just decide to not believe in climate change because I don’t like what it means for my lifestyle. The very same factors that imply anthropogenic causation are absolutely essential to understand paleoclimate, weather, the origins of life, past extinctions, recoveries and on and on. To me and other scientists understanding what is going on in the world is important. That is why you find so few scientists who really understand the theories among the skeptics.
      You claim there are gaps. There are always gaps–but I suspect most of the gaps you see are illusions that arise from your lack of understanding of the science. And this is what I don’t understand about people like you: You are surrounded here and at RC by people who actually understand the science, and yet rather than trying to gain understanding of the science, you persist in attacking your straw men. This is an absurd waste of time on two levels. One, you’re not even attacking the real science. Two, attacking the science here is like burning an art book because you don’t like cubism. This isn’t where the science gets done. And the only way you are going to see the science change is if some new theory comes along that explains the data better. To date, denialists have proposed precisely bupkis. That is why they and you are irrelevant.

    • Dave A // October 17, 2008 at 10:51 pm

      Ray,

      Perhaps I have touched a raw nerve?

      Two points,

      First my questions about climate change have nothing to do with my lifestyle or how that might change. After all, I wouldn’t frequent this and similar blogs if I was into lifestyle would I?

      Second, as a person I don’t think I am “irrelevant” and you have no right to say that

    • George Ray // October 18, 2008 at 12:18 am

      Tamino,

      You said that Lomborg has cherry picked the starting date. What date would you have picked to do the analysis? What statistical methodology would you use to support picking the start date? I believe in AGW and am trying to get my head around the application of the stats.

      Thanks

      [Response: I'd have picked 1975. That's based on studying the entire time span of temperature data and attempting to find the smallest set of straight-line segments which would approximate the temperatures, such that the residuals from that "multi-linear" fit don't show unambiguous deviation from being a random series. So far, I haven't seen any evidence that the data since 1975 are any different from a linear trend plus ARMA(1,1) noise. You can view the residuals from a linear fit for data from 1975-present, for estimates from GISS, HadCRU, and NCDC, here.

      It's legitimate to choose other starting dates, BUT they must NOT be chosen in order to achieve some desired result. Also, the more starting dates you "try," the greater chance of getting a large (positive or negative) trend rate just by *chance* -- so the statistics have to be modified to account for that.

      And of course, you have to apply the statistics in the first place in order to estimate the uncertainty in the result you get.

      Even applying the ARMA(1,1) model (which seems to be appropriate) to the random part in order to estimate the uncertainty, in order to be completely rigorous one must account for the uncertainty in the estimated *parameters* of the ARMA(1,1) model; it means that the actual uncertainty is a bit larger than computed here.

      Lucia and Lomborg have also mischaracterized the IPCC projection; there's more information about that here.]

    • Former Skeptic // October 18, 2008 at 12:18 am

      Steve Bloom:

      Thanks for the succinct summary. I didn’t know about the suspicions of his professional disappointment around the commencement of Climate Science…which now make sense. Personally I think he has recently jumped/or is currently jumping the shark, especially with his recent bizarre insistence that GW has halted since 2004 based on (AFAIK) analysis from unpublished upper OHC data.

      Anyway, back to the topic at hand. Lomborg, ostensibly an adjunct professor, has a personal assistant?? Wow. Talk about style overcoming substance.

    • Ray Ladbury // October 18, 2008 at 1:32 am

      Dave A., Actually, I could not give a rat’s posterior what you think of me–and if you are going to make assumptions about my character and motivations, I’m certainly justified in making assumptions about yours. Certainly, your entire line of argument since coming on here seems to be directed at maintaining rather than updating your beliefs. You have yet to ask a question that you really wanted to know the answer to.

      Your irrelevance in the climate debate is voluntary. It derives from your decision to reject sound science and abandon your place at the negotiating table where we decide what to do about the threats posed by climate change. You’d rather debate science you don’t understand than learn the science. And the science is solid. It won’t change because you don’t like it. So the only possible place for folks like you and me (I am not a climate scientist–just a physicist) is where we decide how to confront the threats. That is why I spend time here, at RC and other places where I can learn more about the science–so that I can exercise that responsibility in a knowledgeable fashion. On the other hand, you’d rather bloviate your misunderstandings in places where they have no effect whatsoever. Fine. Good luck with that.

    • Ray Ladbury // October 18, 2008 at 2:12 am

      Tamino’s point about data being a foreign language to most people is important. I would contend what is more that without a physical theory in which to interpret the data, they won’t be very illiminating. It is true that physical understanding can come from the data, but it still has to come by way of a theory. In the absence of physical understanding you wind up with what I call “weather watchers”–the “alarmists” who raise the alarm to a shrill pitch each time you have an El Nino or a big hurricane and the denialists who look for any slight drop in temperature to proclaim that “warming has ended”.
      The prediction of warming predates the era where it was obvious. When it was not seen, scientists looked for other factors. They didn’t find any that haven’t been known since the 30s or 40s. This is not a science in its infancy.

    • Duane Johnson // October 18, 2008 at 3:10 am

      Ray,

      How much does one learn about a science by being a sycophant for those holding a particular point of view? Does it earn you a place at the table for making those major decisions?

      Honestly, have you spent any time reading Lucia’s blog? She is attacking the question of temperature anomoly trends in a rational way, which leads her to the conclusion that a 2C/century trend since Jan. 1, 2001 is “very unlikely” using terminology adopted and used by the IPCC. And incidentally, the 2001 date was not chosen to produce the minimum trend, and in fact it doesn’t, but you’d have to read her blog to know that. She and Tamino have had some interesting and informative exchanges, reach some different conclusions, but the net result is instructive as well as constructive to the issue.

      I always look forward to what Tamino has to say about her analyses, and the converse is also true.

    • matt // October 18, 2008 at 4:31 am

      Ray Ladbury: And the only way you are going to see the science change is if some new theory comes along that explains the data better. To date, denialists have proposed precisely bupkis. That is why they and you are irrelevant.

      Lack of a correct theory doesn’t make the current AGW theory any more or less correct. You know that. And there’s no need to be a jacka$$ to the guy. I suspect Hansen would have called anyone that stated we’d be below Scenario C “irrelevant”….and yet here we are.

      Elsewhere you note…This is not a science in its infancy.

      It might not be a science in its infancy, but it’s certainly not mature, and pretending that folks have a firm grasp on how this works with any certainty is laughable.

      Aerospace engineering is about 100 years old, about the same amount of time since Arrhenius and others first thought about this. Understanding the mechanics required to successfully model flight is a much simpler problem than understanding and modeling climate. And there has been orders of more magnitude devoted to understand the machanics of flight and everything that goes into that (materials, propulsion, etc). Thus, we are at a point today where after a staggering investment, we are able to reliably model the mechanics of flight with great accuracy.

      Thus, by definition, our understanding and modeling of climate climate is quite poor (orders of magnitude less) when you compare it to our ability to model and understand things that are quite a bit simpler (integrated circuits, flight, etc).

    • michel // October 18, 2008 at 5:31 am

      Lucia has tried darn hard to falsify the IPCC projection

      The implication is that she has an agenda other than simply establishing whether the IPCC projection is supported by the evidence.

      First, I see no sign that she does. She seems to be following the data wherever it leads. She picked the start of her data series for the excellent reason that she wished, when dealing with predictions, to be dealing with predictions which predicted what was in the future at the time they were made. This is perfectly reasonable.

      Second, even if she were pursuing the subject with a view to falsifying the IPCC projections, this would not touch on the validity of her research. It does not matter a bit why she is doing it. What matters is whether she is doing it right. Many of the great discoveries in science have been made because the discoverer set out to falsify an hypothesis, and either succeeded or failed, with startling results.

      All too often in this blog it is thought sufficient to dismiss an argument by casting aspersions on the motivation of the one putting it forwards. These remarks only lessen the credibility of the one making them. As in this case.

    • John C // October 18, 2008 at 5:36 am

      Ray Ladbury wrote :
      Produce one quote by the IPCC that precludes the sort of trend we’ve seen.

      As I already wrote (I hate having to repeat myself) … see p34 of the IPCC2001 report Summary for Policy makers. Link below in case you can’t find it.

      http://www.ipcc.ch/pdf/climate-changes-2001/synthesis-spm/synthesis-spm-en.pdf

      As you can see, and if you actually plot the global temperatures up to 2008 on this graph, this little ‘flat’ period falls below the ENTIRE RANGE of scenarios (those are the different coloured lines) and below the ENTIRE ENVELOPE of uncertainty (thats the shaded grey area - and is stated as the 95% confidence limit). So clearly this little flat period falls below anything they might have expected (even in their wildest dreams) …. otherwise they would have used a bigger range.

      Sometimes a picture speaks a thousand words. You did ask though….

      [Response: The graph on pg. 34 of that link doesn't seem to support your claim. I think you've been very thoroughly brainwashed into believing it.

      You need to give this a good read.]

    • cce // October 18, 2008 at 5:51 am

      Here’s a math problem for Lucia’s supporters. Does the observed trend from January 2001 to September 2008 “falsify” (at the 95% level) the observed trend from January 1979 to September 2008?

    • hswiseman // October 18, 2008 at 6:43 am

      Choose 1975 and stand at the precipice of the big PDO switch, end your time series in 1999 and capture the super elnino, start in 2001 and dodge it. Infer motives against every selection. Avoid fundamental questions (stationary/non stationary/negative-positive feedback), perform science for the purpose of expanding the CI instead of improving the methods and quality of obs. This is what is being taught at the places that teach this science, pearls of wisdom such as poor old Pielke and “his crazed insistence the UHI seriously contaminates the overall surface T increase”, “I suspect there was some major professional disappointment (loss of funding for his RCM?) …”

      You all do it so well…and with so little embarrassment.

    • Ray Ladbury // October 18, 2008 at 11:13 am

      Duane Johnson,
      OK, now let me get this straight. You equate trying to learn the science with sycophancy?

      Hey, whatever, Dude. So how’s the ignorance thing working out for you, then?

      I’ve looked at Lucia, but I do not find her analysis at all persuasive. To draw any conclusions based on a short time-series when the noise can dwarf the signal on such timescales is questionable to say the least. To extrapolate that to a century timescale is risible. What Lucia is doing in this case is weather watching. She is much more interesting when she applies her skills to a meaningful dataset.

      When it comes to making policy, you have to go with the best science available. Not satisfied with that science? Then get a climate science PhD and publish something that does a better job. Otherwise, your opinion isn’t part of the scientific debate. It is still relevant in the “What do we do about it?” debate, but by rejecting good science, all you do is skip the main event to take in a side show.

      Now, I could go on, but given your dismissive attitude toward learning science, I don’t see much point in wasting more of my time on you. And good luck with the ignorance thing.

    • michel // October 18, 2008 at 1:05 pm

      Here’s a math problem for Lucia’s supporters. Does the observed trend from January 2001 to September 2008 “falsify” (at the 95% level) the observed trend from January 1979 to September 2008?

      No. And its not a math problem. There are two sets of observations, neither of which can falsify the other. They are what they are. What the trend is from 1975 on is a different question from the one Lucia is addressing. It may be a more interesting question, at least to some. But whether it is or is not, is irrelevant to whether she is addressing her chosen question correctly.

      I do not count myself as a ’supporter’ of Lucia in the sense that there is some general overall position which she is maintaining on AGW or the IPCC which commands my assent. I am a supporter in the sense that I find her work both competent and creative, on the subjects she has chosen. I’m a supporter also in that, like Lucia, I am very interested in both the methodology and the results of her careful analysis of the validity of IPCC predictions of temperatures post 2001. That is, the IPCC in 2000 made some predictions of temperatureswhich were at the time in the future. Have they been borne out by subsequent events, and if so, to what extent? This is a restricted but legitimate question, and one which lots of us want to know the answer to.

      You can’t say anything useful about her results on this by telling her she should be addressing a different question. Any more than you can by impugning her motives.

    • Ray Ladbury // October 18, 2008 at 2:33 pm

      Matt, First, is it too much to ask you guys to learn the difference between a prediction and a scenario. The best the scenario can do is give the overall trend to be expected–every single model run will be different. There is no meaningful trend that can be extracted from 7 or 8 years of data.

      Second, hmm, lack of a correct model, huh? We wouldn’t be referring to the only model by which we can understand a 2o year warming trend, the paleoclimate, the response of the climate system to volcanic eruptions and perturbations like the hiatus in global air traffic and numerous other pieces of evidence, would we? I’d call that a pretty successful model. What is more, the conclusion on anthropogenic causation is predicated on aspects of the theory about as basic as Bernoulli’s equations. Why not try to learn the science, so that you at least are not trying to demolish a straw man?

      As to Dave A., if you look at our full correspondence, I would contend that I have shown astounding forbearance. For instance, despite being called a “true believer” by someone who clearly has made zero effort to understand the science, not once did I suggest that he was an ignorant food tube.

      As to the accusation of irrelevance–can you think of anything more irrelevant than flogging away against a blog that merely tries to teach the science while the science continues to progress far, far away in academic journals, oblivious of your flailings. Contrary to what Ms. Pailin asserts, causes do matter. The science has been reviewed and found cogent by scientific and professional sciences from the National Academies to the American Institute of Petroleum Geologists. Perhaps if you learn more about it, you will find it cogent as well. Then you can exercise your responsibility as a citizen and look for solutions that are consistent with what you value.

    • Raven // October 18, 2008 at 3:22 pm

      Ray says:
      “I’ve looked at Lucia, but I do not find her analysis at all persuasive. To draw any conclusions based on a short time-series when the noise can dwarf the signal on such timescales is questionable to say the least. ”

      There is no magic interval that seperates climate from weather. The only reason to use longer periods is the CIs decrease with longer periods so it is easier to distinguish between hypotheses. There is absolutely nothing that says cannot measure climate trends over shorter intervals provided one chooses the appropriate CIs. In most cases, the this means that results are too uncertain to tell us anything useful, however, sometimes the trends are so significant that it is possible to reject some hypotheses even if the CIs are wide. That is what Lucia has demonstrated. At this point in time we can safely assumes that either:

      1) The sun has a much greater effect than what was previously claimed by the models.

      2) The models over estimate the amount of warming from CO2.

      So feel free to quibble about Lucia’s choice of CIs, however, insisting that it is ‘impossible’ to analyze climate over shorter time scales makes no sense from a statistical or scientific perspective.

    • cce // October 18, 2008 at 3:41 pm

      Anyone who claims to have “falsified” the IPCC projections, which are ensemble means that eliminate natural variability, based on ~8 years of data is not interested in correct methodology. She has been repeatedly told this, yet she insists on mischaracterizing the IPCC projections. Gavin posted the results of 55 model runs that went into a scenario from AR4. 9 of them (~16%) showed flat or cooling temperatures from 2001 to 2007. She can keep saying that the projections have been “falsified at the 95% level” all she wants, but it has no bearing on the facts.

    • Duane Johnson // October 18, 2008 at 3:59 pm

      Ray,

      I consider sycophancy to be obeisance to some entity, in order to gain perceived benefit.

      You haven’t understood Lucia’s analysis, since the heart of her analysis is to evaluate the variability (you call it noise) in the weather data from historic data from periods that excude major volcanic data. She is not ignoring the weather variability, but is evaluating the extent to which it can explain the validity of a particular (2C/century) from Jan 2001. As Tamino has noted, she doesn’t find, based on GISS data that 2C/century can be excluded at a 95% confidence level. However, her analysis does so at a 90% level, which the IPCC categorized as a very low level of confidence in their advice to policy makers. Her analysis is subject to caveats, which she openly states.

      And she doesn’t claim the duration of the trend is for a century, only for the first portion of the 21st century as projected by the IPCC.

      Tamino and others with the necessary statistical experise can and will critique the analysis, and we can all learn from it.

    • Ray Ladbury // October 18, 2008 at 7:15 pm

      Raven, Your conclusions are entirely predicated on the noise model Lucia assumed–and that is hardly uncontroversial. Her model is entirely statistical. There is no physical motivation, and it has not been peer reviewed. This is the sort of analysis that is much better suited to a journal article than a blog.
      I would doubt that even Lucia would consider her analysis to be definitive. It was meant to be provocative and it at least succeeded to that level.
      Your possibilities should be expanded to include
      3)The noise model does not fully capture the full variability in the real system.
      4)The historical variability is less that that expected in a warmer world (indeed, there is some reason to expect this.
      I am also sure there are other possibilities–but since we’re talking about an analysis with cherry-picked dates that still fails to contradict the scenarios (not predictions) of the IPCC, what would be the point.

    • Ray Ladbury // October 18, 2008 at 7:18 pm

      Duane, You’ve made it clear you have nothing to offer, but even I have to bite at that: Just what possible benefit does your poor, sad, deluded mind think that I gain from accepting the science? The only thing this does for me is allow me to understand a broad range of climate phenomena, preclude my ability to rationalize complacency and ensure that I remain a member of the reality-based community.

    • Dave A // October 18, 2008 at 7:22 pm

      Ray,

      “ignorant food tube”

      You certainly have a way with language. I like that. Ever thought of turning to writing and reconsidering your faith/ certainty?

      BTW, I think I exercise my responsibilities as a citizen pretty well and am certainly not a novice in pursuing causes.

    • Raven // October 18, 2008 at 8:49 pm

      Ray,

      Lucia is careful to point out all of her caveats and I agree that the choice of noise models does affect the results.

      However, I would argue that we have no way to determine what the theoretical climate noise model is so estimating using statistical analysis is the only plausible approach and that Lucia’s approach is perfectly reasonable.

      In any case, I am only arguing that it is possible to evaluate models over the short term and you cannot dismiss an analysis simply because the timeframe is too “short”.

    • Ray Ladbury // October 18, 2008 at 9:05 pm

      Dave A., My position is no different that the overwhelming majority of scientists who’ve looked at the issue–but then I suppose you’ll accuse all the scientis associated the the:
      American Physical Society,
      American Geophysical Union
      American Chemical Society
      AAAS
      NAS
      Federation of American Scientists
      NRC
      American Meteorological Society
      American Quarternary Association
      Geological Society of America
      American Statistical Association
      Not one professional or honorific scientific society that has examined the science has found it wanting. But I guess they’re all “true believers,” too. Or, maybe they just understand the science.

    • Ray Ladbury // October 18, 2008 at 10:48 pm

      Raven, How do you vilidate the choice of noise model–especially over short timespans. You could probably get any result you wanted–and that is why looking at very short periods is inadvisable. On the other hand, a consistent rising (or falling) trend stands out over long periods will stand out. Again, a blog is not the place for such enquiries, as they are unvalidated, unreviewed and unreliable.

    • michel // October 19, 2008 at 7:03 am

      She can keep saying that the projections have been “falsified at the 95% level” all she wants, but it has no bearing on the facts.

      That is not what she says. We have another example of a tactic which has become familiar on this blog, to refute something which the person you are attacking did not say in the futile effort to discredit something different which they did say.

      All she has said is that the projections made in 2000 for the period 2001-8 have been falsified at the 95% level by the observations that have come in so far.

      As she keeps saying, this is a very restricted point. It could well be that subsequent observations will be inconsistent with it. It could well be that this is too short a period to tell us much. What it does to the claim of 2C/century is an entirely different question.

      The simple point is that the claim that temperatures from the period of 2001-8 are consistent with a forecast of 0.2 per decade for this period has been refuted at the 95% level. Its time to accept this as a fact, and then we can all move on and debate what, if anything, it means about the wider issues. But a necessary preliminary to this moving on and any fruitful discussion is going to be acceptance of the point.

      [Response: NO IT HASN't, and it's high time for you to accept that fact. But as long as denialists so staunchly refuse to do so, there's no productive discussion with them about anything.]

    • John Finn // October 19, 2008 at 8:26 am

      Re: Ray’s post

      ” Not one professional or honorific scientific society that has examined the science has found it wanting. ”

      Well not one that has ‘American’ in it’s title anyway. The Russians, on the other hand, think it’s a crock

    • Barton Paul Levenson // October 19, 2008 at 10:40 am

      Raven writes (typically):

      There is no magic interval that seperates climate from weather. The only reason to use longer periods is the CIs decrease with longer periods so it is easier to distinguish between hypotheses. There is absolutely nothing that says cannot measure climate trends over shorter intervals provided one chooses the appropriate CIs. In most cases, the this means that results are too uncertain to tell us anything useful, however, sometimes the trends are so significant that it is possible to reject some hypotheses even if the CIs are wide. That is what Lucia has demonstrated. At this point in time we can safely assumes that either:

      The World Meteorological Organization defines climate as mean regional or global weather over a period of 30 years or more. Lucia’s work is irrelevant because she, like you, steadfastly refuses to work with the right time scale.

      1) The sun has a much greater effect than what was previously claimed by the models.

      No it doesn’t.

      2) The models over estimate the amount of warming from CO2.

      Which ones? All of them? Do you know what the range of sensitivity measures is? Here’s a hint. Just take out the spaces, which are there to get by the spam filter:

      http://www.g e o c i t i e s.com/bpl1960/ClimateSensitivity.html

      So feel free to quibble about Lucia’s choice of CIs, however, insisting that it is ‘impossible’ to analyze climate over shorter time scales makes no sense from a statistical or scientific perspective.

      It makes all kinds of sense. 30 years is the timescale needed to let the noise settle out and analyze the signal. Until you understand that, everything you have to say on the matter is irrelevant.

    • Barton Paul Levenson // October 19, 2008 at 10:48 am

      Raven writes:

      you cannot dismiss an analysis simply because the timeframe is too “short”.

      Sure we can. We just did.

    • Lazar // October 19, 2008 at 10:53 am

      Raven,

      we can

      No sale.
      See?

      Over the short 8 year period, the regressions range from -0.23ºC/dec to 0.61ºC/dec. Note that this is over a period with no volcanoes, and so the variation is predominantly internal (some models have solar cycle variability included which will make a small difference). The model with the largest trend has a range of -0.21 to 0.61ºC/dec in 4 different realisations, confirming the role of internal variability. 9 simulations out of 55 have negative trends over the period.

      The 95% confidence limits for the eight-year period, -0.23<T<0.61 degC/decade, encompass the HadCRUT trend calculated by Lucia of -0.10 degC/decade (which she uses as an exact figure — which is wrong).

    • Lazar // October 19, 2008 at 11:24 am

      which is wrong

      Giving it more thought, I take that back.

    • Raven // October 19, 2008 at 12:36 pm

      Ray,

      Lucia uses >30 years of historical data durng volcano free periods to estimate the noise model. 30 years is more than long enough estimate such a parameter.

      I realize that you would like to argue that the noise model changes over time and that the noise model from the 1930s does not apply today. However, such an argument is speculation at this point and would have to be applied consistently to all tests. e.g. if the noise model for the system changes over time then this must be taken in account before one can claim that we have observed statistically significant warming over the last 30 years.

    • John C // October 19, 2008 at 12:40 pm

      [Response: The graph on pg. 34 of that link doesn't seem to support your claim. I think you've been very thoroughly brainwashed into believing it]

      I don’t think have been brainwashed. I can just plot data on a graph. I had a read through your other post …. and have to say it seems a bit confusing. I prefer a more simple approach ….. just plot the 2000-2007 data (GISS or Hadcrut - adjusted to a 1990 baseline) on the IPCC 2001 projection graph on p34 the data is all just at or below the entire projection range.

      The only conclusion I can draw from your other post is that there have been some pretty basic schoolboy errors in plotting the data. Bizarre.

    • Raven // October 19, 2008 at 12:44 pm

      Ray,

      BTW - the idea that such discussions must take place in “peer-reviewed journals” is extremely out of date. The online world is here to stay and the science community needs to adapt. In fact, I think a secretive peer review process where one can never really know if a paper was rejected for political rather than scientific reasons undermines the credibility of science and we would all be better off if the if the review process was conducted in public on things like blogs.

    • Raven // October 19, 2008 at 1:09 pm

      Lazar,

      Lucia has explained the distinction between the test she is using and the test Gavin uses numerous times. Lucia’s test is only testing the 2 degC/century ensemble mean. It is does not test lower trends such as 1.5 degC/century which are within the bounds provided by the IPCC.

      IOW, Lucia’s test tells us that the actual trend is likely lower that 2 degC/century but it does not tell us how much lower.

    • Raven // October 19, 2008 at 1:12 pm

      Paul,
      “It makes all kinds of sense. 30 years is the timescale needed to let the noise settle out and analyze the signal. Until you understand that, everything you have to say on the matter is irrelevant.”

      Lucia uses 30+ years of data to calculate the noise model. This is sufficient to address your concerns.

    • Lazar // October 19, 2008 at 1:58 pm

      What Lucia did and what the IPCC says…

      For the next two decades a warming of about 0.2°C per decade is projected for a range of SRES emissions scenarios.

      The IPCC projected a range of trends due to forced and stochastic variation, and model bias.
      Lucia did not estimate those sources of error so she treated 0.2 deg C/decade as an exact prediction, which is wrong.
      The RealClimate projections CI contains the bias and stochastic elements but not forcing variation, why it’s a projection not prediction.
      Even HadCRUT eight-year trend is clearly consistent with the model projections.
      Instead Lucia tests whether 0.2 deg C/decade falls within the observational error, calculating confidence intervals for the observations and not the projections is precisely the wrong way round given the data. She is inferring the true i.e. long-term observational trend by estimating it from the sampling distribution, and testing whether that trend is consistend with an exact projected figure. There is no single true long-term projection figure, and over shorter periods the projection variance blows up. The RealClimate approach is much simpler and better; the models project this range of trends over an eight-year period, does the observed trend fall within that range?

    • Ray Ladbury // October 19, 2008 at 3:17 pm

      Raven, one of the reasons we have such confidence that CO2 is behind current warming trends is because it’s signal–a relatively steady rise in temperature over long times–stands out against the shorter term variations that make up the “noise”. We are much less certain about drivers of the noise–only that on timescales of 30 years or so, it averages out. That does not mean that if we take 30 years of data that we will have a representative sample with which to generate a statistical model.
      As to peer review by experts in the field, it works. However, you can also use other measures–how often does the work get picked up and used by others. By any reasonable standard of quality and consensus, denialists have produced bupkis.

      Oh, and John Finn, the delicious irony of conservatives appealing to the authority of a petrogangster state for support–priceless.

    • Lazar // October 19, 2008 at 3:45 pm

      Question for Raven;

      Lucia inferred that the true i.e. long-term temperature trend lies within the 95% confidence interval constructed around the temperature trend between Jan 2001 and Aug 2008. For HadCRUT3, that confidence interval is centered around -0.10 deg C/decade. But for the period Jan 2000 to Aug 2007, the confidence interval is centered around +0.16 deg C/decade.

      Why do you assume that the first confidence interval contains the true population trend, but the second does not?

      It is does not test lower trends such as 1.5 degC/century which are within the bounds provided by the IPCC.

      … so it does not test the IPCC projections. Even this sample does not exclude 2 deg C/decade, Lucia states…

      The hypothesis of 2C/century is not rejected to p=95% based on the average of NOAA, HadCrut3 and GISS using a statistical model treating “weather noise” as “AR(1)+white noise”; that is it does not falsify.

    • TCO // October 19, 2008 at 4:29 pm

      Can’t be bothered to read all the comments.

      Tammy, I think your point that any 10 (or 7) year flat (or slight down) trend is not repudiating the centenial scale prediction. Since we know there is large inherent variability on several year scales (e.g. El Nino).

      I think obsessing on if the “current decade” started in 2000 or 2001 (reminds me of all the pedantry surrounding the millenium definition) is not that important and would give the benefit to someone choosing either.

    • TCO // October 19, 2008 at 4:54 pm

      Consider this a Bayesian provocation. Just throwing it out there, for people to answer. Assuming that you (roughly) agree with the IPCC 2C/century temp rise, from AGW. How many (more) years of ~flat temp, would it take to shake your confidence?

    • dhogaza // October 19, 2008 at 5:01 pm

      Well not one that has ‘American’ in it’s title anyway. The Russians, on the other hand, think it’s a crock

      Not true. They signed on to this statement.

      Why make shit up when we can correct you by spending 30 seconds in Google?

    • Gavin's Pussycat // October 19, 2008 at 6:12 pm

      > we would all be
      > better off if the if the review process was conducted in public on
      > things like blogs.
      I can almost believe you are serious, you weren’t very sane in your earlier comments either. For medicine as well? That’s one country to avoid travelling to ;-(

    • Hank Roberts // October 19, 2008 at 6:14 pm

      > Why make shit up ….

      Because one partisan can tie up a whole company of the enemy’s troops by sniping from good cover and forcing them to pay attention to him, while maneuvers are going on elsewhere.

      It’s their point of view. Annoyance, not collaboration, is their idea of effective action.

    • Gavin's Pussycat // October 19, 2008 at 6:33 pm

      TCO, I know you like reading :-), so this link:

      http://www.realclimate.org/index.php/archives/2008/05/what-the-ipcc-models-really-say/#more-564

      It answers a question rather close to your question, which I hope is good enough: over a period of 20 years, one of the 55 model runs will produce a negative trend, corresponding to approx. p = 98%.

      I would start sweating a bit if that happened ;-)

    • Lazar // October 19, 2008 at 7:00 pm

      TCO,

      would it take to shake your confidence?

      15 years in total.

    • transplant // October 19, 2008 at 7:02 pm

      dhogaza, because they don’t expect the gullible to spend that 30 seconds.

    • Ray Ladbury // October 19, 2008 at 7:56 pm

      TCO asks “How many (more) years of ~flat temp, would it take to shake your confidence?”

      I think that what most people fail to understand that this is not “The theory of anthropogenic climate change,” but rather the theory of climate which coincidentally implies humans are behind the current warming epoch. Since the theory has proven very successful in understanding a broad variety of phenomena and historical data, it’s very unlikely the theory (or even the CO2 sensitivity~3) would be scrapped even if we had a significant trend. Instead, we’d have to start looking at what is different about the current period from previous ones. Only if we couldn’t find any plausible forcer that had changed would we begin to look at a substantially different theory–and it would be markedly different.
      Science is fundamentally conservative: It says if the theory ain’t broke, don’t fix it. We have no evidence the theory is even ailing. I don’t think scientists would even feel much urgency for another 5-10 years, and only after another 20 years would the discrepancies become glaring.

      The really interesting thing about Lucia’s analysis is not the result, but the way denialists have grabbed onto this straw–a purely statistical model of something we don’t even know can be modeled –while rejecting a successful dynamical model that actually has some physics behind it. It shows it’s not “the models” they reject, but rather their implications.

    • cce // October 19, 2008 at 8:14 pm

      michel,

      For your benefit, I will make it crystal clear:

      She can keep saying that 8 year projections have been “falsified at the 95% level”, but it has no bearing on the facts. What it does require is a mischaracterization of the IPCC projections.

    • Barton Paul Levenson // October 19, 2008 at 8:33 pm

      michel writes:

      All she has said is that the projections made in 2000 for the period 2001-8 have been falsified at the 95% level by the observations that have come in so far.

      Yes, we know she said that. But she’s wrong. And you’re wrong if you believe her.

    • Barton Paul Levenson // October 19, 2008 at 8:34 pm

      John Finn writes:

      ” Not one professional or honorific scientific society that has examined the science has found it wanting. ”

      Well not one that has ‘American’ in it’s title anyway. The Russians, on the other hand, think it’s a crock

      The Russians believe UFOs are alien spacecraft, and the KGB spent millions trying to find ways for psychics to read American military documents at a distance.

    • Barton Paul Levenson // October 19, 2008 at 8:37 pm

      Raven writes:

      the idea that such discussions must take place in “peer-reviewed journals” is extremely out of date. The online world is here to stay and the science community needs to adapt. In fact, I think a secretive peer review process where one can never really know if a paper was rejected for political rather than scientific reasons undermines the credibility of science and we would all be better off if the if the review process was conducted in public on things like blogs.

      Modern science runs on consensus and peer review. People who attack either invariably have a pseudoscience axe to grind. The existing system has been tremendously productive; to replace it for no reason other than the fact that it doesn’t tell you what you want to hear would be stupid.

    • Barton Paul Levenson // October 19, 2008 at 8:54 pm

      Raven writes:

      Lucia uses 30+ years of data to calculate the noise model. This is sufficient to address your concerns.

      No, it is not. She’s using 8 years of DATA, for Christ’s sake. On a time series which only gives meaningful trends with 30 years or more. 8 < 30.

    • Raven // October 19, 2008 at 9:21 pm

      Barton says:
      “No, it is not. She’s using 8 years of DATA, for Christ’s sake. On a time series which only gives meaningful trends with 30 years or more. 8 < 30.”
      Why don’t you try reading her blog and understanding what she has done before commenting?

      She used 30+ years of data estimate the noise model for the climate system and then used this model to caculate the CIs for the 8 year trend. This allows here to draw robust conclusions from short trends.

      Now you can quibble with her choice of noise model bit if you do you will be disagreeing with Tamino too since she uses the one that Tamino uses in his posts. The only difference is Lucia is comparing apples to apples by using volcano free periods to determine the noise model.

    • Dave A // October 19, 2008 at 9:48 pm

      Ray,

      Impressive list.

      here’s another fact - in the UK survey after survey over the last 40 years has shown that the majority of people are in favour of the death penalty for murder ( the UK is abit ahead of the US here in having abolished the death penalty in the 1960s). Just because a majority seem to be in favour of something doesn’t mean that it is right.

      Moreover, how many of those esteemed organisations consulted their membership before issuing their statements? Relatively few I would guess. So in fact the the supportive statements could well have been issued by a relatively small number of people. And doesn’t the ‘politics’ always rear its ugly head in the way people get to the top of such bodies. Isn’t it always the case that the decisions are actually taken by a small number of people who rely on the inertia of the majority to push through their point of view?

      Just a few observations after considerable time observing (and being involved in) how bureaucracies and environmental organisations work

    • Hank Roberts // October 19, 2008 at 10:42 pm

      > how many … I would guess. So in fact
      > … could well have been … And doesn’t the
      >‘politics’ always … Isn’t it always the case …

      Some of this you can look up for yourself.
      Why not try asking a librarian? You say “in fact” but have no facts. Get some.

    • Ray Ladbury // October 19, 2008 at 10:56 pm

      Raven, to contend that you get a “robust” result using 30 years worth of data to model “noise” that is the result of hundreds of contributing factors is at best naive and possibly deluded. I doubt even Lucia would call the result robust. At best, this is an interesting exercise.

      And that you believe this result while discounting the ability of modelers to get the contribution of CO2 right, speaks volumes about both your motivations and your lack of understanding.

    • Ray Ladbury // October 19, 2008 at 11:01 pm

      Dave A., Scientific consensus has nothing to do with “democracy” or polling. It has to do with how convincing the evidence is. The best measures of this are the number of peer-reviewed publications incorporating an idea/technique, and the number of times those publications get cited. By these measures, the denialists ideas and approaches are moribund. They’ve done nothing to advance understanding of climate, so they have nothing to say.

    • John Finn // October 19, 2008 at 11:47 pm

      Oh, and John Finn, the delicious irony of conservatives appealing to the authority of a petrogangster state for support–priceless

      Do what? Explain, please.

    • Raven // October 20, 2008 at 12:33 am

      Ray,

      Robust was the wrong word - it has too many implications. Reasonable or plausible is what I meant.

    • Ray Ladbury // October 20, 2008 at 1:15 am

      Dave A.,
      I cannot speak for the politics in every organization I list, but I am familiar with the politics at APS, AGU and the other main physics organizations. These are the people outside of straight climate science that you would expect to have the best understanding of the science. Aside from a very few, they are persuaded by the science–and this despite the fact that it runs counter to their interests as it threatens funding to their (and my) specific disciplines.
      These organizations have taken the position they have because the membership is genuinely concerned about the threats posed by a changing climate the infrastructure of civilization. Pretty much anyone who understands the science is likewise concerned.

    • Ray Ladbury // October 20, 2008 at 1:19 am

      Raven, do you really think it is “reasonable” to characterize the variability of what is in effect weather (and so chaotic) with only 30 years worth of data? Do you really think that it is “reasonable” to draw strong conclusions based on such an analysis when it hasn’t even been peer reviewed–or indeed reviewed in detail by any independent expert? I must say, you have an interesting definition of “reasonable”.

    • Raven // October 20, 2008 at 1:49 am

      Ray,

      I don’t think much of the peer review process any more - there are simply too many examples of bad papers getting the ‘peer-rewiewed’ endorsement followed by people pushing the junk results as the “truth” because they have been peer reviewed.

      I have much more faith in open blogs which allow ideas to be criticized. Lucia’s ideas have been critiqued by many. In some cases, she has adjusted her approach to deal with the critiques yet the conclusions remain the same.

      Ultimately, what convinces me are testable hypotheses that can be refuted. If Lucia’s analysis is testable over the next few years because if her noise model is reasonable then we will not see a sudden reversal of temperatures that puts the trend at or above the 2 degC/century. If we do see such a reversal then your opinion will be vidicated. Until then we don’t know.

    • dhogaza // October 20, 2008 at 3:14 am

      I don’t think much of the peer review process any more

      How much science do you want to toss into the trash, then? Everything from the last 200 years?

      I have much more faith in open blogs which allow ideas to be criticized. Lucia’s ideas have been critiqued by many. In some cases, she has adjusted her approach to deal with the critiques yet the conclusions remain the same.

      Yes, this is very true. The professionals who examine her work point out to her that her so-called analysis is a non-starter, she deals with bits and pieces that she thinks will not impact her work, and she concludes that she’s still right.

      And you think this is better than peer review because … if she then took her modified conclusions, and submitted them to a competent journal with access to experts in the field, they’d say the same as science bloggers say:

      Lucia’s full of shit.

      Yet you have more confidence in her process, which essentially boils down to telling her professional critics, “Naw, I’m right, you’re wrong!”

      It is *precisely* this attitude that the scientific system of publication, review, rebuttal, citation, etc avoids.

    • Raven // October 20, 2008 at 3:44 am

      dhogaza says
      “How much science do you want to toss into the trash, then? Everything from the last 200 years?”
      Peer review is a relatively recent process. Einstein’s works were not peer reviewed. Peer review is not a fundemental part of the scientific method. It is construct designed to allow government agencies to figure out who should get funding.

      The old media sneered at blogs for years but it has been forced to accept and even embrace them. We have a situation today where blogs and traditional news media complement each other.

      The same transition will happen in science. In the meantime it is silly to argue that an idea must be ignored unless it appears in the peer reviewed literature.

    • michel // October 20, 2008 at 6:52 am

      Lazar, thank you very much for a clear, polite and above all specific account of what exactly you find mistaken in Lucia’s approach. Greatly appreciated for itself, but also for the contrast it provides to the mindless chorus which surrounds it.

    • Former Skeptic // October 20, 2008 at 7:43 am

      Einstein’s works were not peer reviewed.

      That’s a pretty good straw man (I assume you are referring to his 1905 papers). However, Einstein, and Watson and Crick, if I may add, were the exceptions to the rule; Their discoveries were ground-breaking but stood up to the scientific method as their results could be repeated by others leading to laws and theories blahblahblah. OTOH…which part of the statistical analysis done by Lucia is groundbreaking? She’ll be the first to admit it isn’t ;)

      Peer review is not a fundemental part of the scientific method.

      Yes it is. How else would you account for possible mistakes in each step of the scientific method? Your proposed alternative has major logical holes in it, as dhogaza pointed out above.

      It is construct designed to allow government agencies to figure out who should get funding.

      …and you ignore that peer review is essential for publishing scholarly work. Were you misled by the snazzy picture on the Wikipedia article on peer review, by any chance?

      The old media sneered at blogs for years but it has been forced to accept and even embrace them. We have a situation today where blogs and traditional news media complement each other.

      The same transition will happen in science. In the meantime it is silly to argue that an idea must be ignored unless it appears in the peer reviewed literature.

      (i) Interesting, but ultimately spurious comparison. Media =/ science.

      (ii) No one’s ignoring ideas from Lucia, AW, or even the “auditors” at CA. But until their ideas get proper assessment from folks in the relevant field who can see thru bullsh*t, such musings will not carry much weight within science.

    • Barton Paul Levenson // October 20, 2008 at 10:46 am

      Raven writes:

      She used 30+ years of data estimate the noise model for the climate system and then used this model to caculate the CIs for the 8 year trend. This allows here to draw robust conclusions from short trends.

      It does nothing of the sort. You can’t magically make a small sample into a large sample. Lucia’s work is useless and her conclusion is meaningless.

    • Barton Paul Levenson // October 20, 2008 at 10:50 am

      Raven writes:

      Einstein’s works were not peer reviewed.

      Einstein’s papers appeared in Annalen der Physik, a peer-reviewed physics journal.

    • michel // October 20, 2008 at 11:55 am

      Raven’s point about blogging is evidenced by the discussions of the statistical basis of certain proxy studies which have recently been taking place on CA. Chunks of R code are being exposed to public view, the commentary to and fro is of a high level, and we are finally getting to a real detailed understanding of the statistical issues.

      Of course, many here would say that we understood them beforehand, all we had to do was read Mann’s 2008 paper. Not really. What the blogging has done is to allow us all (or at least all of us with R on our machines which is presumably most readers here) to follow the working, download the raw data, verify the conclusions, perform experiments for ourselves. Its precisely what BPL is always urging us to do. Blogging has made it much more accessible, and allowed us not to work in a vacuum.

      This blog also makes a real contribution at times. But whether we like it or not, blogging and particularly scientific blogging is here to say. We will have to get used to it. Its like the Bible in the vernacular. After John Huss, that particular cat was never going back in the bag. We are never going back to the old world of a monopoly of scientific publication in the peer reviewed journals. Have to get used to it.

    • John C // October 20, 2008 at 12:52 pm

      I have to say I am amazed at all this discourse on whether the IPCC 2001 projections have falsified.
      I have a suggestion .. maybe even a challenge. Lets actually make a very simple graph of the the HAdcrut annual data points vs. the lower bound of the IPCC 2001 enevelope (which is on p34 of the Summary for Policy makers document and stated as the 95% confidence level). Since the projection was made in 2000, lets plot the envelope projection from 2000-2050 and then plot the Hadcrut data - at least 2000-2008 but earlier years as well if wanted. Suggest we normalise to the 1990 value as per the chart in the IPCC2001 report.
      Lower bound of the envelope can be approximated with following x,y points :
      2000,0.19
      2010, 0.24
      2025,0.45
      2050, 0.80

      The hadcrut series (normalised to the 1990 value) are :
      2000, -0.010
      2001, 0.152
      2002, 0.207
      2003, 0.209
      2004, 0.184
      2005, 0.231
      2006, 0.174
      2007, 0.155
      2008, 0.053 (based on 9 months)

      Now we can clearly have a debate as to whether the fact that these data points are at or below the envelope is ‘falsification’, or whether its just ‘weather’. But my view is, if the IPCC full suite of models so overestimate what has actually happened in the first decade, it hardly gives a lot of confidence to the models predicting the next decade or even century.

    • Ray Ladbury // October 20, 2008 at 1:00 pm

      Raven says, “Einstein’s works were not peer reviewed.”

      Absolute horse puckey. All his papers were peer reviewed except the 1905 relativity paper. This Planck read and used his prerogative as editor to bypass review. However, to argue that getting past Planck was a dodge shows a certain ignorance of that man’s character.

      He digs deeper, “Peer review is not a fundemental part of the scientific method. ”

      Actually it is. The requirement for sponsorship by an academy member for presentation at the British or French academies is a precursor, and journal articles underwent peer review of a sort ever since there were scientific journal, rather than self-published pamphlets.

      And mysteriously concludes, “It is construct designed to allow government agencies to figure out who should get funding.”

      Huh? This makes no sense. You are mixing up peer review of journal articles with review of research proposals. Good Lord, have you ever even known a scientist?

      And my personal favorite: “I don’t think much of the peer review process any more - there are simply too many examples of bad papers getting the ‘peer-rewiewed’ endorsement followed by people pushing the junk results as the “truth” because they have been peer reviewed.”

      So your attitude is to remove all quality control whatsoever? Brilliant. Peer review is a threshold, not a ceiling. It says that one’s peers have looked at the paper and decided that it has enoug interesting and is not too seriously flawed to merit scrutiny by the community as a whole. Good God man, learn something of how science is done!

    • michel // October 20, 2008 at 1:40 pm

      Raven’s point is a rather different one. She does not seem to be arguing that the existing peer reviewed journals should abandon their practice. She is rather pointing out that there is much dissatisfaction with the results of giving peer-reviewed publications a monopoly on what we regard as being scientifically respectable discourse.

      The dissatisfaction includes the time it takes, and the proportion of false positives and false negatives.

      As a matter of fact therefore, in response, more and more scientific argument, comment, publication, is taking place online in various forums. These have the advantage of being immediate, collaborative, interactive and so on. There are also dissatisfactions with the economic policies of the journals.

      We can like or dislike this. We may wish that it wasn’t happening, and wish the only stuff we had to read was still in the peer reviewed journals. But it is just not the case anymore. Insisting on ignoring arguments or work published outside the peer reviewed journals is a bit like not wanting to read scholarly material not written in Latin. There was a period in which it remained a defensible posture. But after a while it became ridiculous, because with all of the disadvantages of publishing in the vernacular, people were just going to do it.

      Its the same with blogs and other online publications. It is going to happen. Peer reviewed journals of various sorts will continue, maybe even keep their present policies. But the monopoly is dead. You will find, for instance, that the fact that Spencer’s upcoming paper on clouds appears in a non-peer reviewed journal does not enable us to avoid discussing it. And getting irritated by this is pointless. Its just the way the world is going.

    • thingsbreak // October 20, 2008 at 2:44 pm

      michel: You will find, for instance, that the fact that Spencer’s upcoming paper on clouds appears in a non-peer reviewed journal does not enable us to avoid discussing it.

      If by “us” you mean skeptics and those who seek to debunk climate FUD on the internet, perhaps.

      If by “us” you mean the scientific community and policy makers, I’m afraid you greatly overestimate the role that Spencer and/or climate blogs play in the real world.

    • Ray Ladbury // October 20, 2008 at 2:45 pm

      Michel,
      Your proposition that “everything is different now” is simply not justified. Informal discussions have always taken place in science–at conferences, colloquia and even around coffee pots. Blogs, etc. merely provide a extend such informal forums.
      What is more, peer review isn’t going anywhere until you can get tenure (or a promotion) based on your blog. Scientists may look to blogs for interesting ideas, but nobody is going to cite a blog entry in a paper. Science only changes when it needs to, and the Internet hasn’t forced any big changes yet.

    • Hank Roberts // October 20, 2008 at 2:59 pm

      Raven says, “Einstein’s works were not peer reviewed.”

      Raven should learn to check this stuff. Just because it’s found on a site where you like the politics doesn’t mean it’s correct.

      “Just because you’re on their side doesn’t mean they’re on your side.”

    • dhogaza // October 20, 2008 at 4:01 pm

      Blogging has made it much more accessible, and allowed us not to work in a vacuum.

      Yes, the internet has made science, and other realms of knowledge, much more accessible. No one argues that this is a good thing.

      However, blogging is not going to replace scholarship, in science and elsewhere.

      Just as television made the wonders of the natural world much more readily accessible to people the world over, whereas in the past you needed to be wealthy to experience the wonders of antarctica, africa, the arctic, south america, north america, and eurasia. That increase in accessibility is a wonderful thing.

      But it hasn’t changed how science does its business.

    • dhogaza // October 20, 2008 at 4:01 pm

      Um, no one argues that this is NOT a good thing. Oops!

    • David B. Benson // October 20, 2008 at 9:41 pm

      Early scientific journals weere only ‘peer-reviewed’ by an editor; this practice continued for PNAS up to at least 1945 CE, when Saunders MacLane had to go discuss with an editor why Saunders ground-breaking paper with Sammy Eilenburg should be published. The editor finally relented, stating that the paper had the least content of any he had ever published.

      The paper was the first to define ‘category’, ‘functor’ and ‘natural transformation’. Of course now there are many books and journals devoted to the subject.

      By the way, this apparent informality was easier since all three were in NYC in 1944, when the paper was written and delivered to the PNAS editor.

    • Dave A // October 20, 2008 at 10:21 pm

      Ray,

      >It has to do with how convincing the evidence is.

      But shouldn’t the organisation then consult its membership about that very issue?

    • Dave A // October 20, 2008 at 10:27 pm

      Dhogaza

      Lucia’s full of shit.

      How pathetic and unworthy.

      If you can’t discuss in a civilised manner why should I ever bother reading any of your comments again?

    • dhogaza // October 21, 2008 at 12:09 am

      If you can’t discuss in a civilised manner why should I ever bother reading any of your comments again?

      Given that there’s no evidence you pay any attention to anything that’s written that doesn’t fit your ideologic preconceptions, who cares?

    • Michael hauber // October 21, 2008 at 1:24 am

      I think a lot of the controversy around Lucia arises as people don’t understand what a ‘95% confidence leve’ means.

      This means that if the calculations are done correctly, the 95% confidence interval gives an outcome that you expect 95% of the time.

      However if the outcome is outside of the 95% confidence interval, what does this imply?

      Thought experiment: consider a bag of marbles. A friend claims that there are 19 white white marbles in the bag and 1 red marble. The 95% confidence interval for this bag is the 19 white marbles.

      You draw a marble out of the bag. It is red. Does this mean your friend’s claim that there are 19 white and 1 red marbles is incorrect?

      This is like Lucia’s claim, she has calculated that if the IPCC claims are correct, then we should have around a 5% chance of observing an 8 year period with a trend of less than a certain amount. We’ve observed 8 years with a trend of less than that amount. Does that mean the IPCC claim is correct, and we’ve just had the luck of the draw to pick the red marble? Or is something else going on?

    • Ray Ladbury // October 21, 2008 at 1:42 am

      Dave A., Policy initiatives usually start with the membership–being raised at a conference. The society will then likely appoint a committee of experts to assess the science and report back to the administrators. It will be debated endlessly and ultimately get a thumbs up or down. As the recent flap over at the Forum on Physics and Society shows, the rank and file understand the evidence and the physics both favor anthropogenic causation. If the membership did not agree with a position taken by the leaders, the latter would definitely hear about it.

    • Gavin's Pussycat // October 21, 2008 at 5:07 am

      What Ray said. Just renewed my AGU membership, and I expect them to engage in the way they do. It’s their proper job.

    • cce // October 21, 2008 at 6:18 am

      The IPCC claim is that warming over the next two decades will be about 0.2 degrees per decade. So what does that mean?

      You have, for example, 55 model runs, the average of which shows “about 0.2 degrees per decade.” 9 of them predict flat or cooling temperatures for the first 8 years.

      Then someone comes along and says that the ensemble mean has been “falsified at the 95% level,” based solely on their own expectations of what the weather is supposed to be, ignoring the weather generated by the models themselves.

      If you want to evaluate the weather, you have to look at the model runs that make up the ensemble. If observations were less than 5% likely, there wouldn’t be 16% of the models predicting results similar to observations. Run the models again, and you’d essentially shuffle the results, but the distribution of outcomes would be largely the same.

      The point is that after two decades, all of this crap cancels each other out, and you are left with warming of “about 2 degrees.”

    • Steve Carson // October 21, 2008 at 8:08 am

      I have a question that doesn’t seem raised here (implied maybe?). I have followed a few discussions in this blog for a little while only, so if it has been covered elsewhere, please feel free to point me to that resource.

      Clearly you can’t take two end points and say that the trend is up or down.

      But how do you determine what statistical analysis to apply to a given period? And how do you determine what period is significant?

      To someone as uninformed as me, it seems to go to the heart of the problem. I’m not a statistician so bear with me. Doesn’t calling variation noise imply that you know what the signal is?

      I’m looking at a graph of global temperatures from 1860 to present, that someone has thoughtfully added a 5-yr average to. It’s an arbritrary choice I’m sure but it makes the swings from year to year disappear. To say that climate is measured over 30-years is again an arbitrary choice. If we put a 30-yr average over the graph, would the cooling from 1940 - 1970 appear to be “noise” until it was over? Or even disappear as noise if you put the right time period of averaging onto it?

      So this is what I’m missing. Do you need to have a climate model to determine the right period? Without a climate model is any period as good as any other, with the only proviso that longer is better? And if that’s the case, how do you ever know that you have picked a long enough time period?

      [Response: It's immensely difficult to know what the "signal" looks like when the noise level is so high. Over a period as brief as a decade, it's not even possible to demonstrate that there's a signal at all -- it could be just noise. But as the time span gets longer, the signal level increases while the noise level (presumably) stays the same, so the signal-to-noise level gets high enough that it finally becomes possible to demonstrate there really is a signal there.

      Then one has to identify the shape of the signal. This can't be done with certainty, we can only approximate it, but the right thing to do is to find the *simplest* description which "explains" the variation in the sense that what's left over (the "residuals") aren't unambiguously different from noise. The data since 1975, for example, are well modeled by a linear increase plus noise. The linear increase is the simplest pattern to explain the signal, and the residuals are indistinguishable from noise.

      Often you can get valuable clues about the signal shape by smoothing the data -- the 5-year averages do exactly that. There's still noise there, but it's less than in the 1-yr averages or the monthly averages. Meanwhile the signal is undiminished, at least that part of the signal on a time scale of about 5 years or longer! Fluctuations on shorter time scales are lost; for example we lose the seasonal changes with 5-yr averages. But we're not really interested in the seasonal changes anyway -- if we didn't get rid of them by averaging we'd want to get rid of them some other way -- so that's OK. But there could be other changes on short time scales that would be "smoothed out" by smoothing on a longer time scale.

      The main thing to keep in mind is that all we get from statistical analysis, in the end, is an approximation. The last 30 years are indistinguishable from a linear increase plus noise, but that doesn't mean the increase is truly linear; it almost certainly isn't. But we can establish for certain that over that time span it's more than just noise. And over the entire span of available data, it's clearly not just a linear increase.

      I realize this is an incomplete answer -- a complete one would take volumes.]

    • Ray Ladbury // October 21, 2008 at 1:49 pm

      Steve Carson,
      Tamino’s done a great job from the point of the statistician. As I physicist, I’d like to chime in that often we can get hints about “the signal” from the physics. So, in that sense, a model (not necessarily computer model) helps you sort out signal from noise.
      I realize that you are not a statistician, but a concept that is helpful is “confidence,” which has to do with the degree to which your conclusions are robust over sampling, etc. On very short timescales (a decade or less), climate data is so noisy that you really can’t draw conclusions with any confidence at all. However, because the “noise” tends to have short timescales (one year to roughly 11 years) while most “climate” signals persist over longer scales, what we can say about climate with confidence increases dramatically as you get toward 30 years of so.

    • cce // October 21, 2008 at 2:52 pm

      Of course, that should be “about .2 degrees per decade,” not 2 degrees!

    • David B. Benson // October 21, 2008 at 7:06 pm

      Ray Ladbury // October 21, 2008 at 1:49 pm — I fear I must disagree about the ‘noise’, climate variability being even roughly 1 to 11 years. Looking at the GISP2 ice core temperatures of Alley, just for the Holocene, the power spectral denisty (fft) shows (approximately) 1/f noise for all computable frequencies f, down to a period of about 20 years, this being about the best obtainable from that ice core.

      Some sources for this variability are known: random changes in TSI, deep ocean mixing times, ocean oscillations (which are correlated with changes in the length of the day). I’ll include Ruddiman’s early anthropocene hypothesis as anothr source of random changes, probably on the centennial and millennial scales.

      By the way, this ice core record ends in 1853 CE. Nothing recent.

    • Ray Ladbury // October 21, 2008 at 7:30 pm

      David, Thanks for clarifying my point. I did not mean to imply that noise sources only had periodicity out to 11 years. I merely meant that, there’s very little hope of resolving signal on periods that short. I stand corrected.

    • Dave A // October 21, 2008 at 9:41 pm

      Dhogaza,

      Pray tell me what my “ideological preconceptions” ,that you apparently can intuit, are.

      In a civilised manner, of course

    • HankRoberts // October 21, 2008 at 10:30 pm

      Dave, you told US what they are, a few weeks ago in an earlier thread. You said … but you know how to look yourself up.

    • dhogaza // October 22, 2008 at 3:47 am

      You said … but you know how to look yourself up.

      Only when it’s convenient, I’m sure.

    • Magnus A // October 22, 2008 at 5:57 am

      Ray Ladbury: “Now take a minute and step back to think about what you are defending: Lomborg took cherry-picked dates designed to give the absolute lowest trend he could and still it only ALMOST statistically falsified. Is that really what you consider a defensible position: “well, he almost wasn’t lying.”

      If the start points are a problems when it comes to if the trend is only slithly positive or slightly negative, isn’t that mostly a problem for thos who think we have huge global warming? :-)

      (Also the hypothesis which aenables the hypothesis of huge global warming, strong positive feedbacks of a magnitude of several hundred percent, is most unlikely, not at all proven, and now olso falsified by Aqua satellite data.)

      Lomborgs information is actually correct, which is proven by the calculations of Lucia Liljegren, and Jeff Id (who proves fundamental errors in Tamono’s calculation).

      [Response: I've seen Jeff Id's post; its reproduced at the garbage dump Anthony Watts' blog. That's where it belongs. It's good for a laugh.]

    • Ray Ladbury // October 22, 2008 at 3:44 pm

      Magnus A., You know, you’d save all of us a lot of time if you’d just learn the real science and not base your arguments on straw men constructions of your own fevered imagination. First, you can say nothing about climate based on 8 years of data.
      Second, you act as if the feedbacks were unique to greenhouse forcing. They aren’t. Any forcing will have the same feedbacks.
      Third, the Aqua data represent only 6 years–hardly time enough to overturn established science, even if they were a major problem. Fourth, they results represent a puzzle to be solved, not a major problem for climate science.
      Fifth, Lomborgs result may be numerically correct, but it is meaningless.

    • Lazar // October 22, 2008 at 6:02 pm

      [Lazar rant]

      Magnus A, Jeff Id, it’s trying enough to read your comments. Poor Tamino has to moderate them. Every day. Pop a $ in the tip jar. I doubt half of Watt’s readers actually believe what is written on Watt’s blog, it’s propaganda in an increasingly lost war. Jeff Id’s post? He doesn’t understand linear regression, doesn’t understand measurement error in the UAH and RSS datasets, and misrepresented Tamino’s work. I’m not going to comment why, Watt’s the point? It’s expendable. There’ll be another false claim tomorrow, the day after that, and the day after the day after that. Today’s shredded claims will be resurrected next year. Ir’a a munitions factory for saturation bombing of any debate that might actually be interesting and useful. There’s no interest in acquiring knowledge. It’s all for politics.

      Climate is the most breathtakingly beautiful thing that I have seen and studied. I can’t believe people choose politics over science. What poor taste.

      [/Lazar rant]

    • Gavin's Pussycat // October 23, 2008 at 2:37 am

      > Climate is the most breathtakingly beautiful thing that I have seen and studied.
      Lazar, I want to kiss you… Seriously, actually understanding climate makes one an all-rounder in natural science. I thought I was before it… wrong.

    • christabel // October 23, 2008 at 11:35 pm

      okay -i don’t know if i am allowed to post or anything here-and i probably won’t explain my opinion too intelligably -
      but all i know is that when i was told i had to read about the copenhagen consensus and watch the lomberg -ted talks thing— i was freaked out—he made no sense –it made me angry because i am a returning college student-older by about ten years than most the people in my class-plus i studied this issue before in a basic geology class about 6 years ago –and actually from what i was taught-on rudimentary charts–has so far come to pass–the scale and pattern of hurricane katrina being a prime example–i knew what was going to happen 2 days before it did-although hoping i’d be wrong-but only because i remembered the charts we were shown so long ago–the weather patterns seem in my opinion, to be consistently going towards the worse side of things-only actually about 5 years before they are supposed to -which scares me more–but even though i am no scientist and only have an iq of 140 anyway, i realize im not smart enough to take this in–but even though i know im not that smart or anything–i want to understand this
      -if i can predict the weather—then people much smarter than myself should see how obvious the changes are– god-if the queen of england actually was alarmed about it 3 years ago as well—id say it seems simple in general–no matter what semantics you all are battling over
      –and when we are learning about technology and society— and these younger kids are given that speech as a basis for — seeing another side to global warming and the enviornment than what we had been reading—i think is ridiculous—
      maybe there are general concerns that the costs of newer technologies is high at the outset, i do not believe he should be considered whatsoever in that -

      he skewed everything so bad, and i know people who havent read too much about this yet in their early college career, should be forming their own opinions about whether it is cost effective to phase in changes in technology–but um not from him maybe?
      - the article we actually read about the copenhagen consensus where they explained the hierarchy of world problems— where they claim to have the foremost experts on the panel— well was actually written by one of the guys on the panel. which is hilarious to me to begin with –
      -but i felt their whole take on things was retarded— i mean some of the problems he spoke of will not be easily fixed by throwing money at 3rd world countries— most of the strife in those places is related to something ecological–either climate changes or the illegal stripping of scarce natural resources-from multinational companies-like coltan, etc.–so i dont understand why under any circumstance that anyone can throw the enviornmental things aside like were all-’fanatical’- for being concerned–that lomberg dude even said that ‘yeah it may make a difference in 50 years but by then–we will be sooo rich we can deal with it then’
      ha—ironically i watched it the day before the banking issue happened–whether or not he cheated or any of that—it seems morally irresponsible to just say those things publicly when, at least the financial part was sooo off–i mean he just blurted out his own opinion of -the whole -futuristic–the world will be so much cooler in 10 or 20 years -we shouldnt care about anything now— i mean isnt he an economist?–how did he not know the state of the stock market and things–people have been talking about it long enough—right? i mean -as i said i dont know numbers and i admit to not at all understanding this chart thing– and i openly admit being naive—- but i thought that the ocean warming up 2 degrees was bad by anyone’s standards— it is to me i guess because i am originally from raleigh, nc—and if what happened in new orleans—which was exactly what was predicted to me–i really hope people start to think about it really hard because -
      of the whole country –there are like 5 places stuff is going to hapen first

      and well–nothing much happens in raleigh now —but this shouldnt be what puts it on the international news—i know i babble really—

      but does anyone get me–? or can help me understand this–i am supposed to be learning it now but apparently –im not going to in class–
      well—peace out–fellas —im going to see robert kennedy, jr—maybe he will make it clearer–
      -but from a mathematical standpoint—please if anyone could help–that would be awesome-

    • David B. Benson // October 24, 2008 at 12:51 am

      christabel // October 23, 2008 at 11:35 pm — I recommend starting with “The Discovery of Global Warming” by Spencer Weart:

      http://www.aip.org/history/climate/index.html

      Review of above:

      http://query.nytimes.com/gst/fullpage.html?res=9F04E7DF153DF936A35753C1A9659C8B63

    • Horatio Algeranon // October 26, 2008 at 7:06 pm

      Short trend reliance
      Is see-saw “science”

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