Open Mind

Explain this

October 1st, 2007 · 83 Comments

This is for those who are still not sure the globe is warming, who think maybe it’s just a false impression due to bias in the thermometer record, or that it’s just “natural variation” due to ever-changing climate, or it’s just the “urban heat island” effect, or who think it’s all just a socialist plot by liberals to ruin our economy and destroy our wealth.

Three months ago, it would have been appropriate for me to ask you to explain this:

seaice1.JPG

Today, following the latest press release from the National Snow and Ice Data Center, we know that the northwest passage was clear this summer, for the first time in human memory. Hence it’s more appropriate for me to ask you to EXPLAIN THIS:

seaice2.JPG

UPDATE UPDATE UPDATE

this map shows the area representing the northwest passage, and the location of Gjoa Haven (click the image for a clearer view):

nwpass.jpg

Categories: Global Warming · climate change

83 responses so far ↓

  • Mark Hadfield // Oct 1st 2007 at 8:11 pm

    Hey, that really *is* a big anomaly!

  • Ken // Oct 1st 2007 at 8:36 pm

    Maybe the sea ice extent anomaly measurer is too close to the air conditioner or parking lot. Anyone have any pictures? Or perhaps it is somehow George Soros or something?

  • jre // Oct 1st 2007 at 9:08 pm

    Ooh, ooh! Can I ask a follow-up question, please?

    Given what we have observed recently in the Arctic ice sheet, is it possible — even likely — that rapid changes in a land-bound ice sheet could occur with even a small perturbation? How about an ice sheet that rests on bedrock under sea level?

  • Glen Raphael // Oct 1st 2007 at 9:20 pm

    Just for comparison, why not include a similarly-constructed plot on *antarctic* ice extent?

  • dhogaza // Oct 1st 2007 at 10:47 pm

    Just for comparison, why not include a similarly-constructed plot on *antarctic* ice extent?

    What’s your point? That, as models predict, the NH is warming more quickly than the SH?

  • fergusbrown // Oct 1st 2007 at 10:58 pm

    Will this do for the time being, glen?
    http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/current.anom.south.jpg

  • cce // Oct 2nd 2007 at 12:21 am

    A lack of cosmic ray activity caused a malfunction in the mie scattering code of Soros-funded air conditioners on Mars, causing the arctic to melt but creating a new ice age on Venus. The Antarctic stayed the same, so it balances out.

  • Deech56 // Oct 2nd 2007 at 12:48 am

    Yeah, but unless next year’s anomaly is more negative the headline will be “Arctic Cooling. Global Warming a Hoax.”

  • nanny_govt_sucks // Oct 2nd 2007 at 1:10 am

    Maybe it’s because of soot:

    http://www.giss.nasa.gov/research/news/20050323/
    “New findings show that soot may be contributing to changes happening at the North Pole, such as increasing melting of sea ice and snow and warming atmospheric temperatures.”

  • Arctic Sea Ice Anomaly | Atmoz // Oct 2nd 2007 at 2:01 am

    […] Tamino has a new post about the lack of sea ice currently in the arctic. I’m not sure why arctic sea ice extent has been featured so much lately in the blogging community, but I best get on the same page as everyone else, right? […]

  • Dano // Oct 2nd 2007 at 2:15 am

    Maybe it’s because of soot:

    Huh.

    Mankind changing climate. Thanks for the reminder. We forgot.

    Best,

    D

  • nanny_govt_sucks // Oct 2nd 2007 at 3:04 am

    Yes Dano, but let’s get the attribution right. Soot and/or CO2? Soot alone? CO2 alone? It makes a difference if you’re really concerned about ice melting in the Arctic. Banning SUV’s won’t make a difference if the problem is soot from Asia.

  • Petro // Oct 2nd 2007 at 3:59 am

    Nanny, the reason you and your peers are called denialists is that you deny the impact of American consumption to the world’s environmental change. If there is a straw to grasp, you surely reach it.

    At the same time you reject hundreds and hundres times more solid scintific evidence contradicting your opinion.

    Nanny, just for curiosity: Do you think evolution is a scientific fact?

  • Hank Roberts // Oct 2nd 2007 at 4:05 am

    The trick is, each time you get to pretend to understand something new, you have to forget something more basic, so you get to start over again by asking for help with the elementary stuff.

    I wish you’d let some other kid ask the questions. Maybe we’d get one who actually wanted to learn something instead of just chase everyone around in circles barking.

  • Chris C // Oct 2nd 2007 at 5:00 am

    You communists have got it all backwards.

    Isn’t it obvious that the low sea ice extent, measured by satellites, is a result of air conditioners and BBQ in space (possibly put there as part of an evil plot by Al Gore, funded by George Soros, to take away the freedom of Americans), causing abberations in lens to give false images.

    James Hansen and Micheal Mann have obviously written poor code to correct these errors, as the ice age they were being alarmist about long ago hasn’t occurred, indicating it’s all and evil conspiracy to get research funding and wipe out Africa.

    Besides, the natural variability of the cosmic rays is causing penguins in the Arctic (yes penguins… the liberals don’t want you to know that they’re in such good shape they migrated all the way around the world) to form an “iris” of white bellys that will cause the Artic to cool again.

    Come on pinkos, get your facts right!

  • Heretic // Oct 2nd 2007 at 5:47 am

    Reading throught the weekly reports of the Polarstern, it seems that soot alone can not be blamed . There were multiple factors at play this year, a major one being warm humid air from Siberia. There was an unusual amount of rain up to the very high latitudes, which would not favor the workings of soot. Oceanic currents are another variable that is not so well understood. All in all, it is an extraordinary event.

  • nanny_govt_sucks // Oct 2nd 2007 at 6:23 am

    Nanny, the reason you and your peers are called denialists is that you deny the impact of American consumption to the world’s environmental change.

    Are we moving the goalposts again? I thought the issue was “increased CO2 concentrations cause global warming”. Now it’s the broader “American consumption”? I’ve posted plenty on CO2, and am not satisfied with the responses by any means. More on this later (I still owe John Cross a detailed response on an earlier thread whic h I hope you’ll look for).

    If there is a straw to grasp, you surely reach it.

    At the same time you reject hundreds and hundres times more solid scintific evidence contradicting your opinion.

    Like multi-proxy climate reconstructions, GCMs, and the surface temp record? For a good summary of these, please see Pat Franks comment #198 at http://www.climateaudit.org/?p=2105

  • Wolgang Flamme // Oct 2nd 2007 at 8:24 am

    Obviously atmospheric CO2 has increased ~ +40 ppm since last year.

  • William Connolley // Oct 2nd 2007 at 9:25 am

    Wellll… OK then. Try this: just as the 2003 european heat wave was such a huge anomaly it didn’t fit the stats, so is this. We can happily attribute the overall trend to GW - its what we expect, and its what the models show. This years anomaly is *not* what we expect and its *not* what the models show. Why should we attribute it to GW?

    What do you expect to see next year?

  • DWPittelli // Oct 2nd 2007 at 12:35 pm

    The arctic sea ice loss is disturbing, especially but not only if it is considerable next year. (No, it would not have to be as bad as 2007 next year to represent a problem, just bad compared to, say, the summers of 2004-2006.)

    Whether primarily soot or CO2 caused, it would be due to human burning of fossil fuels, especially coal. So “soot” is hardly a strong rejoinder from an AGW skeptic. While it is possible to burn coal cleanly as far as soot is concerned (unlike CO2), the replacement of coal electric plants by nuclear and hydro is a likelier means of eliminating both pollutants.

    Although it is possible that such meltings have happened in the past, that does not mean there is no scientific or practical interest in identifying a cause, and I know of no likely non-anthropogenic cause. (To my knowledge the sun is not brighter this year.)

    Then again, despite some claims to the contrary, I am not an AGW denier. I do think that statistical work on the temperature record and temperature stations remains worth doing, as it may enlighten us as to climate sensitivity. But gross changes such as this Arctic melting do put the arguments about the record (which are typically in the range of about 0.1C.) in a different light, because the albedo changes will likely mean increased climate sensitivity.

    Notwithstanding all of the above: Among those whom you might rationally see as prominent opponents, those who are “not sure the globe is warming” are sufficiently rare that your opener is close to a straw-man argument.

  • Dano // Oct 2nd 2007 at 12:40 pm

    Like multi-proxy climate reconstructions, GCMs, and the surface temp record? For a good summary of these, please see Pat Franks comment #198 at

    This is #2, where denialists can’t look to their own body of work and instead must look anywhere but scientific journals, empirical evidence, testable hypotheses.

    Best,

    D

  • Peter Hearnden // Oct 2nd 2007 at 12:41 pm

    Tamino, can you explain what the last three points on the graph are? Month? Season? Is the rest of the graph by month or season, or other?

    [Response: Each point in the graph is the average sea ice extent anomaly for one month; the last three points represent the months of July, August, and September of this year.]

  • fergusbrown // Oct 2nd 2007 at 1:27 pm

    William; it’s early days yet, but I’d take a bet that next year will have a minimum somewhere between this year’s and 2005’s. There’s no strong reason to expect that HP to repeat itself next year, and it’ll be a while before the long-term diagnostics are available for next Summer, but since I called this one back in April, I’m reasonably confident about it.

    Note; wasn’t 2005 also an ‘outlier’ in the same way? I’m not contradicting your analysis, btw, just wondering what the significance, if anything, is of having two such ‘outliers’ within three years.

    regards,

  • DWPittelli // Oct 2nd 2007 at 1:47 pm

    One other (mild) criticism (besides of the straw-man opener): it would be preferable to show a graph of “Arctic Sea Ice Extent” — ideally with a base at zero — rather than “Anomaly” of the same, so that we could readily see how significant these changes are.

  • cce // Oct 2nd 2007 at 2:32 pm

    Here is the total Arctic Sea Ice Extent, although if the goal is to see “how significant the changes are” that is the purpose of the anomaly.
    http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/current.area.jpg

    Here are the seasonal historical data:
    http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/seasonal.extent.1900-2007.jpg

  • jeremy // Oct 2nd 2007 at 2:34 pm

    The Chemtrails are fighting with the Reptoids, duh. That’s just the period where the Reptoids have been winning.

  • richard // Oct 2nd 2007 at 2:50 pm

    “No, it would not have to be as bad as 2007 next year to represent a problem, just bad compared to, say, the summers of 2004-2006″

    Given the trends in the graph, it would take several years of greatly reduced anomalies to reduce concern. Anomalies of the magnitude of those in 2004-2006 would still be anomalies of concern, surely.

  • Hank Roberts // Oct 2nd 2007 at 2:55 pm

    You can find all the charts at the Cryosphere site, although looking at pictures doesn’t really help you tell how significant the difference is in the statistical sense.

    What I haven’t found is a longterm record of winds, and I’ve seen several mentions that it’s the polar winds that are behind the especially low sea ice numbers this year because they’ve moved much of the floating ice off to one side of the Arctic. But I don’t have any better info that those little text mentions.

    I guess the heat gain from the sunrise in six months depends on how thick the current winter’s ice becomes on the currently open areas — or on whether the winter winds can scatter the ice again before it freezes up in its current position, which I guess is more likely. So we’d get ‘multi year’ ice where the ice is now and ‘one year’ ice on the currently open areas, and then how fast does that ‘one year’ ice melt or break up and scatter and how much heat is gained next summer.

    William, are you taking bets on the details? Explaining the details that are being tracked well enough to let people bet on them would be a big help.

  • Hank Roberts // Oct 2nd 2007 at 3:00 pm

    http://arctic.atmos.uiuc.edu/cryosphere

  • Bosboros // Oct 2nd 2007 at 3:57 pm

    Hello,
    I can’t remeber in which thread it was, but you (Tamino) once mentioned that the satellites temperature measurements dont include the arctic and thats the reason why the satelitte data dont schow the year 2005 as warm as 1998. I am currently discussion whit a climate skeptic on this topic and therefore it would be great if you could post your your source for this statement.

    Best regards
    Bosboros

    [Response: I think you’re referring to my statement that the HadCRU temperature time series does not include the arctic, while the GISS data estimate it by interpolation; hence GISS shows 2005 as the warmest while HadCRU shows 1998.

    But the satellite data also exclude the poles; look closely at the MSU data and you’ll note that the area covered by satellite measurements is from latitude 70 deg. south to 82.5 deg. north. Hence it excludes both the far north and the far south.]

  • J // Oct 2nd 2007 at 3:59 pm

    jre wrote:

    “Given what we have observed recently in the Arctic ice sheet, is it possible — even likely — that rapid changes in a land-bound ice sheet could occur with even a small perturbation? How about an ice sheet that rests on bedrock under sea level?”

    There isn’t really an “Arctic ice sheet”, since “ice sheet” generally refers to glacial ice rather than sea ice. The dynamics of the two types of ice are really quite different, even in the case of the below-sea-level ice sheets (WAIS and Greenland).

    There may be a general lesson here (that the earth system can experience surprisingly large anomalies from year to year). We saw that with the 2003 European heat wave, the 2004 and 2005 hurricane seasons, and now with 2007 Arctic sea ice. But I don’t think there are a lot of specific lessons that can be drawn from the sea ice to the (Greenland/WAIS) ice sheets. The physics are just too different.

  • Aaron Lewis // Oct 2nd 2007 at 6:01 pm

    But, does it mean anything? It is worth plotting as standard deviations from the mean. That looks to me like a system that became unstable and is rapidly seeking a new equilibrium.

  • Hank Roberts // Oct 2nd 2007 at 7:26 pm

    > the below-sea-level ice sheets
    > (WAIS and Greenland).

    Greenland?? It will be above high tide even when ice free:
    http://not-clima.net/greenland-glaciers.pdf

  • John L. McCormick // Oct 2nd 2007 at 7:35 pm

    Is our fascination with the Arctic sea ice melt anomaly a diversion (aversion) from the much more important issue of impact on the temperature and precipitation patterns in Westen North America?

    Do we have anyone out there determining the impact on NA climate next growing season in the world’s grain basket? This melt has a lot more to do with the fate of food importing nations than the fate of polar bears.

  • Hank Roberts // Oct 2nd 2007 at 7:41 pm

    Great NYT Science section today on sea ice changes. I don’ t see all the graphics from the actual newspaper when I look online (maybe you need Flash, their ‘multimedia’ button may have the charts they printed). Lots of good links; one of them led to this lovely bathymetry (water depth) chart:
    http://www.oc.nps.navy.mil/~pips3/pips.gif

  • jre // Oct 2nd 2007 at 8:22 pm

    J, I stand cheerfully corrected on the point of usage — make that “Arctic sea ice.” And your point regarding differences in mechanics between floating and standing masses of ice is well taken. Actually, WAIS and Greenland are not both “below-sea-level ice sheets” — much, if not most, of Greenland’s bedrock is above sea level. The bedrock supporting the WAIS is substantially below sea level. WAIS also lacks the mountainous ring that exerts some containment on Greenland’s ice flows. So the three cases of Greenland, WAIS and Arctic sea ice are different, which I think was your point. But mine was both broader and fuzzier: if we see an abrupt change in sea ice from a small increment in the region’s heat content, might we see analogous (not identical) mechanisms act to destabilize the big free-standing ice sheets? And should we be worried about that possibility?

  • DWPittelli // Oct 2nd 2007 at 11:52 pm

    richard: “Anomalies of the magnitude of those in 2004-2006 would still be anomalies of concern, surely.”

    Yes, I agree, and concede I misspoke (is miswrote a word?). Indeed, although it would be nice to have longer-term data to really understand significance, anything landing on the trend line at post-1995 levels would seem to be of significant concern.

  • luminous beauty // Oct 3rd 2007 at 3:35 am

    jre,

    Your question invites one to wonder how much of the increase in Antarctic sea ice extent is ocean surface that has recently become open to freezing due to the recent reductions of the Larsen B ice shelf.

  • Hank Roberts // Oct 3rd 2007 at 4:43 am

    Good question, I wondered too, found the numbers and have forgotten them already. Just compare the total area (summer vs winter) of Antarctic sea ice with the total area of the collapse, both are easy to find.

  • Georg Hoffmann // Oct 3rd 2007 at 11:33 am

    Tamino
    I have compared the statistics of the seaice data with a gaussian distribution. The 2007 event is about 8sigma off and so cannt be explained by a stationary statistic. Also you can add 2007 to the Stroeve/Holland sea ice model-observation comparison. It is really impressing!! Have a look here (sorry in German):
    http://primaklima.blogg.de/eintrag.php?id=11

  • J // Oct 3rd 2007 at 5:05 pm

    Even before its breakup Larsen B was relatively small when compared to the extent of SH sea ice (on the order of 10 000 km2, versus millions of km2). Larsen A was smaller. Finally, most of the (small) increase in SH sea ice area was before 2000, i.e. before the ice shelf collapsed. It’s more of a long, gradual, noisy, and marginally significant trend than a single sudden uptick.

    The significance of the Larsen ice shelves was really their illustration of how suddenly — and unexpectedly — a floating ice shelf can disintegrate.

    Apologies for suggesting that the Greenland ice sheet was similar to the WAIS. Much of central Greenland’s bedrock is isostatically depressed below sea level, but as JRE’s map shows it’s mostly surrounded by bedrock that is above sea level. I was mentally recalling older maps of Greenland that showed the sub-sea-level area as being both larger and more connected to the ocean (Baffin Bay) along the west coast.

    [Response: The increase isn’t even marginally significant. It appears to be so if you treat the random part of the data as a white-noise process, but it’s demonstrably “red” noise, and the trend is not significant.]

  • J // Oct 3rd 2007 at 6:09 pm

    I wrote:

    > [The change in SH sea ice extent is] more of a
    > long, gradual, noisy, and marginally significant
    > trend than a single sudden uptick.

    Tamino replied:
    > The increase isn’t even marginally significant.
    > It appears to be so if you treat the random part
    > of the data as a white-noise process, but it’s
    > demonstrably “red” noise, and the trend is not
    > significant.

    Thanks for the correction. Does this mean you’re about to give us a post contrasting the trends in NH vs SH sea ice? :-)

    [Response: I had thought about it, but concluded that I’ve said so much about sea ice lately it might be “overkill.” But now that I have a request, it just might be a good idea.]

  • Gareth // Oct 4th 2007 at 5:15 am

    T, while you’re in the mood to examine ice data, could I offer a suggestion. If you look at the Cryosphere Today NH anomaly plot , the uneducated eyeball notices a little more than an increase in the negative anomaly in the last 10 years. There also appears to have been a decrease in the variability - the amplitude of the “waggles” has decreased. The SH shows no similar effect. Looking for an explanation, one could surmise that the NH is now experiencing a “forcing” (possibly not in the strict sense) strong enough to dominate over natural system variability. What can we infer from that, I wonder?

    [Response: I’ll take a very close look at it, and probably post on the subject soon.]

  • J // Oct 4th 2007 at 1:43 pm

    Okay, so fools rush in where statisticians tread carefully, but …

    Gareth, I think what you’re seeing is an illusion. I did a quick, simplistic high-pass filter on the data, and the variance seems constant. (To be precise, I started with the monthly anomaly data, calculated the 9-month running average, subtracted that from the original signal to get the high-frequency noise, then calculated the variance using another 9-month window.)

    [At this point Tamino is probably muttering something about “bloody amateurs playing with statistics” but hey, it’s a free country and I can make a fool out of myself if I want…]

    What’s happening here is that a short-period cycle will be more obvious to the eye when it’s superimposed on a basically stationary signal than on a signal that is itself changing. (I’m not explaining this well, but bear with me). This can be demonstrated fairly easily in any statistical software (or even a spreadsheet like Excel).

    Create a 2D data set where the y values are constant (say, y=100), then superimpose some regular small fluctuation (say, +0 units, +5 units, +10 units, +5 units, +0 units and repeat). You get a nice little sawtoothed pattern. Now do the same thing, but starting with a simple downward trend (say, y=100-x). The sawteeth look a bit smaller. Finally, make the underlying trend steeper (y=100-4x), and the sawteeth appear to be vanishing.

    The variance appears constant in the SH ice anomaly data, because the underlying trend is flat. In the NH, the variance appears to be decreasing, because the underlying trend is steeper… but it’s just an optical illusion.

  • Evan Jones // Oct 4th 2007 at 2:57 pm

    I just read that NASA said it was all because of some errant wind of undisclosed origin that blew the ice right out of the arctic ocean and it just melted.

    Stipulating that this is true, one is led to wionder if winds have a continually varying input or whether it’s anomalous

    The earlier comment on dirty snow vs. CO2: It’s FAR easier and cheaper to get the dirt out of the manufacturing process than getting CO2 out.

    If part of GW is due to dirt, we should be grateful: that’s so much easier a problem to solve–and it’s temporary, anyway. China and Inda will modernize and clean up just like the postindustrial west, and they’ll be quicker about it that the US was..

    P.S.

    Hello, Tamino; I’ve read you on other blogs.

    I’m just a poor mercury monkey who thinks that we need better stats. There may have been spurious adjustments, and there’s a heck of a load of statistical snow even if adjustments are made carefully and individually.

    I also don’t think we know as much as we think we know. Either NASA is right or wrong on this wind deal. I wonder how sure NASA is about this in the first place?

    [Response: You shouldn’t just read what someone says NASA said; you should read what NASA said.

    Their press release states that the wind patterns are anomalous, and that the only reason they were able to move the ice around so effectively is the dramatic disappearance of perennial ice, which has been replaced by thinner annual ice (which is so much more susceptible to being pushed around by winds). The press release also makes it clear that the anomalous wind patterns did not exist before 2000; hence they can’t explain the persistent, dramatic, statistically significant downward trend in arctic sea ice which occured *at least* since satellite observations began (in late 1978). In fact you only have to go as far as 1986 (barely more than 7 years) into the data record to find that the trend is significant. The latest announcement by NASA may help explain why the loss of sea ice in the last few years has be so extreme — but it can’t possibly explain the loss of sea ice prior to 2000. The *dominant* factor in arctic sea ice loss is temperature increase.

    We’re all happy to have better stats. But the corrections that have been applied *have* been done carefully and objectively. As for the “statistical snow” — that will always exist, and much of the science of statistics is about quantifying this. We *can* measure whether results are real or just a false impression proceeding from the heat-oppressed snow, so it does *not* lead to false results, just inconclusiveness. And the surface temperature record from thermometers is only one of *many* evidences of a warming planet; the satellite temperature record, worldwide retreat/disappearance of glaciers, decline in snow cover, earlier arrival of spring and later arrival of autumn, migration of species, increasing ocean temperature, greater severity and duration of heat waves, etc. etc. etc.

    Those “mercury monkeys” who work earnestly and honestly to improve data quality will always find that their efforts are welcomed; those who are motivated by a desire to discredit what they don’t want to believe will reveal how prejudice sabotages the ability to do the job honestly.]

  • S2 // Oct 4th 2007 at 9:17 pm

    Following on from Gareth’s comment on The Cryosphere Today NH anomaly plot (and J’s response), I’m intrigued by tale of the tape, also from The Cryosphere Today.
    I realise that this shows the anomaly for sea ice area, which is different to the extent. I’m puzzled by the far right hand edge of the graph, though.

    Previous rapid declines (of the anomaly) seem to be followed pretty quickly by a recovery, but not this year. Instead, we’ve been “stuck” at about the same value for about three months. To my untutored eye, this looks almost like a step change.
    I’m sure it isn’t, and the graph will start to climb soon. But I do think it’s odd.

    Am I just not very good at reading graphs?

  • Steve Bloom // Oct 5th 2007 at 5:00 pm

    S2, this other CT plot shows the situation a little better. Below is the same as the last year of the “tale of the tape” while above is the actual area. Note that the actual ice area is recovering, but slowly enough that the anomaly (the difference between current ice are and the average of the ice areas on the same date for 1979-2000) is increasing rather sharply. This slow recovery (which is unprecedented, although I’m not sure it can be said to constitute a step change) was predicted, and could result in some rather large record anomalies this fall. The physical reason for the slowness is that the large extent of extra open water from the melting season needs to cool down enough to form ice.

  • Evan Jones // Oct 6th 2007 at 2:17 am

    T.,

    Thanks for your polite response.

    On the one hand, you may be right. GW (of whatever pedigree) may be at the root of the whole shbang: mystery wind, current ice composition, what have you.

    But on the other hand, the current melt is no longer a 1-step obvious thingie of “melting due to temperature increase”. Now we have “GW is probably causing the wind to have an effect on this particular ice, which may be particularlyt suceptible, also probably due to GW”.

    The second statement is inherently more indirect and uncertain than the former.

    That’s why I remain somewhat skeptical of the sun worshippers: If it were direct, such as the sun is X hotter and therefore earth is fX hotter. They have an indirect setup involving solar wind vis-a-vis cosmic radiation effect on clouds.

    Even the greenhouse effect is indirect, though well established. (That debate not being as much of an “if” argument, but a “how much” argument.)

    I’m just sayin’ that the science is immensely complex and climate science has not been on the front burner until recently. Besides, the crisis is not imminent.

    What if the governments of the world had gone off half-cocked int the mid-70s to 80s when “experts” told them that resources were nearly depleted and mass starvation within a decade was very likely? A lot of people would have died needlessly is what. (My copy of The Population Bomb sits on my shelf within an arm’s reach; Limits to Growth is packed away somewhere.)

    So I think we need to pick our way forward carefully and with an interdisciplinary approach. It’s important we find out more about this, and there needs to be a lot more debate and a lot more openness.

    I wish the proponents and skeptics would get their heads together on this issue with fewer flying spitballs.

    As a liberal in poor standing, I druther be blowing my bucks feeding babies than stashing carbon. If we are going to do the latter, it will be at the expense of the former. So I’d just as soon take the time to make sure. And how sure can anyone be with the horrid state of the surface station (not to mention the horrendous gaps in the station records themselves).

    I think a little due diligence is called for. And (I repeat) a lot of good, healthy debate!

  • PaulS // Oct 7th 2007 at 12:01 am

    Let’s remember, the topic here is politics, not science, so it gets complicated.

    In the second chart up top there is a spike around 1997 that is nearly as large as the current drop circled in red. So a perfectly valid hypothesis is that the current drop is simply a downward spike of slightly larger magnitude. The data set is risibly tiny, with only a mere 30 or so actual data points (the general minimum each year). Even on a Gaussian assumption, the chart, by itself, can teach us little about the true range of variability. And weather is hardly Gaussian, so the chart can actually teach us virtually nothing about the range.

    So the chart by itself is cause to say, “look, how interesting”, and nothing more. In order to panic, we must look to other data, such as local folk tales informing us that the Northwest Passage has “never” been open before. Data such as that might imply enough additional data points to render the downward spike statistically significant.

    But that process is like summing up oranges and apples. In some contexts, very likely including this one, scientists can defensibly assign coefficients or parameters allowing them to do just that. But whether it convinces lay people is another matter. And remember, nearly all politicians are lay people.

    Now, it may well be that the ice sheet will “remember” this year’s low, and that “memory” will drive next year’s portion of the current spike still lower. The absence of ice at the North Pole would no doubt get plenty of attention in the lay press. But perhaps the ice will rebound instead. In order to know empirically and for sure, we have no option but to wait until next season.

  • WhiteBeard // Oct 7th 2007 at 5:11 am

    Evan,

    I’ll agree that the definition of concrete steps we should take to curb and eventually reduce the release of fossil CO2 has yet to emerge. The underlying economics of which bullets are most golden depends on developments yet to be proven. Of course for those acting locally, conservation is always golden. Given the political régime the US suffers, and the huge amount of disinformation being slung about, I’m amazed that something along those lines is starting to be discussed.

    Dirt on ice is not good, but like almost everything else it works two ways. I live with snow covering the ground for better than 5 months (and growing less) each year. Present in small amounts (which almost has to be the case for the Arctic Ocean ice), it promotes melting from elevated short wave absorption. Enough of the stuff and it becomes an insulator from warmer air.

    In any case I don’t see that as terribly significant for the Arctic ice. That sea is a long way from significant manmade sources, and the size of wild fires (actually very large) on the adjacent land masses have been going on for a long, long time. (Projected high latitude continental warming, on top of what has already occurred, won’t help that).

    Fairly early on in this melt season, the National Snow and Ice data center reported that a high pressure system became established off Alaska’s North Slope and persisted through much of the summer. As well as helping to promote air flow off the Eurasian land mass, it produced abnormally clear skies and enhanced solar absorption by the Arctic Ocean’s surface. They called it a triple whammy. The Chuchki Sea and adjacent Siberian coast’s surface temperature is some 4C above average this year. It’s the area at the top on both edges of the map at: https://www.fnmoc.navy.mil/ncoda_web/dynamic/ncoda_1440×721_global_anom.gif where the scale seems to in Fahrenheit.

    The long term trend and the almost certain reduction of the albedo enhancing ice system’s recovery are the things I find important.

  • alan // Oct 7th 2007 at 11:57 pm

    The sudden increase in the anomaly makes it clear that we have passed the tipping point and that it is to late to stop global warming by reducing CO2 emissions. I may as well keep driving my SUV since it is will no longer make a difference what I drive.

  • Hank Roberts // Oct 8th 2007 at 2:09 am

    Fish here often?

  • luminous beauty // Oct 8th 2007 at 3:27 am

    This is the final stage of denialism.

    “Yes global warming is happening. Yes it is human caused, but we’ve successfully dithered and obfuscated for so long, now it is too late to do anything about it. Ha, ha, joke’s on you!”

  • recon // Oct 9th 2007 at 3:58 pm

    Anyone care to explain this correction discrepancy in Cryosphere data?

    0.5 Mkm² ice just gone missing between December 2006 and July 2007…

  • windansea // Oct 9th 2007 at 9:10 pm

    we know that the northwest passage was clear this summer, for the first time in human memory.

    1905: In mid August, Amundsen sailed from Gjøahaven (today: Gjoa Haven, Nunavut) in the vessel Gjøa. On August 26 they encountered a ship bearing down on them from the west, and with that they were through the passage. eyes. ‘Vessel in sight’ … Vessel in sight.

    [Response: That doesn’t mean the northwest passage was open; Amundsen *started* his journey in 1903! The passage was not “open,” and it took a very long time for his expedition to get from one ocean to another.]

  • Hank Roberts // Oct 9th 2007 at 10:11 pm

    Recon: search “cryosphere today” +data +error and then just click the “Wisdom” button …
    no, wait, read the hits and pick those that appear relevant. Try these:
    adjustments made to either data or algorithms used by NSIDC/Cryosphere Today earlier this year?
    rabett.blogspot.com/2007/09/northwest-passage-is-open-and-it-looks.html

    regarding the adjustments to past data done earlier this Spring by Cryosphere Today? …
    climatesci.colorado.edu/…/

  • windansea // Oct 9th 2007 at 10:33 pm

    typical response, Amundsen wasn’t just sailing the Northwest Passage, he also was researching polar magnetics, sailing to Gjoa haven in the summer has been done frequently, from there to Alaska is the true Northwest Passage. Amundsen called Gjoa haven the most perfect little harbor in the world and stayed there for 2 years conducting research.

    In August 1905 he sailed west from Gjoa and made it through in less than 2 weeks, which kind of mutes your “first time in human memory” statement.

    [Response: Wishful thinking on your part. NOVA did an excellent documentary on Amundsen’s journey, which made it crystal clear that the expedition was not *able* to sail directly through; despite their best efforts, they were ice-locked for a considerable amount of time. By the time they got to Gjoa Haven, the most difficult part of the journey was already over. The update to this post shows the location of Gjoa Haven.]

  • Hank Roberts // Oct 10th 2007 at 1:54 am

    http://www.framheim.com/Amundsen/NWP/NWPassage.html

  • Hank Roberts // Oct 10th 2007 at 3:12 am

    (In which we find, among much else, that after Amundsen made it past Goa, he didn’t manage to finish the trip from there that season).

    As our correspondent above remarks, “from there to Alaska is the true Northwest Passage.” And Amundsen’s ship got caught in the ice north of the Yukon and Alaska.

    Amundsen planned ahead, and the history reminds us too how wise he was to make the attempt with a tiny ship — thanks to that, he only got stranded in shallows twice.

  • Chris O'Neill // Oct 10th 2007 at 11:51 am

    “the true Northwest Passage”

    Regardless of what someones personal favourite “true Northwest Passage” is, it’s worth noting that not only was Amundsen’s shallow route in Canadian national waters open but the internationally accessible deep -water route through McClure Strait was also open. I guess this would have major commercial implications if it became reliably open in the future.

  • windansea // Oct 10th 2007 at 4:31 pm

    I guess this would have major commercial implications if it became reliably open in the future.

    I wouldn’t sell your stock in the Panama Canal.

    http://www.nzherald.co.nz/section/2/story.cfm?c_id=2&objectid=10467905

  • windansea // Oct 10th 2007 at 4:35 pm

    Hence it’s more appropriate for me to ask you to EXPLAIN THIS:

    okay

    wind

    http://www.nasa.gov/vision/earth/lookingatearth/quikscat-20071001.html

    and sea :)

    http://luv.dkrz.de/publications_2005/pub_291_329.pdf

  • More Arctic Sea Ice News | Atmoz // Oct 10th 2007 at 11:11 pm

    […] temperature rises by 6.9C above pre-industrial levels. Numerous posts around the Internet, such as here, show how the arctic sea ice has declined in recent years. They also show that the sea ice decline […]

  • Gareth // Oct 11th 2007 at 3:19 am

    From windansea’s NASA link:

    “The winds causing this trend in ice reduction were set up by an unusual pattern of atmospheric pressure that began at the beginning of this century,” Nghiem said.

    From John L McCormick’s post on Sea Ice, North & South, this link (http://climate.weather.com/blog/9_13685.html, but especially the pdf of Orto’s presentation on that page), posits a significant change in global circulation about 8 years ago…

  • Chris O'Neill // Oct 11th 2007 at 4:52 am

    “I wouldn’t sell your stock in the Panama Canal.”

    We’re not talking about conditions of the last 100 years, which is all that http://www.nzherald.co.nz/section/2/story.cfm?c_id=2&objectid=10467905 talks about. We’re talking about the future where there won’t be any arctic sea ice at minimum anywhere in 20 years, let alone the North West Passage.

  • windansea // Oct 11th 2007 at 4:56 pm

    We’re talking about the future where there won’t be any arctic sea ice at minimum anywhere in 20 years, let alone the North West Passage.

    personally, I wouldn’t bet on that future. You may think the solar issue has been settled, and that the sun’s output has decreased in the latter half of 20th century. Try reading this for starters. (see fig 6)

    http://sait.oat.ts.astro.it/MSAIt760405/PDF/2005MmSAI..76..969G.pdf

    Solar activity, together with human activity, is considered a possible factor for the global warming observed in the last century. However, in the last decades solar activity has remained more or less constant while surface air temperature has continued to increase, which is interpreted as an evidence that in this period human activity is the main factor for global warming. We show that the index commonly used for quantifying long-term changes in solar activity, the sunspot number, accounts for only one part of solar activity and using this index leads to the underestimation of the role of solar activity in the global warming in the recent decades. A more suitable index is the geomagnetic activity which reflects all solar activity, and it is highly correlated to global temperature variations in the whole period for which we have data.

    and this:

    Here we show that measurements of the near-Earth interplanetary magnetic field reveal that the total magnetic flux leaving the Sun has risen by a factor of 1.4 since 1964: surrogate measurements of the interplanetary magnetic field indicate that the increase since 1901 has been by a factor of 2.3. This increase may be related to chaotic changes in the dynamo that generates the solar magnetic field. We do not yet know quantitatively how such changes will influence the global environment.

    http://www.nature.com/nature/journal/v399/n6735/abs/399437a0.html

    and then this:

    “Normally, the conveyor belt moves about 1 meter per second-walking pace,” says Hathaway. “That’s how it has been since the late 19th century.” In recent years, however, the belt has decelerated to 0.75 m/s in the north and 0.35 m/s in the south. “We’ve never seen speeds so low.”

    http://www.space.com/scienceastronomy/060510_sun_conveyor.html

    so, the solar large scale magnetic field has doubled in the last 100 years, but just recently appears to have shut down to record levels.

    The nasa panel on predictions for solar cycle 24 was completely split, some high and some low.

    http://www.swpc.noaa.gov/SolarCycle/SC24/PressRelease.html

    However, I’m betting on Dr Svaalgard (on nasa panel and has best track record) who predicts 24 will be the lowest in 100 years. Almost everyone at NASA predicts 25 will be super low.

    Three main groups of mechanisms have been
    proposed to explain how changing solar activity
    can influence the climate:

    1) variations in the total solar irradiance
    leading to variations in the direct energy input
    into the Earth’s atmosphere (Cubasch and Voss
    2000);

    2) variations in solar UV irradiance causing
    variations in stratospheric chemistry and
    dynamics (Hood 2003);

    3) variations in solar wind modulating cosmic
    ray flux which affects the stratospheric
    ozone and small constituents (Veretenenko and
    Pudovkin 1999) and/or the cloud coverage
    (Svensmark and Friis-Christensen 1997), and
    thus the transparency of the atmosphere.

    It’s going to cool off, how much I don’t know. If we have a geomagnetic reversal during this upcoming Maunder type minimum, then we have real cause for alarm as that could actually initiate an ice age. In which case we will start paying people to emit CO2 :)

  • ks // Oct 11th 2007 at 7:09 pm

    “In which case we will start paying people to emit CO2″

    but if CO2 is not a major player in climate change, why would you make such a suggestion?

  • Lee // Oct 11th 2007 at 10:06 pm

    there is also less multi-year ice, and it seems to be thinner ice, so wind piling the ice up can not be the primary explanation for the decrease in area.

  • Eric // Oct 11th 2007 at 11:21 pm

    WaS

    The carbon we are putting back into the atmosphere was sequestered in the Earth over periods of geological time. On some measures (Peak Oil and so forth) it appears that we have (very roughly) dumped half of it back into the atmosphere within 150 years. It is very suspicious that the climate should be changing just as we have done something so remarkable, don’t you think? In such circumstances, why would you consider something like the Sun to be the _main_ factor in global warming, and CO2 release to be insignificant? Your position isn’t the slightest bit logical.

  • Chris O'Neill // Oct 12th 2007 at 4:40 am

    windansea: “personally, I wouldn’t bet on that future.”

    Being a septic, windansea wouldn’t bet on anything. But he gives us a quote from that well-know climate science journal, The Journal of the Italian Astronomical Society:

    “Solar activity, together with human activity, is considered a possible factor for the global warming observed in the last century. However, in the last decades solar activity has remained more or less constant while surface air temperature has continued to increase, which is interpreted as an evidence that in this period human activity is the main factor for global warming.”

    Actually it’s evidence that the Sun is not the cause of warming in this period based on the silly idea that that if something doesn’t exist (a change in the sun’s radiation intensity) then it can’t cause an effect.

    ” We show that the index commonly used for quantifying long-term changes in solar activity, the sunspot number, accounts for only one part of solar activity and using this index leads to the underestimation of the role of solar activity in the global warming in the recent decades.”

    Who in their right mind would do this when all you have to do is look up the satellite measurements of radiation? Thank you Mr Strawman.

    ” A more suitable index is the geomagnetic activity which reflects all solar activity”

    Not half as suitable as using the satellite radiation measurements. I’ll leave windansea to the rest of his non sequitur strawmen.

  • windansea // Oct 12th 2007 at 8:54 pm

    but if CO2 is not a major player in climate change, why would you make such a suggestion?

    I guess you didn’t see the smiley face.

    it appears that we have (very roughly) dumped half of it back into the atmosphere within 150 years.

    hmmm, currently we are at 380 ppm, during the Cambrian it was 7000 ppm, so I think you need to rethink that one.

  • Hank Roberts // Oct 12th 2007 at 11:59 pm

    I’d guess you’re getting that 7000 ppm figure from the ‘freerepublic’ thread since it’s being honked about there a lot lately with claims the temperature proves there’s no warming from CO2.

    Consider the chalk.

  • Heretic // Oct 13th 2007 at 12:21 am

    I’d support your going to live in the Cambrian for a while and come back to tell us how much you enjoyed yourself.

  • windansea // Oct 13th 2007 at 1:38 am

    Being a septic, windansea wouldn’t bet on anything. But he gives us a quote from that well-know climate science journal, The Journal of the Italian Astronomical Society:

    let me guess, the solar physics stuff is over your head and so you are reduced to adhoms about me and Italian astrophysicists.

    Not half as suitable as using the satellite radiation measurements.

    that makes sense, lets only use data that goes back 30 years to decide how a 5 billion year old star affects our climate, and lets only look at TSI, no fair to see if solar magnetics might influence cloud formation.

  • windansea // Oct 13th 2007 at 1:42 am

    I’d guess you’re getting that 7000 ppm figure from the ‘freerepublic’ thread since it’s being honked about there a lot lately with claims the temperature proves there’s no warming from CO2.

    never go there, I found the graph here

    http://mysite.verizon.net/mhieb/WVFossils/Carboniferous_climate.html#anchor147264

    then clicked on the source for the CO2 data, looks legit to me.

    http://www.geocraft.com/WVFossils/Reference_Docs/Geocarb_III-Berner.pdf

  • Hank Roberts // Oct 13th 2007 at 3:31 am

    Take the hint.

    The carbon from the early Earth’s mostly-CO2 atmosphere is not now in coal from land plants in the Carboniferous — it will never be back in the atmosphere from any fossil fuel.

    It’s mostly in chalk, limestone and dolomite, from the era when life began using it in the oceans.

    “White Cliffs of Dover.”

    http://www.calstatela.edu/faculty/acolvil/sediment/divisions.gif

  • Chris O'Neill // Oct 13th 2007 at 3:35 am

    windansea: “reduced to adhoms”

    adhom: your argument is wrong because you are an idiot.

    not adhom: your argument is not necessarily correct simply because you publish in a spurious journal.

    Chris O’Neill: “Not half as suitable as using the satellite radiation measurements.”

    windansea: “that makes sense, lets only use data that goes back 30 years”

    From windansea’s earlier quote: “the role of solar activity in the global warming in the RECENT DECADES”

    i.e. according to their abstract, their interest was RECENT DECADES. Windansea should try reading his quotes before he decides what the period of interest is.

    “if solar magnetics might influence cloud formation”

    Sure, just like GCR. Any other fairytales?

  • luminous beauty // Oct 13th 2007 at 3:55 am

    It’s telling that windy cites a 1998 letter from Mike Lockwood without reference to Lockwood’s current thinking on the subject:

    http://tinyurl.com/22pepd

    It is only in denialist-world that science works in reverse.

  • luminous beauty // Oct 13th 2007 at 4:18 am

    There are many interesting palaeoclimate studies that suggest that solar
    variability had an influence on pre-industrial climate. There are also some
    detection–attribution studies using global climate models that suggest there was
    a detectable influence of solar variability in the first half of the twentieth century
    and that the solar radiative forcing variations were amplified by some mechanism
    that is, as yet, unknown. However, these findings are not relevant to any debates
    about modern climate change. Our results show that the observed rapid rise in
    global mean temperatures seen after 1985 cannot be ascribed to solar variability,
    whichever of the mechanisms is invoked and no matter how much the solar
    variation is amplified.

    The pdf:

    www.pubs.royalsoc.ac.uk/media/proceedings_a/rspa20071880.pdf

  • windansea // Oct 14th 2007 at 2:39 am

    Tamino has a new thread about solar cycle 24, meet me there.

    Luminous. Lockwood cites about doubling of solar magnetics during 20th century are totally disparate from his erroneous TSI conclusions in the subsequent paper, solar irradiance output is different from solar magnetic output, I am sure he stands by both conclusions.

  • luminous beauty // Oct 14th 2007 at 4:07 am

    windy,

    Read the paper. Fröhlich and Lockwood account for magnetic field variations, both solar and geo.

    So, according to you, Lockwood was right in a 1998 letter that was little more than speculation, but is ‘incorrect’ nine years later after analyzing the accrued data on the matter.

    That’s rich.

  • windansea // Oct 14th 2007 at 5:48 pm

    So, according to you, Lockwood was right in a 1998 letter that was little more than speculation, but is ‘incorrect’ nine years later after analyzing the accrued data on the matter.

    Lockwood 2006 was cherry pickin good

    http://www.geomag.bgs.ac.uk/images/image022.jpg

  • Rui Sousa // Oct 16th 2007 at 10:39 pm

    NASA explains it:

    “The scientists observed less perennial ice cover in March 2007 than ever before, with the thick ice confined to the Arctic Ocean north of Canada. Consequently, the Arctic Ocean was dominated by thinner seasonal ice that melts faster. This ice is more easily compressed and responds more quickly to being pushed out of the Arctic by winds. Those thinner seasonal ice conditions facilitated the ice loss, leading to this year’s record low amount of total Arctic sea ice.

    Nghiem said the rapid decline in winter perennial ice the past two years was caused by unusual winds. “Unusual atmospheric conditions set up wind patterns that compressed the sea ice, loaded it into the Transpolar Drift Stream and then sped its flow out of the Arctic,” he said. When that sea ice reached lower latitudes, it rapidly melted in the warmer waters.

    “The winds causing this trend in ice reduction were set up by an unusual pattern of atmospheric pressure that began at the beginning of this century,” Nghiem said.

    http://www.nasa.gov/vision/earth/lookingatearth/quikscat-20071001_prt.htm

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