RealClimate logo

Technical Note: Sorry for the recent unanticipated down-time, we had to perform some necessary updates. Please let us know if you have any problems.

Who ya gonna call?

Filed under: — gavin @ 22 August 2007

Gavin Schmidt and Michael Mann

Scientific theories gain credence from successful predictions. Similarly, scientific commentators should gain credibility from whether their comments on new studies hold up over time. Back in 2005 we commented on the Bryden et al study on a possible ongoing slowdown in the North Atlantic overturning circulation. In our standard, scientifically cautious, way we said:

… it might be premature to assert that the circulation definitely has changed.

Our conclusion that the Bryden et al result ‘might be premature’ was based on a balance of evidence argument (or, since we discussed this a few days ago, our Bayesian priors) for what the consequences of such a slowdown would be (a (unobserved) cooling in the North Atlantic). We also reported last year on some data that would likely help assess the uncertainty.

Well, now that data has been properly published (reported here) and it confirms what we thought all along. The sampling variability in the kind of snapshot surveys that Bryden et al had used was too large for the apparent trends that they saw to be significant (which the authors had correctly anticipated in the original paper though).

Score one for Bayesian priors.

107 Responses to “Who ya gonna call?”

  1. 1
    Andy Revkin says:

    The revised picture of Atlantic variability also speaks to the importance of the press not jumping on every new study (even peer reviewed) without some scrutiny and context. This paper triggered heaps of ominous coverage, and now that the boat has tipped back the result is what I call “whiplash” journalism — which in the end tends to alienate readers instead of informing them.

    I have a book chapter on this issue here:
    And another coming next month here:

  2. 2
    Edward Greisch says:

    The Sciencemag page is blank on my internet explorer 5.1 running on MacOS 9.1. I will have to buy a new computer to upgrade, but not now. The Scientific American article says that there is great seasonal variability and keep watching for future data.

  3. 3
    Joseph O'Sullivan says:

    I don’t take most of what I read in the popular press about climate science seriously, with Andy Revkin’s work a major exception. The majority of the press gets it wrong playing up the worst case and/or the best case conclusions that can be drawn from the paper. Whiplash journalism is the best term I’ve heard to describe the effect.

    I use the popular press only for the news that a new paper is out. I then look for a more detailed and accurate discussion on a science site like RC, stoat, Andrew Dessler etc, and read the original paper if I have the time to devote to understanding it.

  4. 4
    Josh Willis says:

    You’re right, Andy, but I think the press aren’t the only ones who are jumping the gun a bit here. Personally, I believe that it is premature to discount the trend that Bryden observed on the basis of the variability in the RAPID array. These are fundamentally very different ways of measuring the overturning circulation and there is no reason to expect the two to contain the same amount of variability. Remember that Bryden’s trend (at from the 1980s to the present) was based on large-scale changes in temperature and salinity that extended deep into the water column. In fact, here is another recent analysis of the cruise data suggesting that these deep temperature and salinity trends ARE significant.

    The nature of the RAPID array means that it will capture all of the “sloshing” back and forth across the latitude of the array that doesn’t have anything to do with climate change. In contrast, Bryden’s analysis contains a lot of inferences and assumptions about reference levels and so forth that are designed to tease out the long-term signal. So it is a bit misleading, I think, to look at the 4 to 34 Sverdrup range of values that RAPID got and use them to discount Bryden’s results.

    [Response: Hi Josh, can you expand on what you mean by 'fundamentally different'? My understanding is the opposite, that the array moorings can be thought of as permanent CTD casts and that the processing of the data is analogous. Cunninghams' main point in the GRL paper is that the deep T/S properties are more robust than the geostrophic calculations and that seems valid but he uses a model to assess a potential change in MOC which might be a little less so. - gavin]

  5. 5
    Mark A. York says:

    Excellent observation Andy. Well, they said this and now it’s that! Then again revisions in science are the norm. It usually never means everything was wrong the first time and this is what propagandists do with such info. Sinister, that.

  6. 6
    Edward Greisch says:

    Andy Revkin, your “chapter” is long on words, but misses the goal. Here is what it is: The extinction of the human species is “scheduled” for the year 2200. We have to prevent that. Journalism must play a new role to do so. Before reading further here, stop and read:

    Journalists communicating more with scientists isn’t going to save us. In fact, the prospect is quite grim. Homo Sapiens, on the average, isn’t smart enough to avoid extinction. The prognosis is extinction of the “humans”. The gas that will do it, hydrogen sulfide, cannot be smelled once it is dense enough to kill us.

    FIRST: A degree in journalism has to include at least the Engineering and Science Core Curriculum, and preferably a degree in science. The book: “Science and Immortality” by Charles B. Paul, 1980, University of California Press needs to be required reading in journalism. Why? Because your 20 years of experience in science journalism has not been enough for you to get the message. The message is: Nature isn’t just the final authority on truth, Nature is the Only authority. There are zero human authorities. Scientists do not vote on what is the truth. There is only one vote and Nature owns it. We find out what Nature’s vote is by doing Scientific [public and replicable] experiments. Scientific [public and replicable] experiments are the only source of truth. [To be public, it has to be visible to other people in the room. What goes on inside one person's head isn't public unless it can be seen on an X-ray or with another instrument.]
    Science is a simple faith in Scientific experiments and a simple absolute lack of faith in everything else.
    Journalists have to stop caring Who said it. It doesn’t matter Who said it. You have to do the experiment yourself before you believe it anyway. Journalists have to do and report the experiment, not find non-existent controversy.
    SECOND: A high school diploma has to require [of everybody] enough science to make good citizens of a high technology civilization. A high school diploma has to require 4 years of Physics, 4 years of Chemistry, 4 years of Biology and 8 years of Math at the high school rate of learning. Why? The alternative is extinction. Carbon mitigation has to be voted on. Our best immediate plan of action is to convert coal fired power plants to nuclear. Most Americans are so ignorant that they are paranoid of nuclear power. See:
    I would think that our impending extinction would be adequately dramatic to cover as news.

  7. 7
    ChuckG says:

    Reference comment 2
    Page opens fine using iCab on a 300MHz Powerbook Wallstreet running system 8.6.
    Only browser I have used, mostly, for 10 or so years.

  8. 8
    Blaine says:

    From the SA article:

    Cunningham says. “Do [climate models] have the right sort of nature of the overturning and its variability?” he asks. “There are questions to answer now before you believe their predictions.”

    I’ve been thinking this myself for quite some time now. Specifically, we now have actual measurements showing very high interannual variability in the North Atlantic overturing circulation, yet everytime I read about model predictions of the NAOTC strength here, it is described as realtively stable, with only a slight downward trend due to global warming. Do the models we are relying on for our predictions show this kind of huge interanual variability? If not, why should we believe them?

    Before this study, we had large observed decadal scale variations in the salinity of the North Atlantic and the Arctic Basin, which are easiest to explain as decadal scale variability of the NATOC. Do our current models replicate these salinity changes? Everything I here seems to indicate that they don’t, but if they don’t, why should we believe these models? If current models get the mixing caused by hurricanes so badly wrong that they need to add a fudge factor called “background mixing in order to fix the problem, then why should we believe that they have the rest of their mixing model correct?

    Cryosphere today reports a current sea ice area of 3.22 mkm2, 20% below the previous record minimum, and the sea ice melt for this year isn’t even over. In large part, this appears to be due to a recent increase in this circulation, or at least the amount of it extending into high latitutes.

    Large areas of normally ice-covered ocean have been soaking up sun all summer. If the fresh-water layer is thick, the heat will be trapped at the surface and will be released in the fall, when there as a strong negative feedback effect, and the ice thickness will reset to close to normal. If the fresh water layer is thin, the heat will move deeper into the ocean and a lot of it will come out in the winter and spring, when it will decrease the ice thickness. This will cause the sea ice area to decrease rapidly next year, possibly shoving the global climate over a major tipping point.

    If current global models cannot predicit the interannual variability of the NAOTC, then why should we expect them to correctly predict the results of mixing in the Arctic when it changes from mostly ice-covered year-round to mostly free of ice in the summer? Why should we trust their predictions at all?

  9. 9
    Josh Willis says:

    Hi Gavin,

    Yes you are correct. The moorings do act like permanent CTDs, but the difference is they are only placed at the boundaries. Strictly speaking, this is okay because the geostrophic transport does just depend on the endpoints of the cruise. But as Bryden pointed out in the 2005 paper, eddies can cause a +/- 6 Sv change in the upper ocean transport as they run into the boundary (i.e. through the endpoint of the cruise). Note that this is about the same as the variability in the “Mid-Ocean Transport” curve in Kanzow et al. (2007). Bryden goes on to argue that the trend he reported is not caused by endpoint variability, in part because the temperature and salinity trends that caused the trend in overturning extend into the interior.

    So I guess my point is that the long-term climate signals in the MOC may be more difficult to see if you only have temperature and salinity data at the endpoints.

  10. 10
    pete best says:

    Interestingly enough before all these empirical data devices were put in place across the Atlantic the available data pointed towards a failing MOC system. Therefore it makes me wonder if the models or assumptions being used and made are just a lot of hot air to stir up debate and get climate change ratcheded up on the political agenda.

    [Response: "the available data pointed towards a failing MOC system" - what do you mean? - William]

    Looks like it has back fired.

  11. 11
    Briso says:

    From the previous thread on Bryden:
    [...However, based on this study, which is arguably the most definitive for the timebeing, positive tropical Atlantic SSTs associated with a THC-driven AMO should be contemporaneous with positive anomalies in the THC. In this context, Gray’s public assertions and Bryden et al’s quantitative findings cannot both be correct. -Mike]

    Who was wrong?

    [Response: Almost certainly the former, and perhaps as well, it now appears, the latter. - Mike]

  12. 12

    Re #1 Where Andy Revkin wrote The revised picture of Atlantic variability also speaks to the importance of the press not jumping on every new study (even peer reviewed) without some scrutiny and context.

    IMHO, the lesson the press should learn from these events is not that they should play down each new study because they cannot tell whether it is true. They may never know that! The lesson they should take is that scientists can be wrong.

    Gavin and Michael have managed to spin the story so that it is a victory for the Bayesian logic, but in fact simple logic is enough to show the whole concept of a slowdown in the THC causing global cooling, such as that which happened during the Younger Dryas, is impossible. The THC is driven by the cooling of the saline Gulf Stream. If the North Atlantic region cooled, the THC would intensify not stop. In fact what caused the YD was that the fresh water flowing from Lake Agassiz allowed ice to form in the Nordic Seas, and this stopped the THC, not vice versa. Later, when that sea ice sheet suddenly collapsed the temperatures in Greenland jumped by 10 C, just as they had during previous Dansgaard-Oeschger events. See the article by Tim Lenton. cited by Gavin

    If you apply Bayesian logic to the Arctic sea ice it is obvious that the scientists prediction of an ice free only occurring in 2070 are way off the mark. The Bayesian priors of evidence from McPhee et al, Rothrock et al, Wadhams, and satellite evidence of the ice thinning show that a collapse is imminent.

    It is not the facts that journalists should be checking. It is the motives of the scientists. Here we see two reputable scientists not only claiming a victory from defeat, but also reassuring the public that the disaster of a halting THC will not happen, when a major disaster they should have predicted is looming over civilisation.

  13. 13
    pete best says:

    Re to number 10; Here in the UK the entire debate (for me anyway) surrounding the MOC was started by a Horizon documentary featuring scientists from the Wood Holes institute I believe and their data seemed to be suggesting that the MOC was weakening. However the program made no suggestion that their data could be incorrect or that the MOC was dynamic to within 20 sv’s per annum. Thats the reason why I got into realclimate, in order to gauge the scientific merit of such programs and boy has it all been an eye opener.

    Even books such as Fred Pearces latest one and six degrees by Mark Lynas seem to be broadly in favour of a weakening MOC brought about by freshening northern waters and russion river run off into the north atlantic.

  14. 14
    Simon Edmonds says:

    G’Day Gavin & Michael.
    Yes I can understand a slowing of the North Atlantic Overturning Circulation, but I suspect it will keep going slow while the melt continues. I say this because as I read a lot of similar reports I compare them to a map I have, called ‘The Floor of the Oceans’.
    When I read about all the stuff going on in the oceans I try to compare them to the geography of the floor of the oceans, and most of it makes a lot of sense in why it is happening.
    Wadhams Chimney I suspect is kept going because of the undercurrent coming out of Kangertittvag. From what I see, a drain in the continental shelf their keeps the flow going. Ironically I think the Melt is keeping the Gulf Stream flowing.
    Cheers Crusty.

  15. 15

    Wy don’t you just accept the words of Carl Wunsch and other professional oceanographs? “… the notion that the Gulf Stream would or could “shut off” or that with global warming Britain would go into a “new ice age” are either scientifically impossible or so unlikely as to threaten our credibility as a scientific discipline if we proclaim their reality”.

  16. 16

    And also Carl Wunsch wrote a message to The Economist, regarding if an ice age can occur in Britain (something discussed in an article in that magazine):

    “Your statement that “The Gulf Stream is driven both by the rotation of the Earth and by a deep-water current called the Thermohaline Circulation” is false. The Gulf Stream is a wind-driven phenomenon (as explained in a famous 1948 paper by Henry Stommel). It is part of a current system forced by the torque exerted on the ocean by the wind field. Heating and cooling affect its temperature and other properties, but not its basic existence or structure. As long as the sun heats the Earth and the Earth spins, so that we have winds, there will be a Gulf Stream [...]

    If the sinking motion at high latitudes were completely stopped, by covering that part of the ocean by sea ice for instance, there would still be a Gulf Stream to the south, and maybe an even more powerful one as the wind field would probably then become stronger. If the sinking were stopped by adding fresh water [...], the Gulf Stream would hardly care. [...]

    Many real climate change effects exist and require urgent attention; focusing on near-impossible Gulf Stream failure is an unproductive distraction.”

    We must also consider that there aren’t even close to as muxh ice now than it was in the late ice age, so I don’t think anything will happen, and due to the climate in the artic the ice meltning don’t seem to be a problem:

    Different scientists about the temperature trend in the Artic: “Some cooling is apparent in the Eastern Arctic”, and “The only area of positive [warming] trend has been the Bering Sea”, etc.

  17. 17
    Lynn Vincentnathan says:

    Well, I predicted increased severity of storms/hurricanes back in 1990 on my Earth Day displays (info I got from some 2ndary science sources) and Pat Neuman (a fired-for-speaking-out-about-GW-NWS-hydrologist-in-the-Midwest, who used to blog here) predicted increased flooding in the upper Midwest and tried to warn people about the possibility of greater flooding with GW. And it sort of looks like we may have been right.

    So we see on today the teaser-link: “Mother Nature ‘really cruel’ with Midwest floods.” And attributions like that REALLY irk me. When Katrina hit, a visiting priest said something to the effect in his homily, “Nobody is to blame for Katrina. It was Mother Nature.”

    That’s like saying that because there was not enough “beyond a reasonable doubt” evidence to convict OJ Simpson, ergo it was definitely another person, so let’s start a huge manhunt for this unknown killer on the loose.

    I think it’s wrong to attribute things to Mother Nature at this point that could attributed to GW (bec they fit what is expected), if scientists only had higher confidence.

    BTW, when I read the news story in 2004 about the slowdown in the North Atlantic overturning circulation, somehow I didn’t consider it a completely done deal (I’m not sure if the story had caveats or not), but rather one study on something that (let’s face it) fit part of the big package of things to be expected. So I wasn’t surprised to learn recently in a new study that the variability was just too high to make claims at this point. I was actually a bit relieved that the slow down MAY not have started yet. My sense of foreboding did not increase much with the earlier story (esp since many scientists now say a shutdown may not throw Northern Europe into a deep freeze, due to GW offsetting that), and it certainly hasn’t decreased with this more recent study.

    GW is still a huge problem — that hasn’t changed — maybe one of the most severe humanity has ever faced.

    And that the public (that I swim in) wasn’t even aware of the 1st study or the 2nd, makes this, along with the GW problem (for the most part) much ado about nothing to them. Afterall, every weird and dangerous weather thing is just Mother Nature acting up. What can we do about it, except buy better insurance??

  18. 18
    pete best says:

    We all know the the atmosphere and oceans arw warming but is the knock on effects that the media seem to be interested in. As explained here many times, the earths albedo, land use as well as GHG emissions are causing the warming. 3 degrees is what Gavin and co keep on telling us but from time to time we get 6 and 11 degrees in the media due to +ve feedback processes such as permafrost melt (not sure about this one), Amazon and other rainforest destruction/deforestation, WAIS and Greenland melting, etc.

    As it stands I am sticking with RC’s projections of 3 degrees of warming at a CO2 doubling to 550 ppmv. What comes during this time, bigger more frequent hurriances, cyclones and typhhoons, drought, flood, pestilence and famine etc will be interesting and I am sure continue to fill the papers and TV.

  19. 19
    anony says:

    I apologize for commenting off topic…feel free to delete.

    I know that RC doesn’t want to spend time responding to the ClimateAudit guys, and give them more legitimacy…but it would also be nice from a casual observer’s point of view to hear what you think about what they are doing. It seems like a lot of engineers getting overly excited about equipment and precision/accuracy of measurements. How much does it matter? A post/essay from RC dealing with this might invite unwanted (and irrelevant) chatter, but it also might help for a lot of us non-scientist types.

    thanks…keep up the good work

    [Response: Try: - gavin]

  20. 20
    Philippe Chantreau says:

    Re 17: Actually Lynn, buying insurance might become more and more expensive and eventually there might not be any insurance to buy, see a recent NYT article. Insurers have complicated maths to deliver to them cruelly simple truths: such risk can be insured at such costs, such at higher cost, such can not be insured due to excessive risk and the certitude of expenses that will not be recovered by insuring the other lower risks. For whatever is in that 3rd category, there won’t be insurance. Of course, the all picture is more complicated, with secondary insurance for insurers faced with unusual expenses, and even goverments participating in those schemes, but at the end it boils down to this. If real costly occurrences happen too often, we will run out of possibilities to insure against them. This could happen surprisingly fast.

  21. 21
    Jim Cripwell says:

    I have never hidden the fact that I am dyed-in-the-wool denialist. However, I have a reason for reading Real Climate. Here in Canada, my Member of Parliament is one, David McGuinty, who happens to be the opposition Environment Critic. He was largely instrumental in getting through our Parliament, with it’s minority government, a Bill requiring Canada to fully implement it’s obligations under the Kyoto Protocol. Like the Man from LaMancha, I “dream the impossible dream” of convincing him that AGW is a myth. It is a good idea to read RC, and think up arguments opposed to what is posted here. Rather like stealing signs at a baseball game.
    I realize that on this particular topic, this message is OT, but it is not OT in general. There are a couple of things that I resent when I read people’s opinions of what denialists are; several orders of magnitude worse than the scum of the earth, and in to back pockets of big oil and big carbon. On a personal basis, I am retired, and live by myself after my wife of 50 years died some 9 years ago. My wants and needs are very modest, and my pension more than covers them. Nevertheless, it is always nice to get some extra money. What I, and all the other denialists I know about, are trying to find out is how we can tap into this vast wealth that is lavished on us denialists. If anyone can give me some pointers as to how to get a nice grant from some company like Exxon, I would be most grateful.
    Another point is that we are accused of not being scientific. I always try, but do not always succeed, in being an analyst, not an advocate. After reading parts of RC, I feel like Darcy must have felt in Pride & Prejudice when Elizabeth Bennett says “had you behaved in a more gentleman-like fashion”. In this regard may I refer you to
    I will admit that before I read this document I had never heard of Rhodes Fairbridge, nor the solar inertial motion (SIM). I am now trying to find someone, hopefully from the Royal Canadian Astronomical Society (not known as a hotbed of denialists), who can provide me with the details of the SIM over the next 50 years or so, and how it will affect the sun’s rotation, and solar cycles 24 through 27.
    With the prediction in the above paper that solar cycle 24 will bring the sun’s magnetic conditions to be similar to those in the early part of the 19th century, maybe it will be a good idea to “pay a call on the Dalton”.

  22. 22
    Ray Ladbury says:

    Feel free to listen in–one advantage of telling the truth is that you don’t care if someone finds out your secrets.
    If you seek to tap into the disinformation funds that Exxon et al. are spreading around, might I suggest that you start by learning the science of climate change. You can then decide whether you are convinced or not and whether the price the denialist disinformation machine puts on your integrity is worth it.

  23. 23
    Andrew Sipocz says:

    Maybe a coastal ecologist familiar with the JCR can help explain how the article referenced in comment #21 found its way into the Journal for Coastal Research. I checked the Journal’s web site and sure enough the article is listed in the table of contents though I can’t access it directly as I don’t have a membership. Is this an example of a journal publishing what appears to be a “vanity” article for a fee? Will the increasing cost of journal publishing mean that in the future a reader won’t be able to pick up a journal without having to read through what could amount to pages of “sponsored” articles and safely assume that everything in it is real, peer reviewed science? Perhaps a coal company will sponsor the Journal’s next issue with Dr. Denial being given free rein to publish an article explaining how unseen metachlorions are actually warming the Arctic.

  24. 24
    Hank Roberts says:

    Per Peter Ward*, it’s not a halt of the ocean circulation we should worry about — that would be a red herring.

    What’s likely at some point as the oceans warm is a rearrangement, to another circulation pattern in which the sinking water is warmer and less well oxygenated. This is known to have happened in the past, leaving layers of sediment with very few fossils for a long period of time, in geological terms.


  25. 25

    Re: #2

    Edward –

    If you are surfing with OS 9.1 (as I do sometimes) you really should go get a copy of iCab. The ScienceMag page displays just fine. IE 5.1 is ancient history at this point.

  26. 26
    Timothy Chase says:

    Hank Roberts (#24) wrote:

    What’s likely at some point as the oceans warm is a rearrangement, to another circulation pattern in which the sinking water is warmer and less well oxygenated.

    I have my reservations regarding Peter Ward. Personally I think he gravitates towards the quick catastrophic. If he were right, basically there wouldn’t be anything we could do about it at this point anyway.

    But I would have to agree that the temperature of the land rising more quickly than surface ocean temperatures and the rate at which land temperatures are rising is cause for concern – as are the phosphate runoff from agriculture and dumping of other waste into the ocean. (Heck, the latter should worry us simply in terms of antibiotic resistance making it from port to port along hundreds of miles of coastline – particularly with how quickly bacteria adapt and exchange genes for resistance.) The high pressure over land, low pressure over water changes the circulation – and you don’t have to have the thermohaline shut down to bring up nutrients which encourage the algae blooms, deadzones, hypoxia and anaerobe population growth.

    This is known to have happened in the past, leaving layers of sediment with very few fossils for a long period of time, in geological terms.

    Despite the uv-damage to their spores, fungi did comparatively well for a while.

  27. 27
    Lynn Vincentnathan says:

    RE #21, Mr. Cripwell, I wouldn’t consider you a denialist, but perhaps a contrarian :)

    Just as AGW believers come in all stripes, so do disbelievers. So I’ve come up with some way of sorting them out.

    SKEPTICS are the few remaining scientists who are not convinced by the evidence or models, etc. Perhaps they are like those who disbelieve there is a slowdown of the North Atlantic overturning circulation, because the noise it still to great to tell. A skeptic would readily convert to a AGW believer once there was enough evidence. I’m always reading about climate scientists who didn’t believe AGW was upon us until 1998, 2001, or 2005, when such&such evidence came in and convinced them.

    CONTRARIANS are like skeptics, but probably won’t convert easily to believers, even when mountains of evidence come pouring in. They aren’t being paid by the fossil fuel industries, don’t have stocks in oil, and don’t work for these companies. The main factor in their disbelief is a somewhat contrarian personality, or too close of following the well-known contrarian streams in our Western (esp American) culture.

    DENIALISTS, TYPE A, do have some vested interests in fossil fuels or other industries that might suffer should we all decided to become energy/resource efficient/conservative and go onto alternative energy. They really do disbelieve AGW.

    DENIALISTS, TYPE B, are like TYPE A, except they actually believe in AGW, but don’t admit so publically.

    Now it is possible you are a skeptic, and would easily convert to an AGW believer, should you be made aware of the right evidence. But it seems you’re more a contrarian, since “who-ya-gonna-call” beyond the topnotch, bonafide, working climate scientists, who are near unanimous that AGW is happening.

    Anyway, you don’t seem to be contributing much GHGs, and you live in Canada (which might be one of the better places once GW really starts kicking in), and you (like me) don’t have lots of years left to worry much about harms from AGW (tho, at one point early on Hurricane Dean’s eye path was aimed straight through my house).

    I’m thinking that perhaps you have children and grandchildren, and the idea of GW harming them and their progeny might be so untenable to you that you can’t believe it. I wasn’t blessed with children, so I don’t have that blockage. Or perhaps you have fears of general economic harm or political totalitarianism happening (and harming you and/or your progeny) if we dare address GW. Or it could just be a contrarian personality/cultural thing.

    Or….there is a less than 5% chance you’re right! But then all that paleo-climate-evidence doesn’t jive and basic laws of physics and thermodynamics, if you are.

    I’d suggest reading Mark Lynas’s SIX DEGREES, which can be purchased through — it is well written, and brings together much of the GW research in a format even I can understand (including the controversies, where there are any).

  28. 28
    Marion Delgado says:

    Jim’s not a reasoner:

    A sample of 1 says very little, cats are mammals is not the same as mammals are cats, etc. That paid denialists are out there and having a huge impact he can’t deny, so he red herrings. The fraudulent educational fund in Canada is one example of a more low level process, but really, the contrary position here is that there are such top notch, astute scientists in the tobacco industry that they somehow get the science right every time (even when they switch positions). Why is it, again, that people proven wrong, even deliberately fraudulent, switched into a consortium with energy company scientists to produce denialist materials? No one denies that some denialists are simply conservative idealogues. Indeed, there’s a wonderful book Jim should read by former Young Republican Thomas Frank called “What’s the Matter with Kansas” – it makes the point clearly that conservative idealogues are most definitely not all “in it for the gold” (to use Michael Tobis’ description of the ludicrous claim by denialists that scientists have only embraced global warming to make more research money).

  29. 29
    Michael says:

    We are all skeptics. Generally speaking, if someone makes a claim, your response should be “prove it”, otherwise you’re a trusting fool and should probably stay away from late night infomercials. Compared to the time spans of climate history, the amount of time humans have been studying climate is a blink of an eye. I look at the IPCC reports as best guesses from the science community to a world that wants GW answers NOW. If you are convinced by majority opinions, fine, but you probably have no business thumbing your nose at the people who are waiting for science to play itself out.

  30. 30
    Philippe Chantreau says:

    RE 21: Jim, I’m afraid you missed the boat when the CATO institute was offering 10 grands to anyone who would muster a scientific sounding critic of IPCC’s AR4 (it did not have to be any kind of true scientific work). If you become conversant enough in climate science and GCMs by AR5, you might be able to complement your income nicely.

  31. 31
    S. Molnar says:

    Compared to the time span of gravitational history, the amount of time humans have been studying gravity is a blink of an eye. I look at Newton’s and Einstein’s papers as best guesses from the science community to a world that wants gravity answers NOW. If you are convinced by majority opinions, fine, but you probably have no business thumbing your nose at the people who are jumping off tall buildings waiting for science to play itself out.

  32. 32
    Michael says:


    I pretty sure the laws of gravity will be mostly the same in the year 2075. So sure, that I will put $1,000,000 on it.

    Care to place a bet on the global mean temp within +/- .5C in 2075?

  33. 33
    S. Molnar says:

    Re #31: Michael, if you jump off the top of the Empire State Building in the year 2075, what will be your velocity at impact within +/- .5 m/sec? I’m pretty sure all the laws of physics will be pretty much the same in the year 2075, and that’s what is used to build climate models.

  34. 34
    dhogaza says:

    Care to place a bet on the global mean temp within +/- .5C in 2075?

    One can’t, of course, because there’s no way to predict what humanity will do about carbon emissions.

    This doesn’t say anything about climate science, of course, so it is a bit of a red herring, don’t you agree?

  35. 35
    cc says:

    “Care to place a bet on the global mean temp within +/- .5C in 2075?”

    Would you bet that the climate will cool from now until then? I doubt you would!

  36. 36
    Hank Roberts says:

    Re Peter Ward, after reading his book, I don’t see why you say “If he were right, basically there wouldn’t be anything we could do about it at this point anyway.”

    His book is about the research distinguishing the extinctions that don’t show evidence of asteroid impacts from the one that definitely does — the field trips and study that led away from the “killer asteroids” explanation for all the major extinctions.

    The core samples don’t give absolute temperature information or CO2 levels, the continents have drifted, ocean circulation patterns varied; unless there’s something I’m missing, he’s writing about the elimination of the asteroid impact explanation, and the evidence from the strata suggesting a change to warm deep water — not drawing a line on the chart and saying at some specific level our contemporary ocean circulation will quit taking cold oxygenated water deep.

    He’s worried, yes.

  37. 37
    Ron Taylor says:

    Re 21 – Jim Cripwell – My dear Jim, I am your age and I wonder what universe you are living in! Why are you driven by a compulsion to reject the evidence produced by the vast majority of climate scientists? Really, the world is as it really is and all the wishful thinking imaginable will not change that. We cannot wish away the reality of global warming. Check what your own government is doing in response to the anticipated continuing warming of the arctic. Good grief, man, we have so few years before we are off the scene to try to undo the vast damage of our generation’s ignorance and complacency! Please, wake up and help!

  38. 38

    Reading your chapter in A Field guide To Science Journalism I was struck by your invocation of the Exxon Valdez disaster as a paradigm of marine ecosystem pollution . Like most, I was unaware ” The runoff from parking lots, gas stations, and driveways puts the equivalent of 1.5 Exxon Valdez loads’ worth of petroleum products into coastal ecosystems each year.”

    But suffering from a common affliction among physicists — a knee jerk tendency to subject factoids to dimensional analysis on sight– my immediate response was quantify your vivid meme. It works out to ~115 tonnes of equivalent crude oil release a day. Which, as I read the AGU journals I subscribe to , naturally makes me wonder how much crude oozes into ‘pristine’ marine ecosystems from countless submarine fractures each day ,and how that number compares to the rate of leakage from all the abandoned or ostensibly dry holes thus far drilled in the seabed ?

    It would be remarkable if integrating the leakage from either set of oil sources yielded a sum as small as 115 tonnes – that’s a 5 meter cube of crude , and the marine component of the biogeochemical cycle of carbon –and hydrocarbons — is reckoned in teragrams. Lots of teragrams. Which raises a point of journalistic order: when it comes to Big Oil, you ask: ” So what is a reporter to do?” and answer ” The first step is simple: Know thine enemy. Recognize where the hurdles to effective environmental communication reside so you can prepare strategies to surmount or sidestep them. ”

    With due respect to Pogo, though the enemy often sure is us, what Big Oil does physically resembles what is happening to Oil In The Pristine State Of Nature, it being a mere fact of natural history that, having been tectonically traumatized over the course of deep time, nature leaks like a stuck pig.

    Polemically useful as keeping readers in pristine ignorance of nature’s deplorably messy ground state may be , can ethical journalists leave them so? As with the thermohaline circulation, the point is moot until one knows what the numbers are, and how they determine the ratio of natural to antropogenic release, so I look forward to your account of the steps you take to find out, and communicate them.

  39. 39
    Steve Reynolds says:

    Lynn Vincentnathan Says: Just as AGW believers come in all stripes, so do disbelievers. So I’ve come up with some way of sorting them out.

    How about adding another dimension to your classification dealing with the severity of AGW effects? While the reality of at least some AGW is pretty well established, the impact of the effects (at least as discussed by commenters here) seems to go far beyond what I’ve seen as scientificly plausable.

    So how do you classify someone who agrees with the bulk o economists and other experts that the effects of AGW will not exceed a few % of world GDP compared to those who expect the end of civilization at best?

  40. 40
    Aaron Lewis says:

    Re 32
    Not all the physics are in all of the models.

    Programing does not always perfectly capture the physics intended for that model.

    Re 27
    I would say that there is another group that thinks the AGW problem is much, much worse than anything hinted at in IPCC FAR. Perhaps, we could call these Skeptics B, as they feel the published data does not fully represent the situation.

    Then, there are the GOGs (Grumpy Old Guy) that think rather than talking about changes in global mean temperature, it would be better to talk in terms of global changes in energy.

  41. 41
    Ike Solem says:

    Interesting comments. I would say that in general the US media has done a poor job of covering this issue over the past several decades. The notion of ‘equal coverage’ seemed to be the motivation for always including Lindzen’s or Singer’s or Michael’s opinion as a counterpoint to the hundreds of other professional climate scientists who agreed that AGW was very real.

    Would journalists also give ‘equal time’ to those that claim that the HIV virus had nothing to do with AIDS? How about ‘equal time’ for zero-point energy enthusiasts (please…no responses to that one!)? Flat earth societies? I can’t recall the last time I saw a news article on some aspects of genetics and health that gave ‘creationism’ equal time either… you see my point?

    Thankfully, that era seems to have passed – and I applaud all those journalists and editors who have finally come to their senses. Now if we could just get government agencies such as NOAA to do the same – and I think it’d be good if journalists started asking NOAA some questions about their continuing official claims that “the multidecadal decadal signal (AMO) is the main driving force behind increased hurricane activity”.

    We know there is natural variability, but it seems very clear that the variability is superimposed on an ever-increasing global warming signal.

    This is also why I’d never accept a bet for ‘temp X in 5 years’ – really, you’d be betting on the likelihood of a major volcanic eruption as well.

    However, I might be more willing to bet that a hurricane would make landfall in southern California within the next 50 years… (see C. Landsea’s comment on CA hurricanes)

  42. 42
    Hank Roberts says:

    > how much crude oozes into ‘pristine’ marine ecosystems from countless submarine fractures each day ,
    > and how that number compares to the rate of leakage from all …

    I actually looked that up recently, and posted one answer in a response to the regular drive-by poster “Adrienne” here, who represents the website and book that are claiming naval warfare caused global warming — he or she posts something about the oceans and links to one of their many websites every few months. I’d been asking for numbers. So I finally looked them up

    As I recall — you can look it up by searching for that name, if you want — the contemporary recent estimate is that very roughly leakage from all human sources is about equal to natural seeps of petroleum, on an annual basis. So we about double the natural background.

    During the World Wars the total from human activity was far less than the natural background.

    Now the contemporary estimate was very rough, but one of the authors was from a big petroleum company.

  43. 43
    Michael says:

    I personally believe the AGW group is more believable, and I support their research wholeheartedly. But they will not or can not tell you how much they don’t know – how of the iceberg is submerged and not visible. Maybe because the unknown is unquantifiable?

    #34: You’re right, even if current global climate understanding is 100%, you still couldn’t predict temps in 2075 because humanity is unpredictable. So I will re-phrase: Given a C02 cap of 600ppm what will the sea level be in 2075? Any bets? Climate science is still in its infancy. I am not about throw exclamation points at a skeptic.

  44. 44
  45. 45
    Dan says:

    re: 39. “So how do you classify someone who agrees with the bulk o economists and other experts that the effects of AGW will not exceed a few % of world GDP compared to those who expect the end of civilization at best?”

    Hyperbole aside (“expect the end of civilization at best”), classify them as those who have failed to understand the science of global warming. Or failed to even make an attempt to learn about it.

  46. 46
    pete best says:

    An article in New Scientist Magazine today states that the waters of the north atlantic are getting saltier again:

    Apparantly some freshening occured in the 1960s and it takes some 15 years or so for its effects to have been passed.

    All of this seems to show that the oceans are very dynamic in nature and I doubt that any abstract physical model can capture all elements of what is going on in the atlantic regarding its conveyor system.

  47. 47
    Nick Gotts says:

    Re #39 [So how do you classify someone who agrees with the bulk o economists and other experts that the effects of AGW will not exceed a few % of world GDP compared to those who expect the end of civilization at best?]

    Interesting question. There would need to be at least two dimensions to such a classification: beliefs about the direct impacts of particular schedules of greenhouse gas emissions; and beliefs about the way the planetary socio-techno-ecosystem will respond to those changes. To judge by the SPM, IPCC FAR Working Group II had a go at questions of direct impacts, but (perhaps wisely), didn’t even attempt to explore human responses, or interactions with environmental issues largely independent of AGW, such as soil erosion. Regarding direct impacts, the key questions seem to be whether unmodelled aspects of ice dynamics will cause much faster sea-level rise than WGI anticipates (as Hansen believes is likely); and whether any of the “tipping points” discussed on this site recently occur. Broader responses of the planetary socio-techno-ecosystem to such primary impacts are much harder to get any kind of handle on. My own hunch is that if we collectively fail to take serious mitigation action early enough (when “early enough” is, depends on the factors mentioned above), we’re also likely to fail to deal well with the regional emergencies that will occur if we don’t, and at some stage, some ruling elite fearing loss of control will start a nuclear or biological war. I think the economists you refer to are by training more or less unable to contemplate that the current world-system might actually break down.

  48. 48
    Jeffrey Davis says:

    Hyperbole aside (”expect the end of civilization at best”), classify them as those who have failed to understand the science of global warming. Or failed to even make an attempt to learn about it.

    [insert General Anthony McAuliffe line here]

    The full range of possibilities involved in Global Warming involves extraordinarily serious issues. The threat of incessant war over the droughts predicted has even brought out planning in the Pentagon. By the time the bulk of the effects of Global Warming arrive we could number > 9 billion of us depending upon thin margins of error in our agriculture. What are the odds of that scenario? You tell me. So far, the IPCC sees a 4.5C increase as within the 95% realm of possibility. That puts >4.5C in the 2.5% realm of possibility. A 4.5C increase would definitely produce widespread drought and their attendant wars. (Coming well after Peak Oil and the increased cost of petroleum-based fertilizers, what do you think will happen? a meek return to global subsistence farming?) Greater than 4.5 with its ever-rising ocean waters, droughts, storms, advances in disease and pests and the pressures of over 9 billion people … We’re in the midst of a never-ending war in the Mid East now. You think things are going to improve?

  49. 49

    Re #39 Where Steve Reynolds Says:

    So how do you classify someone who agrees with the bulk of economists and other experts that the effects of AGW will not exceed a few % of world GDP compared to those who expect the end of civilization at best?

    Ill informed optimists!

  50. 50
    Nick Gotts says:

    Further to #48, #49. The rather odd weather this year, which has affected wheat harvests in Canada, Australia, China and Europe, has led to record prices, and a 26-year low in stockpiles ( If such odd (and most important, unpredictably odd) weather becomes much more common, food prices are going to become both higher in general, and subject to sudden hikes. That sort of thing (rather than actual starvation) tends to lead to civil unrest, a search for external distractions by governments under pressure, and the risk of war.

Switch to our mobile site