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Convenient Untruths

Filed under: — group @ 15 October 2007 - (Svenska) (Español)

Gavin Schmidt and Michael Mann

Update 10/18/07: We are very disappointed that the Washington Post has declined to run an op-ed placing the alleged 9 ‘errors’ in a proper scientific context, despite having run an extremely misleading news article last week entitled “UK Judge Rules Gore’s Climate Film Has 9 Errors”.

Last week, a UK High Court judge rejected a call to restrict the showing of Al Gore’s An Inconvenient Truth (AIT) in British schools. The judge, Justice Burton found that “Al Gore’s presentation of the causes and likely effects of climate change in the film was broadly accurate” (which accords with our original assessment). There has been a lot of comment and controversy over this decision because of the judges commentary on 9 alleged “errors” (note the quotation marks!) in the movie’s description of the science. The judge referred to these as ‘errors’ in quotations precisely to emphasize that, while these were points that could be contested, it was not clear that they were actually errors (see Deltoid for more on that).

There are a number of points to be brought out here. First of all, “An Inconvenient Truth” was a movie and people expecting the same depth from a movie as from a scientific paper are setting an impossible standard. Secondly, the judge’s characterisation of the 9 points is substantially flawed. He appears to have put words in Gore’s mouth that would indeed have been wrong had they been said (but they weren’t). Finally, the judge was really ruling on how “Guidance Notes” for teachers should be provided to allow for more in depth discussion of these points in the classroom. This is something we wholehearted support – AIT is probably best used as a jumping off point for informed discussion, but it is not the final word. Indeed, the fourth IPCC report has come out in the meantime, and that has much more up-to-date and comprehensive discussions on all these points.

A number of discussions of the 9 points have already been posted (particularly at New Scientist and Michael Tobis’s wiki), and it is clear that the purported ‘errors’ are nothing of the sort. The (unofficial) transcript of the movie should be referred to if you have any doubts about this. It is however unsurprising that the usual climate change contrarians and critics would want to exploit this confusion for perhaps non-scientific reasons.

In the spirit of pushing forward the discussion, we have a brief set of guidance notes of our own for each of the 9 issues raised. These are not complete, and if additional pointers are noted in the comments, we’ll add them in here as we go along.

  • Ice-sheet driven sea level rise Gore correctly asserted that melting of Greenland or the West Antarctic ice sheet would raise sea levels 20ft (6 meters). In the movie, no timescale for that was specified, but lest you think that the 20 ft number is simply plucked out of thin air, you should note that this is about how much higher sea level was around 125,000 years ago during the last inter-glacial period. Then, global temperatures were only a degree or two warmer than today – and given that this is close to the minimum temperature rise we can expect in the future, that 20 ft is particularly relevant. The rate at which this is likely to happen is however highly uncertain as we have discussed previously.
  • Pacific island nations needing to evacuate Much of Tuvalu is only a few feet above sea level, and any sea level rise is going to impact them strongly. The impacts are felt in seemingly disconnected ways – increasing brine in groundwater, increasing damage and coastal erosion from tides and storm surges, but they are no less real for that. The government of Tuvalu has asked New Zealand to be ready to evacuate islanders if needed, and while currently only 75 people per year can potentially be resettled, this could change if the situation worsened.
    In the movie there is only one line that referred to this: “That’s why the citizens of these pacific nations have all had to evacuate to New Zealand”, which is out of context in the passage it’s in, but could be said to only be a little ahead of it’s time.
  • Climate impacts on the ocean conveyor The movie references the Younger Dryas event that occurred 11,000 years ago when, it is thought, a large discharge of fresh water into the North Atlantic disrupted the currents, causing significant regional cooling. That exact scenario can’t happen again, but similar processes are likely to occur. The primary unresolved scientific issue regards how quickly the circulation is likely to change as we move forward. The model simulations in the latest IPCC report show a slowdown in the circulation – by about 30% by 2100 – but there is much we don’t understand about modeling that circulation and future inputs of freshwater from the ice sheets, so few are willing to completely rule out the possibility of a more substantial change in the future. Further discussion on what this really means and doesn’t mean is available here and here.
  • CO2 and Temperature connections in the ice core record Gore stated that the greenhouse gas levels and temperature changes over ice age signals had a complex relationship but that they ‘fit’. Again, both of these statements are true. The complexity though is actually quite fascinating and warrants being further discussed by those interested in how the carbon cycle will react in the future. We’ve discussed the lead/lag issue previously. A full understanding of why CO2 changes in precisely the pattern that it does during ice ages is elusive, but among the most plausible explanations is that increased received solar radiation in the southern hemisphere due to changes in Earth’s orbital geometry warms the southern ocean, releasing CO2 into the atmosphere, which then leads to further warming through an enhanced greenhouse effect. Gore’s terse explanation of course does not mention such complexities, but the crux of his point–that the observed long-term relationship between CO2 and temperature in Antarctica supports our understanding of the warming impact of increased CO2 concentrations–is correct. Moreover, our knowledge of why CO2 is changing now (fossil fuel burning) is solid. We also know that CO2 is a greenhouse gas, and that the carbon cycle feedback is positive (increasing temperatures lead to increasing CO2 and CH4), implying that future changes in CO2 will be larger than we might anticipate.
  • Kilimanjaro Gore is on even more solid ground with Kilimanjaro. In the movie, the retreat of Kilimanjaro is not claimed to be purely due to global warming , but it is a legitimate example of the sort of thing one expects in a warmer world, and is consistent with what almost all other tropical mountain glaciers are doing. There is indeed some ongoing discussion in the literature as to whether or not the retreat of ice on Kilimanjaro is related to the direct effects (warming atmospheric temperatures) or indirect effects (altered patterns of humidity, cloud cover, and precipitation influencing Kilimanjaro’s ice mass) of climate change, and that argument isn’t yet over. But these arguments would be of more relevance if (a) we were not witnessing the imminent demise of an ice field that we know has existed for at least the past 12,000 years and (b) most of the other glaciers weren’t disappearing as well.
  • Drying up of Lake Chad It is undisputed that Lake Chad has indeed shrunk rapidly in recent decades. While irrigation and upstream water use are probably contributing factors, the dominant cause is the reduction of rainfall across the entire Sahel from the 1950s to the 1980s and with rainfall today still substantially below the high point 50 years ago. There is substantial evidence that at least a portion of this drying out is human-caused. A few recent papers (Held et al, PNAS; Chung and Ramanathan and Biasutti and Giannini) have addressed causes ranging from Indian Ocean changes in sea surface temperature to the increase in atmospheric aerosols in the Northern hemisphere. Gore uses this example to illustrate that there are droughts in some regions even while other areas are flooding. Unfortunately this is exactly what the models suggest will happen.
  • Hurricane Katrina and global warming Katrina is used in the film as a legitimate illustration of the destructive power of hurricanes, our inability to cope with natural disaster, and the kind of thing that could well get worse in a warmer world. Nowhere does Gore state that Katrina was caused by global warming. We discussed this attribution issue back in 2005, and what we said then still holds. Individual hurricanes cannot be attributed to global warming, but the statistics of hurricanes, in particular the maximum intensities attained by storms, may indeed be.
  • Impact of sea ice retreat on Polar bears As we presaged in August, summer Arctic sea ice shattered all records this year for the minimum extent. This was partially related to wind patterns favorable to ice export in the spring, but the long term trends are almost certainly related to the ongoing and dramatic warming in the Arctic. Polar bears do indeed depend on the sea ice to hunt for seals in the spring and summer, and so a disappearance of this ice is likely to impact them severely. The specific anecdote referred to in the movie came from observations of anomalous drownings of bears in 2004 and so was accurate. However, studying the regional populations of polar bears is not easy and assessing their prospects is tough. In the best observed populations such as in western Hudson Bay (Stirling and Parkinson, 2006), female polar bear weight is going down as the sea ice retreats over the last 25 years, and the FWS is considering an endangered species listing. However, it should be stated that in most of the discussions about polar bears, they are used as a representative species. Arctic ecosystems are changing on many different levels, but it is unsurprising that charismatic mega-fauna get more press than bivalves. In the end, it may be the smaller and less photogenic elements that have the biggest impact.
  • Impact of ocean warming on coral reefs Corals are under stress from a multitude of factors; overfishing, deliberate destruction, water pollution, sea level rise, ocean acidification and, finally, warming oceans. The comment in the movie that rising temperatures and other factors cause coral bleaching is undoubtedly true. Bleaching episodes happen when the coral is under stress, and many examples have been linked to anomalously warm ocean temperatures (Australia in 1998 and 2002, all over the Indian Ocean in recent years). Corals are a sobering example of how climate change exacerbates existing vulnerabilities in eco-systems, potentially playing the role of the straw that breaks the camel’s back in many instances.

Overall, our verdict is that the 9 points are not “errors” at all (with possibly one unwise choice of tense on the island evacuation point). But behind each of these issues lies some fascinating, and in some cases worrying, scientific findings and we can only applaud the prospect that more classroom discussions of these subjects may occur because of this court case.

492 Responses to “Convenient Untruths”

  1. 301
    Hank Roberts says:

    > Sea level rise paper

    Yep, it’s a pointer to an area of ideas, not to one single paper — it’s not a last word, it was then an early warning that there was more news than made it into the last IPCC report. That’s not news _now_ but it was _then_.

    And as usual down at the bottom of the page are the papers citing and commenting on that one — and there are more comments here at RC of course. Point being it’s possible to look at how this is being studied and follow the scientists, who do leave excellent tracks for anyone who wants to know “what did someone say _next_ about that?”

  2. 302
    Hank Roberts says:

    The cites followed forward lead to more — and that’s the main lesson, the one people learn who want to follow in the tracks scientists leave to see where they’re going.

    http://www.sciencemag.org/cgi/content/abstract/317/5846/1866d

    And more cites at the bottom of _that_ page. This is the lesson, look at what’s coming out, look forward, not at any one single old paper.

  3. 303
    Chuck Booth says:

    Re # 283 Figen,

    You can read about John Stossel here:
    http://abcnews.go.com/2020/Stossel/
    http://en.wikipedia.org/wiki/John_Stossel

    I posted this on the WSJ thread, but will repeat it here: The Fairness and Accuracy in Reporting website (FAIR; http://www.fair.org) has an archive of its threads critiquing John Stossel’s “news” stories about junk science and other purported exposes (http://www.fair.org/index.php?page=19&media_outlet_id=19; if this link doesn’t work, you can search the FAIR site for “stossel”, or search the FAIR Archives under Media Outlets-Personalities). I will given him credit – a few of the case studies he discusses in his various 20/20 segments and hour-long news specials are right on the mark, and his appeal to common sense is very convincing. However, many of his stories are filled with half-truths, distortions, and downright incorrect facts,all woven together with a libertarian spin. About 20 years ago, he had an hour long special on ABC titled, Junk Science, which was…well.. mostly junk.

  4. 304
    Hank Roberts says:

    Oh, and Timothy, look under Contributors at the right side of the page.

  5. 305
    Joe Duck says:

    Ray I think we’ll have to agree that Gore is sincere and a wonderful activist for greater GW awareness, but disagree about how reasonably the film represents the facts about sea level rise and hurricanes.

    I’m reviewing the online transcripts of the film and I still think the implications are for pending catastrophe. It is certainly possible that my impressions were not what others would take away from the movie.

    Frankly though I’m still shaken by how this debate seems more about people and alliances than about facts and testing. Good science does not spring from personal alliances or enemies – it springs from reason and data.

  6. 306
    Chuck Booth says:

    Re # 305 Joe Duck

    You seem to think that people here (RC contributors, who are climatologists; RC posters who come from all walks of life, some being scientists, some not) get their science from Al Gore and his film – they don’t. Scientists, and those who want to know what science has to tell us, look to the peer-reviewed literature. RC reviewed Gore’s movie and pointed out some flaws. But,on the whole, the RC contributors felt the movie did a credible job of presenting the case for AGW and its potential consequences. I have yet to see a science documentary that got everything right, but Gore’s movie did pretty well. Moreover, the goal of the movie was to increase awareness, not serve as a textbook on the subject. Finally, to those who keep attacking AIT as as politically-motivated spin: As Al Gore does not presently hold an elected office, and there is no evidence that he is seeking elected office (in fact, there is good evidence to the contrary), I don’t see how AIT can be considered “political.” And why would concern about a large scale environmental change that will affect everyone regardless of their political leanings be considered politically partisan?

  7. 307
    Figen Mekik says:

    Thanks Chuck, I appreciate your response #303 to my query.

  8. 308
    Hank Roberts says:

    It’s really regrettable that no one from the moviemakers, or from Mr. Gore’s group, participates in these threads or has a website at which they can post updated pieces of his slide show. That would be a way to keep the focus on what’s currently known, against the strong attempt to attack “founder” work.

    It’s sad to see success by the PR people attacking the movie’s snapshot of an early version of Gore’s work.

    Science moves on. PR can’t keep up so they attack old information and pretend it’s more important than new work.

    http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VFV-4MY0TS1-1&_user=10&_coverDate=10%2F31%2F2007&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=9a07ac9974791f3f99dee25bcd29ac81
    “The temperature is expected to rise by a greater amount in higher northern latitude mountains than in mountains located in temperate and tropical zones. The rate of warming in mountain systems is projected to be two to three times higher than that recorded during the 20th century. The tendency for a greater projected warming in northern latitude mountain systems is consistent across scenarios and is in agreement with observed trends…..”

  9. 309
    Timothy Chase says:

    Hank Roberts (#304) wrote:

    Oh, and Timothy, look under Contributors at the right side of the page.

    So I noticed, but I didn’t want to give him any special breaks.

    I’m not the sort that believes in playing favourites, you understand.

  10. 310
    Rod B says:

    I’m a little chagrined that The Fairness and Accuracy in Reporting website is cited as an exemplary source of fairness and accuracy in reporting…

  11. 311
    Ray Ladbury says:

    Joe Duck, the “debate” does not deal in facts because the facts are all on one side–and Gore has aligned himself with those facts in the vast majority of cases. Look, Gore is a politician. He is a politician who has been convinced by the scientific facts. He is now doing what politicians do–trying to persuade people to his position. Frankly, as a scientist, I’m gratified when a layman even tries to get the scientific facts right. Moreover, you are looking at his presentation through the eyes of a film producer, who is trying to put together an entertaining–and perhaps incidentally educational–film. For the most part they succeeded without doing great violence to the scientific facts.
    The fact that Gore did not spend 30 minutes going into all the nuances of the theory may not suit you, but it certainly results in a much more watchable movie. But look at Gore’s presentation compared to anything else the media has produced (except maybe the NPR/National Geographic series), and it comes off quite well.

  12. 312
    Darrel says:

    Allthough I found AIT an excellent movie and I agree with its main points, I have one issue with the movie that I’m surprised is not addressed here: When talking about the relation between CO2 and temperature in the ice ages, Al Gore steps on the lift to show where CO2 is right now (ie off the y-scale of the last 650,000 years). He then makes the case that it would be extremely problematic when the temperature will follow suit and go off the y-scale oin the same manner. He is not explicitly stating that the temperature will follow in the same manner (which would amount to a 10 degree warming or so?), but he’s implying it will. So allthough he’s not making a factual error on this point, the implied message is wrong. He may be excused for not explaining the whole set of causes and effects of the ice ages, but not for making an incorrect implication. That said, the main point of his movie stands on firm ground, and I would wholeheartedly recommend this movie for showing at schools since it is very good in its kind.

  13. 313
    Dave Rado says:

    Re. #306, Chuck Booth:

    I don’t see how AIT can be considered “political.”

    See #254.

  14. 314
    Chuck Booth says:

    Re # 310 Dave Rado

    Action requires policy changes, yes, but that is independent of which political party is in office at the time decisions have to be made. The term “political” is typically used pejoratively to imply that the views of one political party or philosophy are favored over another. Despite what the British judge wrote, I don’t see that raising awareness of AGW or developing policies to forestall it is inherently political. It seems to me that the effects of sea level rise will be non-partisan – people of all political persuasions and all socio-economic groups will be affected.

  15. 315
    J.C.H. says:

    I would point out that the film does not recommend the construction of dikes around New York City sufficient to mitigate 20 feet of imminent flooding, which is consistent with the obvious theme of the film that the worst negatives are well into the future and avertable without a hastily constructed 40-foot levee surrounding Lady Liberty.

  16. 316
    Dave Rado says:

    Re. #314, Chuck Booth, the problem with the English language is that many words are ambiguous in their meanings. In one sense of the word, the judge was right that the film was “political”. You are right that the word “political” is often used to mean something quite different. Also, the film was “partisan” in the sense that it didn’t cover the uncertainties in the science or qualify statements that ought to have been qualified; and in the sense that it promoted a set of policies that Gore believes in, rather than objectively and impartially analysing the policy options and pointing out their possible costs as well as their possible benefits.

    Have you read William Connolley’s take on AIT?

  17. 317

    Joe Duck posts (typically):

    [[Frankly though I’m still shaken by how this debate seems more about people and alliances than about facts and testing. Good science does not spring from personal alliances or enemies – it springs from reason and data.]]

    Then why don’t you show us some reason and data, instead of endlessly coming up with ad hominem arguments? Write down the reasons you don’t believe in AGW and we’ll see how they hold up in the reason and data department.

  18. 318
    Chuck Booth says:

    Re # 316 Dave Rado: ” rather than objectively and impartially analysing the policy options and pointing out their possible costs as well as their possible benefits.

    That would make a great documentary, but I would expect to see it (in the U.S.) on public television (e.g., Frontline) where it would reach a very small audience. Had Gore taken this approach, his film would have been a total flop and the message lost – any good speaker knows you have to get the audience’s attention and warm them up with basic information before you can present data and more complex concepts. Now that Gore has successfully raised the public’s awareness of AGW, someone should produce the documentary you described.

  19. 319
    Chuck Booth says:

    Re # 310 Rod B “I’m a little chagrined that The Fairness and Accuracy in Reporting website is cited as an exemplary source of fairness and accuracy in reporting”

    I never stated that FAIR was an exemplary source – I merely said it has an archive of its critiques of Stossel’s reporting. In those cases with which I am familiar (mostly Stossel’s attempts to portray legitimate scientific controversy as “junk science,” I have found FAIR’s critiques to be pretty much on the mark – quite frankly, Stossel tends to do a very poor job reporting on scientific matters, and he certainly advocates a partisan viewpoint. As I have noted elswhere, there are websites devoted to defending Stossel against FAIR’s “attacks,” but I have found those defenses quite lame – usually no more credible than the Stossel reports they are trying to defend.

  20. 320
    Dave Rado says:

    Re. #318, I agree. Given the need to reach a wide audience I think Gore’s film did a very good job overall, although I wish it had been peer reviewed prior to release, so that for example, some of the less well chosen illustrations it used to stand in for valid points (Chad, Katrina, Kilimanjaro, malaria) could have been replaced by better chosen ones; so that some important qualifications could have been added (20m sea level rises unlikely in foreseeable future, large scale evacuations due to sea level rises have not yet started albeit they are expected, spelling out the feedback mechanism that explains the ice core records and mentioning the initial “lag”). It would then have been a far more difficult target for the denialists.

    Re. the policy options, I agree it would be difficult, maybe impossible, to discuss those in a non-partisan way in a mass-market film, but merely pointed out that it was therefore partisan in one definition of the word “partisan”.

  21. 321
    Joe Duck says:

    Write down the reasons you don’t believe in AGW

    I can’t , because I believe in AGW and accept the 90%+ likelihood standard used in IPCC 2007 reporting. Yet 90% is far from the 100% standard I see applied, absurdly, in many of the arguments here and in AIT. You don’t believe that AGW is 99.9% likely, but you write as if you do!

    Ad hominem? Hardly, though clearly I’m under attack by you for suggesting the obvious – that AIT implies a strong connection between Katrina and GW and implies that sea level rises of 20 feet are not an unreasonable expectation.

    Ray if you are a professor I hope you apply a different standard with your students than with commenters here who don’t tow the line of GW catastrophism you seem to hold so dear. Do you seriously believe no rational scientist should challenge AGW and no scientist should get funded for research that would challenge AGW?

    Although I’m very interested in the science I’m comfortable with IPCC’s excellent treatments. I’m primarily interested in how we should allocate resources to mitigation. My read on this is that Lomborg has the right idea of allocating first to immediate and pressing third world problems rather than expensive and difficult mitigation efforts here in USA.

  22. 322
    Joe Duck says:

    Ray – Whoa – I owe you a big apology here. I think I just responded to Barton Paul thinking his comment was from you.

  23. 323
    Dave Rado says:

    Re. 321, Joe Duck, re. sea level rise, as has been pointed out many times in this thread and elsewhere, the IPCC projection specifically excluded any melt from Greenland and Antarctica, despite the fact that Greenland is melting rapidly and Antarctica is melting slowly, because of the fact that ice flow dynamics are not well understood.

    Furthermore Arctic ice melt is already way ahead of the AR4 projections, and this is likely to compound itself due to positive feedback from the loss of albedo.

    For all these reasons, most climate scientists would say that the IPCC figure is no more credible as a forecast than the 20 foot figure. The true figure is likely to be somewhere in between, and many distinguished climate scientists would bet on it being nearer the higher end than the lower. The IPCC took the understandable position that it would not include effects such as ice dynamics and some feedbacks that are not yet understood; but that necessarily makes their projections extremely conservative and almost certainly far too low.

    In 1988 James Hansen went out on a limb with models that indicated that a clear AGW signal was already evident and that the consequences were likely to be extremely serious; and his scenario B projections for temperature changes over the next 20 years have proved remarkably accurate. Now he has gone out on a limb regarding sea level rise and it would either be a very brave or a very closed-minded person who would say that, with his track record, his projections can be written off as “implausible”.

  24. 324
    Ray Ladbury says:

    Joe, no offense taken. However, I’m just curious, on what basis would a rational scientist challenge anthropogenic causation of climate change when all the evidence points to it. The 90% confidence number is a product of the fact that we don’t know what evidence WILL BECOME AVAILABLE in the future, not of any inconsistency in the current evidence. By all means fund good research, regardless of its implications, but it’s very hard to oppose the consensus position on the basis of empirical evidence at this point.

  25. 325
    Hank Roberts says:

    Dave Rado, make sure to distinguish between projections and observations; look again at Hansen (1988). You write that his models indicated that a clear AGW signal was already evident at that time.

    That’s not what he wrote or observed.

    This is why a direct quote with cite is always going to be more helpful. In the abstract you can read “(2) The greenhouse warming should be clearly identifiable in the 1990s”

    http://pubs.giss.nasa.gov/abstracts/1988/Hansen_etal.html

    This makes your point stronger above. “Prediction is always difficult, especially about the future.” Models Hansen was using then were already good. He’s continued to improve the models and to project scenarios, and those for sea level rise are increasingly clear.

  26. 326
    Joe Duck says:

    most climate scientists would say that the IPCC figure is no more credible as a forecast than the 20 foot figure. The true figure is likely to be somewhere in between, and many distinguished climate scientists would bet on it being nearer the higher end than the lower.

    Dave if this is true I’m simply floored and also confused by IPCC’s conclusions. Am I reading correctly that you feel there is a consensus that due to melting not addressed in IPCC 4 the actual sea level rise is likely to be more like 10 feet in next 100 years than in the IPCC range of 18-59cm? This does not sound reasonable to me at all – are you a scientist yourself?

    [Response: The so-called IPCC range is not what you think it is. Read our discussion on the topic. The IPCC specifically state that the extra effect from dynamic changes to ice sheets is hard to quantify but may be large. It does indeed appear to be the case that many scientists think that this number could be large – but we lack the understanding to say how large how soon. It’s not a great soundbite, but that’s just the way it is . – gavin]

  27. 327
    joe says:

    J.S. M.

    “I’m a child of the “duck-and-cover” 50s. I grew up with the bomb. We all did.”

    I agree that children are resiliant but I’m wondering if the showing if AIT to children in school and suggesting that they do X,Y and Z to combat AGW (IE: from changing lightbulbs through Kyoto) is any different that telling kids in the 1950’s that hiding under their desks and covering their heads would somehow protect them from a nuclear blast.

  28. 328
    Joe Duck says:

    on what basis would a rational scientist challenge anthropogenic causation of climate change when all the evidence points to it

    Since I accept the consensus view in favor of AGW this is hard to answer, but unless I’m mistaken there is enough uncertainly to suggest we should keep investigating alternative hypotheses to AGW.
    The stakes are simply *enormous* with respect to GW and the costs of mitigation, so if you are wrong (and I’d sure like to see people here assign a likelihood to that possibility), the costs to society are dangerously high. Even if the IPCC numbers are right (I think they are right), then the costs of massive mitigation are probably not justified, but we want to act on GW to the degree suggested by many responsible economists who study resource allocation (rather than allocate mitigation resources to the degree recommended by emotion and politics).

    Now, if I thought Dave was right above where I think he’s suggesting that sea levels are more than 50% likely to rise catastrophically within a century I would agree that we should probably feed the AGW skeptics to the Polar Bears to mitigate the effects of GW on their food sources, and then spend like crazy on mitigation and levee systems.

    Have I misconstrued the meaning of the 90% number in IPCC 4? Isn’t it suggesting an uncertainty level between 0 and 10%?, presumably closer to the 10% uncertainly level or they would have used a 95% likelihood of AGW?

    If we were talking about evolutionary theory we could say it is 99.9+% likely evolution explains change in animals. Science is reasonably certain about this and few rational scientists study creationism.

    However I’m under the impression that many climate scientists still feel there *may be* alternatives to the AGW interpretation of GW. I think they are scared to come to this blog, so maybe you didn’t realize how many there were out there :)

  29. 329
    Sonja Christiansen says:

    Several asked what I meant by ‘sophisticated sophistry’ as a description of teh defence of Al Gore’s position. Wished I had as much time as the Real Climate people !
    I am indeed biased against environmental alarmism (limits to growth, death of ocean from oil, acid rain and forest death, population bomb, ozone hole and skin cancer etc) and consider it an ideological position not based not on science but on the belief that humanity is destroying the earth. It is a new version of many old religions which predict the end of the world thanks to human wickedness. While all ‘predicted’ environmental catastrophes had a grain or two of truth in them, or even more- humna beings can degrade the earth but they can also enhance it – were always exaggerated as part of normal politics. The climate change debate is hugely politiced. Why?? I can’t anser this here.

    Environmental threats/computer model predictions have become the foundation of a pseudo-religion, in my view, of a pessimistic, often puritanical and in the end anti-human ideology that selects and misuses science, and especially computer models. The latter are highly sophiticated but in the end, predict what you want them to, or hwat is ‘policy-relevant’and hence fundable.

    I have followed the global warming science and energy policy debates since the mid 1980s, and know how ‘interests’ use environmental threats. I know about the behaviour of Big Science, apowerful and well organised political actor with excellent communication skills, and I know a lot about how the energy industries are using the climate threat, most skilfully. I have written a book with A Kellow on the Kyoto Protocol.(Boehmer-Christiansen and Kellow, EE, 2002) and have done three years research on the politics of the IPCC, and published a lot on this. I still see as a political body underpinning policy made to a large degree alreay in the 1970s aimed at the replacement of fossil fuels. Nuclear power interests have long supported the AGW hypothesis, just as coal and oil have been more sceptical. I consider this normal behaviour and wished there was more emphasis on admitting this. All political and economic interests/institutions use ‘science’ and what they declare to be science.
    I wished you discussant would put less emphasis on what is not known than on proving a belief with still doubtful ingredient, and stopped insulting each other science – this is sophistry and done by very experienced communicators and spin doctors on BOTH sides.
    This is also normal political behaviour, given the high stakes. Climate modeling is based on one practical science, or rather mixture of sciences, meteorology and statistics. I read the critiques and teh IPCC, and do not believwe that science advances by consensus, though I admiot that scientists can be persuaded to negotiate a consensus among a selected group.
    I was warned in France in 1992 that if we listened too much to them, meteorologists would soon run the world! How true in one sense, a great deal of political ambitions are now dressed up as ‘saving the planet ‘ from climate change, or is it fossil fuels and overconsumptions? As if climate has ever been stable! Meteorology and climate modelling excludes many branches of science’.

    I am primarily a physical geographer that switched to political science/environmental international relations and science policy later in life, and now research the arguments and interests of ‘climate sceptics’. I must admit, they have persuaded me to say that we do not know enough about the causation of climate and how it changes to rush into policies that go beyond ‘no regret’. Such policies cannot be global as climate change will affect regions very differently. I opt for adaptation and and encouragement of technology change by those who can afford it. I remain critical of cap and trade schemes, and artificially high energy prices.
    I have experienced so many environmental alarms in my life (and di dmy PhD on one of teh early ones…teh dyong of teh ocean ion the 1970s), and met so many people that confuse knowledge with ideology, and had so many bad experiences with ideology, that I remain happy to be counted among the moderate and rational sceptics, distrustful of ideologues with political ambitions like Al Gore, and contemptuous even of people like Lovelock and O’Flannery…. However, among sceptics you also find extremists, people too optimistic or too averse to state intervention in anything. Our personal beliefs and financial interests tend to shape what science, or rather which bit of science, we select to believe in.
    Sonja

  30. 330
    Fred Staples says:

    A rational scientist would have many reasons for doubting AGW, Ray (324).

    Take James Hansen, for example, writing in 1978:

    He charts a 1 degree centigrade fall in average global temperatures from 1200 to 1700, and a lesser increase from 1700 to 1980. Over the past century, he shows the peak temperatures to have been in the late 1930’s.

    Not surprisingly he writes:

    “Although the observed warming in the 1970s is consistent with the increased trace gas abundance, the changes cannot be confidently ascribed to the greenhouse effect. However, if the abundance of the greenhouse gasses continue to increase with at least the rate of the 1970s, their impact on global temperature may soon rise above the noise level”. For significance, he was looking for 0.4 degrees centigrade increase.

    His well known scenarios A, B and C, postulated in 1988, anticipated a temperature increase of 0.2 degrees centigrade for scenarios B and C to year 2000, which the charts show. Thereafter, scenario C assumed no further increase in CO2 and, consequently, no further increase in temperature. Scenario B, often quoted as the most accurate, looked for a further increase of almost 0.5 degrees between 2000 and 2010.

    In fact, global temperatures peaked in 1998 and have not risen since 2000. CO2 has continued to increase at a rate consistent with scenario A, which looked for an increase of more than 1 degree by 2019. We are experiencing scenario A CO2 combined with scenario C temperature increases.

    [Response: You are strongly mistaken about both the forcings we have experienced, the temperature trends and the Hansen projections. The graphs can be seen in this post. – gavin]

    More fundamentally, the 33 degree K difference between the surface temperature and the tropopause temperature cannot be attributed wholly to the presence in the atmosphere of trace “greenhouse” gasses, any more than the temperature inside a greenhouse can be attributed to back radiation from its glass. As Professors Gerlich and Tscheuschner point out, the simple blanketing effect of low thermal conductivity gas will increase the surface temperature. If the surface of the bare rock earth would be 255 degrees K, the earth surface with a dry N2/O2 atmosphere would be very much warmer.

    [Response: G&T are as useful to a science debate as a G&T is useful to an alcoholic. For the same albedo, the planet would be cooler by 33 deg C (ish) with a pure N2/O2 atm. – gavin]

    The lapse rate of air temperature depends on pressure,not radiation, and you can reach a zero average by climbing a very modest mountain.

    Take the planer Venus for a worked example.

    James Hansen calculated the surface temperature (at a presssure of 90 bar) to be 720 degrees K from the lapse rate, and 685 degrees K from the “greenhouse” radiative balance.

    So here is a simple question. If the almost 100% CO2 atmosphere on Venus were to replace with an equivalent mass of dry air, would the surface temperature go up or down?

  31. 331
    Mark A. York says:

    “I am primarily a physical geographer that switched to political science/environmental international relations and science policy later in life, and now research the arguments and interests of ‘climate sceptics’.”

    The prosecution rests.

  32. 332

    Joe Duck writes:

    [[You don’t believe that AGW is 99.9% likely, but you write as if you do!]]

    On the contrary, I think AGW is virtually certain at this point. Kindly don’t tell me what I think.

    [[Ad hominem? Hardly,]]

    Ad hominem arguments are exactly what you are engaging in when you say this site is about partisanship rather than science. You are accusing people and talking about their motives. If you aren’t doing that, what do your comments mean? As long as you are discussing the people or their motives or their behavior, rather than the issue, you are by definition engaging in ad hominem argument. That’s what the term means.

  33. 333

    Joe Duck posts:

    [[The stakes are simply *enormous* with respect to GW and the costs of mitigation, so if you are wrong (and I’d sure like to see people here assign a likelihood to that possibility), the costs to society are dangerously high.]]

    Most qualified observers of the subject feel that there are enormous costs to doing nothing, too. You’re assuming that everything will be fine if we do nothing. And you’re not factoring in the benefits from mitigation that have nothing to do with climate change — like reducing pollution, saving the oceans, and eliminating dependence on foreign oil.

  34. 334
    Nick Gotts says:

    Re #329 [Our personal beliefs and financial interests tend to shape what science, or rather which bit of science, we select to believe in.
    Sonja]

    True, but much more so for some people than for others.

  35. 335

    Sonja Christiansen posts:

    [[I am indeed biased against environmental alarmism (limits to growth, death of ocean from oil, acid rain and forest death, population bomb, ozone hole and skin cancer etc)]]

    There are limits to growth, since we live in the real world. Do you think industrial production can rise forever? You do realize the Earth’s volume is finite, don’t you? Or do you think an increase of several percentage points a year can be sustained forever by mining asteroids? I have news for you — given an exponential rate of growth, we’re going to run out of asteroids, too.

    [[ and consider it an ideological position not based not on science but on the belief that humanity is destroying the earth.]]

    Ad hominem argument. Strike one.

    [[ It is a new version of many old religions which predict the end of the world thanks to human wickedness. ]]

    I’d say human wickedness is pretty much an established fact for anyone with an ounce of knowledge about what’s going on in the world, or even in their own community.

    [[While all ‘predicted’ environmental catastrophes had a grain or two of truth in them, or even more- humna beings can degrade the earth but they can also enhance it – were always exaggerated as part of normal politics. The climate change debate is hugely politiced. Why?? I can’t anser this here. ]]

    Ad hominem again. Strike two.

    [[Environmental threats/computer model predictions have become the foundation of a pseudo-religion, in my view, of a pessimistic, often puritanical and in the end anti-human ideology that selects and misuses science, and especially computer models.]]

    And ad hominem again. Strike three, you’re out.

    [[ The latter are highly sophiticated but in the end, predict what you want them to, or hwat is ‘policy-relevant’and hence fundable.]]

    And ad hominem yet again.

    Such models can’t “predict what you want them to” if they remain at all true to the physical laws they embody. And the “fundable” is yet another ad hominem smear. The fifth, by my count.

    If you want to learn how climate models work, I’d suggest reading McGuffie and Henderson-Sellers’s “A Climate Modeling Primer.” Other helpful books would be John Houghton’s “The Physics of Atmospheres” and Grant W. Petty’s “A First Course in Atmospheric Radiation.”

  36. 336
    Nick Gotts says:

    Re #333 p.s. And some of us think we should at least try to resist that tendency, individually and collectively.

  37. 337
    Hank Roberts says:

    Sonja Christiansen writes
    > policies that go beyond ‘no regret’

    Problem is, for a conservation-minded biologist, reducing coal use is a “no regret” step.

    The Western Fuels Association is there to lobby for burning more coal. They argue for burning coal as a “no regret” choice.

    Have you any suggestions for “no regret” steps everyone could agree on?

  38. 338
    Nick Gotts says:

    Nick Gotts says:

    “Re #333 p.s…”, but should have said (unless the numbering changes again!) “Re #334 p.s…”

  39. 339
    John L. McCormick says:

    RE # 329

    you said:

    [I am primarily a physical geographer that switched to political science/environmental international relations and science policy later in life, and now research the arguments and interests of ‘climate sceptics’.]

    Yes, you might be all of what you claim. But, you are uninformed or failed to read the science of acid rain and forest death (dieback). Even high school students are taught the consequences of acid rain on forest and lake ecology.

    And, regarding the ozone hole: where have you been practicing your old and new professions? There are alarmists and there are educated persons who understand the problems of acid rain and the Antarctic widening ozone hole. They might, in fact, be the same persons and have been proven to know that of which they have written and speak. Join the club.

  40. 340
    Joe Duck says:

    Gavin – thanks for link about the IPCC sea level rise projection discussion. I appear to have more reading to do on this topic.

    Sonja – a very thoughtful post about how human dynamics drive discussions. Science and reason are the remedies which is why alarmism dressed up as science is so troubling.

    Barton-Paul wrote:
    I think AGW is virtually certain at this point … what do your comments mean?

    In short, my comments mean that I think the science has taken a back seat to alarmist rhetoric, and that for the sake of rational, long term policy making and resource allocation everybody should rally around the best science rather than the best rhetoric.

    I’m worried that talking about catastrophe is leading to our foregoing GDP or funding very expensive mitigation efforts while current catastrophic conditions of health and poverty in 3rd world are too widely ignored.

    If others here share your level of certainty about AGW it helps me understand the confrontational tone here against those suggesting anything but unqualified support for AGW and in most cases a strong likelihood of catastrophic change within 100 years.

  41. 341
    J.S. McIntyre says:

    re 327

    “I’m a child of the “duck-and-cover” 50s. I grew up with the bomb. We all did.”

    I agree that children are resiliant but I’m wondering if the showing if AIT to children in school and suggesting that they do X,Y and Z to combat AGW (IE: from changing lightbulbs through Kyoto) is any different that telling kids in the 1950’s that hiding under their desks and covering their heads would somehow protect them from a nuclear blast.

    ==============

    Ah, so we’re going from the rhetoric of “It’ll frighten the kids” to “It’s probably no better than hiding upder a desk.”

    Actually, your example is a bit of an apples and oranges, not to mention a comparison of opposites. Hiding under a desk is a defeatest, do nothing and hope I survive sort of act.

    Suggesting that people do something to lessen their personal impact upon the climate – and by extention, the environment, for pretty much ANY negative effect on the climate parallels negative effects on the environment.

    You cite specifics (“light bulbs”), but that is but a part of the larger message: when you look at what AIT was really doing, it was pushing the idea that people make an effort to help turn the situation around.

    That’s a far cry from asking people to give up and cower under a desk.

  42. 342
    James says:

    Re #329: [Environmental threats/computer model predictions have become the foundation of a pseudo-religion, in my view, of a pessimistic, often puritanical and in the end anti-human ideology…]

    Anti-human? Hardly. Anti the subset of humans who think I’m gullible enough to be convinced that they’re doing me favors by dumping their trash in my back yard? Yes, indeed :-)

    I see this “anti-human” claim all too often. It seems that those with a vested interest in pushing Madison Avenue’s latest consumer fad are so egotistical that they dismiss anyone who doesn’t want it (or its side effects) as being somehow less than human. I’d say the truth is more the other way around.

  43. 343
    Dick Veldkamp says:

    Re #340 Certainty about AGW

    Joe, the tone of some people here is confrontational because they are tired of hearing the same old arguments against AGW, which have been considered, and shown to be false. Scientists agree about the basics of AGW (although there is plenty of discussion about the details): that is: IPCC + every scientific body that put out a statement on the subject, they all agree: AGW is real, it is human caused, it is most probably bad. What more do you need?

    If all those people who have studied the matter tell us we’d better do something about it before it’s too late, that is a warning we should heed. That is not alarmism, that is common sense.

  44. 344
    Joe Duck says:

    Paul Barton your use of “ad hominem” is rather unique (not to mention excessive!). Usually it would take this form:

    “Joe Duck’s study maintained that sea levels are unlikely to rise more than a meter over the next century”. However Joe Duck is ugly and stupid. Therefore, we reject Joe’s findings.

    You seem to suggest that questions or speculations about motivation, ideology, economic relationships, and other societal or psychological factors are not relevant here. But have you forgotten that this is a discussion about alleged alarmism in the film AIT, and alleged support here for that alarmist tone?

    Alarmism is a subjective charge – by definition. Motivation, ideology, psychology, and politics are very relevant to that discussion and frankly even to a discussion of potential bias in grant funded science.

    Also, though you keep asking for discussion of data I’ve tried desparately to get some feedback about why people seem to think sea level rises dramatically greater than the IPCC projections are “likely”, but commenters here seem very reluctant to speak in terms of mathematical probabilities associated with various events. That’s too bad because assigning probabilities accurately is a cornerstone of good science and critical to how we should allocate resources in an effort to mitigate the negative effects of GW.

    Gavin (thanks!) directed me to a discussion where he concluded that perhaps an extra ~25cm [Gavin pls correct me if this is not a good read of your points there] should be added to the IPCC’s 18-59cm ranges due to likely additional melting of ice. This is hardly the 20 feet many here and in the film seem to be obsessing about, so I remain very confused by the support for the film’s extensive discussion of a 20 foot rise without much discussion of the scenarios that are highly likely – a rise of (per my read of Gavin’s take on this) about a meter.

    There appears to be only an extremely tiny probability of a 20 foot rise. My take (based admittedly on a modest level of study) is that the likelihood of a rise greater than 20 feet in the next century would be on the order of “less than 1 in 1000 chance” – is that also your take on this probability?

    I would love to hear from the scientists here about this key point of the likelihood of catastrophic sea level rises this century.

    There are many ad hominem attacks in this thread but aren’t most of them against those nasty “ignorant food tube” AGW deniers? Am I correct that you are OK with that, because you see them as deserving of the attacks? Hmmm – you’ve got me really curious and I’ll try to count those pesky ad hominems.

  45. 345
    Ray Ladbury says:

    Sonja Christiansen,
    I would contend that there is a lot you do not understand about science. First, if science is not decided by consensus, then how is it decided? There are biologists who do not believe in evolution and physicists who do not believe in in quantum mechanics or in quarks. Yet these are the standard model, yet Einstein went to his grave dissenting from accepted science. Now contrast this situation with that of Newton’s advocacy of the corpuscular theory of light–it set English optics behind the continent by DECADES. If you do not understand the need for consensus in science, you do not understand science.
    You also have a rather distorted idea about the scientific consensus about climate change. Nearly every professional scientific society (AGU, AIP, NAS…) has accepted this consensus–and it is certainly not because it benefits them. On the contrary, it means there is likely to be less resources for them to explore their specielties in the future. They have acquiesced to the consensus because that is what the overwhelming evidence indicates. That is not alarmism. It is not even environmentalism. It is science.

  46. 346
    Joe Duck says:

    AGW is real, it is human caused, it is most probably bad. What more do you need?

    Dick I agree but we all need more than that – a lot more!. I see those reasonable assumptions as the beginning rather than end of the important part of the GW discussion which is *what are we going to do about it?*. Lomborg and many economic experts (though notably not the Stern report, which allocates benefits and costs in a fairly unique fashion) suggest we should do the cheap mitigation stuff but not the expensive stuff.

    This makes sense to me. However if a 20 foot sea level rise within 100 years is “likely”, then I’d agree we damn well better start mitigating, and even bailing water like there is no tomorrow because … there is not!

    Fortunately the chance of catastrophic sea level rise is much smaller than the film implies, so we can and should do the cheap mitigations but not the expensive ones.

    Agree? If not, what do you think the chance of a 20 foot rise is based on your take on the science? Also relevant would be the probabilities associated with mitigation efforts.

  47. 347
    Hank Roberts says:

    Joe, why do you keep talking about a 20′ sea level rise “this century” please? Aside from one error in an Associated Press bulletin that got reprinted a lot before it was corrected, nobody’s evern said that was likely. It’s clear what would have to happen to cause it — collapse, sudden breakup — this century — rather than slow melting over centuries — of that much water currently in the form of ice above sea level.

    Odds of a big meteor impact on an icecap, or a massive volcanic outbreak under an icecap? Quite low.

    Odds that surface melting will pour enough meltwater into moulins and crevasses to lubricate glaciers and break up icecaps? Nobody knows — that’s why it’s not in the IPCC, that’s why it’s not in the models currently in use.

    Click the link in the right hand column for Rasmus Benestad and follow links to his publications and read up on what’s actually been published about what we can’t yet say for sure.

  48. 348
    Timothy Chase says:

    Joe Duck (#344) wrote:

    Gavin (thanks!) directed me to a discussion where he concluded that perhaps an extra ~25cm [Gavin pls correct me if this is not a good read of your points there] should be added to the IPCC’s 18-59cm ranges due to likely additional melting of ice. This is hardly the 20 feet many here and in the film seem to be obsessing about, so I remain very confused by the support for the film’s extensive discussion of a 20 foot rise without much discussion of the scenarios that are highly likely – a rise of (per my read of Gavin’s take on this) about a meter.

    The IPCC estimate largely assumes a linear growth in the rate of sea level rise – and as has been pointed out numerous times before, does not take into account the non-linear behavior of ice melt. The empirical evidence simply in terms of the trend in rise over the past few years already appears to be showing that it is underestimating the rate at which sea levels will rise. Based on that trend, more recent estimates have included 1-2 m, with the likelihood of exceeding 2 m being less than one percent.

    Alternatively, Stefan Rahmstorf has published a paper recently which gives a semi-empirical analysis based on trends relative to temperature in which he concludes that the proper estimate is more about 1 to 1.4 m. However, his analysis neither includes positive feedback nor the declining mass balance of glaciers which after a time will contribute less to sea level rise.

    Then there is Jim Hansen who expects considerable positive feedback, partly based upon the paleoclimate record and geometric growth which appears to be taking place in Greenland. Given a doubling per decade, he concludes that the actual rise in more likely in the neighborhood of several meters. In fact assuming just a doubling per decade puts the amount of sea level rise in the neighborhood of 5 m, although at no point does he suggest that it may be higher than this. This would put the level at 16 feet. However, the most recent decade for Greenland showed a tripling.

    I wouldn’t suggest calculating the consequences of a tripling per decade, however, as I have already done so and the results do not seem realistic even to me.

  49. 349
    Dave Rado says:

    Re. #346, Joe Duck:

    I’ve tried desperately to get some feedback about why people seem to think sea level rises dramatically greater than the IPCC projections are “likely”

    The current consensus is that sea level rises significantly greater than the IPCC projections are likely, and that sea level rises dramatically greater than the IPCC projections are possible. As for why some distinguished climate scientists think that the latter are likely, please read Hansen 2007 a bit more carefully than you appear to have read the articles Gavin linked to.

    commenters here seem very reluctant to speak in terms of mathematical probabilities associated with various events.

    As the articles Gavin linked to make clear, that’s because the probabilities are unknown – largely because ice flow dynamics are not well enough understood to be included in the models; which is precisely why the IPCC AR4 ignored ice flow dynamics, while stating (as Gavin has already mentioned to you) that the extra effect from dynamic changes to ice sheets is hard to quantify but may be large.

    Gavin (thanks!) directed me to a discussion where he concluded that perhaps an extra ~25cm

    That’s only if one uses the observed sea level rise of the past century to calibrate a linear projection of future sea level. Read the article Gavin linked to more carefully. Your estimate ignores ice flow dynamics, and also ignores other possible factors that the article discusses.

    I would love to hear from the scientists here about this key point of the likelihood of catastrophic sea level rises this century.

    I’m not a scientist but even I know that “catastrophic” is not a word that has any scientific meaning.

  50. 350
    joe says:

    J.S. M.

    Apples and oranges…maybe, maybe not, and I’m not saying AGW isn’t occuring.

    In retrospect, the “duck and cover” of the 1950s WAS “defeatest” and “do nothing and hope I survive”… I agree. At the time however, “D&C” was the conventional wisdom. You practiced it at school. It was pro-active behavior and people actually believed it could make difference. Could this be occuring now with regard to AGW, and what we do about it?

    Bjorn Lomborg (with much critizism from the “do something,do anything… but do it now” crowd) has written that full Kyoto implemetation would have a “miniscule” effect on warming, at great expense.

    I’ve got no problem with keeping the earth as clean as possible, but in 30 or 40 years (if not sooner or already), the notion of different light bulbs or driving a Prius… all the way to Kyoto implementation, in order to stop the earth from warming is likely to be just as absurd as the”D&C” protocol of the 1950s. Seems a bit hasty just to make yourself feel good.