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Convenient Untruths

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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. 51
    R. Laurence Davis says:

    RE: #25 and #27: Kelsey expects a world wide sea level rise and this is well-documented by dozens of studies in the peer-reviewed scientfic literature including the Bahamas (using Mangroves-and the Bahamas are amongst the most tectonically stable places on the face of the earth), New England, using salt marshes, from tide gauges all up and down the east coast, and those are only the ones that I’m familiar with.

    In terms of plants…we have to differentiate between CO2 that is in the active part of the carbon cycle and that which is fossil. Any carbon in plants came out of the atmosphere recently (years to dozens of years) and goes back in. There is a balance. Where the excess is coming from is fossil fuels, which are “fossil” because for the most part they come from fossil plants that were buried (along with their carbon) tens to hundreds of millions of years ago. When we burn them, we are releasing this “fossil” carbon from storage and releasing it at a rate far greater than the active carbon cycle can pick it up.

    I know I’m wasting my time presenting real science as it’s so inconvenient when it conflicts with political opinion, but it’s worth the try if only to answer Kelsey’s “points”

    (from a geologist/college professor)

  2. 52
    Paul Dietz says:

    Ever see the Panama Canal? There’s a reason why they have to take the boats through multiple locks–the Pacific and Atlantic oceans are at different levels.

    The Panama canal would have multiple locks even if the Atlantic and Pacific were at precisely the same level — the middle of the canal is higher than either end. A sea level canal would have been prohibitively expensive to dig.

  3. 53
    Raplh Smythe says:

    Opinions are opinions.

  4. 54

    I agree with Sean O (#1) that RC has spun this. I have no complaints with the factual information in their entry and in the background links. But given the facts, they’ve tried to cast Gore’s comments in the best light possible.

    RC on ice sheets: “the rate at which this will happen is highly uncertain”. Spin-free comment: Gore omitted relevant information essential for understanding the threat.

    RC on Pacific islands: “could be said to be only a little ahead of its time”. Spin-free comment: The statement is false, or at best an exaggeration.

    RC on ocean conveyor: “few are willing to completely rule out the possibility of a more substantial change in the future”. Spin-free comment: Research since the making of AIT suggests that this danger is less likely than it was portrayed.

    RC on CO2 in ice cores: “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.” Spin-free comment: The crux of Gore’s point was that any idiot could see that temperature goes up when CO2 goes up. If my notes from the movie are correct, he said something like “When there is more CO2, the temperature gets warmer.” His portrayal was misleading.

    RC on Kilimanjaro: “a legitimate example” of a real, widespread phenomenon caused by global warming. Spin-free comment: a poor example of a real, widespread phenomenon caused by global warming.

    RC on Chad: “Gore uses this example to illustrate that there are droughts in some regions even while other areas are flooding.” Spin-free comment: He also implies that this specific drought is caused by global warming, and that global warming was the primary cause of the vanishing of the lake. The final statement, given the variety of causes of both lake shrinkage and drought, is less defensible.

    RC on Katrina: “Katrina is used in the film as a legitimate illustration of … the kind of thing that could well get worse in a warmer world.” Spin-free comment: AIT presented Katrina in the context of natural signs that global warming was already having a visible effect, not as a hypothetical example.

    Polar bears: I agree with RC’s assessment that Gore’s description was accurate but oversimplified.

    Coral reefs: I agree that Gore’s description was accurate and fair.

    In my opinion, overall the science (in AIT and elsewhere) is quite robust enough to stand up to a spin-free discussion of it.

  5. 55
    Ray Ladbury says:

    I would like to call attention to what I feel is a very serious psychological manifestation: Goreophobia. Yes, I know that politicians of all stripes tend to elicit a gag reflex among all right-thinking people, but the visceral reaction to this one particular politician seems to have severe debilitating effects on many individuals. Effects include: inability to accept conclusions backed by overwhelming evidence merely because they resemble talking points of Al Gore, foaming at the mouth, an overwhelming urge to engage in “debate” and make irresponsible wagers that the sufferer later forgets.
    The cure for this malady is long and involved. It involves first and foremost accepting the need to address the issues of climate change. If enough of the sufferers do that, they will find that Al Gore doesn’t have a podium to stand on. Until then, he will be in their face constantly, and their prognosis will be grim.

  6. 56
    Jim Eager says:

    Oh my, we seem to have attracted more than few posters who don’t seem to have even a basic grasp of the carbon cycle, let alone the physics of greenhouse gasses, but then threads about Al Gore and AIT tend to do that.

    Re 4 chip: “For what it’s worth, I have read several books about Britain’s search for the NW passage in the 1800s, and they often mention years when the Arctic waters were largely ice free.”

    I suggest that you take a look here
    to get some idea of where the bulk of Arctic ice melt occurred this summer and how truly large a mass of ice melted. We’re not talking about the northwest passage, which runs through the more southerly channels through the Canadian Arctic archipelago. We’re talking about the open Arctic sea to the north and northwest of the archipelago.

    Re 7 Sean O: “I just wish that RC, which has such a great reputation as a scientific site, would have clearly said that Gore was 100% correct or 100% wrong on each issue”

    That would have required that he be 100% correct or 100% wrong on each issue. Humans rarely attain that level of black and white perfection or error.

    Re 13 cant say: “Ice-sheet driven sea level rise
    “No time scale was specified” what the hell type of excuse is that.”

    It’s not an excuse, it’s a fact. Gore’s exact words were: “If this [West Antarctic Ice sheet] were to go, sea levels worldwide would go up 20 feet.” How long it would take for it to melt depends on how hot it gets and how fast. What time scale would you have had him choose? Imagine the hue and cry if he HAD picked a time frame.

    Re 25 David Kelsey
    Let’s see, you question that CO2 is a even greenhouse gas, which has only been known and demonstrated experimentally since the 19th century, and assert that there is too little of it to matter in any case. Is it too much to expect that you would do even a rudimentary bit of research on the subject of greenhouse gasses before making such comments? Here’s a good place to start:

    Then you go on to assert that human respiration is contributing to the rise of atmospheric CO2, complete with gratuitous and disingenuous comments about mass genocide. Did you come straight here from the comments section of Huffington Post? Perhaps you should do some reading on the carbon cycle, which can be found in any basic high school physical geography or earth science textbook.
    Here’s one that’s real easy to grasp:
    And here’s one that’s more comprehensive on-line source:
    Here’s another:

  7. 57
    SecularAnimist says:

    Gavin and Michael wrote: “Individual hurricanes cannot be attributed to global warming, but the statistics of hurricanes, in particular the maximum intensities attained by storms, may indeed be.”

    Certainly no one can say “this particular hurricane formed at this particular location at this particular time because of global warming.” Thus it would be unsupportable to say that hurricane Katrina, for example, was “caused by global warming.”

    However, it is my understanding that the development of hurricane Katrina — which had weakened while passing over Florida from the Atlantic, and then strengthened to Category 5 and grew to enormous size over the Gulf of Mexico — can be directly attributed to the unusual warmth of the Gulf water in August 2005, and thus can be attributed to global warming.

    In this sense I believe it is legitimate to “link” hurricane Katrina to global warming, not in the sense that global warming caused that particular hurricane to come into existence at that particular time, but in the sense that global warming directly contributed to Katrina’s growth into a highly destructive “mega-storm”. Thus the destruction and devastation that we have come to refer to as “Hurricane Katrina” can legitimately be pointed to as an example of what global warming has in store for us in the future in terms of more frequent development of such hurricanes as do occur into more powerful and destructive storms.

    And Gore’s point about our lack of preparedness to deal with Katrina is very important. We — and I mean the USA, the richest and most technologically advanced society on Earth — are ill-prepared to deal with many of the likely effects of global warming; not only mega-hurricanes but droughts, floods and fires. Much of New Orleans and the surrounding region is still in ruins two years later. Most of the world is even less prepared and less well-equipped to deal with such disasters.

    And as far as I can tell, all of the empirical evidence indicates that the disasters will be many, frequent, and bigger and sooner than anyone has anticipated.

  8. 58
    Tom Fiddaman says:


    This site seems to be little more than a platform for google ads, with little original content, and lots of false controversy borrowed from the wrong side of the media tracks. You can check it’s street cred by googling links to the site. Not a very powerful or plentiful harvest.

    Please don’t feed the trolls.

  9. 59
    Dick Veldkamp says:

    #39 Sea level & gravity

    Ray, your equipotential argument sounds very convincing to me.

    However I do not think that a level difference between the oceans is the reason for locks in the Panama canal. As far as I know, you just have to get over the hill somehow. The Suez canal has no locks; apparently if the resistance of a canal is large enough it doesn’t matter that there is a little flow back and forth.

  10. 60
    Dave Rado says:

    Re. 25 and 27, David Kelsey, you clearly have not read up on the subject. Try reading up on the carbon cycle and once you’ve read that, click the Start Here link on menu at the top of this page, and follow the links from there.

  11. 61
    Tom Fiddaman says:

    Re 25, 27 (human and plant respiration)

    “Forgive my ignorance” was a good way to begin the discussion of genocide and deforestation as strawdog green policies.

    All of the CO2 contributed to the atmosphere by plants, animals, and humans was originally removed from the atmosphere by photosynthesis. As long as the inflow and outflow are in equilibrium, there’s no problem. Trouble only arises when there’s a net contribution of CO2 to the atmosphere, from burning forests or fossil fuels for example.

  12. 62
    robert says:

    Re: 25 & 27, David Kelsey,

    Not to pick on you Mr. Kelsey, but I’d like to use your comments as an example of what I find particularly exasperating in this and other scientific discussions among lay people (and, by the phrasing of your comments, I’m assuming you’re not a scientist):

    The questions Mr. Kelsey raises are perfectly reasonable questions for a lay person to ask. It’s true CO2 is a trace gas, that anthropogenic additions to the total carbon cycle are small, and that living systems outgas CO2. Further, it’s true that, at first glance, these facts seem to run counter claims of AGW. But one would hope it would also occur to a lay person that it’s likely that the scientists who study climate change are aware of these facts and have taken them into condideration. Consequently, it’s likely that there’s a perfectly good explanation as to why they do not, in fact, refute AGW.

    So in asking the questions, one would hope the phrasing were more congenial, rather than confrontational. In particluar, Mr. Kelsey’s comment #27 is phrased less like a question than a “gotcha!” It makes him look downright ignorant – not of the science, but of the competency of the scientific community. And it’s this attitude among a significant number of lay people, that is difficult to reason with. If you’re seriously posting a comment as basic as “biomass returns carbon to the atmosphere, so there!” on a blog run by and frequented by professional climate researchers, it’s clear you have no idea how much you don’t understand, and how much others do. It’s a complete lack of appreciation for the level of knowledge among the professionals – as though anyone could be a climate expert w/ just a few night courses at the local community college.

    Sure, ask the questions, they’re not dumb questions. But give the community of thousands of researchers, working for decades, the benefit of the doubt.

  13. 63
    David B. Benson says:

    Dick Veldkamp (52) — The Red Sea has a slightly higher stand than the Mediterranean Sea. The Suez cnal has led to an invaszive species problem in the easttern Mediterranean Sea.

  14. 64
    Dave Rado says:

    Re. the CO2 lag in the ice core record, the guidance notes [PDF] for schools state:

    “Note: Pupils watching this segment might get the impression that the graph plotting CO2 against temperature over 650,000 years proves that recent rises in temperature are caused by CO2. The latter conclusion is accepted by the great majority of the world’s climate scientists, but cannot be proved by reference to this graph. Closer examination shows that, for most of the last 650,000 years, temperature increase precede CO2 increases by several hundred years. Some sceptics have used this to support their claim that recent temperature rises may not be caused by CO2. But it is generally accepted that the causative relationship between CO2 and temperature over the last 650,000 years goes both ways and that, now, it is CO2 which is driving temperature. The relationship between increases in CO2 and increases in temperature is not linear, it is logarithmic. The IPCC estimates that the equilibrium warming if CO2 concentrations were doubled is likely to be in the range of 2°C to 4.5°C with a best estimate of 3°C.”

    Not exactly a clear explanation of the feedback mechanism! And no mention of the fact that that most of the eventual warming was GHG-induced.

    Poor show.

  15. 65
    Vinny Burgoo says:

    Re Theo (currently #46): “The core complaint by Mr Dimmock, who took the issue before the courts, against AIT, was that the film was “political indoctrination” so contrary to the 1996 (UK)Education Act. This is probably more interesting, and the arguments for and agaist, than the science itself. The judge most usefully ruled that AIT was not ‘political indoctrination’.”

    I agree that the political aspect is more interesting than the “errors” (though I think some of the “errors” were indeed errors) but that last statement is wrong. The judge didn’t rule that AIT isn’t political indoctrination; he ruled that no teaching material, no matter how controversial (he mentioned Nazi propaganda films), is itself politically indoctrinating. It all comes down to how materials are presented in the classroom.

    Everyone in court – defendant, claimant and judge – agreed that the film is politically partisan: that it promotes a particular view of what we should do in response to climate change. If teachers didn’t point out these political aspects, that would be political indoctrination. The judicial review worked out a new set of guidance notes for teachers that would help them stay on the right side of the law and allow the film to be shown. No matter what Mr Dimmock’s intentions were (he is said to be a GW sceptic), by the time his complaint came to court, the science was secondary.

    Vicki (#43), it came to court because whoever decides these things thought there was a real chance that the government’s initial distribution of the film was in breach of the law. And so it proved. There was initially a clearly stated intention to indoctrinate children. There was also a lack of guidance to teachers on how to treat those parts of the film that were political (and/or non-IPCC science).

    (Thanks to those who provided explanations of weak gravity, low water. My brain is still sizzling slightly, but that’s my problem.)

  16. 66
    Sean O says:

    Re 55. Tom – I am sorry that my site doesn’t fit your standards. I try to be fair and balanced and discuss both sides of the issue. The site is barely 6 months old so it only has a few thousand links (use the Google Webmaster tools not the link tool that you referred to). According to my feed stats, I have several hundred regular readers that must see value in the format that you deride.

    You don’t have a URL tied to your posts. What is your site on the subject and how many external links does it have? I am wondering if a glass house analogy may not be in order.

    Yes, I have ads on the site. The pennies that I get per click on an ad barely cover my hosting bill and come nowhere near my time and effort. Don’t disparage me because I am not independently wealthy and want to cover my costs.

  17. 67
    Ray Ladbury says:

    Dick Veldkamp. No, there are many reasons for locks in the PC. Gravitational differences are not one. Wind and currents are. The Pacific sea level is different than that of the Atlantic–mainly due to prevailing winds. As I said, a lot of things contribute to local sea level. The gravity reference was specific to Vinny’s question.

  18. 68
    Ray Ladbury says:

    Sean O. Oh dear, another “fair and balanced” site. So tell me, Sean, how do you balance the fact that all the evidence is on only one side?

  19. 69
    Hank Roberts says:

    Sean O’s wish that RC would provide “100 %” answers, and claim to presenting “both sides” of questions, shows he’s not writing about science in his “fact or fiction” page. RC gets a lot of people posting their sites blogflogging. Setting “nofollow” might avoid pagerank benefits, if it’s an option you can elect per site.

  20. 70
    bigcitylib says:

    Gavin and Michael, this

    …is just a news story, but glacier guy P. Mote seems pretty adamant that the Kilimanjaro thing CAN’T be blamed on GW.

    [Response: Ray Pierrehumbert, our resident atmospheric water vapor expert, has clearly articulated here before an argument for why the imminent demise of Kilimanjaro likely is related to anthropogenic climate change. This was from before Ray was a regular here–the article was posted as a guest article by our resident glaciology expert Eric Steig. -mike]

    #4 The St. Roche spent several months on its first arctic run stuck in the ice. The second, shorter run still took 86 days. Conditions were hardly “ice free”.

  21. 71

    [[Forgive my ignorance, but isn’t sea level a worldwide thing? How can the sea level rise in the area of some Indian islands without its being noticed, say, around England or New York?]]

    Sea level is not the same everywhere in the world. It varies with local gravity, temperature, salinity, currents, and winds.

    [[ Could the flooding of low lying islands not equally be due to tectonic plate activity?]]

    No, probably not.

    [[ Of course, the latter can’t really be blamed on man, so it won’t get much publicity. While I am writing this, exactly how do we know CO2 is a greenhouse gas? ]]

    Because John Tyndall demonstrated that it was in the lab in 1859.

    [[There isn’t a hell of a lot of it in the atmosphere – 0.036% of the global atmosphere – so how does this minuscule proportion affect the global temperature?]]

    For a precis, try John Houghton’s “The Physics of Atmospheres.” And the 384 ppmv of CO2 in the air amounts to 5.88 kilograms for every square meter of the Earth’s surface, which is plenty to affect radiative transfer.

    [[ And as human exhalation accounts for 38 billion tonnes of CO2, and animals probably the same again, what remedies do the warmers have in mind for this? Mass genocide?]]

    Animal and plant respiration is balanced in a natural cycle. The vast majority of CO2 produced every year is taken up by natural sinks. Human burning of fossil fuels raises the source levels enough that the total in the atmosphere keeps accumulating.

  22. 72
    Mary C says:

    Re 39. What do you take this statement to mean and what was the claim in the court arguments about it? Are you implying that “over-representation” somehow equates to “falsification” or am I mis-interpreting your reason for posting this statement?

  23. 73
    Chris says:

    # 70

    looks like it can be, but, the vast majority of glaciers are retreating world wide and humans are having a great deal of influence on this. When Lonnie Thompson said a few more years before it’s gone, I don’t think Kilimanjaro cared too much- but it is like the dice game in my comment 6 — Chris

  24. 74

    [[Oh Gosh, I forgot the plants. There are apparently 1877 billion tonnes of biomass, half of which is carbon. Virtually all of this is presumably expressing CO2 during the hours of darkness, and oxygen in daylight, due to photosynthesis. What’s the green answer to that? Cut down all the forests?]]

    Where did you get the idea that photosynthesis reverses itself at night? If your model were correct, plants would get no nutrition and would all die.

  25. 75

    [[ I am sorry that my site doesn’t fit your standards. I try to be fair and balanced and discuss both sides of the issue.]]

    Do you address both sides of the issue of white supremacy, slavery, or the Holocaust?

    Sometimes it has been established by massive amounts of evidence that one side or the other is WRONG. So giving equal play to both sides is like giving equal play to a real physicist and a crackpot who claims he can disprove relativity.

  26. 76
    Dr. J says:

    Yes, sea level rise is a relative phenomena, as many coast lines on the globe are rising in response to isostatic rebound (from glacial unloading as the ice sheets melted during this interglacial, and it is still occuring in many parts of the northern hemisphere). Tectonic uplift of coast lines around the Pacific Rim (ring of fire) is also common. These uplift effects are many times 3 to 5 times more rapid than sea level rise due to ice melt over the last century or so, many are 10mm per year. There are also coast lines that are subsiding due to downwarping of the earth’s crust by rapid sediment loading, such as the deltas of the Mississippi, Ganges, Nile, etc. and due to rapid fluid withdrawal. So Mr. Gore’s gross exaggerations on ice melt drowning the world are total misrepresentations of the scientific facts for political gain. Why any true scientist could endorse his distortions and half truths is beyond my comprehension and ethical understanding of what science should stand for in society. However, it also tells me some scientists are willing to compromise their professional ethics to salve their environmental motives and use any means to justify their ends.

  27. 77
    Eachran says:

    A bit generous with Mr Gore, I think : maybe even partial, particularly with the Pacific

    But having said that, Mr Gore has actually stood up and been counted.

    I didnt think that the Judge in the case did at all badly : he is clearly almost as
    switched on as most of the posters on RC. I particularly liked his comments on ‘balance’,
    which the media might like to read and take to heart.

    The prime issue for me is not temperature increases, which looks like a slam dunk, and its
    evident effects on marine and land based life and land based agriculture, whilst not forgetting
    the impacts of extreme weather events, mass migrations and the rest, but on sea level rise
    which is a known unknown (if I may put it like that).

    I keep reading the science stuff on this as recommended by your excellent selves
    and then I read some of Mr Hansen’s stuff and it does all fit. The problem seems to be that
    we dont know how it fits because the detailed science hasnt yet caught up with the informed
    and educated intuition.

    Starting from base, I would doubt that there is a respectable climate scientist/modeller who
    would bet against a more than 1m rise by the end of the century. I suspect that the futures
    market is insufficiently developed for that time frame, so we shall never know.
    But 1m does seem to be the base number, hunches included

    But if the base is 1m then how do the bets shape up for 2m or more. One metre is bad
    enough, perhaps a major disaster, but 2 and then three looks to me like a
    mega disaster in the making.

    Returning to the Hansen et al 2007 paper which tried to be positive about controlling
    temperature to 1C, sea level rise popped up again.

    I dont know how organised the science community is with respect to ice sheet study but
    does it make sense to keep a running commentary at 6 monthly rests in one easy to read
    document, on : mass balance, melt water flows, glacier movement, glacier calving, quakes
    and/or whatever is important ? A bit like a doctors report on the patient’s progress.
    It seems important enough to me, but is it, and if it is then who would do it?

  28. 78
    tamino says:

    Off topic of course, but the “recent comments” and “with inline responses” lists on the main page don’t seem to be working. I miss ’em.

    [Response: Sorry. We are having database overload issues and the recent comment searches are particularly unfriendly. Any experts in mySQL and php who want to help can email me! – gavin]

  29. 79
    Tom Fiddaman says:

    Re 55 / 66

    I gave your site a second look. There’s more material than first meets the eye, but I don’t see the balance to which you aspire.

    For example, I chose the Getting Warmer-Human Fault category, and looked at the first few links. The first four, while they report on pro-AGW developments, all have AGW-skeptical editorial comments. On the other hand, the Not Getting Warmer category’s first few posts are presented without criticism, even though they come from what I would consider to be extremely dodgy sources and contain flaws which have been repeatedly pointed out elsewhere. I see a distinctive anti-AGW slant to your content; the tone reminds me of Tech Central Station.

    I would like your site better if you did one or more of the following:
    – abandon the pretense of balance (or get some balance; balance does not mean equal quantities )
    – go meta, i.e. continue reporting on developments in the popular media, but just keep score on which side is winning, rather than treating the product of lobbyists as science
    – go deeper, tracing skeptical and other arguments back to reasonable sources in the science literature
    There’s plenty of noise out there, so GW sites need to serve as filters, not repeaters.

  30. 80
    richard says:

    re 79. “but I don’t see the balance to which you aspire. ”

    I think you are confusing balance with something else. In the first place, the ‘skeptical’ arguments you refer to ARE sourced, the problem is that those arguments are simply very weak. That is why the climate science community has largely agreed with the IPCC findings; there are no substantive counter-arguments. Ths discussion points now are revolving around 1. how bad will it get 2. what can be done.

  31. 81
    David B. Benson says:

    Dr. J stated: “So Mr. Gore’s gross exaggerations on ice melt drowning the world are total misrepresentations of the scientific facts for political gain.”

    Not so. There is ample evidence that during the previous interglacial, the Eemian around 134,000 years ago, the sea stand was about 4 meters higher that it is now. This is attributed to higher temperatures in at least Greenland and possibly also West Antarctica.

    Mr. Gore did not state how long it would take for the sea stand to rise this far. No one knows, although Dr. James Hansen has recently stated that it might be much sooner than previously estimated.

    With mis-statements such as yours, I suppose our descendants will find out…

  32. 82
    Richard Ordway says:

    [[Forgive my ignorance, but isn’t sea level a worldwide thing? How can the sea level rise in the area of some Indian islands without its being noticed, say, around England or New York?]]

    You need to learn physics. Two forces, at least can make this so. One is that water expands when heated. If warmer ocean currents are shifted then they rise more than colder ones. El Nino raises its tongue surface height by at least 15 cm (or about 1/2 of a foot).

    Second reason, some places like New England are still rebounding from the last ice age…yes, they are rising after the weight of the ice…but that is taken into account.

    Some places in Australia actually had no real sea level rise over the last 50 or so years…you need averages, averages averages….not single cherry pickings.

    All this is not really radical.

    The peer review system (Fourier), although it was hard to accept for the times, indicated that humans might be able to change local surface climates even in 1827. P.21.

    The basics have been hashed out pretty well by world scientists since 1827.

  33. 83
    Figen Mekik says:

    Same for me Tamino. The web site was down for part of the weekend and maybe it hasn’t fully recovered yet?

  34. 84
    tidal says:

    Ah… just for some levity… from “The Daily Mash”:
    He said the former US Presidential candidate’s assertions that all dolphins had melted and that elephants were being forced to make footballs for Nike in India for slave wages were also, “a lot of cock”.

    Justice Brubaker said: “According to Mr Gore climate change has forced monkeys to install air conditioning in their jungles and led to snakes growing arms so they can hold one of those personal electric fans. I don’t think so.

    “Anyway, if it is that bad why doesn’t he try turning off a few lights in his own mansion before telling the rest of us we have to recycle our own turds to stop our children from catching fire.”

    However, the judge said the film could still be viewed in British schools as long as the head teacher stood up before each showing and said: “This is a flammed up can of old shite. Ignore it.”

  35. 85
    Jim Eager says:

    Re 76 Dr J: “So Mr. Gore’s gross exaggerations on ice melt drowning the world are total misrepresentations of the scientific facts for political gain.”

    Please define gross exaggeration in this case.

    What is exaggerated or half true about the statement: “If [the West Antarctic ice sheet] were to go, sea levels worldwide would go up 20 feet?”

    Or the statement: “If Greenland broke up and melted, or if half of Greenland and half of West Antarctica broke up and melted, this is what would happen to the sea level in Florida?”

    It’s easy enough to calculate if those statements are factual or not, is it not? And is it or is it not a fact that sea level has been that much higher in the past at times when temperatures were only 1-2ºC higher than they are today, as Gavin and Michael stated?

    It was you, Dr J, who used the phrase “drowning the world,” not Gore. It seems to me that it is you who is exaggerating and misrepresenting what Gore said for political gain.

  36. 86
    Lynn Vincentnathan says:

    Well, this just reconfirms it to me that Gore is much closer to the conservative “science” side of the discussion than the “environmentalist” side. Too bad. I don’t blame him, the way the denialists have snuck into to the discussion with a forceful vengeance and railroaded it over somewhere between denialists’ “we need 99% or 101% certainty” and scientists’ “we need 95% certainty,” totally pushing out the victims’/potential victims’ position of wanting to avoid harm. I just wish someone would stand up a bit stronger for the victims and potential victims, and just ignore the denialists.

  37. 87
    truthout says:

    In geological circles it is well understood that coral islands develop on volcanic sea-mounts which may or may not reach sea level. It is also known that the weight of the volcanic edifice, and the coral structures developed on it, cause subsidence since the underlying oceanic crust yields to the weight. Volcanic activity can re-commence, lifting the whole edifice. This is demonstrated on many coral islands by the coral ‘terraces’.

    So, apparently rising sea-levels on coral islands are much more to do with local subsidence than an overall global rise in sea-levels. How can it be so difficult to miss this obvious point?

    We should also acknowledge that coral islands have a self-correcting mechanism to deal with subsidence. Coral is an active organism, and it grows to reach the surface. If the island sinks a little, the coral grows a little to compensate.

    I think you will get much further in understanding the issues relating to sea-level rise on coral islands if you look at the politics of the situation. Many coral island based nations are losing population due to the lack of a viable local economy. An example I am familiar with is the island nation of Niue which has only 1500 local residents, but a population of 20,000 expatriates living mostly in New Zealand, but also in Australia. Niue is keen to find ways to restore the local economy so that it can welcome many of the expatriates back home.

    It is not surprising that some of the small island nations are capitalising on the AGW situation in an attempt to secure funding support.

  38. 88
    Sean O says:

    Re. 79
    Tom – thank you for taking another look. I followed the links that you referred to (I am not going to reproduce them here since I was called a link troll here today and that was not my goal). I have to politely disagree with your characterization of the 10 posts at each category. While I was probably harder on Mr. Gore (whom I think created a sham movie) and carbon trading (which I think is counter-productive to the goals of appropriate energy usage), I have been chastised much harder for my comments against the skeptics (I don’t think that Imhofe’s people will ever talk to me again).

    Oh well, thank you for at least being open minded enough to take a look.

    Re. 69 Hank – Nofollow is already set for RC. It is a WordPress blog and nofollow is automatically set for WP blogs unless the administrator explicitly turns it off. My comments here were not a link trolling expedition but rather pointing out that Gore took liberties with the truth and RC wimped out by not calling him on it.

  39. 89
    Dave Rado says:

    Re. #88, Sean O, other than possibly “Pacific island nations needing to evacuate”, I don’t see what evidence you have that AIT “took liberties with the truth”. It over-simplified at times (most documentaries do), and in one case (sea level rise) it departed from the scientific consensus by implication, but that’s not the same thing as taking liberties with the truth. With only minor tweaks and qualifications (such as using a different illustration of glacier retreat rather than Kilimanjaro) his film could have stuck to the consensus and yet made exactly the same points. Fundamentally the AIT film is accurate (unlike the Swindle film, which the AGW deniers are trying to promote as a counterpoint to AIT, and which is fundamentally dishonest).

    Also, in a documentary film which mentioned hundreds of facts it is not surprising if it got a small number of them wrong and over-simplified others. It’s main points were all scientifically accurate, again in stark contrast to Swindle.

    Even in the case of the evacuation issue, there seems little doubt (and the IPCC AR4 WGIII report confirms this) that the balance of probability is that huge numbers of people (probably tens of millions) worldwide will be displaced during the coming century as a result of sea level rise, so although his specific illustration was misleading, the point he was making was accurate.

    Having said that, I do wish Gore had had the film’s transcript peer reviewed before release – that would have prevented it from becoming a relatively easy target for the AGW deniers. It could have made the same points just as effectively, with better illustrations and more qualifications, and would have been better for it. But fundamentally it seems an honest film to me, unlike Swindle, and I see no evidence to back your implication that it this isn’t the case.

  40. 90
    Rod B says:

    I’ll second Sean (#1) with a little twist. I do think you’re looking carefully for obscure loopholes that correctly conclude that Gore did not say exactly this or that, when the perfectly clear implication from the movie is to get people to believe all those things that Gore did not actually say. That said, I think the original court case was making much todo over nothing, let alone trampling all over freedom of expression (which I don’t know if it has the same legal weight in England.) If the courts assessed all textbooks and media with the same guidelines, students would have nothing to read or watch. Most things have an error here and there, and, as RC cogently states, “….people expecting the same depth from a movie as from a scientific paper are setting an impossible standard.” I’m on the skeptic side of things and disagree with Mr. Gore on a number of things, and think he skewed a few things in the movie; but there is no good reason under the sun that it should not be able to be distributed and shown in schools or any place else. Nor should it be obligated to be shown with a “truth-in-lending” disclaimer — that’s downright silly.

    I congratulate Mr. Gore on winning the Nobel Peace Prize, but I have no idea what his stance on global warming has to do with wars, conflicts, disarmament, armies, peace, and such. Academy Award? Well, it was at least a movie, and for all I know the best of the category. More congrats.

  41. 91
    Lynn Vincentnathan says:

    I was somewhat disappointed that Gore’s film didn’t go far enough with the harms — like leaving out a discussion of possible runaway warming or hysteresis — positive feedbacks of our initial warming causing nature to emit more GHGs, causing more warming, causing nature to emit more, and so on up to massive extinction and tremendous human genocide. That’s a lot of bang for our GHG emissions. However, on the AIT DVD in the extra info section he does mention it a bit.

    I think any classroom in which AIT is shown should make it a point to discuss the high end harms, which though less likely are something we need to keep in mind. Cautious claims are for scientists and ultra-cautious claims for denialists with politico-economic agenda. Those concerned about avoiding serious threats to our life-support systems in the near and distant future should not require high certainty to address these issues. Would a life-loving person take poison because there was only a 70% chance it would kill them, even 30% chance? Yes, of course, many people do eat and drink things that harm them, but it is unconscionable to bring death and destruction upon other people, upon our progeny.

  42. 92
    J.C.H. says:

    Comment by Sean O — 16 October 2007 @ 7:18 PM

    … While I was probably harder on Mr. Gore (whom I think created a sham movie) …


    I have no doubt that Dr Stott, the Defendant’s expert, is right when he says that:

    “Al Gore’s presentation of the causes and likely effects of climate change in the film was broadly accurate.”

  43. 93
    Dave Rado says:

    Re. #90, Rod B:

    but I have no idea what his stance on global warming has to do with wars, conflicts

    Are you really serious that you have no idea? See here, for example. It really isn’t rocket science!

  44. 94
    Rich Briggs says:

    truthout, here’s a response from somewhere deep inside a geologic circle (sometimes a hole!).

    In geological circles it is well understood that coral islands develop on volcanic sea-mounts which may or may not reach sea level. It is also known that the weight of the volcanic edifice, and the coral structures developed on it, cause subsidence since the underlying oceanic crust yields to the weight. Volcanic activity can re-commence, lifting the whole edifice. This is demonstrated on many coral islands by the coral ‘terraces’.

    Oops, you have it backwards – volcanic activity provides the load that depresses the crust (and raises an annular ‘donut’ around the point load). When the activity ceases, slow uplift (or subsidence in the surrounding annular arch, as the ‘donut’ is more properly called) occurs as the load erodes away. But putting that aside, for flexural volcanic loading to affect uplift measurements, you need an active, or recently active volcano — of which there are surprisingly few in the Pacific; it drops off quickly after Hawaii, Samoa, and the Society Islands. Your example, Niue, is long dead and readjusted.

    So, apparently rising sea-levels on coral islands are much more to do with local subsidence than an overall global rise in sea-levels. How can it be so difficult to miss this obvious point?

    This is far off the mark – and in two directions. First, it’s simply not true that all coral islands subside. A closer look at the history of your example, Niue, is a great illustration along these lines – more on that below. Second, eustatic sea level rise (not ‘apparent’ or ‘relative’) is clear from long-term tide global gauge records and, most convincingly, from satellite measurements in an external reference frame. The obvious point, in geologic circles, is that accelerated eustatic sea level rise is bad news for low-lying atolls.

    We should also acknowledge that coral islands have a self-correcting mechanism to deal with subsidence. Coral is an active organism, and it grows to reach the surface. If the island sinks a little, the coral grows a little to compensate.

    This one is true, and truly beside the point. Live coral requires sea water, so islands would already be flooded in this scenario. Are you envisioning coral somehow growing beyond low-tide elevation? I’m baffled. The few meters of relief that defines most of the lowest-lying Pacific atolls reflects the mid-Holocene far field highstand, when corals were indeed playing catch-up to a quickly rising sea level.

    An example I am familiar with is the island nation of Niue

    Your example of Niue bears closer examination. It is a beautiful emergent atoll that sits on the forebulge of the Tonga trench. As Niue moves toward the subduction zone, it is climbing up and over the flexural trench forebulge – and consequently, it has actually emerged 0.4 – 0.9 m since the mid-Holocene (even with the mid-Holocene RSL high taken into account). Take a closer look at the fringes of Niue on Google Earth and admire the emergent wavecut benches cut into the Pliocene to modern reef. This is hardly an example of continual subsidence. If this type of thing catches your fancy, check out Rennell Island in the Solomons for another beautiful example of an island lifted by the forebulge.

    For everybody who is truly interested in sorting out geodynamic/eustatic/hydro-isostatic contributions to relative sea level, the paper “Paleoshoreline record of relative Holocene sea levels on Pacific islands” by W.R. Dickinson (2001) in Earth-Science Reviews is a great place to start (and the rates for Niue above are his work).

  45. 95
    Edward Greisch says:

    1. The legal profession has jargon like all professions. The judge may have been using the word “err” to mean something other than what we mean by “error.”

    2. Al Gore was very mild on the problems caused by global warming. It is almost like he is trying not to scare people. I have found more scientists who say that we have only about 200 years before we humans go extinct. The cause would be H2S. The web sites are:

  46. 96
  47. 97
    Doug Watts says:

    I’m a bit confused by the folks who say they are a “skeptic” but fail to provide any scientific evidence which supports their skepticism. Using the same argument and evidentiary standards, I guess I could say I’m skeptical about the existence of gravity and the chemical formula of sodium chloride. I’m just skeptical.

  48. 98
    Kiminori Itoh says:

    I think the film AIT may be a good teaching material if it is suitably used. It will give pupils a rough sketch on the global warming issues. How should it be “suitably” used then? I want to show an example here.

    Pupils in England would not care if the first thinker of the CO2 measurement is Keeling or Revelle (the former, according to S. R. Weart, “The Discovery of Global Warming,” Harvard University Press, 2003). But, they will have a strong impression that the reason for the frequent close of Thames Barrier is that sea level is rising due to the CO2 increase. Of course, this is not true; according to London City, “The Barrier is now also being closed in response to high water levels in Thames tributaries rather than only when a tide is exceptionally high ( An interesting point is that the amount of rain was relatively small during 1995-1997 when the barrier was closed often. Thus, it may be a good traning for the pupils to look for real reasons why the Thames Barrier are closed so often recently.

    Moreover, the sea level rise near London is largely due to the subsidence of the southern part of the Great Britain; this is, as is known well, because of post-glacial rebound (the northern half is raising).

    Thus, the film should be supported by “accurate information”when it is shown in the classrooms. I hope Mr. Gore will revise his film in near future.

  49. 99

    “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.”

    No one has ever accused the members of Norway’s Storting,whence Peace Prize nominations and Committee members largely stem, of having any better taste in films than nominees, many of whom are not exactly in Ingemar Bergman’s bracket.

    I took the precaution of blowing the whistle on CEI’s Iain Murray last week, for glossing over the High Court ( no more to be confused with the Law Lords than the Low Kirk) invocation of the IPCC report and ignoring the judge’s focus on the problem of partisanship in nations where Green is a Party:

  50. 100

    “it is clear that the purported ‘errors’ are nothing of the sort. The (unofficial) transcript of the movieshould be referred to if you have any doubts about this.”

    Really? The thing speaks for itself in all its sublime truthiness.

    What fraction of the audience do you suppose kept their eyes closed ? The film is about 100 minutes times 50 words long, and consists of several hundred beats, each picture being canonically worth a thousand words. Go figure.

    Like most intelligent laymen, judges can recognize cant when they hear it and cartoons when they see them, and evidently this judge did. Seldom in the annals of rubber graph paper has the disconnect between text and icon been more guilefully constructed than when Al uses a virtual cherry picker_ to obscure the scale expansion of the opening graph, and even for the sake of a movie trailer, inundating a Silicon Graphics Statue of Liberty is a very odd way to validate a GCM or illustrate a centimeter per year of maximum sea level rise.

    He and Guggenheim should be ashamed of themselves, but that’s not much of an occupational hazard among those hell bent to save the world. With the conspicuously honorable exceptions of Mike MacCracken , Jerry Mahlman and Steve Schneider , the only lesson those involved seem to have garnered from the media hype attending Carl Sagan’s modeling run for the Peace Prize a generation ago is:

    ‘If at first you don’t succeed, try waiting for scarier special effects ‘

    [Response: You appear to be talking about The Day After Tomorrow, rather than AIT. And if you think a cm/yr sea level rise is nothing to worry about, I have some basement property in Battery Park City to sell you. – gavin]