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Climate Hustle

Peer reviewed impacts of global warming

Posted on 24 January 2010 by John Cook

If the IPCC's mistaken prediction that the Himalayan glaciers would be gone by 2035 taught us anything, it's that we should always source our information from peer reviewed scientific literature rather than media articles. Consequently, I've spent the weekend overhauling the list of positives and negatives of global warming so that all sources were peer reviewed. The list is by no means comprehensive and I welcome any comments mentioning other impacts of global warming found in peer reviewed papers (good or bad). Please include a link to either the abstract or if possible, the full paper. Note to skeptics - here is an opportunity to pad out the positive column if you can find peer reviewed papers outlining any benefits of global warming.





  • Decelerating tropical forest growth (Feeley 2007)
  • Increase of wildfire activity (Westerling 2006)
  • Increased range and severity of crop disease (Evans 2008)
  • Encroachment of shrubs into grasslands, rendering rangeland unsuitable for domestic livestock grazing (Morgan 2007)
  • Decreased water supply in the Colorado River Basin (McCabe 2007)
  • Decreasing water supply to the Murray-Darling Basin (Cai 2008)
  • Decreasing human water supplies, increased fire frequency, ecosystem change and expanded deserts (Solomon 2009)
  • Decline in rice yields due to warmer nighttime minimum temperatures (Peng 2004, Tao 2008)


  • Winter deaths will decline as temperatures warm (HPA 2007)


  • Increased deaths to heatwaves - 5.74% increase to heatwaves compared to 1.59% to cold snaps (Medina-Ramon 2007)
  • Spread in mosquite-borne diseases such as Malaria and Dengue Fever (Epstein 1998)
  • Increase in occurrence of allergic symptoms due to rise in allergenic pollen (Rogers 2006)

Arctic Melt

  • An ice-free Northwest Passage, providing a shipping shortcut between the Pacific and Atlantic Oceans (Kerr 2002, Stroeve 2008)

Arctic Melt

  • Loss of 2/3 of the world's polar bear population within 50 years (Amstrup 2007)
  • Melting of Arctic lakes leading to positive feedback from methane bubbling (Walter 2007)
  • Less compacted ice, hazardous floes and more mobile icebergs posing increased risk to shipping (IICWG 2009)
  • Drying of arctic ponds with subsequent damage to ecosystem (Smol 2007)


  • Greener rainforests due to higher sunlight levels due to fewer rain clouds (Saleska 2009)
  • Increase in chinstrap and gentoo penguins (Ducklow 2006)


  • Rainforests releasing CO2 as regions become drier (Saleska 2009)
  • Extinction of the European land leech (Kutschera 2007)
  • Decrease in Adélie penguin numbers  (Ducklow 2006)
  • Disruption to New Zealand aquatic species such as salmonids, stream invertebrates, fishes (Ryan 2007)
  • Oxygen poor ocean zones are growing  (Stramma 2008, Shaffer 2009)
  • Increased mortality rates of healthy trees in Western U.S. forest (Pennisi 2009)
  • More severe and extensive vegetation die-off due to warmer droughts (Breshears 2009)
  • Increased pine tree mortality due to outbreaks of pine beetles (Kurz 2008)

Ocean Acidification

  • Oceans uptake of carbon dioxide, moderates future global warming (Orr 2005)

Ocean Acidification

Glacier Melt

Glacier Melt

  • Severe consequences for one-sixth of world's population dependent on glacial melt for water supply (Barnett 2005)


  • Increased cod fishing leading to improved Greenland economy (Nyegaard 2007)


  • Economic damage to poorer, low latitude countries (Mendelsohn 2006)
  • Billions of dollars of damage to public infrastructure (Larsen 2007)
  • Reduced water supply in New Mexico (Hurd 2008)

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Comments 1 to 50 out of 96:

  1. "If the IPCC's mistaken prediction of disappearing Himalayan glaciers taught us anything [...]"

    John, most of us understand what you mean by that, but it might be worth rephrasing slightly. Obviously, the majority of glaciers in the Himalayas are in fact disappearing; the "mistake" was suggesting that could happen by 2035. But someone who comes here from a site like WUWT might take your opening sentence as confirmation that glaciers are not in fact disappearing at all.
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    Response: Agreed, I can see how the original wording could be miscontrued - have updated the text.
  2. Good work on this page. Have you read Fred Pearce's book _Six Degrees_? He references hundreds of peer-reviewed citations in constructing his account of expected impacts of each added degree (I read up through 3 degrees before I wimped out on the rest!)

    Maybe you'll want another source or two on glacier loss impacts, knowing how this is the current hot button?

    Can you re-word this one for clarity?
    "Increased deaths to heatwaves - 5.74% increase to heatwaves compared to 1.59% to cold snaps"
    First the dash confused me as I read it as a minus sign; second, is the 1.59% to cold snaps a (smaller) reduction? (and is that apples to apples, or are these % changes in two distinct absolute numbers which might be unequal? The 2003 heat wave in Europe killed ov 37,000, while the first list I found (wikipedia on disasters by death toll) lists far fewer deaths from "blizzards" (in the hundreds annually), and recent news headlines mention, e.g. 22 dead in the UK from the past month's extreme winter weather.
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  3. Didn't the original report state that the Himalayan glaciers would be substantially reduced by 2035?

    Quite a bit different than disappearing by 2035.

    If the IPCC is this succeptible to media hype, then the deniers have already won, and all the good work here is for naught.

    Might as well grab some popcorn, sit back, and watch the world burn.

    Unless you all find your balls, and fight back. I won't hold my breath.
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  4. we, as fleas on the butt of gaia can, do nothing to affect a changing climate. therefore the solution is to adapt not try to impede.
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  5. Excellent stuff, John.

    I do agree with Ned, though, on the wording of that one sentence.
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  6. How about the negative geopolitical factors such as:

    1) China and India pass the US as economic superpowers
    2) Increased immigration
    3) Higher food costs
    4) Greater government subsidies (higher taxes)
    5) Higher insurance rates
    6) Increased authoritarian governments
    7) Increased terrorism
    8) Nuclear proliferation
    9) Regional and global wars between countries with nuclear weapons

    which I outline here

    and also on my blog at:
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  7. Just this morning there was a letter to the editor about this. It's amazing how fast the denier camp to jump on these things.
    And naturally they're using this as an argument against global warming.
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  8. I'd like to second birdbrainscan's recommendation of "Six Degrees" (though note that it's by Mark Lynas, not Fred Pearce).

    It does a fantastic job of summarizing the peer-reviewed literature on impacts of warming, grouped by magnitude of warming (1, 2, 3 ... 6 degrees).

    Very eye-opening.
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  9. RE #8 Ned, "six degrees",that's great, but to quote an old adage, "if a tree falls in the forest, and there's nobody there to hear it, does it make a sound???

    The short answer would be no.
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  10. John,

    anonymous peer review is not a sacred cow. In it's present form it was introduced only after WWII, when the US as the sole indisputable victor of the armed conflict took over leadership in science. Government spendings soared and the state felt the need of some handle on this crowd of weirdos called scientists. The procedure has it roots in eighteenth century state censorship by absolute monarchies. The political charge of the institution as it is practiced now is related to its introduction and dissemination by US government policy guidelines.

    By the time of its post WWII reinvention, early forms a peer review were mostly abolished and replaced by a more informal and free system.

    As a quality control measure, it neither performs particularly well nor does it promote efficiency. After WWII scientific progress definitely slowed down compared to the pace of previous (from mid XIX. to mid XX.) century. Especially if the prodigious increase in both the number of "scientists" and expenditures are taken into account.

    The sorest spot is anonymity with its lack of accountability.

    Open peer review can be a remedy, perhaps.

    Nature (2006) | doi:10.1038/nature05005
    Can 'open peer review' work for biologists? Biology Direct is hopeful.
    Eugene Koonin, David Lipman, Ros Dignon &. Laura Landweber

    So, peer review in itself would solve neither the problems of climate science in general nor those of IPCC in particular.

    The reason IPCC should have sticked to peer reviewed literature is entirely different.

    They have it in their own guidelines as a requirement. Yet in their AR4 report they frequently rely on non peer reviewed NGO material from WWF, Greenpeace and the like. It was the same with this Himalayan glacier issue, but the example is far from unique.

    More Dodgy Citations in the Nobel-Winning IPCC Report
    blogpost by Donna Laframboise

    The whole scandal is more like a public political and legal issue than an internal affair of science.
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  11. Berényi Péter at 06:36 AM on 25 January, 2010

    Your polymath attention to matters such as hypothetical issues w/peer review makes those times when you appear here with an attempt at scientific arguments against mainstream science automatically appear less credible.

    Better stick to science, or your reputation will wear out prematurely.
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  12. Berényi Péter,
    I'm shocked. The link you quote provide a whopping 16 non peer reviwed citations, over some 10,000 in the WG2 report. And i found even more, from WMO, World Bank, and the like. Is this supposed to be the proof of non-scientific political bias?
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  13. re #10

    Peer review is a pretty good system Peter. It's a basic quality control for published science, and has the positive effect of ensuring that competent scientists present their work to a good standard (if they wish to publish anywhere of note). Of course it has its flaws (what example of organized human affairs doesn't?). But it's a strong part of the process of dissemination and accumulation of scientific knowledge. And of course it doesn't work in a vacuum. Most published science has already gone over the hurdles of peer review through departmental, conference or funding-source presentations, and once published has to live or die according to subsequent analysis.

    I wouldn't have said climate science, as science, has any particular problems. Of course it's a science that happens at this particular time to have strong political significance, and therefore it's subject to rather incessant attempts at misrepresentation and dirty tricks. But the best means of dealing with that is to focus on the science (i.e. what's passed the hurdles required to publish in a decent journal).

    Not sure the IPCC has any particular problems either. It's generally considered to be doing a good job of periodic assessment of the science with a view to informing policymakers and public. Of course it's not perfect either, and (like climate science and scientists in general) is subject to the rather hysterical attempts to make mountains out of molehills. Again the best means of addressing that is to focus on doing a good job.

    One might counter your assertions with the warning about the perfect being the enemy of the good. But in reality, those that are engaged in hyperbole and over-reaction against real or perceived errors aren't really interested in improving the systems of science...I suspect what they would like is to create the impression that the systems are sufficiently flawed that any old rubbish posted on the internet would have equivalent authority as the science. What a world that would be, eh Peter!?

    Otherwise, it's not easy to see what the problems are. It's good that errors or instances of poor practice are identified, wouldn't you say? That happens all the time in science (peer-review being part of that process). Identifying errors is the best means of correcting them. Not sure why we have to accompany the identification of errors with bouts of contrived indignation!
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  14. Absolute rubbish, Berenyi. Peer review-of one form or another-has actually existed for well over 150 years. The only thing which changed is that it went from being an ad-hoc process to being much more organized. It is also nonsense to try & suggest that Peer-review has slowed down the rate of scientific progress. In many fields, progress has gone ahead at an even faster pace (molecular biology & information technology stand out). If anything has stymied the rate of technological progress its the industrial sector, not the scientific community. Many very powerful, vested interests have used a host of measures to try & impede social & technological innovations that threaten said interests-whether via "Think Tanks", political lobbying or the buying & suppression of patents.
    Though Peer Review is imperfect, it's better than having no oversight of research, & at least the proponents of AGW can cite a wide body of peer-reviewed literature, whilst the denialists are largely forced to rely on information from web-sites like & Wattsupwiththat or-worse still-joke journals like Energy & Environment.
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  15. The top item in your list of Negatives doesn't inspire much confidence in the objectivity of your selections. You must know that there's a lot of uncertainty about tropical forest growth rates. Many other studies have found accelerated growth and say that it is probably driven by increased CO2 and is probably pan-tropical. The Feeley study found decelerated growth and says that it is probably driven by local weather changes (and perhaps by human interactions - including research activity itself!) and that all such growth trends are strictly regional. So you have chosen an atypical study whose results might not be related to AGW (the study doesn't ascribe the changed weather to human activities) and which claims no more than regional significance and presented it in a way that suggests pan-tropical, anthropogenic significance. At the same time, you have ignored studies that claim pan-tropical significance and an anthropogenic cause but show an opposite, 'Positives' effect.


    If you insist on including such an unresolved issue in your tabulation, you might like to balance the Feeley paper with one that finds an increase in tropical forest productivity. Most such papers hypothesize that the observed increase will eventually be reversed by the effects of increased temperature. This one finds no evidence for that happening any time soon:

    _Effects of rising temperatures and CO2 on the physiology of tropical forest trees_, Lloyd and Farquhar, 2008

    Your second item is also regional, so could surely be countered by a study of a different region showing an opposite effect (assuming anyone can get funding for such studies).

    So is your third - and the model found an increased range and severity for *a* crop disease. It's dishonest to drop the indefinite article, especially when only one small region is covered.

    Your fourth might have global implications - but not for the real globe. Cattle like to munch young shrubs.

    Fifth: regional.

    Sixth: regional.

    Seventh: unambiguously global. Hurrah! And the study more or less says what you say it says. (Because the study itself is biased in favour of alarmism? Probably. Susan Solomon, innit. But hers is peer-reviewed alarmism, so I'll let you have this one.)

    Eighth: regional.

    That's the Agriculture section done with and I've had enough. This is a very silly enterprise. I have no doubt that studies identifying possible negative regional impacts outnumber those that identify possible positives. I also think it's plausible that changing climates will actually have more negative than positive regional impacts. But a tabulation like this isn't the way to prove it. Do you really want to have long lists of single studies with limited geographical scope - single studies whose caveats you ignore and which, in any case, may well have been superseded by more recent research? You're trying to be a one-man IPCC. It's silly. It would be better to point to synthesis studies. Best of all: simply point to the relevant IPCC chapters.
    To prove that the above isn't an attempt to hide a failure to come up with peer-reviewed Positives, here are a couple of studies for your lefthand column. They were easily found. Both were included as positives in the recent RealClimate team 'consensus update', _The Copenhagen Diagnosis_.

    Positives: Agriculture
    Increasing human water supplies
    _Projected increase in continental runoff due to plant responses to increasing carbon dioxide_, Betts et al., 2007

    Positives: Agriculture
    The greening of the Sahara
    _Atmosphere/vegetation feedbacks: A mechanism for abrupt climate change over northern Africa_, Patricola and Cook, 2008
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    Response: Thanks for the feedback. I wasn't aware of Lloyd 2008 - it's apparent that the impact of climate change on forest productivity is an open question so I've removed Feeley 2007 from the list.

    Global studies are always preferable over regional studies but this doesn't mean regional studies should be excluded if no global synthesis is available. However, the list should indicate if the study is regional in focus so I've updated some of the text accordingly.

    The need for this page is two-fold. One to rebut the common skeptic argument that global warming is good. Secondly (and sadly) because of the persistent campaign to discredit the IPCC. People need reminding that beneath the politics, there is solid peer reviewed science studying the impacts of global warming. This page removes any barriers between the public and the original science.

    However, I agree the list is incomplete and in need of improvement - my goal is to refine it over time and replace older studies with newer studies, regional studies with global studies as they become available. Plus I hope to improve the representation of the peer reviewed science as I find the time to read more deeply. Consequently help and feedback is very welcome to improve the content so again, thanks for your very specific suggestions.
  16. Coral reefs

    There is a reference to warming oceans but I can't get into the article. As always it is hard to tease out how much is due to global warming and how much due to other factors.
    One-Third of Reef-Building Corals Face Elevated Extinction Risk from Climate Change and Local Impacts
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    Response: Thanks for the links. You can actually access both those papers for free by signing up for a free membership with Science. The first paper doesn't go much into causes of coral degradation. The second paper (Carpenter 2008) looks at the increased risk of coral extinction due to bleaching and diseases driven by warming waters. I've added Carpenter 2008 to the Positives and negatives of global warming. Thanks again, appreciate you tracking those down!
  17. Hi John, I'm surprised not to see sea level rise not mentioned on this page. And I didn't see anything about storms, but I could have missed it in a quick reading.
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    Response: I've now added a sea level section to the Positives/Negatives of global warming and welcome any links to papers on the impacts of sea level rise.
  18. doug_bostrom at 06:44 AM on 25 January, 2010:
    "Better stick to science"

    Agreed. However, our host made the bold _political_ statement "If the IPCC's mistaken prediction that the Himalayan glaciers would be gone by 2035 taught us anything, it's that we should always source our information from peer reviewed scientific literature" which cannot go unnoticed.

    What I was trying to set forth is that it was convoluted a bit, mixed two different things up.

    1. IPCC was in fact bound by its guidelines to rely on nothing but peer reviewed papers.
    2. Scientific discussion, on the other hand, should stick to truth (not "credibility").

    IPCC happened to fail on both points. Intentionally, as Dr Murari Lal has admitted: "We thought that if we can highlight it, it will impact policy-makers and politicians". Of course. Impact is urgent, truth can wait.

    If peer review, scientific honesty or something else served truth better, remains to be seen. Anonymous peer review as such is inherently vulnerable to corruption (or redefinition à la Jones) indeed.

    Riccardo at 09:10 AM on 25 January, 2010:
    "Is this supposed to be the proof of non-scientific political bias?"

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  19. eh? What's "political" about the John Cook's statement you reproduced?

    "IPCC was in fact bound by its guidelines to rely on nothing but peer reviewed papers."

    Was it Peter? In the IPCC Procedures Documentation available here [*] it states concerning source material:

    "Peer reviewed and internationally available scientific technical and socio-economic literature, manuscripts made available for IPCC review and selected non peer-reviewed literature produced by other relevant institutions including industry".


    "2. Scientific discussion, on the other hand, should stick to truth (not "credibility")."

    Scientific discussion should stick to the evidence, I would have thought.

    "Anonymous peer review as such is inherently vulnerable to corruption (or redefinition à la Jones) indeed."

    In practice, I suspect this isn't much of a problem. If something is publishable it will get published, no question. Of course one might not get one's precious paper in the journal one might have hoped for.

    The only instance of substantial corruption of the peer review system I'm aware of is the one involving the Soon/Baliunas paper in Climate Research in which a biased editor let through a flawed paper. That was unfortunate, but has little scientific impact, since the scientific community recognises its flaws and ignores's a good example of the "misrepresentation and dirty tricks" that I described in my post above though!

    There is a bit of a problem with Geophys Res Letters which seems occasionally to allow through some dodgy stuff. But scientificall that doesn't matter - though it helps fuel the misinformation industry...
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  20. You make a good point there Chris. Why does Peter assume that Peer Review is the "last line of defense" against bodgey science, when in truth it is the 1st & 2nd. Should a error laden paper somehow slip through the cracks, the scientific community as a whole is usually quick to highlight its flaws. Case in point is the original Manne paper relating to Paleo-climatology. Fellow researchers complained to the National Academy of Science, their claims were found to be valid & Manne was forced to redo & resubmit his original paper. If only the non-scientific world were subject to the same levels of scrutiny.
    Oh, & compare the level of peer-review in ISI journals to that of a journal like Energy & Environment. Remember that awful paper by the biology teacher Beck? The one which apparently proved that CO2 levels were higher in the 19th century than they are today (in spite of error bars which were almost as large as the actual values). That paper was utterly riddled with errors-errors easily pointed out by analytical chemists, atmospheric scientists & the like-yet it still got published, & is now held up as *proof* against global warming by those in the denialist industry.
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  21. "Scientific discussion should stick to the evidence, I would have thought."

    Well said, Chris!

    "Truth" is a dangerous thing. Just look at the many & ongoing religious wars over whose version of the "Truth" is correct.

    Lee Grable @ #9:
    Are you seriously suggesting that the generation of acoustic pressure waves is dependent upon whether there is a human observer present?
    Amazing, then, how all those animals that evolved in areas with no human population developed such a good sense of hearing... :-)
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  22. chris at 10:54 AM on 25 January, 2010:

    Thanks, chris for the clarification. The IPCC could use whatever it saw fit after all. What passed its own review process, of course ("The circulation process among peer and government experts is very wide, with hundreds of scientists looking into the drafts to check the soundness of the scientific information contained in them").

    One can get a clear enough impression about the depth of this process by considering the Himalayan glacier case (10.6.2). I am not allowed to cite or quote anything from it, for in order to access the reviews I was forced to accept a kind of non-disclosure agreement.

    But anyone can have a look.

    Both the First & Second Order Draft Comments worth reading. Search for Himalaya or glacier.

    Evaluation is OK, I suppose.

    Almost all the expert comments are vague, except E-10-468 in First Order Draft Comments. It implies glaciers in the Karakoram region are growing (true) but was dismissed. The Japanese GOVT comment (G-10-121) is the only one which expresses some doubt, if only indirectly. No one notices the year 2035 thing.
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  23. RE#19 Chris
    The physicist Jan Hendrik Schön incident at Bell Labs is probably the worst I've heard of. He went so far as to include the same noise in his data for two experiments done at different temperatures.

    He eventually got busted due to scientists out there by doing their job. That is, critically assessing other peoples work and independently trying to replicate/verify their results.

    The only criticism I could have is that his colleagues eagerly slapped their name on his work as part of the "et al" without themselves bothering to check up on it's integrity.

    And I believe it was the editors of Nature were the ones who first discovered his misconduct. Shouldn't we then be congratulating the peer review system?ön
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  24. My contribution (for now):

    Coastal erosion, with a focus on Nigeria.
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    Response: Many thanks for the link, much appreciated! I've added (belatedly) a sea level section to the Positives/Negatives of global warming and included coastal erosion.

    Finding it hard to think of a positive impact of sea level rise...
  25. Can you do a section on natural disasters? It's the latest "scandal" being promoted by The Times, would be good to have something to counter it with.
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  26. The problem with the Himalayan glacier data wasn't so much that it wasn't peer-reviewed rather that it was just plain wrong. Peer-reviewed data can just as easily be wrong, especially when its re-inforcing the particular concieved notions and prejudices of the day.

    Ned post #1 Just to be even more accurate. Global glacier reached their most recent maxima around 1750 and have generally been in retreat ever since.
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  27. HR, that's because it was the end of a mini ice-age. Glaciers were in a very slow retreat throughout the 19th & early 20th century-in line with a solar induced warming trend. Then, around 1950, they stabilized & even grew again, but have been in a state of accelerated retreat for the last 30 years-& are, according to my best information, at levels lower than they've ever been since we first started studying them in the mid 19th century.
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  28. I am of the opinion that most websites dealing with the issue of climate change, both pro and anti the theory of AGW, are rapidly loosing credibility as they tend to utilize the ‘straw man argument’ which is generally propped up by the postings of sycophants.

    This approach does not lead to a more informed common understanding of the issue and in fact appears to be polarizing and entrenching opinions with the members of both camps refusing to impartially consider and evaluate differing views and resorting to name calling and demeaning the views expressed by contributors who are not members of what they perceive to be the ‘accepted scientific community’. This is clearly not in the interests of science and undermines efforts to formulate appropriate strategies to enable the human population to respond to changing circumstances, whether these caused by natural processes or human activity or a combination of both.

    Perhaps Skeptical Science could break the stalemate and before posting an article, why not submit it for review by a credible peer who has a different view (I am sure that many of the 141 signatories to the open letter to the Secretary-General of the United Nations, dated 8 December 2009, would oblige) and then post the article and review simultaneously with both authors being afforded the opportunity to respond to the subsequent postings of the contributors?
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  29. "Finding it hard to think of a positive impact of sea level rise..."

    Think Lex Luthor, Superman One (a relatively patient Lex Luthor, perhaps). The "global warming is good" crowd could play that up. Slowly sink the elite Hollywood celebrities so the rest of us can have beachfront property.
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    Hmm, interesting suggestion. Now if only Lex Luthor had published any peer reviewed papers. In Energy and Environment, maybe? :-)

  30. What greater form of denial is there than to assume that the Earth's temperature can't change over time, or shouldnt be affected by an overdimensioned human footprint? if Global Warming comes as a surprise and should'nt be happening.

    And even if Global Warming was a purely natural phenomenon, all these positives and negatives would exist just the same. It should be clear that the problem is compounded due to the order of magnitude of the Earth's current human population.

    On a similar note, if a city wants to install a nuclear reactor, they should be forced to store the nuclear residuals and waste within the city limits. Similarly, dont try to fool yourself about solar panels and windmills being ecological as you have them spreading all over the Earth's surface.

    There is no free lunch, but there is a large crew of peer deniers.
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    Response: I know of no climate scientist who asserts Earth's temperature can't change over time. So please refrain from strawman arguments.

    It is well established and undisputed that climate changes naturally - because climate is sensitive to radiative forcings. When the sun's output changes, climate changes at a rate of 3°C for every 3.7 Wm-2 of radiative forcing from the sun. This is the same climate that changes at a rate of 3°C for every 3.7 Wm-2 of radiative forcing from CO2. The natural climate change you cite actually provides evidence for the climate's sensitivity to CO2.
  31. OK, so what do all you experts out there regard as the optimum average world temperature that will best benefit the current eco system (because this is what all this hot air is really all about) and is it actually possible for us to achieve this utopian situation?

    John, "Finding it hard to think of a positive impact of sea level rise...” Perhaps a positive impact of sea level rise is that it results from an increase in sea water volume and therefore a greater capacity to sequester the extra CO2?
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    Response: Hmm, higher sea levels leading to more CO2 absorption? Not sure if that's true as the ocean's ability to absorb CO2 is expected to diminish. In fact, evidence indicates this is already happening (Quéré 2007, Schuster 2007, Park 2008). But points for creativity - I never would've thought of that! :-)
  32. Terrific topic, John. Despite being so relevant, it's not easy to find (at least summarized and well documented) information like this. Next on my list for translation!

    Riccardo, Chris, Marcus, I find your points of view insightful and thought-provoking. Hope you keep on sharing them with us for long ;-).

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    Response: Don't translate just yet - still tweaking and adding papers. Maybe give it a few days.
  33. Ubique, according to everything I've read, the optimum annual average global temperature-at this particular period of history (namely the Holocene) is probably around 14 degrees. This was approximately the temperature in which agriculture & the very first civilizations truly flourished, around 8,000 years ago-with even slight changes, above or below, being fairly detrimental (the collapse of the Mayan, Anasazi & Khmer civilizations-due to mild warming-& the Viking Greenland colony due to the Little Ice Age-come to mind). Of course how detrimental a temperature change can be will also be down to factors like (a) how quickly the change occurs, (b) how marginal the environment is to start with (in terms of soil fertility & precipitation etc), (c) available technology & (c) the willingness of the whole society to make the necessary sacrifices needed to adapt to changing conditions. Ultimately though, given the current speed of change, the fear is that our societies will not be able to adapt quickly enough to global warming-& its attendant consequences-to save ourselves; especially given the penchant for extreme, short-sighted selfishness on the part of certain quarters of society-& so mitigation is seen as our best bet.
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  34. Hi guys , Ive been reading this site for ages now using it to counter deniers claims all good but , these small mistakes means an even greater effort is needed in the wider press to show the science is not weakened .
    the denier arguement now where i work (basic blue collar industry ) is that all the data is corrupted or faked and he is the proof .I try but my memory fails me and my debating skills :( .
    We have Monckton here in Australia and hes useing climategate and the glacier 2035 plus something about Darwin temp data being changed to show a warming trend to basically debunk AGW as either a great socialist /facist conspiracy and or scientists on the make for more funds .
    He will go down a treat here as most average australians dont trust politicians and dont really understand science .
    Its great all you guys debateing each other here but all this never get out to the general public , the counter arguement is never seen these people like Monckton never really get pulled up and shown to the people how they are misrepresenting the facts .

    Still this is a great site just wish i could take it with me all the time .
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  35. Ubique,
    although i'm no expert, there's the obvious answer to your question: there's no such temperature.
    What i mean is that you always have parts of the ecosystem that will do better and other that will do worse after any change in temperature. So, how could be such a ideal temperature be defined?

    Things look different if you look from the point of view of our own specie and its current civilization. Given that its development occurred during a relatively stable climate, there is again an obious answer: no change at all. Of course there's some resilience up to a certain level of change, but it has an overall cost. We need to balance the two, some inevitable warming and the costs of limiting it; the former is the science of climate, the latter is economy.
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  36. Also, I used to try & debate this stuff at places like The Australian's website, but found the place dominated by denialists who had not a clue about holding a decent debate-& instead resorted to name calling & conspiratorial whispers about "global government" (aka the UN) trying to impose their rules on sovereign nations like Australia. It really just got pathetic, so I gave up!
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  37. John,
    OK fine,... climate scientists acknowledge that a global temperature change is possible without man, and likely should happen at a slower rate than what we are seeing. Just out of curiousity, what triggers this change in nature?

    That question aside, as I was trying to point out, there seems to be two approaches to dealing with this problem:
    A) trying to stop global warming
    B) finding ways to adapt to it

    Theme B seems more relevant given that there currently are no guarantees that A is possible, again since if Nature wants to, it can change course without our consent.
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    Response: "climate scientists acknowledge that a global temperature change is possible without man, and likely should happen at a slower rate than what we are seeing"

    Actually, natural forcings on their own are showing a slight cooling effect over the last few decades (Meehl 2004).

    As for the two approaches (mitigation or adaption), we need to be throwing our energies into both mitigation and adaption. This is because if we don't mitigate, future impacts will be even worse. And we need to prepare for adaption because we've already committed to a great deal of warming still "in the pipeline" (a topic I sorely need to write a post about which I will do as soon as I get the time).
  38. John (inline comment in #32),

    Ok, thanks! I'll probably wait a week or so for the translation, just in case new comments contribute more relevant papers.
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  39. Personally, I see why it's better to go with the peer reviewed literature, but I doubt too many are aware that non-peer reviewed literature was allowed anyway as set out in the IPCC's 'Appendix A to the Principles Governing IPCC Work' Annex 2.

    Anyway, here's one concerning the detrimental effects of nitrogen deficit constraining CO2 uptake by plants:
    Wang et al. Nitrogen constraints on terrestrial carbon uptake: Implications for the global carbon-climate feedback. Geophysical Research Letters, 2009; 36 (24): L24403 DOI:

    ScienceDaily's take on the paper:
    "The authors considered the amount of nitrogen plants require to store additional carbon and found that a substantial deficit of nitrogen exists for plants in most areas of the world. They argue that most climate models that do not take into account nitrogen have overestimated carbon uptake and therefore underestimated predicted global warming."
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  40. Saturation of the Southern Ocean CO2 Sink Due to Recent Climate Change
    Le Quéré et al, 2007;316/5832/1735

    Anomalies of methane in the atmosphere over the East Siberian shelf: Is there any sign of methane leakage from shallow shelf hydrates? – Shakhova et al. (2008)

    Escape of methane gas from the seabed along the West Spitsbergen continental margin – Westbrook et al. (2009)
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    Response: Many thanks, have added the two methane papers to a subsection of Arctic melt on the Impacts Page. While looking at your papers, I discovered AGW Observer has a page devoted to papers on methane emissions which I'll need to peruse when I get the chance (well, rediscovered as AGW Observer is in my blog reader).
  41. A long-term association between global temperature and biodiversity, origination and extinction in the fossil record.
    Mayhew et al (2007)
    Articles from Proceedings of the Royal Society B: Biological Sciences
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  42. J Bowers:

    "Personally, I see why it's better to go with the peer reviewed literature, but I doubt too many are aware that non-peer reviewed literature was allowed anyway as set out in the IPCC's 'Appendix A to the Principles Governing IPCC Work' Annex 2."

    Further to that, considering all the grumbling about "suppression" of contra-mainstream findings, if the IPCC had not allowed material not passed through peer review I'm fairly sure we'd be listening now to endless complaints about IPCC censorship.

    Anyway, everybody participating in the next report will be more careful next time around. Once burnt, twice shy.
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  43. Thanks for your friendly response to my somewhat snarky comment.

    Alas, the description of the Evans et al. paper is still misleading. This isn't really your fault. The paper itself consistently misdescribed the area it studied as 'the UK'. What it actually predicted was that the range and severity of the disease will increase on the island of Great Britain. It didn't model the offshore islands or Northern Ireland.

    That's a minor point. More serious objections remain. I've already said that I don't think it's helpful or meaningful to include single, narrowly focused studies in isolation. You have replied that the tabulation is a work-in-progress. Fair enough. But if I had the time, I could probably find peer-reviewed studies contradicting most of the studies listed in your Negatives column. This wouldn't be easy. Climate research tends to concentrate on Negatives. (This isn't necessarily proof of systematic alarmist bias. People need prior information about possible negative impacts; positive impacts can be embraced without little or no prior planning.) But it's possible. You could then restock the right-hand column with more citations. I'd go a-hunting again. Then you. Then me. And so on. I'd do this not to prove that global warming is a good thing (you'd certainly win in the end) but to reinforce the point that lists of single studies don't prove anything.

    Back to the Evans et al. study. First the increased range. It's insignificant. Evans et al. predicted that phoma stem canker will newly colonize parts of eastern Scotland. A subsequent study of the same disease and its effects on the same crop in the same region (and once again misdescribing it as 'the UK') using the same model and by two of the same authors - Butterworth et al., 2009, below - predicted that the disease will have such mild effects in the newly colonized area that fungicides won't be necessary. So it's not a big deal. But your description implies that it is. Crop disease to increase its range! Help!

    Second, the real-world implications of all the Evans et al. predictions. The follow-up, Butterworth et al., predicted that yields of fungicide-treated oilseed rape will increase throughout 'the UK' (Great Britain). That is, despite increased opportunities for the disease, sensible management will result in a net Positive.


    Individual papers can be knocked down - sometimes by papers from the same authors using the same data, techniques and models. Even when done honestly, your tabulation has no hope of being helpful or meaningful.

    And I have to say that I don't think your intent *is* wholly honest. Else why the note about some of the Positives being tongue-in-cheek? And that hot/cold deaths reference: that also leaps off the screen ... But I've gone on long enough, so I won't get into that now.


    Agriculture: Positives
    Increased oilseed rape yields throughout Great Britain
    _North–South divide: contrasting impacts of climate change on crop yields in Scotland and England_, Butterworth et al., 2009
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    Response: I've removed Evans 2008 from the Impacts Page - Butterworth 2009 shows that the overall impact of global warming on crop disease is ambiguous. Thanks for the link to the additional paper.

    I would be quite happy if you were to take the time to find more papers showing contrary results to papers currently listed. I appreciate the feedback you provided on forest growth and crop disease. It's not a competition to see who gets the biggest list but an effort to portray the state of the science.

    The tongue in cheek remark was an artifact of the older version of the paper when I was referencing many media articles as my sources - originally, I was padding out the meagre positives column with entries like "Lots of work and money for lawyers" and "New extreme sport of glacier surfing". Once I got serious with only peer review sources, that comment was out-of-date and I've now removed it.
  44. Since Berényi Péter already mentioned Eugene Koonin and Biology Direct. I invite people to see how tough the peer review process really is (the reviews are directly attached to the article at the bottom of the webpage):

    This paper was four years in the making...
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  45. Marcus at 23:28 PM on 25 January, 2010:
    "the fear is that our societies will not be able to adapt quickly enough to global warming [...] so mitigation is seen as our best bet"

    The best bet is education. Not education about global warming, just plain old education, spiritual, moral, mental & physical. Education of the poor, education of girls. An educated society can adapt quickly enough to almost anything. This is the most efficient use of scant resources.

    Everything else can wait.
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    Response: I agree that education is crucial to society, especially education for the poor. However, human society is capable of tackling more than one issue at a time. Setting aside global warming until we solve education for the poor is hardly a practical response, particularly as every year of inaction only exacerbates the problem - which happens to impact poor nations the greatest (Mendelsohn 2006).
  46. Here are a couple of generally positive papers:

    Nemani, R.R., Keeling, C.D., Hashimoto, H., Jolly, W.M., Piper, S.C., Tucker, C.J., Myneni, R.B. and Running, S.W., 2003. Climate driven increases in global terrestrial net primary production from 1982 to 1999. Science. (June-06-2003).
    Zhou, L, Tucker, C.J., Kaufman, R.K., Slayback, D., Shabanov, N.V., and Myneni, R.B. Variations in northern vegetation activity inferred from satellite data of vegetation index during 1981 to 1999, J. Geophys. Res., 106 (D17):20069-20083.

    Cheers, :)
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    Response: Thanks, have added these to the Impacts Page.
  47. In terms of glacier melting you have to include the negatives of sea level rise , which also occurs due to thermal expansion. Glacier melt also impacts hydropower, note many specific glaciers such as Zongo Glacier
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    Response: Thanks, Vermeer 2009 on glaciers contributing to sea level rise is a worthy addition to the Impacts Page. Considering I'd already blogged about Vermeer 2009, you'd have thought I'd already included it (if I was more organised, I would've).

    Re Pelto 2008, the abstract doesn't mention hydropower and unfortunately the full paper is hidden behind a paywall.
  48. Peter, how much easier will it to be to get people that education if they're not dirt poor? Over-reliance on non-renewable sources of energy has kept many nations deeply in debt to those nations who have large surpluses of those resources-& so the cycle continues. I'm not suggesting its the only cause of poverty, but imagine how much more money they'd have to spend on health & education if they didn't have to spend billions per year-to foreign nations-on enough fossil fuels to keep vehicles running & the lights running.
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  49. Oh, here are some papers which might be of value for the impacts page:

    There's this paper about reduced micro-nutrient uptake by plants in high CO2 environments.

    "Rising atmospheric CO2 and human nutrition: toward globally imbalanced plant stoichiometry?"
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  50. "Response: While looking at your papers, I discovered AGW Observer has a page devoted to papers on methane emissions which I'll need to peruse when I get the chance (well, rediscovered as AGW Observer is in my blog reader)."

    Yes, it's an excellent resource. Go to the Index page for a wealth of resources.
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