22 March 2010

A Summary of Richard Tol's look at IPCC AR4 WGIII

A guest post by Richard Tol

The Fourth Assessment Report of Working Group 2 of the Intergovernmental Panel on Climate Change has been widely criticised for being overly pessimistic about the impacts of climate change. The IPCC has admitted that errors were made, but argues that the mistakes were just that. However, all errors point in one direction: alarmism about climate change. This suggests, at least, an inadvertent bias.

In the previous guest posts, I (in one case jointly with Chris Green) argue that Working Group 3 also contains mistakes, and that most errors point in one direction: optimism about the impacts of climate policy. The other mistakes reveal the inability of the IPCC to constructively engage with valid criticism. I also looked at the reviewer comments and the responses. The errors were identified during the review process, but made it into the final report nonetheless.

In the post about population projections, I show that the IPCC misquotes a paper that cast doubt on the IPCC SRES scenarios. In the post about exchange rates, I demonstrate that the IPCC misrepresents or omits papers that criticise the IPCC SRES scenarios. These two cases suggest that the IPCC has lost the ability to be self-critical.

In the post about double dividends, I show that the IPCC’s claims that climate policy would stimulate economic growth and create jobs are not based on peer-reviewed literature. Furthermore, the IPCC fails in its role as policy advisor. Ecological tax reform could promote growth and employment – but only under very narrow conditions. An honest broker would spell out those conditions. A stealth advocate would suggest that those conditions are rather easily met – as does the IPCC.

In the post about technological progress, I show that the IPCC emphasizes the results of studies that show that the costs of emission reduction are lower than previously thought, while suppressing or misquoting studies that show the opposite – despite credible evidence that the latter papers are closer to the truth. The IPCC assessment is certainly incomplete, but I would argue it is biased.

In the post about selection bias, I demonstrate that the IPCC summarises the results of multiple abatement studies in a misleading way, failing to alert the reader to the fact that the estimates of the costs of stringent emission reduction are unrepresentative of the literature and severely biased downwards. This is deception pure and simple.

In the post about double-counting, we show that the IPCC confuses carbon savings due to “market forces” with carbon savings by “climate policy”. This again would suggest to the unsuspecting reader that emission reduction is cheaper than it really is. The IPCC again did this in spite of protests by the referees. The IPCC deliberately puts the reader on the wrong foot.

In sum, the review process of the IPCC failed miserably. AR4 of WG3 substantially and knowingly misrepresents the state of the art in our understanding of the costs of emission reduction. It leads the reader to the conclusion that emission reduction is much cheaper and easier than it will be in real life.

Dr Ottmar Edenhofer of the Potsdam Institute for Climate Impact Research was one of the lead authors of Chapter 11 where most of the “errors” originate. He has since been appointed as the co-chairperson of WG3 for the Fifth Assessment Report of 2014.


  1. Richard:
    Nice summary.
    Have you sent Dr. Edenhofer your comments and asked for his reactions?

  2. Richard It would be great if you could get published in say the NY Times.

  3. I was surprised that the economist (to my knowledge) completely ignored this issue in their(otherwise) very thorough summary of climate science. I would think that this would be an area of interest to them. Am I the only one?

  4. Thank you Richard, that is a useful non-technical summary for those of us who are not experts in this field.
    The issues you raise are much the same ones as arise repeatedly in WG2 and WG1:
    * Ignoring valid comments at the review stage
    * Misleading the reader, behaving as a 'stealth advocate'
    * Biasing the literature review by ignoring or dismissing papers that don't support the story the IPCC wants to tell.

  5. "However, all errors point in one direction: alarmism about climate change. This suggests, at least, an inadvertent bias"

    I'm not an expert but I thought that statement about Working Group 2 was too sweeping a generalisation. Doesn't IPCC "official science" cut two ways suppressing both more alarming and less alarming studies than it's official position? Isn't Roger's post about sea level rise in IPCC an example of IPCC suppressing a worse case scenario? Also Hansen relates a case in his book where an article he wrote for Scientific American was held up from publication for years because the editors kept changing it to conform with the more conservative IPCC position, see page 76 of Hansen's book: Storms of My Grandchildren. Because of this Hansen withdrew the article but eventually the editors got back to him and it was published alongside another article with the official IPCC position.

  6. It's pretty clear that the IPCC seriously low-balled sea level rise, contrary to your strawman. This affects WGII as well as WG I.

  7. "It's pretty clear that the IPCC seriously low-balled sea level rise, contrary to your strawman."

    Richard Tol made points about: 1) population projections, 2) exchange rates, 3) double dividends, etc. He provides hyperlinks six points, total.

    Which of those six points do you think is invalidated by your claim that the IPCC "low-balled sea level rise"?

  8. It's pretty clear that the IPCC seriously low-balled sea level rise, contrary to your strawman.

    I don't reckon they low-balled it at all. They had a range of hysterical projections which turned out to be obviously wrong. So they scaled back their projections.

    That doesn't make them right. I would say that they are still on the high side.

  9. -5-Bill
    WG1 excluded ice from their sea level rise projections. You may argue that they erred on the conservative side, at least in this instance.

    I wrote about WG2 and WG3.

    The impact estimates of WG2 are mostly based on older sea level rise projections, which include ice.

  10. @Bill and Eli:

    While the ipcc may have underestimated sea level rise, this one example is being used across the blogosphere as proof that the ipcc is balanced if not overly conservative. There is apparent over-exaggeration in numerous areas of their reports; economic impacts, effects on biodiversity, severe weather, glacier melt.

    The sea level error is a disagreement between projections from different models, an academic dipute. While on the other hand, one could have obtained better information about Himalayan glaciers from an encyclopedia. The scope and nature of the errors is entirely different. I would like to see an example where the ipcc makes a claim minimizing the effects of climate change that is based in NO actual scientific literature whatsoever.

    I realize this is an ultimately subjective issue, but I find the argument that the ipcc is downplaying the effects of climate change pretty hard to support.

    This is a good topic, I'd like to hear more from you guys.(and others)

  11. EliRabett said... 6

    "It's pretty clear that the IPCC seriously low-balled sea level rise, contrary to your strawman. "

    Sadly, as we saw in the Himalayan Glacier story it would appear the ability of IPCC scientists to calculate the rate of ice melt is seriously impaired.

    Then we have the arctic sea ice problem. It would now appear that the melt rate due to 'warming' may have been overestimated by 30%. The rate of melt appears to be a function of which way the wind is blowing.

  12. Sea level increases, which have shown no evidence at all of accelerating (except in the minds of fear mongers), is perhaps not the best area for the AGW community to rally around in an effort to keep the fear alive.
    In fact, I would suggest that AGW promoters avoid mention of the sea, since it reminds people of the acidification scam, as well as the false claims about cyclones.

  13. EliRabett:
    How much do You need for Yourself looking in the mirror saying: "Hi, You are a trustworthy person?"
    Or/and: please tell who's governing You + Your statement(s)?

    Go figure...

  14. OT

    Just a couple of thoughts that may have bearing on future CO2 emissions

    First up, the country with the 5th largest coal reserves(7% of global total) starts importing in a big way.


    "Indian thermal coal imports surged last year to a little less than 60 million tons from about 30 million in 2008, Macquarie Group Ltd. said in a report in March. India plans to almost double electricity generation capacity by 2012, when the shortage of coal will exceed 200 million tons."

    Second thought - Country with 3rd largest coal(13% of global total) reserves goes crazy for nuclear


    "Under the original plan announced in 2005, China was to spend 400 billion yuan to add 40 gigawatts of nuclear capacity by 2020 to help reduce reliance on more polluting coal and oil. The capacity will exceed 70 gigawatts by then under the revised plan"

  15. Thanks for the reply richard

    I've downloaded some of your papers and am reading them. Currently, I'm looking at your recent paper on WAIS and your 2008 paper on the social cost of carbon

    The only point I am trying to make is that discrediting the official science or economics of the ipcc (I gather that your analysis is more about the economics than the science) does not in itself discredit the scientific case made by some alarmists such as Hansen. (Einstein said somewhere that it only takes one good scientist to get it right in response to some science presented to him by a committee.) The issues that worry me are the time and cost required swap to nuclear, the uncertainty of predictions and inertia of the systems (ice and ocean). I'm glad that you are addressing some of these questions fairly directly.

  16. Richard,
    Post-2012 climate policy dilemmas: a review of proposals
    When I click on the Download(.pdf) button for this paper I get a "Page Not Found" message. I can read the paper online and / or print it out directly but would prefer to download it, as would others who I am arguing (mostly) and discussing (sometimes) with on this issue.

  17. @Bill Kerr

    Richard and Roger Pielke Jr. are not questioning the fundamental science of climate change, they are criticizing the way in which the IPCC presents its assessments of the scientific literature to the public.

    Could I characterize your complaint as 'people making reasonable and constructive criticisms of the IPCC should take more care to differentiate themselves from from unreasonable critics, such as James Delingpole or James Inhofe'? If this is so, then I completely agree.

    And I think Roger is critical of James Hansen's roll as a political advocate/scientific expert, rather than his scientific works themselves. (Roger, please correct if I have misinterpreted your views)

    sorry for putting words in your mouth...

  18. -15-Bill
    Agreed. The case for climate policy is as strong now as it was in October.

    It's hard to explain to the average voter, though.

  19. Richard Tol said... 18

    "The case for climate policy is as strong now as it was in October.
    It's hard to explain to the average voter, though."

    In the US at least, the 'political problem' is that the party that cares the most about 'climate change' has the least support for nuclear power, while the party that could care less about 'climate change' overwhelmingly supports nuclear power.

    The average voter accepts there has been some global warming. The average voter is prepared to pay somewhere between $10 and $25 extra a month for electricity. 1 to 2 cents per kilowatt on top of a current 11 cents/kw average.

    Nuclear power is doable in the price range the average voter is prepared to pay for 'climate action'

    The only way nuclear becomes 'undo-able' is if someone insists the waste has to rendered 'non-radioactive' rather then 'reasonably harmless'.

    I would note that one of the loudest proponents of Climate Change Action, Joe Romm at Climate Progress is also one of the loudest critics of nuclear power.

    In the end the problem with action on climate change rests with those within the environmental community that won't accept the reality that 'Perfection is the Enemy of the Good'.