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U.S. Climate-Change Impacts: A Peer-Review True-Up (Cato Institute study irks alarmists)

By Chip Knappenberger -- October 29, 2012

The Cato Institute’s Center for the Study of Science (which I am part of) will soon release the final version of its major report examining the potential impacts of climate change in the United States.

Addendum: Global Climate Change Impacts in the United States grew from our desire to show how the government report, after which the Cato report was modeled, could have/should have looked if the original scientists involved had included a more thorough (less narrow) review of the scientific literature and had not been obviously predisposed towards climate-change doom-and-gloom.

Cato’s “Addendum” title draws attention to the fact that the original 2009 report from the U.S. Global Climate Change Research Program (USGCRP) was incomplete and insufficient on the day it was published–and is out-of-date given peer-review studies of the last several years. So our report includes both important, new scientific results and relevant scientific research that was overlooked or ignored in the original document.

In general, the Cato report, while pointing out that the earth’s temperature is rising and that human activities play a role, paints a more modest picture of climate change and its effects in the U.S. and emphasizes our adaptive capacity to handle a large amount of change in virtually all aspects of society. The overall tone of the Cato report is an optimistic one—a stark contrast to the pessimism that pervades the USGCRP report.

USGCRP Authors React

The Cato report has drawn ire both from climate-change alarmists , as well as from a subset of the group of scientists which authored the original USGCRP report. This author subset released a statement airing their discontent in which they note (those who signed the group statement make up barely a third of the original USGCRP author team):

As authors of [the USGCRP] report, we are dismayed that the report of the Cato Institute, ADDENDUM: Global Climate Change Impacts in the United States, expropriates the title and style of our report in such a deceptive and misleading way. The Cato report is in no way an addendum to our 2009 report. It is not an update, explanation, or supplement by the authors of the original report. Rather, it is a completely separate document lacking rigorous scientific analysis and review.

In fact, one of the primary ways that the Cato report was intended to make its point was by mimicking the style of the USGCRP report. It was meant to show what the government report would have looked like had the authors been more open-minded and inclusive of the scientific literature. In places where it was determined the original authors had done an adequate job, those sections were included verbatim, which we were certainly explicit about! This was all clearly explained in the “About this Report” section of the Cato report (p. 8):

This Addendum is similar in format to the 2009 USGCRP report, allowing a facile reference for science that was omitted. In some places, we have moved text verbatim from the 2009 report to this Addendum.

How is that “deceptive or misleading.” On the front cover of the Cato report, smack in the middle of the page it says “Center for the Study of Science, Cato Institute.” The back cover is completely blank except for the prominent Cato Institute logo. There is a letter of introduction (p. 3) written and signed by (then) Cato President Edward Crane. And “The Cato Institute” is included in the running header of every left-hand page in the document. All of this led blogger Anthony Watts to state “How anyone with even limited intelligence could get the idea that the report is from the US Government/NOAA is truly laughable, because if they can’t read “Cato Institute” clearly printed on the front and back cover, then they probably aren’t capable of reading and interpreting the original report either.”

As to the USGCRP co-authors statement that the Cato report is not “an addendum…an update, explanation, or supplement by the authors of the original report” this is certainly true. The original authors had nothing whatsoever to do with the Cato report. In fact, it was their poor job that required a subsequent addendum, update, explanation, and supplement, or whatever you chose to call it, by Cato’s Center for the Study of Science.

And as to their claim that the Cato report is “lacking rigorous scientific analysis and review,” I think that any reader of the Cato report will find the text to be well documented and derived overwhelmingly from well-accepted material. The Cato report describes its source material this way:

This Addendum is primarily based upon the peer-reviewed scientific literature, peer-screened professional presentations, and publicly-available climate data. We include literature through the beginning of 2012, which of course could not be in the 2009 [original USGCRP]report. But there are also a plethora of citations from 2008 or earlier that were not included in the USGCRP document. Why that is the case is for others to determine.

These sources are no less rigorous than those assessed/included by the original USGCRP authors.

The co-authors of the USGCRP report go on to note four other points that they wish to emphasize.

Quality References

The first has to do with the number/quality of references included in the USGRCP report vs. the Cato Report. Both reports draw primarily from the peer-reviewed scientific literature. That the Cato report includes a large number of peer-reviewed studies directly relevant to climate change impacts in the United States that were not included in the USGCRP report, and which support a more modest impact, in and of itself speaks volumes. Instead of quibbling over the number of references, the USGCRP co-authors ought to be apologizing for producing such an incomplete original report.

Effectiveness of Public Comment

Another bone of contention is that the USGCRP report was open to public comment while the Cato report was not. But, as Ed Crane described in his introductory remarks in the Cato report, the public comment process for the USGCRP report left a lot to be desired:

[The Cato report] grew out of the recognition that the original [USGCRP] document was lacking in scope and relevant scientific detail. A Cato review of a draft noted that it was among the worst summary documents on climate change ever written, and that literally every paragraph was missing critical information from the refereed scientific literature. While that review was extensive, the restricted timeframe for commentary necessarily limited any effort. The following document completes that effort.

And, of course, our Addendum is a public comment. As is the letter of the USGCRP report’s original authors.

Modest Climate Change

Here is the third point made by the USGCRP author team:

The authors of the Cato Institute report agree with our Committee’s conclusions that global warming is unequivocal and consistent with a change in greenhouse gas effects attributable to human activities. They also conclude that climate change will continue to occur as greenhouse gas concentrations increase. However, their conclusions that future climate change will be benign, if not beneficial, and easily adapted to, diverge markedly from our Committee’s view regarding the seriousness of the risks. This is because the Cato Institute authors assume—based on their own analysis and contrary to peer-reviewed, contemporary science—that warming, intensification of weather extremes, polar ice cap melting, and sea-level rise will all be at the lowest end of the ranges projected in the Fourth Assessment of the Intergovernmental Panel of Climate Change.

I largely concur with all of this except the phrase “based on their own analysis and contrary to peer-reviewed, contemporary science”—in fact, the entire Cato report is largely built upon the peer-reviewed, contemporary science. And goes to prove that “conclusions that future climate change will be benign, if not beneficial, and easily adapted to” are well-supported by the literature (and, as we point out, common sense). That the USGCRP co-authors find otherwise, or at least fail to even consider this very strong possibility, it the primary fault in their report that the Cato report addresses.

NAS Reports

The fourth and last point made by the USGCRP author team is that the USGCRP findings are backed by recent National Academy of Sciences reports. To me this is a hollow claim, as the NAS reports are about as selective in their science as the USGCRP report. Most of the NAS reports mentioned by the USGCRP authors in support of their report have been taken apart by the Cato Center for the Study of Science staff (see here and here, for example).

Future Updates

And finally, the USGCRP co-authors note:

The next U.S. National Climate Assessment is underway under the auspices of the U.S. Global Change Research Program, with draft sections of its report to be released in December and completed in 2013. We are confident that this new assessment will reinforce and extend the findings of Global Climate Change Impacts in the United States.

Well that last line sure sounds like a bummer. My guess is that there will soon be another Addendum report from Cato’s Center for the Study of Science in the making!

NOTE: I will update this article with a link to the final version of the Cato report Addendum: Global Climate Change Impacts in the United States when it becomes available. In the meantime, this is a link to a near final draft. I would invite everyone to compare the USGCRP and the Cato reports side by side to see for yourself that there is a plethora of scientific literature which supports a much more positive view of the future of the U.S. under a changing climate than was included in the USGCRP report.

(Additional note: The current draft form of the Cato reoprt is a substantially cleaned up version from that I discussed back in July and which was submitted as part of a public comment to the U.S. Environmental Protection Agency’s (EPA) proposed Standards of Performance for Greenhouse Gas Emissions for New Stationary Sources.)


  1. jdroz  


    It’s good that CATO is doing this, and I’m sure your contributions are helpful.

    It seems though that CATO has missed an important opportunity to further distinguish their assessment from USGCRP report.

    Words are important with these matters, and the term “Climate Change” is a meaningless marketing term that has been hijacked by those promoting a political agenda.

    IMO CATO should pointedly reject that phraseology as unscientific and continue to call the proposed hypothesis AGW or Global Warming.


  2. cknappenberger  


    Thanks for the comments.

    Temperatures don’t rise in isolation, but have associated impacts throughout the climate system. So “climate change” seems a perfectly reasonable (and more inclusive) terminology to me. I am comfortable using the two (“global warming” and “climate change”) interchangeably.



  3. Jon Boone  

    “…warming, intensification of weather extremes, polar ice cap melting, and sea-level rise will all be at the lowest end of the ranges projected in the Fourth Assessment of the Intergovernmental Panel of Climate Change.”

    It’s hard to see how any of this can be falsifiable in the short term of, say, the next 50 years.

    Thanks to Cato for at least entering into a club house sort of arms race discussion with the USGCRP. As I write this, the latest storm of the century approaches an area that has over the last 40 years doubled its population, infrastructure, and electricity network, mostly with overhead lines nestled near tree limbs that receive virtually no preventative maintenance. The impact will be substantial. But surely not evidence of “climate change.”

    The evolution of the term climate change out of the term global warming surely is grist for at least some satire, particularly since both are political slogans, not scientific descriptors about much in the empirical world.


  4. jdroz  


    I guess that our understandings differ.

    I was always under the impression that “climate change” is a truism, as climate is ALWAYS changing (and has ALWAYS been changing) due to naturally occurring mechanism.

    Yes, that makes it more inclusive, but so what? Is Cato (or any other group using that banal term) really doing a comprehensive balanced assessment of ALL of the mechanisms that affect climate?

    Unless they are they have no business using such a comprehensive phrase.

    For example, does the Sierra Club, Greenpeace, etc. do such an assessment? Of course not. They have “cleverly” tried to hijack and redefine a broad term to mean their very focused target: AGW.

    Technically competent people (e.g. Cato) should not be tricked into such concessions.


  5. Ed Reid  

    Chip & John,

    I would argue that each of the terms has a specific meaning and should be used carefully.

    John, all global warming is not anthropogenic.

    Chip, all climate change is not global warming.


  6. cknappenberger  


    AGW leads to climate changes. So do other things. The Cato report looks at climate change, potential and observed, with a special eye on that part which may have a human influence—after all, it is that part which regulators/legislators are eyeing. The Cato report generally finds that the anthropogenic contribution to climate change will likely be modest and further emphasizes our adaptive capacity to deal with climate change (regardless of its cause).

    It is hard to see how we have been tricked into anything.



  7. jdroz  


    1) Over the last few years the AGW hypothesis has been successfully attacked as not being scientifically sound.

    2) Rather than abandon their crusade, the promoters of AGW have instead morphed their campaign into a focus on “climate change.”

    3) As a critical part of their PR appeal to the public, they purposefully chose a phrase (climate change) that is a truism. Who can argue that a truism is false?

    4) Those of us who have a greater degree of understanding of this technical matter should not accept the purposefully deceptive sales terminology that the AGW proponents are using to sway the masses.

    5) Cato should be sensitive to this in all of their AGW related publications.

    6) From what I have seen, “Addendum: Global Climate Change Impacts in the United States” implicitly accepts this anti-science change of venue.

    IMO that is a significant strategic mistake.


  8. pmichaels  

    Just a note that AGW is a truism. Add carbon dioxide to the atmosphere and you will get a radiative change. The key concept is not change but rather the true net sensitivity, which certainly appears to be lower than values typically used in the IPCC model ensembles. Policies are rightfully contingent upon sensitivity rather than mere existence, and low sensitivities should associate with a “hands off’ policy because natural technological change rates are so high that the issue becomes a non-problem.

    The alternative hypothesis of a climate change largely driven by the sun in recent decades suffers from the problem of stratospheric cooling. Increasing solar output would have the opposite effect, while increasing carbon dioxide is highly consistent with it. Stratospheric cooling is a problem dragon slayers.


  9. rbradley  

    Yes, I think the debate is or needs to be beyond a human influence on climate, and in the direction of warming, other things the same.

    The real action regards how much the anthropogenic warming, the benefits of increased CO2 in the atmosphere (versus the costs), and the costs of government intervention relating to the issue.


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