Dr. Carlin's error was a review of climate change skeptical about the potential for carbon dioxide emissions to explain it.[3] The report has been made available on a Web site maintained by political opponents of government regulation. Dr. Carlin was reassigned from climate change analysis to updating a grants database. CBS News may have picked up the story from WorldNet Daily, which reported it about a day earlier.[4]
Dr. Carlin began investigating climate change issues in 2003 and does not have a career invested in them. He operates as an outside critic, looking for problems with assumptions, methods and data. The main theme of his March, 2009, paper was to ask whether global temperature measurements since the last major review by the U.N. Intergovernmental Panel on Climate Change (IPCC) called into question that review's conclusions about rising temperatures and their potential associations with carbon dioxide emissions.
In contrast to a rapid run-up of temperatures leading to a spike in 1998, the last three years show a declining trend in satellite temperature measurements, about 0.1 Centigrade degrees per year, based on data summarized by the Hadley Center at the University of Alabama, Huntsville. Until moderated by the current deep recession, world carbon dioxide emissions continued to accelerate. Dr. Carlin shows that recent temperature measurements are in substantial disagreement with IPCC predictions published in 2007.
In an article published the year before his run-in with EPA management,[5] Dr. Carlin surveyed familiar potential contributors to global temperatures: solar output, clouds and water vapor, greenhouse gases, aerosols and urbanization of land. He describes IPCC numerical modeling and notes its susceptibility to the choices of data used to estimate effects that cannot be adequately described by physical principles alone. He recalls fears of an impending ice age that seized climate researchers a few decades ago and emphasizes major uncertainties remaining in determining conditions that could lead to run-away temperature changes under positive feedback.
Dr. Carlin's main conclusion in [5] was that it is impossible to estimate reliably the economic consequences of decreasing emissions of greenhouse gases (GHGs) as the exclusive approach used to control global warming: "Climate sensitivity, the key technical variable describing climate [response] to increased GHG levels, appears to be unknowable in advance."[6] His reasoning calls to mind the discovery of intrinically chaotic mathematics by Prof. Edward Lorenz at MIT in 1961, while trying to develop models of weather systems.[7]
The suppressed Carlin paper later develops an adversarial tone: "One of the most glaring problems of all with the EPA's Endangerment TSD (technical support document) is the nearly complete disregard of observed trends...."[8] The paper contains internal evidence suggesting a document that circulated within its agency over an extended period. For example, a footnote on p. 67 says "comment by Ken Gregory--June 21, 2008." A discussion of climate model assumptions notes that IPCC modeling assumed nearly constant global humidity, while long-term data show declining trends, opposing the effects of increases in atmospheric concentrations of carbon dioxide.[9]
Dr. Carlin's style tends to hyperbole, for example, the assertion that climate sensitivity is "unknowable in advance," which could be a factor in his current situation. The article he cites from Gerard S. Roe and Marcia B. Baker [6] shows instead that climate sensitivity can be described through probability distributions. However, the distributions are extremely broad, with significant probabilities over a tenfold or greater range. So in terms of economics, Dr. Carlin appears to be correct. Based on available evidence, we cannot reliably predict effects of control strategies that depend on climate sensitivities to greenhouse gases.
In a 2007 article,[10] Dr. Carlin reviewed mid-1990s proposals by Dr. Edward Teller and collaborators, reported from Livermore National Laboratory, for airborne or spaceborne solar reflectors.[11] The Teller report, in turn, claims derivation from ideas of Dr. James Hansen and collaborators at NASA Goddard Institute for Space Studies, published several years earlier.[12] Some ill-informed criticism of those proposals [13] suggests that physical intervention in solar absorption would be inconsistent with claims about lack of reliable ability to predict climate. However, some of the approaches proposed in the Teller report are reversible or have short decay times, allowing them to be adapted to ongoing climate behavior. The central point of Dr. Carlin's review is that the probable cost of solar reflection would be far lower than the probable cost of greenhouse gas control.
[1] Lisa P. Jackson, Statement by Administrator-designate, U.S. Environmental Protection Agency, January 23, 2009, available at http://yosemite.epa.gov/opa/admpress.nsf/0/2297C12A9F4773D285257547006497D4. "...I will ensure EPA’s efforts to address the environmental crises of today are rooted in three fundamental values: science-based policies and programs, adherence to the rule of law, and overwhelming transparency."
[2] Declan McCullagh, EPA may have suppressed report skeptical of global warming, CBS News, June 26, 2009, available at www.cbsnews.com/blogs/2009/06/26/politics/politicalhotsheet/entry5117890.shtml.
[3] Proposed NCEE comments on draft technical support document for endangerment analysis for greenhouse gas emissions under the Clean Air Act, U.S. National Center for Environmental Economics, March 16, 2009, made available at http://cei.org/cei_files/fm/active/0/DOC062509-004.pdf.
[4] Chelsea Schilling, EPA's own research expert 'shut up' on climate change, WorldNet Daily, June 25, 2009, at www.worldnetdaily.com/index.php?fa=PAGE.view&pageId=102031 (retrieved June 27, 2009, from Google cache).
[5] Alan Carlin, Why a different approach is required if global climate change is to be controlled efficiently or even at all, Environmental Law and Policy Review, 32(3):685-757, 2008, full text available on the Internet at http://carlineconomics.googlepages.com/Endangermentcommentsv7b1.pdf.
[6] Cited: Gerard S. Roe and Marcia B. Baker, Why is climate sensitivity so unpredictable?, Science 318(5850):629-632, October 26, 2007, full text available on the Internet at http://earthweb.ess.washington.edu/roe/Publications/RoeBaker_Science07.pdf.
[7] Recounted in: James Gleick, Chaos: Making a New Science (1987, Viking), The butterfly effect, pp. 11-31.
[8] Ref. [3], p. 64.
[9] Ref. [3], pp. 67-70.
[10] Alan Carlin, Global climate change control: Is there a better strategy than reducing greenhouse gas emissions?, University of Pennsylvania Law Review 155(6):1401-1497, June, 2007, available at http://pennumbra.com/issues/pdfs/155-6/Carlin.pdf.
[11] Edward M. Teller, Lowell Wood and Roderick Hyde, Global warming and ice ages: Prospects for physics-based modulation of global change, UCR Livermore National Laboratory Report UCRL-JC-128715, August 15, 1997, available at www.osti.gov/accomplishments/documents/fullText/ACC0229.pdf.
[12] James E. Hansen and Andrew A. Lacis, Sun and dust versus greenhouse gases: An assessment of their relative
roles in global climate change, Nature 346:713-719, August 23, 1990.
[13] "Eris,"Re: CEI releases global warming study censored by EPA, Message 3, Colbert Nation, June 27, 2009, at http://forum.colbertnation.com/tcr/board/message?board.id=conspiracy&message.id=4655. "Carlin appears to be a big fan of geo-engineering, but how this squares with his apparent belief that we know nothing about what drives climate, is puzzling. A sine qua non of geo-engineering is that we need models to be able to predict what is likely to happen."
