A biased economic analysis of geoengineering

Guest commentary by Alan Robock – Rutgers University

Bjorn Lomborg’s Climate Consensus Center just released an un-refereed report on geoengineering, An Analysis of Climate Engineering as a Response to Global Warming, by J Eric Bickel and Lee Lane. The “consensus” in the title of Lomborg’s center is based on a meeting of 50 economists last year. The problem with allowing economists to decide the proper response of society to global warming is that they base their analysis only on their own quantifications of the costs and benefits of different strategies. In this report, discussed below, they simply omit the costs of many of the potential negative aspects of producing a stratospheric cloud to block out sunlight or cloud brightening, and come to the conclusion that these strategies have a 25-5000 to 1 benefit/cost ratio. That the second author works for the American Enterprise Institute, a lobbying group that has been a leading global warming denier, is not surprising, except that now they are in favor of a solution to a problem they have claimed for years does not exist.

Geoengineering has come a long way since first discussed here three years ago. [Here I use the term “geoengineering” to refer to “solar radiation management” (SRM) and not to carbon capture and sequestration (called “air capture” in the report), a related topic with quite different issues.] In a New Scientist interview, John Holdren, President Obama’s science adviser, says geoengineering has to be examined as a possible response to global warming, but that we can make no such determination now. A two-day conference on geoengineering organized by the U.S. National Academy of Sciences was held in June, 2009, with an opening talk by the President, Ralph Cicerone. The American Meteorological Society (AMS) has just issued a policy statement on geoengineering, which urges cautious consideration, more research, and appropriate restrictions. But all this attention comes with the message that we know little about the efficacy, costs, and problems associated with geoengineering suggestions, and that much more study is needed.

Bickel and Lane, however, do not hesitate to write a report that is rather biased in favor of geoengineering using SRM, by emphasizing the low cost and dismissing the many possible negative aspects. They use calculations with the Dynamic Integrated model of Climate and the Economy (DICE) economic model to make the paper seem scientific, but there are many inherent assumptions, and they up-front refuse to present their results in terms of ranges or error bars. Specific numbers in their conclusions make the results seem much more certain than they are. While they give lip service to possible negative consequences of geoengineering, they refuse to quantify them. Indeed, the purpose of new research is to do just that, but the tone of this report is to claim that cooling the planet will have overall benefits, which CAN be quantified. The conclusions and summary of the report imply much more certainty as to the net benefits of SRM than is really the case.

My main areas of agreement with this report are that global warming is an important, serious problem, that SRM with stratospheric aerosols or cloud brightening would not be expensive, and that we indeed need more research into geoengineering. The authors provide a balanced introduction to the issues of global warming and the possible types of geoengineering.

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