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Samuel Thernstrom |
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At an AEI event in early June on how to control global warming, scientists and climate policy experts examined a unique idea called geoengineering--that is, employing technologies that would change features of the earth's environment in ways that would counteract the warming effects of greenhouse gases.
"There is not much question that there is some real risk that the consequences of warming may prove to be significant, and possibly catastrophic," AEI's Samuel Thernstrom said, and geoengineering could be a "safety valve" if other mitigation policies do not work. Thernstrom, along with AEI's Lee Lane, directs a new project at AEI that will explore the policy implications of geoengineering, which, according to Thernstrom, is the "most original and potentially important idea in climate policy--and also the most controversial."
The science is in its infancy, but Thernstrom believes that geoengineering could offer a potential solution to the worst aspects of global warming because it could be "fast, effective, and affordable"--virtues that mitigation at the moment cannot claim. The consequences of warming are hard to predict, but geoengineering might well be the only feasible solution if they prove to be serious.
The fundamental problem with current climate policy proposals is the paucity of affordable clean energy technologies that can be produced on a mass scale and the lack of a global political consensus to employ these technologies throughout the world. As a result, atmospheric concentrations of greenhouse gases are expected to rise significantly over the course of this century, causing unpredictable but potentially serious changes in the global climate. Scientists are studying various different technologies that could be used for geoengineering, and the research to date has been promising, but a federally funded research program would be needed to determine whether these technologies could really be safe and effective.
During the first panel of the event, which examined the science of geoengineering, Tom Wigley of the National Center for Atmospheric Research explored one idea that seems particularly promising: solar radiation management, which would involve distributing very fine sulfur aerosols in (or above) the stratosphere to block a small fraction (roughly 1 or 2 percent) of incoming sunlight, cancelling out the warming that is expected to occur during this century. But, Wigley stressed, "geoengineering cannot be looked at as a replacement for mitigation" since at least one important consequence of a high-CO2 atmosphere (ocean acidification) cannot be corrected through geoengineering.
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Lee Lane |
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The second panel focused on the policy issues surrounding geoengineering. At the outset, Lane reiterated the lack of consensus among nations about greenhouse gas reduction. "I have yet to hear any plausible solution that anyone has suggested to the problem of how to bring China and India into a system of international greenhouse gas controls." Talking about geoengineering, he continued, is one part of a larger process of expanding the range of options for climate policy that deserve serious consideration, which contrasts the "tunnel vision" of legislators focusing only on "short-run emissions cuts."
Scott Barrett of Johns Hopkins University called global climate change the "greatest collective action problem in human history." Because of the decades-long lag between the reduction of emissions and the resulting change in mean global temperature, he said, it is important to have an option like geoengineering that sees quicker effects.
Thernstrom noted that the Climate Security Act, sponsored by Senators Joseph Lieberman (I-D-Conn.) and John Warner (R-Va.), was not expected to pass--it was, in fact, pulled later that week--but it is likely that climate legislation of some sort will be enacted within the next couple of years.
For video, audio, and a report on this event, visit www.aei.org/event1728/.
