For more than twenty years, policymakers have struggled to find ways to reduce greenhouse gas emissions enough to stop global climate change. Congress is likely to enact federal climate legislation in 2009, but many scientists fear that emissions reductions may not occur quickly enough to prevent significant warming. Some scientists also fear that potentially catastrophic effects, such as the melting of the polar ice caps, could happen unexpectedly quickly. If warming proves to be uncontrollable and dangerous, what could we do?

A growing number of climate scientists believe that there may be only one possible answer to that question: change features of the earth’s environment in ways that would offset the warming effect of greenhouse gases, a concept known as “geoengineering” (or “climate engineering”). The most plausible way of doing this would be to use very fine particles in (or above) the stratosphere to block a small fraction (roughly 2 percent) of sunlight. While geoengineering science is in its infancy, most scientists who have studied the idea believe it is likely to be feasible and cost-effective.

Is geoengineering feasible? What do scientists know about it--and what do they need to learn if we want to have the option of deploying these technologies in an emergency? If geoengineering proves to be feasible, would it be desirable? What are the policy implications of this revolutionary idea? What should it mean for the current debate over climate policy in Congress and for international climate negotiations? Who would benefit from geoengineering? Which countries might object--and how should their concerns be addressed?

To explore these and other questions, Lee Lane and Samuel Thernstrom will host a series of AEI conferences that will present the findings of original commissioned research papers on the policy implications of geoengineering. Speakers at this event will provide a broad overview of the state of the science of geoengineering and the range of public policy questions raised by this revolutionary concept. Tom Wigley, senior scientist at the National Center for Atmospheric Research, will examine the state of the science; Kerry Emanuel of the Massachusetts Institute of Technology and Vaughan Turekian of the American Association for the Advancement of Science will comment. Subsequently, Johns Hopkins University professor Scott Barrett will explore the policy implications of geoengineering, followed by commentary from Fred Iklé of the Center for Strategic and International Studies.