This is a question I asked Robin at today's lunch. Soon afterwards, I learned that AEI just had the first of a series of conferences on this topic, known as "geoengineering":
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.
My knowledge of natural science is minimal. Is this a pipe dream - or a practical solution that the man in the street is too dogmatic to consider?