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The Answer to Climate Change?

Monday, June 30, 2008

‘Geoengineering’ may not be a panacea for global warming, but it deserves more attention from policymakers.

As Congress debates legislation to mandate reductions in greenhouse gas (GHG) emissions, a more radical type of intervention to reduce global warming has gotten relatively little attention. Earlier this month, the American Enterprise Institute held the first in a series of conferences to examine the scientific and policy implications of “geoengineering.” The event was hosted by AEI scholars Lee Lane and Samuel Thernstrom. As AEI President Christopher DeMuth noted in his introduction, mitigating GHG emissions is very expensive; but while scientists and engineers have been discussing geoengineering for years, it has not yet made its way into policy discussions. 

Conference participants generally agreed that while geoengineering is not a panacea for climate change, it does have the potential to slow (and perhaps even halt) planetary warming and would cost much less than GHG mitigation. 

If mitigating climate change through reductions in GHG emissions were cheap, or if the benefits of doing so were large, Scott Barrett of John Hopkins University said, it would already have been done. In fact, while current technology allows us to make small emissions cuts relatively cheaply, significant reductions would be extremely expensive and require major economic sacrifices. In addition, global climate change may be, as Barrett declared, “the world’s greatest collective action problem,” since no country acting alone can reduce greenhouse gases enough to slow it. Lane agreed, saying that no mitigation-based solution is possible without China’s participation—and there is little the United States can do to force China to curb its emissions. 

Geoengineering has the potential to slow (and perhaps even halt) planetary warming and would cost much less than GHG mitigation.

Geoengineering may be a way to solve this collective action problem. Several different types of interventions have been discussed and modeled. Tom Wigley, a scientist at the National Center for Atmospheric Research, discussed how injecting ultra-fine sulfur particles into the stratosphere or spraying clouds with saltwater to increase their reflectivity could reduce climate change. Estimates for how much a solution like this would cost are not definitive, since research has been limited and no field testing has been done; but if geoengineering proves feasible, it would almost certainly be far less expensive—and would require less extensive global cooperation—than GHG mitigation. 

Geoengineering has its limits, though: some of the problems associated with carbon dioxide emissions, such as ocean acidification and its possible impact on marine life, would require other solutions. Wigley presented geoengineering as a way to buy more time to create new technologies to produce low-cost clean energy. Yet as Thernstrom observed, the Intergovernmental Panel on Climate Change’s estimates of future technological progress may be excessively optimistic: its predictions assume that, even without policy changes, new technologies will significantly reduce carbon intensity. In fact, Thernstrom said, even with drastic policy changes we will probably not reach the low emissions levels that many scientists recommend. Wigley and Massachusetts Institute of Technology professor Kerry Emanuel agreed, however, that mitigation will in the long run have to be a central feature of our response to climate change.

A recent report from the Peter G. Peterson Institute for International Economics concluded that although agricultural productivity in some countries is likely to suffer from gradual global warming, other countries may actually see their agricultural output increase. But abrupt climate change will not help any countries, Barrett said, which is why geoengineering may become so important. 

The conference participants widely agreed that more research needs to be done into geoengineering. For instance, very little modeling has been done on the regional effects of technical solutions to global warming. Climate systems are complex, and an intervention that brings down the average global temperature might also change regional weather patterns, such as the length or intensity of the monsoon season. 

Geoengineering is gaining acceptance in mainstream climate science, but funding is still very limited and only a few scientists are actively studying the concept. Eventually, geoengineering experiments will have to be performed in the real world, outside the realm of computer simulations. Which is why, as Fred Iklé of the Center for Strategic and International Studies stressed, it is time for global leaders to act on proposals for serious research and development.

Abigail Haddad is a research assistant at the American Enterprise Institute

Image by Shutterstock/ Darren Wamboldt.

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