Solar Radiation Management: The Future of Environmentalism

June 6, 2013

Measures to reduce greenhouse gas (GHG) emissions have long dominated public discourse about responses to man-made climate change. However, major institutional and political hurdles dim future prospects for controlling emissions. While adaptation to climate change can accomplish much, flawed institutions are likely to limit its efficacy; but there could be a solution: solar radiation management (SRM), say Lee Lane, of the Hudson Institute, and J. Eric Bickel, of the University of Texas at Austin.

  • SRM would seek to enhance and manage physical processes that currently reflect sunlight back into space.
  • For example, most researchers have envisioned implementing this concept by adding to the layer of sulfuric acid that is already present in the lower stratosphere.
  • All else remaining equal, global mean temperatures would fall even though GHG levels would not; the Intergovernmental Panel on Climate Change estimates that physical processes such as these already offset about 40 percent of global warming.

Recent technical developments have advanced our understanding of important aspects of SRM.

  • First, the regional impacts of SRM will be variable and these differences are likely to become a source of disagreement regarding SRM deployment.
  • Second, given the uncertainties about SRM technologies, there is a pressing need for research and development funding.
  • Third, in contrast to GHG control, SRM may offer a cost-effective way of managing the risk of crossing climate tipping points.

The economic benefits of a successful SRM program would flow from a reduction in climate damages owing to warming and a reduction in economic damage caused by GHG controls. Determining the optimal amount of GHG controls to implement in the presence of SRM is an ongoing research effort.

The incentives for using SRM appear to be stronger than those for GHG control. Much analysis has used this valid point to conjecture that SRM would be too easy to employ. This fear is largely misguided. Global power politics militate against any state bidding for sole control of an SRM system. While SRM remains a speculative option, a workable SRM system could offer a highly useful backup and supplement to current policy options.

Source: Lee Lane and J. Eric Bickel, "Solar Radiation Management an Evolving Climate Policy Option," American Enterprise Institute, May 2013.


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