Given the urgency of the risks posed by climate change, the U.S. should pursue a research program for solar geoengineering—in coordination with other nations, subject to governance, and alongside a robust portfolio of climate mitigation and adaptation policies, according to a new report from the National Academies of Sciences, Engineering, and Medicine. The report emphasizes that solar geoengineering is not a substitute for reducing greenhouse gas emissions, says CIRES Fellow Lisa Dilling, who served as a member of the committee that wrote the assessment. “We need to succeed in other parts of the policy agenda no matter what,” she says.

Solar geoengineering refers to strategies designed to cool Earth either by adding small reflective particles to the upper atmosphere, by increasing reflective cloud cover in the lower atmosphere, or by thinning high-altitude clouds that can absorb heat. While such strategies have the potential to reduce global temperatures and thereby ameliorate some of the risks posed by climate change, they could also introduce an array of unknown or negative consequences, says Reflecting Sunlight: Recommendations for Solar Geoengineering Research and Research Governance.

"Research is needed since there’s just simply not enough understanding of solar geoengineering yet, " said Dilling, who is also Director of the Western Water Assessment and a CU Boulder Professor of Environmental Studies. "We need to know how it would perform, how to do it, and what the risks and effects would be. But equally importantly is how the research proceeds—making sure that any research that is undertaken follows a set of principles and mechanisms to ensure that it is transparent, encourages public engagement and is coordinated with other countries."

News release from the National Academies.

More about the report.