Solar geoengineeringExploring the Possible Risks, Benefits of Geoengineering

Climate change is creating impacts that are widespread and severe — and in many cases irreversible — for individuals, communities, economies, and ecosystems around the world. 2020 was one of the three warmest years on record, bringing with it a number of costly climate disasters, including the worst wildfire season ever recorded in the Western U.S., historic flooding in China and other parts of Asia, and severe droughts in South America. With every year of inaction on global efforts to address climate change and drastically reduce greenhouse gas emissions, more frequent and more extreme events of this kind could become more likely, potentially increasing the need to consider some high-risk approaches

One such approach, solar geoengineering, was the subject of the fourth event in a series of “Climate Conversations” hosted by the National Academies of Sciences, Engineering, and Medicine and the topic of the National Academies’ recent report Reflecting Sunlight: Recommendations for Solar Geoengineering Research and Research Governance. 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.

Participating in the discussion were Chris Field, director of the Stanford Woods Institute for the Environment, who chaired the committee that authored the National Academies’ report, and National Academy of Sciences President Marcia McNutt, a geophysicist who chaired a 2015 study on climate interventions. Award-winning journalist Frank Sesno, director of strategic initiatives at George Washington University’s School of Media and Public Affairs, moderated the conversation.

Reducing greenhouse gas emissions should be the centerpiece of efforts to combat climate change, said Field, but given the current climate trajectory, there is good reason to explore the viability of solar geoengineering and how it might fit into a broader set of climate change strategies.

“The fundamental question that [the National Academies] were asked to address is: Does it make sense to have a research program to further explore the question of whether or not solar geoengineering ought to be further considered for a place in the portfolio of climate change solutions?” said Field. “Because the impacts of climate change are advancing so rapidly, we really need to have a clear understanding of what the whole portfolio of possible solutions might look like and whether there’s a spot for geoengineering.”