There is growing concern that greenhouse gas emissions are not falling quickly enough to avoid dangerous levels of global warming. As a result, there is the impetus to examine other options. Among these are geoengineering, which is one of the most contentious issues in climate policy. Geoengineering embodies many risks that make even seriously considering it seem risky in itself.
Despite this, the National Academies of Science, Engineering, and Medicine has issued a report saying that governments urgently need to know whether solar geoengineering could work and what its side effects might be.
Solar geoengineering is also called solar radiation modification, which entails reflecting more of the sun’s energy back into space. This would likely be accomplished by injecting aerosols into the atmosphere, much like what happens after large volcanic eruptions.
Schemes for solar geoengineering raise numerous issues. Although solar geoengineering might cool the earth’s surface to a global temperature target, the cooling may not be evenly distributed, affecting many ecosystem functions and biodiversity. It would likely upset regional weather patterns in potentially devastating ways, for example by changing the behavior of the monsoon in South Asia. It might dangerously relax public commitments to reduce greenhouse emissions.
Despite these concerns, or perhaps because of them, the committee that produced the report believes that technology to reflect sunlight deserves substantial funding and should be researched as rapidly and effectively as possible. Once any geoengineering projects get into the hands of policymakers, they may gather momentum that bypasses the advice of scientists. So, it important to make progress on the science while geoengineering is still only theoretical.
Photo, posted August 3, 2018, courtesy of Tomasz Baranowski via Flickr.