A team of scientists led by the U.S. National Science Foundation National Center for Atmospheric Research (NSF NCAR) has published a paper outlining recommendations for evaluating proposals to inject sulfur dioxide into the stratosphere, a technique known as stratospheric aerosol intervention (SAI). The goal of the research is to assess the technical feasibility, cooling potential, and potential ecological and societal side effects of implementing SAI as a means to offset Earth’s warming temperatures. The scientists emphasize the importance of providing policymakers and the public with the best scientific understanding of SAI to make informed decisions.
Sulfur dioxide injected into the stratosphere would create sunlight-reflecting sulfate aerosols, which have been shown in previous studies to have a cooling effect similar to that of a major volcanic eruption. These aerosols could continue to cool Earth for decades or even centuries, providing a temporary solution to offset the impacts of heat-trapping greenhouse gases. However, the research also highlights potential risks associated with SAI, such as altering the stratospheric ozone layer and global precipitation patterns. Informed policy decisions require a comprehensive understanding of both the benefits and risks of SAI.
To assess SAI developments, the paper proposes eight research criteria, including technical and economic limitations, cooling potential, ability to meet climate objectives, impacts on human and natural systems, and mitigation of risks through governance. The research and governance structure would involve fair representation from both the Global South and North to oversee SAI research and technology developments. This assessment process would involve issuing reports on SAI developments every few years with globally representative participation to ensure a comprehensive understanding of the potential benefits and risks.
The criteria outlined in the paper can also be applied to other solar radiation modification proposals, such as the brightening of marine clouds. The ultimate goal of these criteria is to promote optimal approaches to addressing climate change while carefully weighing the benefits and risks of implementing SAI. It is crucial to include the perspectives of underrepresented groups and the Global South in the decision-making process to ensure that any solar geoengineering methods are evaluated thoroughly and with a global perspective. Overall, the research aims to provide policymakers and the public with the necessary information to make informed decisions about the potential implementation of SAI as a climate intervention strategy.