Organic Solar Radiation Modification

Despite the urgency to mitigate climate change, global greenhouse gas concentrations are still increasing, and even global emissions are still growing. Furthermore, the global sinks—both natural and technical—are not improving rapidly enough. Therefore, discussion and investigations to utilize solar radiation modification (SRM) have resurfaced. Stratospheric Aerosol Injection (SAI) is one of the most studied methods, particularly using sulfate aerosols. However, sulfate SAI includes several risks, such as deposition of acidic aerosol particles on the Earth’s surface, increasing acidification and ozone depletion, and changing weather patterns. Here we propose an alternative approach, namely Organic Stratospheric Aerosol Injection (OSAI). The OSAI is initiated by an injection of isoprene or monoterpenes, which, according to our conceptual investigations and global model simulations, seem to be plausible candidates for this purpose. The organic SAI is likely to avoid some of the problems inherent to sulfate SAI, even though further research is needed in terms of its potential influences on stratospheric heating and the ozone layer. While SRM is still preferably avoided, our results suggest that organic aerosols may be an alternative to sulfate for further consideration if it is deemed a viable and necessary option.