Stratospheric Aerosial Injection (SAI) has been proposed as a method to reduce global surface temperatures. This approach would mimic the effects of volcanic eruptions through injections of sulfate aerosols or it precursor into the stratosphere. Earth System Models (ESMs) are the only tool available for quantifying global effects of SAI. Here, we review the impacts on ecosystems, agriculture, and terrestrial carbon cycle as they are represented in ESMs and global land surface and crop models due to changes to total, diffuse, and UV-B radiation, global rainfall changes, changes to circulation patterns, and changes to surface-level ozone.
Our review highlights some areas that have limited representation in models: canopy radiation and impacts of diffuse radiation on photosynthesis, ozone damage, and interactive simulations with fire emissions and burnt area. Models that represent fire emissions do not link these emissions to atmospheric chemistry and radiation, limiting the ability to assess feedbacks. Other processes are essentially non-existent in current modelling studies, including the effects of enhanced UV-B radiation, which is expected as SAI would delay the recovery of the ozone layer. In addition, southern high latitude ecosystems are often overlooked in global studies, partially due to the relatively small amount of land area and partially due to lack of representation of the relevant plant types in global models, but these ecosystems would experience some of the more robust effects seen across SAI simulations. High resolution modelling and more focused model development for high latitude and novel ecosystems (exposed as glaciers recede) are therefore needed.
