Collaborative Research: Global Agricultural Impacts of Stratospheric Aerosol Climate Intervention

Lead PI: Dr. Jonas Jägermeyr

Unit Affiliation: Center for Climate Systems Research (CCSR)

April 2021 - September 2022
Project Type: Research Outreach Education

DESCRIPTION: Stratospheric aerosol climate intervention has been suggested as a strategy to compensate for anthropogenic global warming. Much research has focused on climate changes associated with stratospheric aerosol climate intervention (also called stratospheric aerosol geoengineering – SAG), but only a few studies have addressed its potential societal impacts, in particular global agricultural productivity. The work proposed here will examine how climate changes from SAG, compared with the present and a future without SAG, interact with the global agriculture system, influence crop growth, and impact world food production. Spatially explicit climate changes considered here associated with SAG include less total solar radiation, more diffuse solar
radiation, reduced surface temperature, changed precipitation, changed surface ozone concentration, and different global mean CO2 levels. The intellectual merit of the proposed activity This project will probe connections between climate changes of SAG and the agriculture system. It will be the first multidisciplinary collaboration to evaluate global agriculture impacts of SAG with an integrated assessment framework, including a state-of-the-art Earth System Model linked to multiple mechanistic crop models. These models advance the frontier of process-based crop modeling with representations of ozone damage and diffuse radiation in photosynthesis processes. Impact uncertainties will be systematically quantified through the model ensemble setup and multi-crop model assessment, and by using different downscaling methods for climate forcing data. Detailed impacts of individual climate factors on crop yields will be studied, while considering feedbacks from the agriculture system to the SAG climate.

The results of this project will provide new quantitative evidence of SAG implications for world food production in view of present day and potential future climates without SAG. This project will foster communication between the climate modeling community (including the Geoengineering Model Intercomparison Project) and the crop modeling community (the Agricultural Model Intercomparison and Improvement Project), to advance understanding of agricultural impacts under global warming and a future climate with stratospheric aerosol intervention. It will encourage interdisciplinary work under the specific climate of SAG, and ignite new crop model developments. Agriculture is important to everyday life and the world economy. This project will provide information on the dynamics of the agriculture system under SAG climate, and how human decisions affect the two systems – climate and agriculture. Furthermore, simulating the SAG influence on agriculture clearly has broad impacts. Climate intervention is not advocated in any of the proposed work. Rather the focus is to understand its potential for any positive and negative agriculture impacts. Results from this study will inform policymakers of the possible changes, along with uncertainties, to agriculture if SAG is applied to counteract anthropogenic warming, so that informed decisions can be made in the future. Additionally, this project will support early-career scientists, including a female, and therefore will directly support diversity within the atmospheric sciences.