Estimating global agricultural effects of geoengineering using volcanic eruptions

Area of Science:

• Climate Science
• Agricultural Science
• Atmospheric Science

Background:

• Solar radiation management (SRM) is proposed to mitigate global warming by reflecting sunlight.
• Potential economic impacts of SRM, particularly on agriculture, are not well understood.
• Volcanic eruptions offer natural experiments to study SRM effects.

Purpose of the Study:

• To estimate the impact of stratospheric sulfate aerosols on sunlight quantity and quality.
• To assess how these sunlight changes affect global crop yields.
• To model the net agricultural effects of SRM.

Main Methods:

• Utilized data from El Chichón and Mount Pinatubo volcanic eruptions as natural experiments.
• Developed a model to estimate sunlight-mediated effects on crop yields (C3 and C4 crops).
• Applied the yield model to a projected SRM scenario.

Main Results:

• Stratospheric sulfate aerosols negatively impacted yields for both C4 (maize) and C3 (soy, rice, wheat) crops.
• Projected mid-century agricultural damages from reduced sunlight roughly equal cooling benefits.
• SRM using stratospheric sulfate aerosols may offer minimal net agricultural benefits against climate change.

Conclusions:

• SRM via stratospheric sulfate aerosols could negate its agricultural benefits due to reduced sunlight.
• The net effect of SRM on global agriculture may be negligible.
• Further research should explore SRM impacts on other global systems like health and ecosystems.