Significant Reductions in Crop Yields From Air Pollution and Heat Stress in the United States

Abstract

The joint exposure of plants to surface ozone, atmospheric aerosols, and heat stress can lead to considerable decreases in crop yields. Surface ozone negatively impacts plant photosynthesis while aerosols can have positive or negative effects from its dual impact on light and temperature. Here, using a statistical model, we show that in the United States, as a result of improvements in air quality, the damages caused by ozone and aerosols have decreased since 1980. Historically, relative yield losses due to ozone were 8.7% and 4.8%, and due to aerosols were 11.3% and 23.2% for maize and soybean, respectively. Maize yields are more sensitive to ozone pollution while soybean yields are more sensitive to aerosol pollution. In future RCP 8.5 scenario, absent significant reductions in emissions or improvements in air quality, maize, and soybean would have on average, 58.5% and 36.9% additional yield reductions, respectively, mainly caused by warming. Future climate warming and fossil fuel combustion driven changes to air pollution may have differing impacts on crop yield and should be jointly considered in any assessment of U.S. food security.