Heat stress, air pollution, and crop yield

Agriculture is facing an unprecedented risk due to climate change. Feeding the world population requires coping with emerging global warming and extreme weather events. However, due to fossil fuel combustion, the human system has emitted tons of air pollution precursors that adversely impact human health and substantially influence vegetation.

Considering the compound drivers of crop yields, such as heat and ozone episodes, crop failure may be larger than previously thought. To account for these factors, we collected a wide range of data in the U.S., including statistics, climate, and air pollution, and merged them into a panel dataset. We built a regression model to investigate the relationships between these variables and crop yields. The model includes fixed effects to account for invariant factors in counties and common trends in agricultural practice.

Our research reveals that climate and air pollution interactions are vitally essential to crop yields. We find that air pollution mitigation can improve crop yield and reduce the damage from the interactive effects of air pollutants and climate change.

Article

“Significant Reductions in Crop Yields From Air Pollution and Heat Stress in the United States”, Earth’s Future.

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.