Effects of Surface Ozone and Climate on Historical (1980–2015) Crop Yields in the United States: Implication for Mid-21st Century Projection

Surface level ozone pollution imposes significant crop yield damages. However, the quantification has mainly involved chamber experiments, which may not be representative of results in farm fields. Additionally, the relative impacts of ozone under future climate change and their possible interactions remain poorly understood. Here we attempt to empirically fill this gap using historical county-level crop yield, ozone, and climate data in the United States. We explore ozone impacts on corn, soybeans, spring wheat, winter wheat, barley, cotton, peanuts, rice, sorghum, and sunflowers. We also incorporate a variety of climatic variables to investigate potential ozone-climate interactions. The results shed light on future yield consequences of ozone and climate change individually and jointly under a projected climate scenario. Our findings indicate significant negative impacts of ozone exposure for eight of the ten crops we examined, excepting barley and winter wheat. Meanwhile, corn exhibits to be more sensitive to ozone than soybeans. These results differ from those found under chamber experiments. We also find rising temperatures tend to worsen ozone damages while water supplies mitigate that. We find that the average annual historical damages from ozone reached $6.03 billion (in 2015 U.S. dollar) from 1980 to 2015. Finally, our results suggest that the damages caused by climate change-induced ozone elevation are much smaller than the damages caused by the direct effects of climate change itself.