Current benefits of wildfire smoke for yields in the US Midwest may dissipate by 2050

Abstract

Wildfires throughout western North America produce smoke plumes that can stretch across the agricultural regions of the American Midwest. Climate change may increase the number and size of these fires and subsequent smoke plumes. These smoke plumes change solar radiation, meteorological conditions, and surface pollutant concentrations during the crop growing season and consequently influence yields of both corn and soybeans. We use a twelve-year panel of county-level yields from all counties east of the 100th meridian combined with measures of exposure to smoke plumes of low and high-density during the growing season to show that low-density plumes enhance yields while high-density plumes decrease yields. These effects appear to be driven by different changes in solar radiation induced by each type of plume but we observe changes in surface pollutants and precipitation as well. Because there are more low-density plumes today, the net effect is a slight increase in yields on average. As climate change makes wildfires larger and more frequent, the overall impact of smoke on yields would be be substantially more negative.