Dry spells and global crop production: A multi-stressor and multi-timescale analysis

More frequent and punctuated severe events such as dry spells are among the more salient manifestations of climate change. Because dry spells often co-occur both with heat waves and with longer-term agricultural drought and their effects may interact, understanding the effects of dry spells and heat waves requires a multi-timescale and multi-stressor perspective. Using a global panel of daily precipitation and temperature from 1979 to 2016, we provide evidence that 4-5 week dry spells that occur during the hottest part of the year depress growth in aggregate crop production. The effects of these extreme events are modified by existing drought, aridity, and by heat waves. Our findings, focused on punctuated events, multiple stressors, and aggregate crop production across the globe, complement prior investigations focused solely on longer-term phenomena, those that study extreme heat or precipitation in isolation, and studies that restrict attention to a small number of crops or locations.