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 with drought and heat waves, 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 crop production. The effects of these extreme events are modified by existing drought, aridity, and by heat waves. After accounting for productivity and crop choice, losses in yields from dry spells are concentrated in areas that are not equipped for irrigation, suggesting a possible role of adaptation in dampening the effects of dry spells. Our findings, focused on punctuated events and multiple stressors, complement prior investigations focused solely on longer-term phenomena and those that study extreme heat or precipitation in isolation