Temperature‐driven harvest decisions amplify US winter wheat loss under climate warming

Abstract

Most studies quantifying the impacts of climatic variability and warming on crop production have focused on yields and have overlooked potential areal and frequency responses, potentially biasing future projections of food security in a warming world. Here we analyze US winter wheat production from 1970 to 2017 and find that harvest area ratio (harvested area/planted area, HAR) has declined while yields have risen, standing in stark contrast to other US staple crops. Although lower profitability due to declining wheat prices appears to explain the HAR trend, fluctuating wheat yields—largely explained by temperature exposure—drive the interannual variation of HAR. Our analysis suggests that warming‐induced declines in HAR are comparable in magnitude to heat‐related yield losses, and lower wheat prices amplify the sensitivity of HAR to warming and yield variation. Although irrigation mitigates some temperature‐driven yield effects, it does little to change HAR, likely due to infrastructure cost and limited influence on relative profitability. Our results suggest that an accurate quantification of climate impacts on crop production must account for harvested area response, and that future adaptation strategies should not only target crop choice and management but also harvest incentives.

U.S. winter wheat yield loss attributed to compound hot-dry-windy events

“…The county - level hard winter wheat yield data between 1982 and 2020 were obtained from information provided by the United States Department of Agriculture’s National Agricultural Statistics Service (USDA - NASS). All yield data in this study were directly taken from survey yields, and the irrigation fraction was <5% on average in our study domain 19 .…”

“…Here, Y ′ is relative to the 5 - year running mean yield ( Y i ), thus removing the interannual variation 19 . We then defined a yield shock year in each county as a year in which Y’ fell below the 25th percentile over total yield years.…”

“…With respect to such compound events, few efforts have evaluated their impacts, and most of the existing research has focused on changes or distribution shifts of crop water supply and temperature. The simultaneous combination of high temperature, low relative humidity, and high wind events in the near-surface atmospheric boundary layer [hereafter referred to as hot-dry-windy events (HDW)] poses a particular climate risk to global crops 11 , 15 , 16 , especially in the United States Great Plains that experience irregular, hot, dry, and windy conditions coupled together 17 – 19 . For example, a decade of drought occurred in the 1930s in the U.S. and this decadal drought desiccated much of the agricultural land surface of the U.S. Great Plains causing one of the most severe environmental and social catastrophes in the world, namely the 1930s “Dust Bowl” 20 .…”

“…Previously, the standard practice in determining climate-crop relationships for winter wheat has been to partition its growth stages by fall, winter, and spring calendar seasons 9 , 19 . The use of such fixed calendars with subsets of seasons or months, however, might potentially misrepresent the climate-crop association 22 due to varied local phenological timings, stage-specific crop sensitivity to adverse weather, differences in crop management, and spatially variable regional climates 7 .…”

Climate Change Effects on Texas Dryland Winter Wheat Yields

“…Changes in climate such as precipitation, temperature, and increases in atmospheric CO2 affect crop production [14]. Increases in temperature have a more negative impact on crop yields [15]. Climate change is inevitable and has an impact on various industries, including agriculture.…”