Impact of coupled extreme water and heat stress on global crop yield under future climate change

The devastating impact of extreme climate on food production has been widely recognized and will show an increasingly severe trend. However, there is still a serious lack of quantitative research on this issue at the global scale. Therefore, we modified the crop yield module in the Community Water Model (CWatM) to assess for the first time the potential impact of coupled extreme water and heat stress caused by climate change on the yield of 4 major crops (rice, corn, soybean and wheat) worldwide. Results show that crop yields are projected to increase by up to 40% due to improved heat availability at high latitudes by the late 21st century, while low latitudes will experience reductions ranging from 20–40%. Furthermore, climate extremes are projected to increase significantly under high-emission scenarios. This will result in severe yield loss magnitude, increasing by 60–80% compared with those caused by extreme climate events during 1990–2019. While advancements in agricultural technology may somewhat mitigate heat stress, they cannot fully offset the adverse effects of extreme water and heat stress. These insights enhance our understanding of the risks climate change poses to food production and offer a robust scientific basis for policymakers to develop long-term agricultural policies and climate adaptation strategies.