Extreme heat and drought at flowering could threaten global wheat yields under climate change

Global food security is a major challenge in the 21st century, exacerbated by increasing frequency and intensity of extreme climatic events under climate change. The extreme climatic events around flowering, such as intense heatwaves and droughts, threaten crop yields by impacting reproductive development and grain setting. Our study estimated the potential impacts of short-term, high impact extreme temperature and drought events during flowering on global wheat yields under future climates, using climate projections from CMIP6 and a state-of-the-art wheat model (Sirius). Results show that although extreme drought around flowering currently poses a higher yield loss than extreme heat, global yield loss due to drought is predicted to decrease by 9% and 18% by 2050 and 2090, respectively. Yet, global yield losses from heat stress are expected to increase significantly, by 32% and 77% by 2050 and 2090, respectively. Consequently, heat stress at flowering emerges as a serious threat to global wheat yields under climate change, substantially increasing the vulnerability of wheat. Therefore, developing new cultivars tolerant not only to drought but also heat stress during flowering is critical for enhancing future wheat yields and sustainability in changing climates.