Global Warming Determines Future Increase in Compound Dry and Hot Days within Wheat Growing Seasons Worldwide

Abstract

Abstract Compound drought and hot extremes are proved to be the most damaging climatic stressor to wheat production thereby with grave implications for global food security, thus it is critical to systematically reveal their future changes under unabated global warming. In this study, we comprehensively investigate the global changes of compound dry and hot days (CDHD) during dynamic wheat growing seasons of 2015–2100 under 4 socio-economic scenarios (SSP1-2.6, SSP2-4.5, SSP3-7.0 and SSP5-8.5) based on the latest downscaled Coupled Model Intercomparison Project Phase 6 (CMIP6) models. The results demonstrate a notable increase in CDHD’s frequency (CDHDf) and severity (CDHDs) in the future, by the end of 21st century, global average (CDHDf) and (CDHDs) are expected to increase by 6.5 ~ 27.5 days and 0.43 ~ 1.43 with reference to 1995–2014. Adopting a low forcing pathway will reduce CDHD in up to 95.1% of wheat planting grids. As the top 10 wheat producer, Ukraine, Turkey and America will suffer much more and stronger CDHD in future wheat growing seasons under all SSPs. Global warming will dominate the future increase of CDHD worldwide directly by promoting hot days to increase and indirectly by enhancing potential evapotranspiration (PET) thereby promoting drought events. This study helps to optimize adaptation strategies for mitigating risks from CDHD on wheat production, and provides new insights and analysis paradigm for investigating future variations in compound extremes occurring within dynamic crops growing seasons worldwide.