Compound drought-heatwave events and crop loss amplified by inconsistency

The intensification of compound drought-heatwaves (CDHWs) poses a mounting threat to human and food security, fueled by the growing prevalence of inconsistency. Existing inconsistent CDHWs monitoring usually ignores multidimensional inconsistent variations associated with seasonality, and corresponding quantitative impacts on crop yields remain vague. In this research, CDHWs under multiple potential inconsistent scenarios were focused to reveal spatial-temporal variations and differential frequency shifts. A joint generation was established to obtain the multiple inconsistent scenarios, and the CDHWs were quantified in different geo-ecosystem regions. The variations of CDHWs were obtained by differentiating the historical and inconsistent scenarios. The results show that: (1) CDHWs have exhibited wide and significant inconsistent variations across China; (2) Inconsistent seasonality significantly reshapes the spatial-temporal characteristics of CDHWs, which manifests as the dispersion of the original major high-frequency center into multiple sub-centers. Severity of CDHWs largely remains stable but duration will decrease significantly, thereby resulting in rising intensity; (3) Inconsistency will drive CDHWs more extreme, with more high-frequency CHDWs in high magnitudes (averaged +6.07%) and less low-frequency CHDWs in low magnitudes (averaged −7.09%). Moreover, inconsistent CDHWs lead to a 3.46% yield loss of China’s four main crops, with spring wheat suffering the greatest reduction (4.35%). These findings provide theoretical guidance for disaster prevention and crop management under climate change.