Extreme climate indices calculation

Climate change and the associated extreme climate events (such as drought, heavy precipitation, and heatwaves) present challenges to crop yields and food security. However, the response of crop yields to various extreme climate events, and the future impact of these events on crop yields, has remained unclear. This study aims to identify the significant extreme climate events affecting 11 crop yields at the district level (Landkreis level in Germany), based on historical datasets and an explainable LightGBM prediction model. The model elucidates the contribution of these events to crop yields and identifies their tipping points. Based on these events and their corresponding tipping points, this study projects future risks to crop yields induced by extreme climate events at spatial and temporal scales under multiple carbon emission scenarios from 2025 to 2100. The results of this study demonstrate that high carbon emissions may mitigate the impact of extreme climate events on the yield of crops such as potato, grain maize, rye, winter barley, winter rape, sugarbeet, and silage maize. However, it may amplify the effect of extreme climate events on the yield of triticale, summer barley, and oats. Frost events, minimum temperature, meteorological drought, and consecutive dry days are the dominant extreme events affecting the yields of 11 crops in Germany. This study presents a framework for identifying key extreme climate events and tipping points, projecting risk regions and periods, and offering valuable insights for adaptive agricultural management and precision yield estimation.