Honigeinlagerung

Yield stability is critical to farm income and food security. The impact of future climate change on crop yields and yield stability was assessed for Swiss croplands, focusing on four key regions: Eastern Jura, Western Plateau, Central Plateau, and Northeastern Plateau. Projections for eight different crops were performed using the process-based model DayCent and downscaled climate scenarios for Switzerland (CH2018 framework), using outputs of 12 climate models for the scenario without mitigation measures (RCP 8.5) and for the scenario with stringent mitigation (RCP 2.6). Change in yield stability was gauged by means of relative change in the standard deviation (SD) of inter-annual yield fluctuations between 1981–2010 (reference) and 2045–2074 (mid-century). The average yields of most crops tend to increase as a result of warming and elevated CO2 levels, particularly under the RCP 8.5, although associated with a considerable divergence within the ensemble of climate models. On the other hand, a substantial increase in yield variability, i.e. decline in yield stability, is consistently projected for all summer crops under the RCP 8.5, with changes that are higher in magnitude than for cereal winter crops. The Central Plateau is projected to experience the greatest decline in yield stability for summer crops, with SD under RCP 8.5 increasing by over 50 % for maize, 40 % for potatoes, 60 % for soybean and 25 % for sugar beet. Elevated CO₂ levels tend to overall alleviate this negative impact, especially for maize, for which the projected increase in SD in Central Plateau lessens from 50 % to 20 %. Overall, our results emphasize the contrast between summer and cereal winter crops in terms of yield stability, which can guide future strategies for adapting cropping systems to climate change.