Due to its intrinsic exposure to the climate, agriculture is one of the economic sectors most directly affected by climate change. Although long-term average precipitation in Switzerland is sufficient to ensure crop production, summer drought is increasingly posing problems to the agricultural sector, as evidenced by the drought events of 2003, 2011, 2015, 2018, 2020, 2022 and again 2023. It is therefore not surprising that insurance companies in Switzerland and other European countries have added coverage to drought-induced crop yield losses to their product portfolio. However, defining viable insurance strategies for the future, from both an agronomic and economic perspective, depends on knowing the potential level of losses. In this study, we assessed how climate change is likely to impact the yields of summer crops (maize and potatoes) in the four most important cropland regions in in Switzerland. Our analysis is based on the current Swiss climate scenarios (CH2018) targeting the mid-century (2050-2070) and the end of the century (2089-2099). It focuses on a representative concentration pathway (RCP) that does not envisage mitigation measures (RCP 8.5) and considers only one of the most extreme scenarios within the ensemble of available model chains. In this extreme scenario, the summer period presents a drastically negative climatic water balance (‑500 mm by the end of the century), and mean dry spell duration increasing in duration by around 50%. In the Western Plateau, these conditions entail a factor-of-two yield reduction in 60% of the years for maize and in 30% of the years for potatoes. Results further indicate that yield stability is likely to substantially decrease for both crops, as indicated by an increase in the coefficient of variation by a factor of more than two. In general, our findings stress the importance of summer crops as target of future drought-related insurance products.
