The vulnerability of European agricultural areas to anthesis heat stress increases with climate change

Climate change poses a significant threat to agriculture, primarily through yield losses due to droughts and heatwaves. The flowering phase is a particularly critical period during which many crops are highly susceptible to heat, resulting in longterm damage and substantial yield reduction. By imposing the large-scale atmospheric circulation of the 2018 to 2022 heatwaves in a CMIP6 model, we explore the potential impact of such a multi-year event within future climate scenarios as a storyline. We developed a heat stress index to quantify the amount of stress experienced by crops due to heat exposure during flowering relative to unstressed conditions. This index was then applied to the storylines over the European domain and evaluated for major cereal crops (maize and wheat). Extrapolating 2022 conditions to a scenario with global warming of +4 K, we show that over 30% of the harvested area would experience severe heat stress, resulting in a 10% yield reduction across Europe. Our investigations highlight that the timing and severity of a heatwave can have a much higher impact than the mean warming level, emphasizing the need for accurate seasonal forecasts. ... mehrAddressing these challenges will require proactive management adaptations, including dynamic forecast-based decisions on planting dates, crop, and variety selection.