Emerging climate constraints for olive cultivation in Europe under CMIP6 projections

Olive cultivation is key to European agriculture and cultural landscapes, yet it is increasingly at risk due to climate change. Despite existing research on climate impacts on olive trees, it remains unclear how future climate conditions will alter the frequency of agroclimatic threshold events associated with major olive stressors across Europe. In this research, we translated daily downscaled CMIP6 multi-model data into four threshold-based agroclimatic indicators for European olive groves. These indicators were calculated for a historical period (1984-2014) and two future periods (Near-Term Future, 2020-2050; Long-Term Future, 2070-2100) under a “stress-test” scenario (SSP5-8.5): Hot Dry Days (HDD), Frost Days (FTD), Chill Days (CHD), and Warm Humid Days (WHD; a climatic suitability proxy for the olive fruit fly). Results show a strong increase in HDD (from an average of 9.6 days in the historical period to 24.6 and 70.5 days in the near- and long-term future, respectively), indicating increasing exposure to hot and rain-free conditions during summer. FTD decreases together with CHD, indicating warmer dormancy conditions and emerging chilling limitations. WHD generally decreases with spatially heterogeneous trends, suggesting reduced climatic suitability for the olive fruit fly, though not a direct pest-pressure metric. Overall, European olive groves face a complex pattern of agroclimatic exposure that varies across countries. This mapping provides a reproducible, pan-European screening to identify areas where adaptation assessments may be prioritised.