Anthropogenic Influence on Temperature and Precipitation Trends in the Western Mediterranean: A Multi-Method Approach

The Western Mediterranean (WMed) is one of the regions most affected by climate change, where the interplay between anthropogenic forcings and strong natural variability produces complex spatial and seasonal patterns of change. This study analyses the anthropogenic imprint on 1951–2020 seasonal temperature and precipitation trends across climate-derived sub-regions of the WMed using multiple detection and attribution methods. A performance-based filtering of CMIP6 models was implemented to ensure an adequate representation of observed regional trends prior to attribution analyses. Detection and attribution were assessed using CMIP6 DAMIP single-forcing experiments through the Signal-to-Noise Ratio (SNR), the Fraction of Attributable Risk (FAR), and a statistical optimal fingerprinting method. Results reveal a robust anthropogenic imprint on temperature, with the amplitude of forced signals exceeding twice that of internal variability across all sub-regions. Greenhouse gas forcing emerges as the dominant driver of warming in both summer and winter, while anthropogenic aerosols exert a cooling effect that partially offsets greenhouse gas–induced warming. In contrast, precipitation trends remain within the bounds of internal variability, although detectable drying signals associated with greenhouse gas forcing appear over northern Africa and the southwestern Iberian Peninsula in winter. In summer, precipitation trends show contrasting responses to greenhouse gas and aerosol forcings. These findings highlight the value of regional-scale attribution frameworks and model performance filtering for reducing uncertainty in Mediterranean climate analyses, providing a basis for further attribution studies in this highly vulnerable region.