Future Mediterranean summer drying across models: opposing dynamic and thermodynamic constraints

Mediterranean summers are projected to become drier under global warming, with a large inter-model spread. However, models with stronger global-mean warming produce little additional drying. Using Coupled Model Intercomparison Project Phase 6 simulations, we show that this muted sensitivity arises because thermodynamically driven drying is offset by dynamically induced wetting. Changes in vertical motion linked to dynamic response dominate the drying uncertainty, controlled by two independent sea surface temperature patterns: enhanced warming over the subpolar North Atlantic and over the equatorial eastern Pacific for a given level of global warming, with the former intensifying as warming increases. These warming patterns influencing vertical motion are mediated by dry enthalpy advection, whereby subpolar North Atlantic warming exerts a stronger upper-tropospheric temperature-induced effect, while eastern Pacific warming primarily affects the mid-to-lower troposphere through zonal-wind anomalies. These findings clarify why models diverge under identical greenhouse-gas forcing and highlight the central role of warming patterns.