Intensified future regional record-shattering precipitation events from convection-permitting ensemble downscaling

     Recent precipitation extremes have shattered historical records over the Beijing-Tianjin-Hebei (BTH) region, causing devastating losses of life and property. While climate change is expected to increase the probability of precipitation extremes, how the frequency and intensity of rarest events will change remains unclear. Here, we develop an integrated framework combining long-term observations, large-ensemble Earth system simulations, and convection-permitting regional modeling to project the likelihood and magnitude of such “rareness” precipitation events. Using the Community Earth System Model Large Ensemble (CESM2-LE), we find that the likelihood of regional events comparable to the July 2023 BTH extreme precipitation event (“23.7 BTH” event) increase by 159% under the SSP3-7.0 scenario, primarily driven by thermodynamic intensification linked to more frequent moisture-abundant conditions. We further find that the local intensity of the most extreme future storms may increase by approximately 30%, with hourly precipitation rate nearly doubling. Our framework provides a robust pathway to quantify the frequency and magnitude of unprecedented regional extremes, offering critical implications for flood management, hazard mitigation, and climate adaptation planning.