Warming climate reshapes China's urban flood-resilience inequality

Global urban flood infrastructure remains critically dependent on obsolete assumptions of climate stationarity, leaving cities fundamentally exposed to evolving climate hazards. By constructing a comprehensive database of urban flood-triggering thresholds derived from crowdsourced data, we systematically assess the baseline flood resilience of 698 Chinese cities. Results reveal that since 2010, intensifying extreme precipitation has caused flood occurrences in the historically arid North to exceed designed structural capacities, surpassing Southern occurrences by 17.2%. Consequently, this nonstationary climate forcing creates severely asymmetric future adaptation costs under high-emission scenarios, leaving Northern cities facing a 49% to 61% surge in required resilience investment. These systemic mismatches dictate a critical transition toward spatially differentiated, forward-looking urban resilience paradigms to guide global climate adaptation strategies.