Global cities under multiple climate hazards

Source abstract

Abstract Cities concentrate population, infrastructure, and economic assets, yet climate risk studies are still largely conducted at regional or national scales. We provide the first global city-scale assessment of climate change emergence and coastal flood exposure across ~11,000 urban areas, distinguishing four city typologies. Using the policy-relevant CORDEX-CORE ensemble of high-resolution regional models, we analyse projected climatic hazards. We show that many cities experience stronger changes than the surrounding regional average and we quantify when projected climate signals emerge from historical variability under high- and low- emission scenarios. Heat extremes have already emerged in most cities, while by 2050 all analyzed hazards will emerge everywhere. Mitigation delays emergence, with heterogeneous benefits across city typologies and continents. Coastal flood exposure is strongly shaped by socio-economic gradients, and flood protection reduces wealth-dependent disparities. These findings highlight the need to move beyond a megacity-centric view of climate risk and include small and intermediate coastal cities in global adaptation planning.