Amplifying population exposure of extreme precipitation across Yellow River Basin, China at 1.5° C, 2.0° C and 3.0° C global warming

Intensified extreme precipitation events are expected in a warming climate, yet the specific impacts of such events at 1.5 degrees C, 2.0 degrees C, and 3.0 degrees C global warming levels on socioeconomic factors in the Yellow River Basin (YRB), China, remain unclear. This study investigates population exposure (PE) to extreme precipitation under these warming scenarios using downscaled and bias-corrected outputs from the latest Coupled Model Intercomparison Project phase 6 (CMIP6) and population data aligned with shared socioeconomic pathways (SSPs). Our findings indicate that while extreme precipitation is concentrated in the upper YRB, the population exposure in these areas is relatively low. In contrast, under 3.0 degrees C global warming, the lower YRB experiences a PE that is 7.57 and 3.11 times higher than under 1.5 degrees C and 2.0 degrees C warming, respectively. The total change in population exposure (PETC), primarily influenced by the population change effect (PCE), shows a significant decrease, estimated at -234 people/km(2) at the 3.0 degrees C warming level, due to migration or population decline mitigating the hazards of extreme precipitation. The climate change effect (CCE) is identified as the primary driver of PETC across the YRB. These results suggest that limiting global warming to between 1.5 degrees C and 2.0 degrees C could significantly reduce the PETC for extreme precipitation events in the YRB.