Increased Risk of Extreme Precipitation Over an Urban Agglomeration With Future Global Warming

Understanding the response of extreme precipitation (EP) at a city scale to global warming is critical to reducing the respective risk of urban flooding. Yet, current knowledge on this issue is limited. Here, focusing on an urban agglomeration in the tropics, Singapore, we reveal that future global warming enhances both frequency and intensity of EP, based on simulations with a state-of-the-art convection-permitting regional climate model. EP intensification can reach maximum super Clausius-Clapeyron rate (>= $\ge $+7% per K warming) rate, implying a new normal of extreme events get more extreme, which is consistently for both Representative Concentration Pathways 8.5 and 4.5. The intensification is lower for moderate and light precipitation. Also, global warming was found to dampen the urban effect on EP events. The EP enhancement is attributed to the increased atmospheric moisture and convective inhibition due to enhanced low-level stratification that delays a convection to develop until it becomes more intense.

Automated summary

In an urban agglomeration in the tropics, Singapore, future global warming is predicted to increase the frequency and intensity of extreme precipitation events. The intensification of extreme precipitation can reach maximum rates, implying that extreme events will become more extreme. However, the increase in intensity is less for moderate and light precipitation. Furthermore, global warming dampens the urban effect on extreme precipitation events.