Global projections of compound coastal meteorological extremes

Compound coastal and inland flooding can result in catastrophic impacts in densely populated low-lying coastal areas. The dynamics and interactions between the underlying meteorological drivers in view of climate change are not fully understood at global scale. Here, we show that under a high emissions scenario the concurrence probability of extreme meteorological tides and inland precipitation would increase by more than 30% on average along coastlines worldwide by 2100 compared to present. In latitudes above 40 degrees north, compound meteorological extremes would become more than 2.5 times as frequent, while they would happen less frequently in parts of the subtropics. Climate-induced dynamics in precipitation extremes contribute to about 80% of the projected change in concurrence probability, while dynamics in meteorological tides account for 16% and those in the dependence between the two extremes for 4%. Our results indicate that not accounting for these effects in adaptation planning could leave coastal communities insufficiently protected against flooding.