Journal Article

Coastal flooding will disproportionately impact people on river deltas

Siani, Sacha M. O., Caldwell, Rebecca L., Edmonds, Douglas A., Brondizio, Eduardo S.

2020

Overview

Climate change is intensifying tropical cyclones, accelerating sea-level rise, and increasing coastal flooding. River deltas are especially vulnerable to flooding because of their low elevations and densely populated cities. Yet, we do not know how many people live on deltas and their exposure to flooding. Using a new global dataset, we show that 339 million people lived on river deltas in 2017 and 89% of those people live in the same latitudinal zone as most tropical cyclone activity. We calculate that 41% (31 million) of the global population exposed to tropical cyclone flooding live on deltas, with 92% (28 million) in developing or least developed economies. Furthermore, 80% (25 million) live on sediment-starved deltas, which cannot naturally mitigate flooding through sediment deposition. Given that coastal flooding will only worsen, we must reframe this problem as one that will disproportionately impact people on river deltas, particularly in developing and least-developed economies. Coastal river delta regions are particularly impacted by the effects of climate change, yet though these regions are densely inhabited, robust estimates of population are lacking. Here the authors use global datasets to predict the number of people and regions most threatened by flooding and extreme weather.

• Publisher: Nature Publishing Group UK,Nature Portfolio
• Subject: 704/172 / 704/2151/215 / 704/844 / Humanities and Social Sciences / multidisciplinary / open climate campaign / Science / Science (multidisciplinary)