Environment: Global river delta population reveals flooding vulnerability

339 million people globally were living on river deltas in 2017, reports a study published in Nature Communications. Of this total, 89% live on deltas found in the same latitudinal zone as most tropical cyclone activity. Given that coastal flooding is likely to worsen in the future, the paper concludes that flooding will disproportionately impact people living on river deltas, especially in developing and least-developed economies.

River deltas are particularly vulnerable to coastal flooding owing to their low elevations. In addition, events, such as tropical cyclones, are predicted to become more intense by the end of the century. However, the number of people living in these areas and their vulnerability to flooding is unknown, which hampers planning to mitigate these hazards.

Douglas Edmonds and colleagues developed a global dataset of 2,174 delta areas to determine the number of people living in these regions and their vulnerability to flooding hazards. The authors found that there were 339 million people living on these areas in 2017 of which 329 million were living in developing or least-developed economies. Of the projected 76 million people globally thought to be living in areas exposed to flooding as a result tropical cyclones, the authors’ analysis suggests that 41% (31 million) live on river deltas. Of this, 28 million people (92%) live in developing or least-developed economies, which lack the infrastructure needed for hazard mitigation.