Overview
- ESA Sentinel-1 radar data from 2014 to 2023 mapped vertical land motion at 75-meter resolution across 40 major river deltas.
- Average subsidence outpaces the current global mean sea-level rise in 18 deltas, increasing near-term flood risk for about 236 million people.
- In 38 of 40 deltas more than half the area is sinking, with hotspots such as Thailand’s Chao Phraya, Indonesia’s Brantas, and China’s Yellow River averaging around 8 mm per year.
- Densely populated systems including the Mekong, Nile, Ganges–Brahmaputra, and Mississippi show widespread elevation loss that can dominate relative sea-level rise in the lowest-lying zones.
- Researchers recommend locally actionable steps such as groundwater regulation, managed aquifer recharge, sediment restoration, and land-use controls to reduce risk.