Overview
- The Nature study reconstructs Holocene sea levels and finds an average global rise of about 1.5 millimeters per year since 1900, the fastest multi-centennial rate in roughly four millennia.
- Scientists attribute the modern surge primarily to ocean warming that expands seawater, with additional volume from melting glaciers and ice sheets.
- China’s coastal cities face a compounded hazard because deltas naturally compact while human activities accelerate sinking, with at least 94% of rapid urban subsidence assessed as anthropogenic.
- Parts of Shanghai subsided by more than one meter in the 20th century due to excessive groundwater use, though regulation and aquifer reinjection have slowed the city’s sinking.
- The team analyzed subsidence across about 20 coastal cities and produced maps to guide planning, warning that heightened flood risk threatens large populations, key manufacturing hubs and global supply chains.