Major cities worldwide are sinking, satellite data reveal

AI Summary

A satellite-data assessment finds that major cities around the world are experiencing land subsidence, or gradual ground sinking. Subsidence can damage buildings and infrastructure, disrupt drainage, and heighten flood risks, giving policymakers a basis to identify places where intervention may be urgent.

Land subsidence is the gradual sinking of the ground, which can damage buildings, foundations, and drainage and sewage systems, and may increase flood risks. However, information on land subsidence dynamics remains limited, which makes it difficult for policymakers to identify where risks are intensifying and where urgent intervention may be needed. Previous assessments have often used different methods or time periods, or focused only on small numbers of cities, which has made global comparisons difficult.