Overview

• A Rutgers-led analysis finds coastal areas near Shanghai, Shenzhen and Hong Kong have sharply subsided over the past century due to extensive groundwater extraction.
• The team reports local sea level in the region began rising about 1.5 mm per year in the early 1900s after roughly 4,000 years of stability.
• Parts of Shanghai sank by more than one meter during the 20th century, with local authorities now taking steps that researchers say are slowing the subsidence.
• A separate McGill study estimates that under an extreme 20 meter sea-level rise scenario, 136 million of 840 million mapped buildings would be affected, with high exposure in Africa, Southeast Asia, and the Americas.
• UN experts project a 30–50 cm global rise this century, while some scientists caution it could be several times higher, and McGill’s Eric Galbraith says the consequences will reach far beyond oceanfront communities.