WMO Report: Mumbai among cities facing biggest threat as global sea levels rise

Between 2013 and 2022, sea levels rose by 4.5 millimetres (mm) per year on average according to the World Meteorological Organization. The rate of rise between 1901 and 1971 was only one third of this.

India is especially vulnerable to sea level rise because of its 7,516.6 km coastline. Mumbai, India’s financial capital with a population of about 22 million is at high risk because sea level rise threatens coastal farmlands, water reserves and resilience of infrastructures, human lives and livelihoods.

Apart from India, other countries that are most likely to be affected include Bangladesh, Netherlands and China. While the rate of rise has been mounting since the early 20th century, it has been the highest in the last decade.

From 1971-2018, factors that contributed to sea level rise were varied in proportion. But compared to 1992-99, ice losses increased four times in 2010-19.

Human influence was very likely the main driver for the rise since 1971. The global ocean has warmed faster over the past century than since the end of the last deglacial transition (around 11,000 years ago).

Sea-level rise imposes significant risks for small islands, coastal ecosystems, people and infrastructure and will continue to increase beyond 2100. According to the report, rapid and sustained GHG emissions reductions will limit further sea-level rise acceleration and projected long-term sea-level rise.

According to the Intergovernmental Panel on Climate Change, the Earth is currently 1.1°C warmer than it was in the late 1800s. Besides Mumbai, several major, thickly populated cities across the world are also threatened by sea level rise. These include Shanghai, Dhaka, Bangkok, Jakarta, Maputo, Lagos, Cairo, London, Copenhagen, New York, Los Angeles, Buenos Aires and Santiago.