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Global sea levels are rising at unprecedented rates, driven primarily by thermal ocean expansion and melting glaciers

While Western hubs such as Miami and New York face staggering financial infrastructure risks valued between $2 trillion and $3.5 trillion, the defining vulnerability in South Asia is mass human displacement. Representational pic/PTI
Millions of residents in Kolkata and Mumbai are facing an immediate risk of permanent displacement and home loss due to accelerating global sea-level rise.
A United Nations report titled Challenges Related to Sea Level Rise and Ways and Approaches to Address It, presented by UN leadership, warns that rising ocean levels are no longer a distant environmental concern but an ongoing systemic crisis already damaging critical coastal infrastructure, transport networks, energy grids, and freshwater aquifers.
Over 14 Million Displaced Across South Asian Deltas
The report highlights a sharp regional contrast in how rising seas impact global metropolitan areas. While Western hubs such as Miami and New York face staggering financial infrastructure risks valued between $2 trillion and $3.5 trillion, the defining vulnerability in South Asia is mass human displacement.
In low-lying delta regions encompassing Kolkata, Mumbai, and Dhaka, more than 14 million people live under direct threat of losing their homes to permanent inundation.
Accelerating Sea-Level Metrics and Land Subsidence
Global sea levels are rising at unprecedented rates, driven primarily by thermal ocean expansion and melting glaciers. Key data points flagged by the UN include:
- Record Sea-Level Rise: Global mean sea levels rose by an average of 4.7 mm annually between 2014 and 2023, surging to a record 5.9 mm in 2024 alone due to exceptional ocean warming.
- Extreme Population Exposure: Globally, nearly 770 million people—roughly 10% of the world’s population—reside in coastal zones less than five metres above the high-tide line.
- Compounding Land Subsidence: The interplay between rising sea waters and urban land subsidence is worsening coastal erosion, destroying natural habitats, and contaminating drinking water wells through saltwater intrusion.
Threat Multiplier for Health and Infrastructure
Beyond physical habitat loss, the report underscores that rising seas act as a severe threat multiplier for public health. Severe flooding damages sanitation and medical infrastructure, increasing exposure to water-borne diseases, causing physical injuries, and creating acute mental health stress for displaced communities.
The United Nations has urged coastal nations to integrate long-term adaptation planning, predictable climate financing, and robust legal frameworks to safeguard vulnerable urban populations before permanent inundation forces unmanageable crisis-level relocations.
Quick Answers
Alongside Kolkata and Mumbai, the city of Dhaka faces similar immediate risks of permanent home loss and human displacement from rising sea levels. Additionally, other coastal cities such as New York, Boston, and Miami are projected to face increasingly severe flooding risks by 2050.
About the Author

Pathikrit Sen Gupta is a Senior Associate Editor with News18.com and likes to cut a long story short. He writes sporadically on Politics, Sports, Global Affairs, Space, Entertainment, And Food. He tra…Read More
September 02, 2026, 02:43 IST
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