Climate change

Sea levels are rising: These are the cities in danger of sinking due to climate change and overpopulated areas

Scientists say millions of people face a double threat as oceans rise while the ground beneath many of the world’s largest coastal cities continues to sink.

Calum Roche

Managing Editor AS USA

Sports-lover turned journalist, born and bred in Scotland, with a passion for football (soccer). He’s also a keen follower of NFL, NBA, golf and tennis, among others, and always has an eye on the latest in science, tech and current affairs. As Managing Editor at AS USA, uses background in operations and marketing to drive improvements for reader satisfaction.

Update: Jul 13th, 2026 04:55 EDT

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Sea level rise is usually blamed on climate change. And that’s true – but it’s only half the story.

A new international study has found that millions of people living along the world’s coastlines are seeing the ocean creep closer much faster than expected because the land beneath them is also sinking. Put the two together and the result is a much bigger problem than rising seas alone.

Researchers calculate that coastal communities are currently experiencing relative sea level rise of around 0.24 inches (6 millimeters) per year on average, roughly double the rate of climate-driven ocean rise by itself. In other words, for many cities, what happens below ground is now almost as important as what happens in the water.

Why are some coastal cities sinking?

The culprit isn’t always nature.

The study found that much of today’s land subsidence is linked to human activity. Pumping huge amounts of groundwater, extracting oil and natural gas, draining wetlands and simply building on soft coastal sediments all cause the ground to gradually compact and sink.

That’s why the problem is most severe in heavily populated coastal regions. Researchers estimate that 71% of the world’s coastal population now lives in areas where the land is subsiding, increasing the risk of flooding, storm surges and long-term coastal damage.

By analyzing satellite observations of Java Island, Indonesia, researchers found that sinking land will drive up to 85% of relative sea-level rise along Java's coast by 2050, outpacing the effects of global ocean rise.

Learn more in @ScienceAdvances: https://t.co/gvMlVCNCvO pic.twitter.com/706MSUDbSx
— Science Magazine (@ScienceMagazine) May 3, 2026

Which cities are sinking the fastest?

Several of the world’s largest cities stand out as major hotspots. The researchers highlight:

Jakarta, Indonesia
Tianjin, China
Bangkok, Thailand
Lagos, Nigeria
Alexandria, Egypt

Most are built on river deltas or low-lying coastal plains, where decades of groundwater extraction have accelerated subsidence. In Jakarta, some neighborhoods are sinking at more than 1.6 inches (42 millimeters) per year, although the rate varies considerably across the city.

The study also points to some of the world’s biggest river deltas – including the Mekong, Nile, Yangtze and Ganges-Brahmaputra – as places where millions of people face an increasing combination of sinking land and rising seas.

In California’s San Joaquin Valley, this pole shows how far the ground had sunk by 1977.

The markers show the approximate land surface in 1925, 1955, and 1977 — a drop of about 9 meters / 30 feet in just 52 years. The cause was not an earthquake, but decades of groundwater… pic.twitter.com/MhPxOrSgrD
— Things From the Past (@pastarchive) July 8, 2026

How does this affect the United States?

Americans aren’t exempt from the trend.

The researchers found that coastal populations in the United States experience average relative sea level rise of around 0.16 to 0.20 inches (4-5 millimeters) per year, higher than climate-driven sea level rise alone because some populated coastal regions are also subsiding. The Gulf Coast is among the areas where this issue is particularly important, although local conditions vary widely around the country.

The findings also underline that national averages only tell part of the story. Some neighborhoods are stable, while others are sinking fast enough to noticeably increase flood risk over just a few decades.

Can cities slow the problem down?

Unlike climate change, given where we are, subsidence isn’t always unavoidable.

Scientists say better groundwater management, limiting excessive pumping and improving monitoring of land movement could help slow sinking in many vulnerable cities. That wouldn’t stop global sea levels from rising, but it could buy valuable time for communities already on the front line.

The message from the study is simple: for many of the world’s biggest coastal cities, adapting to sea level rise isn’t just about watching the ocean. It’s also about paying attention to the ground beneath their feet.