Major coastal cities around the world could disappear under rising seas by 2100
The idea of entire cities sinking beneath the waves might seem like science fiction. Yet, recent research on rising sea levels suggests that this scenario could become reality within the next 75 years.
A study from Nanyang Technological University (NTU) in Singapore predicts that global sea levels could rise by as much as 6.2 feet (1.9 meters) by 2100 if carbon emissions continue to climb.
Such a drastic increase would have catastrophic consequences for coastal cities worldwide, leaving millions displaced and vast regions uninhabitable.
“The high-end projection of 1.9 meters [6.2 feet] underscores the need for decision-makers to plan for critical infrastructure accordingly,” said Dr. Benjamin Grandey, lead author of the study.
“More importantly, these results emphasize the importance of climate mitigation through reducing greenhouse gas emissions,” he warned.
If these projections come true, countless coastal towns and major cities could be submerged underwater. The impact would be felt across all continents, from the United Kingdom and Europe to the United States and beyond.
Rising sea level projections
Projections of sea-level rise depend on complex climate models that factor in various processes. Some projections focus on well-documented trends, such as the melting of glaciers.
Others incorporate less predictable events, such as the sudden collapse of ice shelves. The combination of these different elements results in a wide range of possible outcomes.
The Intergovernmental Panel on Climate Change (IPCC) addressed this uncertainty in its 2023 Sixth Assessment Report. Under high-emission scenarios, the IPCC estimated global sea levels would rise between 1.9 and 3.2 feet (0.6 and 1.0 meters).
However, researchers at NTU argue that existing models often fail to provide a clear picture. They have developed a “fusion” approach that combines statistical methods with expert opinions to refine sea level predictions.
“Our new approach tackles a key issue in sea-level science: different methods of projecting sea-level rise often produce widely varying results,” Dr. Grandey explained.
By integrating multiple approaches, researchers hope to provide a more accurate estimate of what the future holds.
Threat to the United Kingdom
If sea levels rise by 6.2 feet (1.9 meters), vast areas of the United Kingdom will be at risk.
London would be particularly vulnerable, with many neighborhoods along the River Thames facing severe flooding. Areas such as Bermondsey, Greenwich, Battersea, and Chelsea would likely experience catastrophic inundation.
The impact would extend far beyond the capital. The east coast of England is expected to suffer the most, with towns such as Hull, Skegness, and Grimsby facing complete submersion. Even inland locations, including Peterborough and Lincoln, could experience severe flooding.
Climate Central’s Coastal Risk Screening Tool provides a detailed look at which regions will be affected. By setting the water level to 6.2 feet (1.9 meters), users can see which areas are predicted to disappear beneath rising seas. The results paint a grim picture, with entire coastal stretches marked in red.
The west coast of England and Wales would also feel the effects. Low-lying communities such as Weston-super-Mare, Newport, and Cardiff would be heavily impacted. Meanwhile, parts of Southport and Blackpool could also face destruction.
Scotland and Northern Ireland, however, appear to be less affected due to their higher elevations. While some localized flooding may occur, these regions will likely escape the worst of the crisis.
Global perspective on rising seas
The threat of rising seas extends far beyond the U.K. Across Europe, heavily populated coastal areas could vanish.
Climate Central predicts that the entire coastline from Calais in France to southern Denmark could be submerged. The situation in Italy is equally dire, with Venice – that is already battling frequent floods – potentially disappearing beneath the water.
The United States is not immune to the dangers either. Coastal cities in the southern states, including New Orleans, Galveston, and parts of the Florida Everglades, are among the most vulnerable.
With much of New Orleans already sitting below sea level, an increase of 6.2 feet would make it nearly impossible to protect.
Many other regions worldwide would also be at risk. Island nations in the Pacific, such as the Maldives and Tuvalu, could become totally uninhabitable.
Coastal megacities like Jakarta, Bangkok, and Mumbai would face relentless flooding that would threaten the homes and livelihoods of millions.
Can anything be done?
The findings from NTU highlight the urgent need for climate action. The continued rise in carbon dioxide emissions remains the primary driver of global warming and ice melt. Without significant reductions, future generations could witness the submersion of major cities.
“This NTU research represents a significant breakthrough in sea-level science. By estimating the probability of the most extreme outcomes, it underscores the severe impacts of sea-level rise on coastal communities, infrastructure, and ecosystems, emphasising the urgent need to address the climate crisis,” noted Professor Benjamin Horton, Director of the Earth Observatory of Singapore at NTU.
Reducing greenhouse gas emissions is essential, but adaptation strategies must also be considered. Governments must invest in flood defenses, sustainable urban planning, and disaster preparedness.
Without such efforts, the world could soon face an era of climate-driven displacement on an unprecedented scale.
The future of coastal cities depends on immediate action. With each passing year of unchecked emissions, the likelihood of a submerged world grows more certain.
The research study was published in the journal Earth’s Future.
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