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300 million people at risk of rising seas: Study

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New research reveals far more people vulnerable as scientists warn climate change can reshape cities

PARIS : Coastal areas home to 300 million people will be, by 2050, vulnerable to flooding made worse by climate change, no matter how aggressively humanity curbs carbon emissions, scientists said.

By mid-century and beyond, choices made today will determine whether the coastlines remain recognisable to future generations, they reported in the journal Nature Communications.

Destructive storm surges fuelled by increasingly powerful cyclones and rising seas will hit Asia hardest, said the study.

More than two-thirds of the populations at risk are in China, Bangladesh, India, Vietnam, Indonesia and Thailand.

Using artificial intelligence, the new research corrects ground elevation data that has up to now vastly underestimated the extent to which coastal zones are subject to flooding during high tide or major storms.

"Sea level projections have not changed," co-author Ben Strauss, chief scientist and chief executive of Climate Central, a US-based non-profit research group said. "But when we use our new elevation data, we find far more people living in vulnerable areas than we previously understood."


With the global population set to increase two billion by 2050 and another billion by 2100, even greater numbers of people will be forced to adapt or move out of harm's way.

There are already more than 100 million people living below high tide levels, the study found.

Some are protected by dykes and levees, most are not.

"Climate change has the potential to reshape cities, economies, coastlines and entire global regions within our lifetime," said lead author and Climate Central scientist Scott Kulp.

"As the tideline rises higher than the ground... nations will increasingly confront questions about whether, how much and how long coastal defences can protect them."

Several factors conspire to threaten populations.

One is the expansion of water as it warms and, more recently, ice sheets atop Greenland and Antarctica that have shed more than 430 billion tonnes a year over the last decade.

Since 2006, the waterline has gone up nearly four millimetres a year, a pace that could increase 100-fold going into the 22nd century if carbon emissions continue unabated, the UN Intergovernmental Panel on Climate Change (IPCC) warned in a major report last month.

If global warming is capped below 2 deg C - the cornerstone goal of the Paris climate treaty - sea level is projected to rise about 50cm by 2100. At current rates of carbon pollution, the rise would be nearly twice as much.

A second ingredient is tropical storms amplified by a warming atmosphere.

"It doesn't take a big rise in sea level to lead to catastrophic problems," said Professor Bruce Glavovic from Massey University in New Zealand, who was not involved in the study.

Major storms that until recently occurred once a century will, by 2050, happen on average once a year in many places, especially in the tropics, the IPCC report found.- AFP