Far more people at risk of rising seas than feared - climate study

  • Far more people at risk of rising seas than feared - climate study

Far more people at risk of rising seas than feared - climate study

Bangladesh and China will be the worst affected with about 93 and 42 million people respectively getting impacted in the coastal flooding by 2050, as per the new data. Even with sharp, immediate cuts to carbon emissions, it could rise another 0.5 m this century.

The study, which found that today's dykes, sea walls and levees already allow 110 million people to live below the high tide line, did not factor in the impact of these or possible future defences, the authors said, citing a lack of data.

The paper's authors - New Jersey-based nonprofit Climate Central's Scott A Kulp and Benjamin H Strauss - developed a more accurate method of estimating the effects of sea level rise, and found that about 150 million people are now living on land that may be below the high-tide line by midcentury.

Earlier estimates had put that figure at about 80 million.

Among the coastal cities that are under threat is India's financial capital Mumbai.

"In the decades ahead, sea-level rise could disrupt economies and trigger humanitarian crises around the world", Climate Central said. That means the method can overestimate elevation levels in places like forests or cities.

Strauss and computational scientist Scott Kulp used a computer algorithm to fine-tune NASA's elevation estimates to account for trees, bridges and other structures. 250 million people live on land below current annual flood levels - compared to the 65 million previously thought.

By 2100, if emissions continue unchecked, and ice sheets rapidly disintegrate, then land where 250 million people now live in those six countries will fall below the waterline at high tide - putting nearly five times more people at risk than assessments based on previous elevation data had found.

"These assessments show the potential of climate change to reshape cities, economies, coastlines, and entire global regions within our lifetimes", said Dr. Kulp in a statement.

As the tideline rises higher than the ground people call home, nations will increasingly confront questions about whether, how much, and how long coastal defence can protect them, he added.

And the new report is still on the optimistic side - it assumes countries meet the deadline for emissions cuts outlined in the Paris agreement.

"The results indicate that, yes, a great deal more people are on vulnerable land than we thought", said Benjamin Strauss, one of the study's co-authors and CEO of non-profit organization Climate Central. "Our data improve the picture, but there is still a great need for governments and aerospace companies to produce and release more accurate elevation data".