Pakistan, Bangladesh, Egypt, Thailand, Nigeria and Vietnam are expected to be the most vulnerable. Climate, ice sheets & sea level : the news is not good.

Paris : Parts of Earth's ice sheets that could lift global oceans by metres will likely crumble with another half degree Celsius of warming, and are fragile in ways not previously understood, according to new research.

The risk, which will play out over centuries, may also be greater than expected for a significant portion of the world's population in coastal regions.

New research suggests that the number of people threatened by sea level rise has been underestimated by tens of millions because of poorly interpreted satellite data and lack of scientific resources in developing countries.

Ice sheets in Greenland and Antarctica have shed more than half-a-trillion tonnes annually since 2000 - six icy Olympic pools every second.

These kilometres-thick ice cubes have replaced glacier melt as the single biggest source of sea level rise, which has accelerated three-fold over the last decades compared to most of the 20th century.

A 20 centimetres increase since 1900 has boosted the destructive wallop of ocean storms made more powerful and wide-ranging by global warming, and is driving salt water into populous, low-lying agricultural deltas across Asia and Africa.

Up to now, climate models have underestimated how much ice sheets will add to future sea level rise because they mostly looked at the one-way impact of rising air temperatures on the ice, and not the complicated interaction between atmosphere, oceans, ice sheet and ice shelves.

Looking only at a 200 horizon is misleading, because oceans will continue to rise for hundreds of years no matter how quickly humanity draws down emissions.

The new analysis shows that a given amount of sea level rise - whether 30 or 300 centimetres - will devastate twice the area projected in most models to date.

Remarkably, a misinterpretation of data is mostly to blame : radar measurements of coastal elevations used until recently, it turned out, often mistook tree canopy and rooftops for ground level, adding meters of elevation that were not in fact there.

Most vulnerable will be tens of millions of people in the coastal areas of Bangladesh, Pakistan, Egypt, Thailand, Nigeria and Vietnam. [AFP]


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