Sea levels to surge 'at least a metre' by century end

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(Agencies)
Updated: 2009-03-11 09:07

COPENHAGEN – Months before make-or-break climate negotiations, a conclave of scientists warned Tuesday that the impact of global warming was accelerating beyond a forecast made by UN experts two years ago.

Icebergs break off the Vatnajökull Glacier before floating to sea in 2006. [Agencies]

Sea levels this century may rise several times higher than predictions made in 2007 that form the scientific foundation for policymakers today, the meeting heard.

In March 2007, the UN's Intergovernmental Panel on Climate Change (IPCC) concluded that global warming, if unchecked, would lead to a devastating amalgam of floods, drought, disease and extreme weather by the century end.

The world's oceans would creep up 18 to 59 centimetres (7 to 23 inches), enough to wipe out several small island nations, and wreak havoc for tens of millions living in low-lying deltas in east Asia, the Indian subcontinent and Africa.

But a new study, presented at the Copenhagen meeting on Tuesday, factored in likely water runoff from disintegrating glaciers in Greenland and Antarctica, and found the rise could be much higher.

The IPCC estimate had been based largely on the expansion of oceans from higher temperatures, rather than meltwater and the impact of glaciers tumbling into the sea.

Using the new model, "we get a range of sea level rise by 2100 between 75 and 190 centimetres when we apply the IPCC's temperature scenarios for the future," said climate expert Stefan Rahmstorf of the Potsdam Institute for Climate Impact Research.

Even if the world manages to dramatically cut the emission of greenhouse gases driving global warming, the "best estimate" is about one metre (3.25 feet), he said.

"A few years ago, those of us who talked about the impact of the ice sheets were seen as extremists. Today it is recognized as the central issue," said glaciologist Eric Rignot of the University of California at Irvine.

"The world has very little time," IPCC chief Rajendra Pachauri told the meeting after the new findings were presented.

Participants also spoke out about fears that greenhouse gases -- mainly emissions from oil, gas and coal -- could trigger tipping points that would be nearly impossible to reverse.

The shrinking of the Arctic ice cap, and the release of billions of tonnes of greenhouse gases trapped in melting permafrost are two such "positive feedbacks" that could become both cause and consequence of global warming.

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