Tough to ink deal as sea levels inch up

Michael Richardson, Straits Times 16 Nov 09;

NEGOTIATIONS on a new treaty to curb climate change are proving difficult. After two years of talks, the best outcome from the high-level meeting to be convened by the United Nations in Copenhagen next month is now expected to be... more talks, stretching through next year.

Does history tell us that the nations of the world should hasten to conclude a deal?

When British explorer James Cook ventured far south of Australia in his sailing ship in 1773 to search for a fabled southern continent, he was driven back by icebergs and storms.

He wrote that if others went farther, they would find 'a land doomed by nature... to lie for ever buried under everlasting ice and snow'.

On the opposite side of the globe from Antarctica (eventually discovered in 1820), vast sheets of ice up to 80m thick covered the Arctic Sea. For centuries, they blocked the path of ships seeking a short cut between Asia and Europe.

Global warming in the modern era has had a major impact on the ice caps in both the antipodes. Earlier this year, two German freighters successfully navigated their way through the Arctic, from South Korea to their home port in Europe, without the aid of icebreakers.

An increasing number of experts say that the North Pole will be completely ice free in summer by 2030, for the first time in a million years.

This may be good for shipping, trade and the exploitation of oil, natural gas and minerals in the region. But what about the health of the planet and the people who crowd its land?

The Arctic is warming several times faster than most other places on earth, for as the ice melts ever larger expanses of darker sea water are exposed. While ice reflects the sun's rays, the water absorbs them, thus warming more quickly and melting more ice.

The latest scientific research indicates that warming at both poles is intensifying, although the North polar region is less stable than the South polar zone.

While both are far from Asia, the melting of ice sheets on land - in Antarctica, Greenland - would raise sea levels around the world. A report last week by the World Wide Fund for Nature warned that Asia, with hundreds of millions of people living in low-lying areas close to the sea, was among the regions most vulnerable to climate change.

Since Arctic Ocean ice floats on water, its melting does not directly add to sea level rise. However, the radiator effect, from above and below the shrinking Arctic ice, has spread to the ice sheet on nearby Greenland, which contains enough water to lift the global sea level by 7m.

Satellite sensors can measure changes in the mass of ice over large areas in both Greenland and Antarctica. A team of scientists from Britain, the Netherlands and the United States reported last week that the melting of the Greenland ice sheet accelerated rapidly from 2000 to last year, as about 1,500 billion metric tonnes of water flowed into the sea.

The scientific panel advising the UN on climate change estimated in 2007 that world sea levels had risen 17cm in the past century and could rise by as much as another 59cm by 2100, mainly as a result of water expanding as it warmed. It said more research was needed to assess the possible contribution of ice sheet melting.

The British, Dutch and US team concluded that melting Greenland ice was currently raising the sea level by about 0.75mm a year. This would amount to 7.5cm if continued for 100 years.

The stability of the Antarctic ice sheet is of even greater concern than Greenland because the former contains enough water to raise sea levels by 58m, with the most fragile section in West Antarctica contributing up to 6m.

Much of the Antarctic ice sheet and the rock on which it rests are below sea level. The ice is therefore affected by rising temperatures in both the surrounding air and water.

New Zealand scientists reported last week that massive ice shelves were protecting the frozen southern continent from warming waters. The shelves are extensions of ice sheets that float on the ocean. They ring about half of the Antarctic coastline.

However, the New Zealand group cautioned that this buffer might not last. About 10 ice shelves have collapsed on the Antarctic Peninsula, the most rapidly warming part of the continent, in the past 50 years, and some scientists say the disintegration rate is increasing.

Among the most pessimistic scientists is Professor Stefan Rahmstorf, of Germany's Potsdam Institute for Climate Impact Research. He expects sea levels to rise by about 1m this century. 'The crux of the sea level issue is that it starts very slowly, but once it gets going, it is practically unstoppable,' he added.

For officials negotiating an accord on stopping global climate change, this is a devil of a problem. Their scientific advisers cannot accurately predict the rate of sea level rise. It may be gathering pace but the rise seems as yet small - unless you are living on an atoll in the Pacific or Indian oceans.

Will the present generation of taxpayers happily pay for potential future damage that is so difficult to assess?

The writer is a visiting senior research fellow at the Institute of Southeast Asian Studies.