Ice cap meltdown warning

By SIMON COLLINS, science reporter

A New Zealand scientist who has discovered a gaping crack in an Arctic ice shelf believes that the whole northern ice cap could melt within 70 years.

Dr Warwick Vincent, an Auckland-born expert on lakes who is now a professor at Laval University in Quebec City, Canada, has been overwhelmed by media calls since he announced on Tuesday that the Ward Hunt ice shelf at the northern tip of North America was breaking up.

"I've had calls from Singapore to Los Angeles to London and Paris," he said yesterday. "It's really a phenomenon that people are concerned about climate change."

Dr Vincent, 50, left New Zealand in 1990 just before the closure of his Taupo laboratory run by the former Department of Scientific and Industrial Research (DSIR).

He still contributes to nutrient enrichment studies in Lake Taupo by the DSIR's successor, the National Institute of Water and Atmospheric Research (Niwa).

But his main research is now on lakes and rivers in Canada's far north, including the Disraeli Fiord, the mouth of which has been blocked for the past 3000 years by the Ward Hunt ice shelf along the north coast of Ellesmere Island, 4000km north of Quebec City.

As recently as 1967, fresh water from surrounding snow and ice formed the top 43 metres above deeper seawater in the 400-metre-deep fiord, indicating that the ice shelf at the fiord's mouth was also about 43 metres deep.

Careful measurements since then, taken annually by Dr Vincent's team in the past few years, have shown a gradual shrinkage of fresh water to 28 metres by 1999 and just three metres last year - suggesting that the ice shelf was melting.

In the past four years, the ice has cracked. A major north-south break is 80 metres wide at the mouth of the fiord, and has almost drained its fresh water.

"The very unusual ecosystem of Disraeli Fiord has now been lost," Dr Vincent said.

The remaining 443sq km of the Ward Hunt ice shelf are the last remnant of ice that once extended along the whole north coast of Ellesmere Island.

Since 1967, the average temperature in the area has risen by 0.4C a decade, thinning the 1m to 3.5m thick layer of pack ice which floats in the Arctic Ocean north of the continental shelf.

Parts of northern Russia and Alaska are warming even faster, and Dr Vincent said the average of a range of forecasts suggested a further 5C warming by 2070.

"That would be enough to melt the Arctic ice cap," he said.

"The Arctic Ocean connects as part of the global conveyor belt, producing that cold water that flows southwards and maintains the return flow that keeps Europe nice and warm.

"So there is a great deal of concern about what the impacts of that warming might be."

He said the melting of the ice cap would not affect global sea level, because the pack ice is already floating in water.

However, the world's oceans would rise by 6m to 7m if the massive continental ice shelf over Greenland melted.

Dr Vincent has kept close links with New Zealand, and holds Canadian and NZ citizenships.

But he is "pretty much committed" to staying in Canada."I have spent a lot of time and energy building up a research group here."

His wife, Connie Lovejoy, is an American oceanographer.

His son Aaron, 19, who was born in Rotorua, "speaks English with a Kiwi accent and French with a Quebecois accent".

Dr Vincent is enthusiastic about Canada's new policy of increasing its research spending from 15th largest in the world to among the top five countries in the next 10 years.

"Things are really taking off," he said. "There is a major effort to implement new programmes, new infrastructure, new facilities for universities, and to increase the critical mass of research and technology in this country in a way that I hope New Zealand can emulate."

Warming in the Arctic

Since 1967: A 0.4C rise each decade, thinning pack ice in the Arctic Ocean.

By 2070: Forecasts suggest a further 5C, which would melt the Arctic ice cap.