Our melting planet: ominous warning signs in the Arctic

The Age, August 4, 2008

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• http://www.theage.com.au/environment/our-melting-planet-ominous-warning-signs-in-the-arctic-20080803-3pc9.html?page=fullpage#contentSwap1

THE vast Arctic sea ice that spreads across the North Pole could disappear during the summer within five years, leading ice and snow scientists are warning.

The Canadian Coast Guard's strongest icebreaker, the Louis S. St Laurent, (pictured above) took The Age and an ABC 4 Corners crew with a team of scientists going to the Arctic at the beginning of this summer's melt last month to examine first hand the extraordinary changes there.

Only a few years ago, climate modellers predicted the Arctic sea ice would not melt out in summer until at least the end of the century. "Then they said 2070, and then they said 2050 and then they said 2030," said Robie Macdonald, a leading Canadian Arctic scientist on board the Louis.

"Not only do I see the change but it's like they're moving the goal posts toward me and it's an amazing thing."

The team on-board the Louis are some of the thousands of scientists from 60 nations working to draw attention to the rapid changes in the Arctic and Antarctic during International Polar Year. The Louis' route took us through thick sea ice at the entrance to the fabled Northwest Passage where over the centuries navigators perished, most famously Sir John Franklin, the former governor of Tasmania.

Last year the Northwest Passage was virtually ice free for the first time in memory, when the Arctic sea ice shrank to its lowest level since satellite observations began.

US Interior Secretary Dirk Kempthorne announced in May the drastic loss of Arctic sea ice had forced him to list the polar bear as an endangered species because its populations could collapse within a few decades.

Hopes that the Arctic sea ice would return to robust levels after last year's record low are now unlikely to be realised, the latest figures from the US National Snow and Ice Data Centre reveal. While this year's melt is not expected to shatter last year's record, the sea ice is already significantly below average as the melt season peaks.

"We might see an ice-free Arctic Ocean by the year 2030, within some of our lifetimes," said Mark Serreze from the centre.

"There are some scientists out there who think that even might be optimistic."

The loss of the Arctic sea ice in summer would be unprecedented in human history, said Don Perovich from the US Army's Cold Regions Research and Engineering Laboratory. "As near as we can tell looking at the historical record, there's been ice in the Arctic in the summer for at least 16 million years," he said.

"There's a group that makes a very strong case that in 2012 or 2013 we'll have an ice-free (summer) Arctic, as soon as that. It's astounding what's happened," said Ted Scambos, another research scientist from the Snow and Ice Data Centre.

The sea ice melt is leading Arctic nations, including Canada, Russia and the US, to seriously examine new shipping routes through the Arctic, including the Northwest Passage, and the potential expansion of huge oil and gas fields.

"As the ice recedes, it's opening up not only the Arctic passage but all the resources in the Arctic Ocean," said Scott Borgerson, from the US Council on Foreign Relations.

Last year's melt was produced by a "perfect storm" of natural weather patterns and the rising temperatures in the Arctic from global warming, caused in part by burning fossil fuels.

The Arctic is warming at twice the average rate of the rest of the planet and the sea ice is now considered by many scientists to be a "coalmine canary" for monitoring the speed of global climate change.

The more the bright white sea ice melts, exposing dark ocean, the more the Arctic absorbs sunlight, melting more sea ice and feeding back into global warming.

The disappearance of the Arctic sea ice could have serious ramifications for the earth's climate and weather patterns, polar scientists say, explaining that it would be like leaving the refrigerator door open on the planet.

"We could think of the Arctic as the refrigerator of the northern hemisphere climate system," Dr Serreze said.

"What we're doing by getting rid of that sea ice is radically changing the nature of that refrigerator. We're making it much less efficient.

"But everything is connected together, so what happens up there eventually influences what happens in other parts of the globe."

Scientists are now rapidly working to understand how much the loss of the Arctic sea ice in summer might change weather patterns amid fears it will intensify extreme storms and rainfall in some regions and prolong drought in others.

"The Arctic really can feed back into the global climate system," said Dr Macdonald, who has worked with the UN's Intergovernmental Panel on Climate Change. "You know what happens when you get feedbacks - you get surprises, and we don't like surprises."

The Louis' ice specialist, Erin Clark, explained that much ice at the entrance of the Northwest Passage this July was "first-year ice", frozen over just last year and prone to melting. The extent of this year's melt will not be known until mid-September, with six weeks still left in the melt season.

"A race has developed between the waning sunlight and the weakened ice," the US Snow and Ice Data Centre's report for the end of July says.

Despite a colder winter in parts of the Arctic and cooler temperatures in the last weeks of July, the size of the sea ice is expected to shrink to levels close to the second or third-lowest on record by September, the centre's analysis shows.

Arctic researchers are trying to understand how much of the record melting is due to the extreme natural variability in the northern polar climate system and how much to global warming caused by humans. The Arctic Oscillation climate pattern, which plays a big part in the weather patterns in the northern hemisphere, has been in "positive" mode in recent decades, bringing higher temperatures to the Arctic.

Igor Polyakov, of the International Arctic Research Centre in Fairbanks, Alaska, explained that natural variability and global warming are crucial to understanding the sea ice melt.

"A combination of these two forces leads to what we observe now and we should not ignore either force," Dr Polyakov said.

"There have been numerous models run that have looked at (the two forces) and basically they can't reproduce the ice loss we've had with natural variability. You have to add a carbon dioxide warming component to it."

As the sea ice fails to recover, there are concerns it will become one of the tipping points pushing the planet to faster climate change.

A number of scientific papers are now raising concerns that global warming, especially in the Arctic, will begin to thaw some of the region's vast areas of permafrost, especially in Siberia and Alaska. If that happens, infrastructure including roads, railways, bridges and pipelines could collapse.

The Four Corners report on the Arctic will air tonight at 8.30.