They cling precariously to the top of what is left of the ice floe, their fragile grip the perfect symbol of the tragedy of global warming.
Captured on film by Canadian environmentalists, the pair of polar bears look stranded on chunks of broken ice.
Although the magnificent creatures are well adapted to the water, and can swim scores of miles to solid land, the distance is getting ever greater as the Arctic ice diminishes.
“Swimming 100 miles is not a big deal for a polar bear, especially a fat one,” said Dr Ian Stirling of the Canadian Wildlife Service.
“They just kind of float along and kick. But as the ice gets farther out from shore because of warming, its a longer swim that costs more energy and makes them more vulnerable.”
The plight of the bears was highlighted as the prospect of a gloomy future emerged from leaks of the most comprehensive report into global warming yet undertaken, which is to be published on Friday.
Concluding that it is “highly likely” that mankind is to blame for climate change, it talks of more droughts, torrential rains, shrinking Arctic ice and glaciers, and rising sea levels for the next century.
And it warns that the effects of a build-up of greenhouse gases in the atmosphere will last far longer.
Studies of polar bears have revealed that not only have their numbers declined � by nearly one quarter in just 20 years to around 25,000 � but so has their physique.
The bears can be 10ft tall and 1700lbs in weight, using their body fat to keep them alive when the temperatures plummet in the harshest part of their winter to minus 45C.
But the scientists have observed that in the struggle for survival, the bears – and females especially – are now much thinner.
Scientists believe that four bears which recently drowned off the coast of Alaska had simply been unable to cope with a violent storm.
Dr Stirling says that the phenomenon of a female giving birth to triplets is now part of history with usually only single cubs recorded. Soon, he says, the species may be extinct.
Usually at this time of year, polar bears would be sheltering with their young in the dens they carve for themselves in mountain slopes near the shoreline or in snowdrifts on the sea ice.
But global warming, which has raised the temperature in the Canadian Arctic by 4C in the last 50 years, means their habitat is inexorably disappearing.
In Hudson Bay where the ice melts completely in summer, scientists have noted that it is now happening three weeks earlier than normal.
This is having a catastrophic effect on the bears which hunt seals over the winter and spring before coming ashore where they rely on their build-up of body fat to survive � and feed their cubs.
Reports are now being received of polar bears, perfectly equipped for Arctic survival with two coats of insulating fur and a four inch layer of blubber, scavenging for scraps in rubbish tips and camp sites.
Scientists say the survival of polar bears may rely on special conservation areas, but even that seems a forlorn hope with a United Nations report expected to say that sea levels will carry on rising for over 1,000 years even if greenhouse gases can be curbed.
The report from the UN’s Intergovernmental Panel on Climate Change draws on the work of 2,500 researchers from more than 130 nations and is the most comprehensive overview of climate change for guiding policy-makers.
It will say that global warming was “very likely” caused by human activity, delegates to a climate change conference said.
Dozens of scientists and bureaucrats have been editing the new report in closed-door meetings in Paris. Their report, which must be unanimously approved, is to be released today.
Two participants, speaking on condition of anonymity because the meetings are confidential, said the group approved the term “very likely” in yesterday’s sessions. That means they agree that there is a 90 percent chance that global warming is caused by humans.
The last report, in 2001, said global warming was “likely” caused by human activity. There had been speculation that the participants might try to change the wording this time to “virtually certain,” which means a 99 percent chance.
The report is considered an authoritative document that could influence government and industrial policy worldwide.
- Former U.S. Vice President Al Gore has been nominated for the 2007 Nobel Peace Prize for his wide-reaching efforts to draw the world’s attention to the dangers of global warming, it emerged when nominations closed.
During eight years as Bill Clinton’s vice president, Gore pushed for climate measures, including for the Kyoto Treaty, and after leaving office in 2001 has campaigned worldwide, especially with his Oscar-nominated documentary on climate change called “An Inconvenient Truth.”