Bear facts and polar opposites
by: Greg Roberts
From The Australia
December 17, 201112:00AM
A polar bear and her cub on Wrangel Island, Russia. Picture: Rod Eime Source: The Australian
SCATTERED across a wide valley on remote Wrangel Island, 16 polar bears were in view from the deck of Russian expedition ship the Spirit of Enderby.
The bears foraged quietly in short-grassed tundra and along the rocky shore, unperturbed by the human interlopers. During a cruise conducted by New Zealand-based Heritage Expeditions through the Russian Arctic at the end of the northern summer this year, we spotted 106 polar bears in six days around Wrangel, Herald and Kolyuchin islands.
The bears were concentrated on the islands because this summer the sea ice, from which they hunt seals, was well to the north. Since our visit, the bears have spread out on the ice as it returned in the northern autumn to resume their seal hunting. They appear to have managed well enough while land-bound; on Wrangel Island, we saw several bears feeding on the carcasses of walrus.
The popular public perception is that polar bears are on the road to extinction as their Arctic sea ice habitat disappears because of global warming. Former US vice-president Al Gore made much of this claim in his book and movie, An Inconvenient Truth. The polar bear has emerged as a powerful image in the debate about climate change, with environmentalists arguing that the fate of the largest land predator on earth is a dramatic indication of what is at stake.
Now, Russian scientists are challenging studies by their US counterparts that are used by Gore and others to promote the view the polar bear is on the brink. They say bears are not disappearing because of reduced sea ice because they can survive on land - as they have during historic periods of global warming - although numbers may be affected by hunters having greater access to the animals.
Moreover, the Russians and some American experts accuse US government scientists of mistreating polar bears in one key study, and of misinterpreting the results of that study to link the fate of the species to climate change.
A paper published earlier this year in the journal Polar Biology reports the results of a study by US Geological Survey scientists. A female polar bear and her cub were tranquillised and fitted with satellite collars on the Alaskan coast. The adult bear, without her cub, was found subsequently to have swum 685km, reaching the edge of the pack ice before returning to another part of the mainland, losing 22 per cent of her body weight in the process.
The study has been widely interpreted as evidence that bears are forced by melting ice to spend abnormally long periods in the water, putting them at risk of drowning. The Los Angeles Times described the study as "one of the most dramatic signs ever documented of how shrinking Arctic ice impacts polar bears".
It lent support to findings in a 2007 study by the US Bureau of Ocean Energy Management, Regulation and Enforcement. That study, also reported in Polar Biology, outlined sightings of four drowned polar bears during an aerial survey off the Alaskan coast. The authors warned global warming could lead to further drownings. It was this study that prompted Gore to warn in his book: "A new scientific study shows that, for the first time, polar bears have been drowning in significant numbers. Such deaths have been rare in the past. But now, these bears find they have to swim much longer distances from floe to floe."
Gore's movie depicts an animation of a bear pitifully attempting to haul itself on to one of the few remaining ice floes.
Russia's leading polar bear expert, Nikita Ovsyanikov, says he was horrified to learn the facts behind the study of the female bear and her cub. Ovsyanikov says the researchers did not wait until the animals had recovered from being sedated before leaving the site and it was likely the cub died after being separated from its mother in traumatic circumstances.
According to Ovsyanikov, the female bear would never have made its marathon swim of its own free will, as normally it would have waited on the mainland until the autumn ice returned. He believes it much likelier the bear took to the water reluctantly because it was traumatised or was searching for its lost cub.
"The day before capture she was a happy mother bear that had reached safe land with her cub after the annual sea ice disappearance," Ovsyanikov tells Inquirer. "Her capture ruined her life. It would have been more humane to shoot her on the spot. Animals should not suffer for ambitious scientists." He says it is wrong for the Americans to claim the bear made the swim voluntarily, allowing them to make the linkage with climate change. "Bears go into the sea at this time - when no sea ice is around and they are on the land - only if they are disturbed."
American polar bear researcher Laurie McHargue agrees. "This mother bear, tuned to survival with the natural rhythms of the Arctic over thousands of years of evolution, would never have gone for a swim but for the irresponsible actions of a team of researchers," McHargue says. "Extreme circumstance forced this bear into the ocean. The disappearance of her cub and-or the trauma of being chased, captured and tagged." She adds that during the capture of the two bears, the cub attempted to escape by sea but was forced back to land by a helicopter, where it was sedated along with its mother.
One of the authors of the study, Eric Regehr, agrees some disturbance to animals is inevitable during research involving sedation. "Our efforts to quantify this effort suggest that it's a temporary disturbance that is unlikely to have a significant impact on the animal's ability to survive and reproduce." Regehr concedes the sedating and collaring may have been a factor in the female bear's long swim.
However, "several dozen other bears were also captured and released as part of this study and, to our knowledge, other bears did not undertake similar swims".
What of the initial study that reported the four drowned bears? Its authors, Charles Monnett and Jeffrey Gleason, have been under investigation by the US Office of Inspector-General as their linking of the drownings to global warming has come under fierce attack from climate change sceptics, who claim there is no evidence for the linkage. Monnett was stood down earlier this year during the investigation and, although he has since been reinstated, he is no longer responsible for monitoring his office's $50 million-a-year research program.
Monnett and Gleason declined to comment to Inquirer on their evidence for linking climate change to the drownings, which occurred in stormy weather. Instead, Gleason points to the mother polar bear's marathon swim in the study by Regehr and his colleagues as evidence of the "potential implications" for the species from changed sea-ice conditions.
Speaking on behalf of Monnett and Gleason, Public Employees for Environmental Responsibility director Jeff Ruch is highly critical of the ongoing probe by the OIG. "I would say that in the 30 years I have been doing this work, this is the most cock-eyed and idiotic investigation I have ever encountered," Ruch says. "It is utterly inappropriate to have criminal investigators assessing how scientific publications are edited."
The media has been quick to seize on the plight of the polar bear in its coverage of global warming. Newspapers across the world in 2009 featured prominently a photograph distributed by the Canadian government showing two bears on an ice floe. Said one typical caption: "They cling precariously to the top of the ice floe, their fragile grip the perfect symbol of the tragedy of global warming." It emerged that the photograph was three years old; that it was taken in summer, when bears could be expected to be resting on ice floes; and that in any event the animals were within swimming distance of shore.
So are polar bears threatened by global warming?
Regehr, a US Fish and Wildlife Service biologist, believes they are. He says loss of sea ice due to climate change is the primary conservation concern for the bears, and that the species was listed as threatened by the US in 2008 on the basis of observed and projected sea ice loss. "There is a very solid case for serious, long-term concerns about polar bears due to climatic change," Regehr says. "The vast majority of climate scientists have provided evidence that Arctic sea ice will continue to decline in the next century. Based on the fundamental ecology of the polar bear, this will likely lead to reduced numbers and distributions."
Ovsyanikov disagrees. "During their previous evolutionary history, polar bears have successfully survived at least four global warming periods, which were thousands of years long and stronger than the present one," he says. "Biologically, polar bears are capable of surviving such changes." Ovsyanikov adds research on Wrangel Island has established how they do it: by adapting to ice-free seasons in coastal and island tundra habitats, like their very close relative, the brown bear.
Ovsyanikov sounds a note of caution, however. Reduced sea ice has allowed greater access to polar bears by traditional hunters, with government authorities in the Arctic, especially the US, doing little to control hunting. "Times have changed and native people do not need to hunt polar bears for their living. The real threats to the survival of this animal are human greed and incompetence."