06 Jul 2009: Analysis

Climate Threat to Polar Bears:
Despite Facts, Doubters Remain

Wildlife biologists and climate scientists overwhelmingly agree that the disappearance of Arctic sea ice will lead to a sharp drop in polar bear populations. But some skeptics remain unconvinced, and they have managed to persuade the Canadian government not to take key steps to protect the animals.

by ed struzik

In the spring of 2008, U.S. Interior Secretary Dirk Kempthorne — an appointee of President George W. Bush — held a conference call with a blue-ribbon panel of scientists to discuss whether polar bears should be placed on the endangered species list. Given the Bush administration’s environmental record, many of the 19 scientists were apprehensive about how Kempthorne was going to respond to their report, which warned that projected climatic changes in the Arctic would lead to the probable elimination of two-thirds of the world’s 20,000 to 25,000 polar bears in much of their range within 45 years.

Kempthorne said he had given serious consideration to the studies by U.S. and Canadian experts that led them to support listing polar bears under the Endangered Species Act. He then thanked them for their work and said he could find no flaw in any of the nine studies they had conducted to come to their conclusion.

“My hope is that the projections from these models are wrong, and that sea ice does not recede further,” Kempthorne said a few days later in announcing his decision to list the polar bears as a “threatened” species. “But the best science available to me currently says that this is not likely to happen in the next 45 years.”

If ever a set of facts — and a government action — underscored the impact of global warming, this was it. But in the months since Kempthorne’s decision, global warming skeptics have insisted that the climate change models used by the panel of experts were wrong, that polar bears have survived warming in the past, and that the species can adapt to a life on land by eating goose eggs and berries.

The war of scientific words over the future of the polar bear has not just taken place on fringe Web sites, but has spilled into the pages of The New
Unlike projections of future climate disruption, these changes are happening now.
York Times, the U.K.s Daily Telegraph, and several scientific journals. And though the arguments of global warming skeptics have been widely discredited, they seem to have created enough of a gray area to provide cover for the Canadian government not to initiate management plans that might help some polar bear populations weather the warming that is destroying their icy habitat.

One reason the polar bear has become such a passionate topic of debate is its power as a symbol of climate change, with one skeptic lamenting that the bears have become the “poster-series for doomsday prophets of global catastrophe from anthropogenic climate change.”

But the polar bear image has power for a reason: Arctic sea ice is rapidly shrinking. Polar bears are being adversely affected as the key element in their habitat — ice — disappears. And unlike models and projections of future climate disruption, these changes are happening now — swiftly and dramatically.

The debate over whether the polar bear is truly in trouble vividly highlights the assault that global warming skeptics often make on mainstream science, with a disparate band of dissenters — many of them weighing in on issues in which they have little expertise — challenging the extensive research of a wide array of scientists. Among those offering dissenting views on polar bears and climate change are a marketing professor from the University of Pennsylvania, a graduate student in ornithology from the City University of New York, and a fisheries scientist. Other entities such as the Safari Club, an organization representing big-game hunters, and the Alaska state government, under Gov. Sarah Palin, have also tried to discredit the science underlying Kempthorne’s decision.

These groups and individuals have taken on members of the blue-ribbon advisory panel, including polar bear biologists and climate experts from the U.S. Geological Survey, the U.S. Fish and Wildlife Service, the Woods Hole Oceanographic Institute, the Canadian Wildlife Service, the Wildlife Conservation Society, and several American universities.

“It has been frustrating,” acknowledges Ian Stirling, a Canadian Wildlife Service scientist who has worked on polar bears for more than 35 years. “But nothing that has been said or written changes anything. The science here is as solid as it can be.”

The science is straightforward. As greenhouse gas concentrations in the atmosphere rapidly increase, the Arctic is warming significantly. Satellite images show that the extent of Arctic summer sea ice has decreased by roughly 30 percent since 1979, reaching a historic low two years ago. Thicker, multi-year sea ice also is disappearing.

Those facts are incontrovertible. So is the fact that over tens of thousands of years, polar bears have evolved to spend most of their lives — and do nearly all of their hunting for their favored prey, ringed seals — on sea ice. This is especially true in spring, when the bears fatten up on seals so the female polar bears can put on sufficient calories to gestate and nurse cubs. Not only is Arctic sea ice declining overall, but it is breaking up earlier in spring; in some regions — such as western Hudson Bay — sea ice has been melting three weeks earlier than in the mid-1980s, depriving polar bears of a vital feeding opportunity.

Over the past two decades, studies in western and southern Hudson Bay show that polar bears are growing thinner, that undernourished females are having smaller litters, and that females are giving birth to lighter cubs that do not survive as well.

Stirling and Steve Amstrup, a U.S. Geological Survey polar bear biologist who headed the blue-ribbon study panel, have seen telltale signs that polar bears are also in trouble in the southern Beaufort Sea. In Alaska especially, polar bears are increasingly likely to den on land rather than on the sea ice because the ice is not as stable a denning platform as it once was. Furthermore, increasing numbers of polar bears have been seen hundreds of miles inland or swimming far offshore.

The latest authoritative estimate on the health of polar bear populations comes from the Polar Bear Specialist Group at the International Union for Conservation of Nature (IUCN). The group reported in early July that eight of the Arctic’s 19 polar bear subpopulations are in decline. In western Hudson Bay, for example, populations have fallen from roughly 1,200 to 1,000 in the past two decades. Three subpopulations are stable and one is believed to be increasing, the Polar Bear Specialist Group reported. No good data exists on the remaining seven subpopulations.

Some of the contrarian views on polar bears started off innocently enough. In the journal Polar Biology, for example, ornithologist Robert Rockwell and graduate student Linda Gormezano, both associated with the American Museum of Natural History and City University of New York, suggested that polar bears on the west coast of Hudson Bay — which now spend as much as five months fasting on land in summer and fall — might find relief in the future by turning their attention to snow goose eggs. The study evolved out of Rockwell’s decades-long work on snow geese in Hudson Bay.

The snow goose specialists aren’t alone in suggesting that polar bears could adapt to life on land. In the current issue of The Journal of Mammalogy, Markus G. Dyck, an instructor at Nunavut College in Iqaluit, and Ermias Kebreab, an associate professor at the University of Manitoba, suggest that if sufficient berries are available on land, they could possibly replace calories the bears lose from eating fewer seals at sea. Dyck and Kebreab predict that polar bears will adapt if sea ice continues to decline.

But polar bear researchers say it is highly unlikely that goose eggs and berries would ever be able to replace the trove of calories the bears now ingest from eating fatty seals. Andrew Derocher, chairman of IUCN's Polar Bear Specialist Group, has written a soon-to-be published paper with an associate demonstrating that there are simply not enough resources on land — be they goose eggs, kelp, or berries — to replace what the bears get on the ice.

“A few good feedings of goose eggs will pretty much wipe out that resource,” said Derocher, who has worked on polar bears in Svalbard, the Beaufort Sea, Hudson Bay, and Wager Bay in northern Canada. “In the long run, goose eggs can contribute nothing of energetic consequence to polar bears.”

Even the snow geese scientists concede that in 40 years, only six bears — four since 2000 — have been seen feeding on snow goose eggs. In addition, Derocher and Stirling have shown that polar bears lose about a kilogram per day when they are stuck on land. Those periods of food deprivation on land have become prolonged in recent years, but still the bears have not turned to goose eggs or berries for sustenance.

“If polar bears could offset that weight loss and its associated population impacts by taking eggs or other supplemental food they would be doing so now,” said Amstrup.

Another global warming skeptic who has joined the polar bear debate is J. Scott Armstrong, a marketing professor at the Wharton School at the University of Pennsylvania who specializes in forecasting methods. He has made numerous statements in the media and to Congress casting doubt on global warming and its threat to polar bears. Armstrong insists that models used by climatologists to forecast the future of the polar bear in an increasingly ice-free Arctic are worthless. He also maintains that the Earth currently has as much chance of cooling as it does of warming — a statement contradicted by the overwhelming majority of the world’s climate scientists.

The Alaskan government has signed a contract with Armstrong to provide justification for the state’s opposition to the listing of polar bears as a threatened species, despite Armstrong’s lack of scientific credentials.

So far, the most important impact of global warming skeptics on the polar bear issue is their influence over a key Canadian scientific committee that advises the government on endangered species. The Committee on the Status of Endangered Wildlife in Canada decided last year that, despite ample scientific evidence that polar bear populations are facing a grave threat, there was no need to change the status of the creature from “special concern” to threatened.

Their decision was based on a report co-authored by Mitch Taylor, a former polar bear biologist for the Nunavut government in Canada whose
The Canadian government has not adopted a plan to help polar bears adjust to a warming world.
study did not link the future decline of polar bears to a loss of sea ice. Taylor is a global warming skeptic who has criticized the U.S. decision to list the species as threatened, has stated that CO2 emissions are not causing Arctic warming, and has claimed that — other than the Arctic — the globe has been cooling since 2000. All of his contentions are contradicted by facts or disputed by the vast majority of climate scientists and polar bear experts.

What most concerns Canadian polar bear experts is that by failing to acknowledge the threat, the Canadian government has not adopted a management plan to help polar bears adjust to a warming world. That plan could include controls on Arctic development, reduced hunting of polar bears, and pollution reduction.

No one is disputing that polar bears have survived periods of warming that occurred during the last interglacial period, about 120,000 years ago. The issue, however, is a red herring. The maximum temperatures of the last interglacial were roughly 2 degrees F warmer than now. Given the rate at which greenhouse gas emissions and temperatures are currently rising, the Earth could easily undergo 3 to 4 degrees F of warming by the end of this century — significantly greater than anything polar bears have experienced during their evolutionary history.

Derocher also noted that the current situation is much different.“There were no people back then hunting bears,” he says. “There was no oil and gas development, no shipping or pollution. People weren’t pumping greenhouse gases into the atmosphere like they are today. You can’t compare the situation today to the one 125,000 or 250,000 years ago and suggest that bears will do just fine.”

Said Stirling, “Given all the controversy, it might sound complicated, but it isn’t: Without sea ice to hunt seals, polar bears are in big trouble.”

POSTED ON 06 Jul 2009 IN Biodiversity Biodiversity Climate Forests Antarctica and the Arctic Asia 


It seems that most articles on E360 are about climate change, and now almost all of them draw responses from climate change deniers. If this website is to be a serious forum for discussion, and not just another outlet for rants, I call on those commenters who deny the existence and/or magnitude of anthropogenic climate change to cite the science that supports their positions, not just your opinions. The mainstream climate science is out there for anyone to critique; give us yours so we can judge whether you have anything substantive to add to the discussion.
Posted by Dave Harmon on 06 Jul 2009

Computer modeling is now fact?

How did those quaint trading models work out for the financial institutions?
Posted by Troy on 06 Jul 2009

Nice article! This is the high time to take necessary steps to prevent global warming. If not, the fauna and flora of these earth would be extinct within 10-20 years. Right article at right time.
Posted by Wildlife Luver on 06 Jul 2009

The Canadian Harper Govt of today emulates the past one of George Bush. They will go out their way to do nothing if they can - no matter what the evidence. Their efforts are meager if they do choose to do something ... I wished they cared more and for something special like a polar bear.
Posted by Bobster on 07 Jul 2009

The IUCN Polar Bear group research suggests the hunting is still the biggest threat. Where kills are less than 2 percent, populations are growing or stable; where 3 percent, populations are mainly stable; where more than 3 percent, declining.

Go to:
and click on PolarBears.
Posted by Julius St Swithin on 07 Jul 2009

There is anthropogenic created climate change and it is caused by fine particulate matter [aerosols] from the burning of fossil fuels, not the messenger elevated CO2. Aerosols are creating global hazes which are wreaking havoc with the weather everywhere. The most dense and damaging haze is located in the equatorial Indian Ocean region. Where it is cooling sea surface temperatures and preventing evaporation for the formation of clouds.

Undoubtedly, the dense populations of Asia create most of the problems with their fossil fuel burnings, ably compounded by forest fires and coal industrialisation.
The soot/black carbon component of aerosols settling on snow/ice when warmed by the sun is enough to cause abnormal melting.

So if you want the ice to remain intact for polar bears etc. eliminate emissions of soot from fossil fuel burnings.
Posted by Oceanic on 07 Jul 2009

Polar bears have existed for at least 100,000+ years. In that time, they have survived warmer
periods than today. The ice core records show that temperatures 100,000 years ago were far higher than today and they managed to survive then.

The Holocene Climate Optimum (5000-9000 years ago) temperatures were very high in the Arctic and again they survived. During the MWP, they survived a warm period plus being hunted by the Vikings and the Inuit who were advancing northwards during this period. During the 1920's, reports from Spitzbergen mention the lack of seals in the area due to warming (temperatures up to 15C) - yet the polar bears survived then as well. Conservation is important but polar bears have survived worse warming than today.
Posted by Ian George on 07 Jul 2009

The fate of polar bears in the face of global climate change is a pressing issue that requires input from many corners. Those needs are not necessarily well-served by somewhat one-sided essays that misrepresent or misinterpret scientists’ findings. (Note that no one with views contrary to Derocher, Stirling and Amstrup were interviewed or at least quoted.)

In Struzic’s piece, he misrepresents our findings (Rockwell and Gormezano 2009 Polar Biology) when he reports: “Even the snow geese scientists concede that in 40 years, only six bears — four since 2000 — have been seen feeding on snow goose eggs.” The point of our paper is that IF global change continues as predicted THEN polar bears will increasingly overlap the nesting colony of snow geese and COULD take advantage of a rather large nutritional resource at low capture expense. The fact that so few have been seen so far is consistent with that overlap not yet occurring. The recency of several of the observations coincides with the advancing shift in the onshore arrival date of the bears related to global change. The quote: “If polar bears could offset that weight loss and its associated population impacts by taking eggs or other supplemental food they would be doing so now...” is equally disappointing as it indicates that at least one of the blue ribbon panel fails to grasp the point we made. (That quote is now attributed to Amstrup although an earlier posting attributed it to Derocher.)

We also feel that Struzic does the public a disservice when he transitions from our work to the statement “Another global warming skeptic who has joined the polar bear debate…”. The implication is that we do not believe in global climate change. Had he read our paper, he would have seen the second line states: “There is little doubt that the global climate is changing and even less that these changes are negatively impacting polar regions…”. Our paper is predicated on global climate change leading to a change in the onshore arrival date of polar bears. To insinuate in any fashion that we doubt global climate change is a disservice to the public and academic community and an insult to us.

As a last point, our paper grew out of 41 years spent by Rockwell and his students studying not just snow geese but observing predators consume snow geese (and other species) during the summer, ice free season.

RF Rockwell and LJ Gormezano

Posted by rf rockwell and lj gormezano on 07 Jul 2009

"Satellite images show that the extent of Arctic summer sea ice has decreased by roughly 30 percent since 1979, reaching a historic low two years ago. Thicker, multi-year sea ice also is disappearing."

Pretty disingenuous. With a historic low reached TWO years ago...multi year ice HAS to be less.
No word on the studies that show the ice loss in 2007 was caused by a decadal shift in warm ocean currents and not "warming."

Anyone looking at the full ice record in the Arctic since 1979 will see a slow decline and a sharp one year drop which recovered by 11% last year. We'll know in another 60 days what the low will be for this year...but at this moment there is more ice than there was last summer.
Here's the full artic ice record from the Cryosphere today UofI site.

And here is the SOUTHERN hemisphere sea ice record...inconveniently increasing rather nicely.

Last year they were talking about a decrease in ONE YEAR old ice (due to 2007) ...this year they are talking about multi-year ice so they can include 2007 without admitting that one year old ice has increased due to 2008! All of this suggests NO reason for panic and natural rather than man made causes for cyclic changes in the ice. The only reason for panic is alarmist reports about what MAY happen rather than data like Julius posts above. It is often not what you say...but what you leave out that counts.
Posted by Cam on 07 Jul 2009

Quote from article.
'No one is disputing that polar bears have survived periods of warming that occurred during the last interglacial period, about 120,000 years ago. The issue, however, is a red herring. The maximum temperatures of the last interglacial were roughly 2 degrees F warmer than now.'

Whoops! How about 3C higher than today. Check the Vostok ice core data. The bears
survived that warming.

Then a quote from Derocher. “There were no people back then hunting
bears,” he says. But there was during the MWP when temperatures were as high as today and the Inuit were moving northwards. And they were being hunted in the 1920s when there is enough evidence that sea ice cover was poor and temperatures were high.

It's misinformation like this that causes the problem of skeptics remaining unconvinced. Polar bears deserve better than this.
Posted by Ian George on 08 Jul 2009

Skeptics can be defined in many ways in the climate change debate, especially when the subject relates to polar bears.

There are those like Prof. Armstrong who dismiss the models that show that sea ice is thinning and threatening the future of these animals, despite overwhelming evidence to support this. Then, there are those like Linda Gormezano who accept the fact that climate change is happening, but still give Armstrong credence that he doesn't deserve. In Andrew Revkin's blog in the NY Times, Ms. Gormezano says she is not a fan of the forecasting methods used by Dr. Steve Amstrup to conclude that a two-thirds reduction in polar bears is possible by midcentury if summer sea ice continues retreating. She also said that a recent paper in a statistics journal by Armstrong et al. raised legitimate questions.

“Armstrong et al deliver their message in a bit of an antagonistic tone which weakens the impact of their message, but it still warrants consideration in my opinion.”

If that isn't a skeptical statement, I don’t know what is.

And then there are those like Robert Rockwell who accept the fact that climate change is affecting polar bear habitat, but who raise the prospect that polar bears might adapt to a more fruitful life on land by shifting their attention to eggs, berries and kelp. Robert Rockwell is a first rate snow goose scientist. I have been in the field with him and his colleagues and reported the findings of their work in a cover story for Equinox Magazine several years ago.

But there is a big difference in the biology of a snow goose and the biology of a polar bear. Robert Rockwell is not a polar bear scientist. Polar bear scientists like Amstrup, Ian Stirling and Andrew Derocher — who have spent as much, or more time in the field as he has researching geese — disagree with his views. Even the Bush Administration, which did its best not to list the polar bear as threatened, accepted the studies that they (Derocher was not among them) and others did for the USGS.

That should have brought some badly needed clarity to the issue. Instead, we get skeptics who continue to muddy the story. No wonder the public is confused.
Posted by Ed Struzik on 09 Jul 2009

Mr. Struzik,

Dr. Armstrong’s paper contains numerous criticisms that go beyond whether or not the ice is thinning and whether that is good or bad for polar bears. Personally, I have little doubt that current changes in the ice will negatively impact polar bears, but the points in the paper that I was referring to are very specific: (1) there is a tendency to underestimate the complexity of polar bear behavior and (2) to ignore the uncertainty regarding their ability to utilize alternative food sources. It is not clear to what extent polar bears will seek other foods in the future (which we state in our paper), but the potential effects of any dietary shifts are important and certainly should be incorporated into long-term models to predict polar bear survival — which they were not. This is the root of my criticism of Dr. Amstrup’s model, not the methods used.

You have, for some reason, latched onto a few comments taken from someone else’s blog (some taken out of context) and labeled me as a skeptic. First, a global warming skeptic — because you didn’t bother to read our paper and now a skeptic ‘by association’ because I agree with a few points in another paper that you passionately disagree with but clearly did not read in its entirety. Furthermore, these incorrect and rather insulting assertions were made without any attempts to contact me to clarify them — although, it appears that you extended that courtesy to other scientists.

If you have any questions regarding my views on polar bears, global warming or anything else please feel free to contact me first before misrepresenting me.
Posted by LJ Gormezano on 13 Jul 2009

I have read Armstrong's paper. I have also listened to his testimony before Congress — http://www.youtube.com/watch?v=-Yr5HxJTQAw — his interview with the BBC, and read his letters to Al Gore. (See excerpt below.)

I suggest that Ms. Gormezano have a look:

"Despite our literature searches and our appeals both on the Internet and in our published paper on climate change, my colleague and I have been unable to find a single scientific forecast to support global warming. If you are aware of such a study, I appeal to you directly to reveal it to the scientific community so that it can be subject to peer review and so the public can see the scientific basis for your claims."

How does one respond to that?
Posted by Ed Struzik on 14 Jul 2009

Skepticism is perpetuated by misrepresentations and one-sided reporting. Although Ed Struzik seems to have admitted in his posting that I too believe in climate change, he still did not address a main point of my posting – that he misrepresented our paper. He also did not address why he only interviewed members of the “polar bear club”. The one-sided interviewing and the failure to address it, well, makes me skeptical!

He did address the one-sided aspect a bit, indicating that bear biologists are to be trusted more about bear issues than goose biologists. There are several problems with that view. First, I am a biologist trained in the finest traditions of Queen’s University. Even a cursory examination of my publications indicates that they cover a broad range of biological topics.

Second, I have spent 8 to 12 weeks annually for the past 41 years observing polar bears foraging during the ice free period. I have great admiration for the works of Stirling, Derocher and Amstrup, but they do not spend the time with the polar bears in western Hudson Bay during the ice free period that I and my students do and they do not have the detailed knowledge of the bear’s summer foraging behavior that we have collected over the years. We are in the process of writing up all that information.

Third, the general notion of only talking to or believing the experts is circularly limiting. In science – perhaps not journalism – we are trained to examine alternatives and try and see which fit best with the observations. Often, we find that novel ideas turn out – at least for a while – to come closest to truth. My students and I are attempting to do just that. Study what we observe and report our findings, even if they do not fit in with standard dogma.

One sided commentary that does not accurately reflect the published work and that impugns the character of those publishing it does a disservice to all but those interested in promoting skepticism.

Posted by robert rockwell on 14 Jul 2009

USFWS has acknowledged that the polar bear is going to be extinct, no matter what we do now, because the CO2 levels are too high to support the habitat for them. They just haven't done it publicly.
Posted by Richard on 22 Jul 2009

Don't worry about those polar bears. The oldest known remains of a polar bear were uncovered on the Svalbard archipelago in the Arctic.

The jawbone was pulled from sediments that suggest the specimen is perhaps 110,000 or 130,000 years old. And what’s interesting about that is that the Eeemian - the last interglacial - was much warmer than the Holocene (the present).

Somehow, the polar bears survived through that.
Posted by Mary Brown on 24 Aug 2009

Evolution requires extinction for it to work. Climate has always changed whether humans were here or not. That is why we are here and the dinosaurs are not.

It is a ludicrous position to try and make climate adapt to the creatures by having it remain constant forever.

Posted by Bob on 14 Apr 2010

Comments have been closed on this feature.
Canadian author and photographer Ed Struzik has been writing on the Arctic for the past 27 years. He is the 2007 recipient of the Atkinson Fellowship in Public Policy and was a finalist for the Grantham Prize for Excellence in Reporting on the Environment in 2008. His latest book is The Big Thaw, published by John Wiley and Sons.



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