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Why polar bears became an icon of climate change

I’m not a climate change denier.  I’m not a climate scientist either.  My knowledge of climate and weather extends to a couple undergraduate classes in ecology and environmental science.  Still, when the majority of scientists in a particular field all agree on something, it obviously means there’s very little doubt.  

Scientists by the very nature of their profession are prone to disagreement and critical of new ideas. For a vast majority to come to consensus means there’s already a preponderance of evidence.  Still, I sometimes cringe at how quickly people are to blame something as complex as climate change for specific problems.

I’m suspicious of animals held up as symbols of human destruction.  It isn’t that our species isn’t destructive, we are incredibly destructive.  The fact is that for every rhino or panda or great ape that is threatened with extinction, there are many more insects, reptiles and non-descript rodents that face similar threats.  Why should we as a species or as individuals care more about the panda we’ll never see in the wild than a cockroach wiped from its wild habitat by mining?

One case is a perfect example of why I was suspicious.  There was a photo circulating of a male polar bear holding a dead cub in his mouth.  The photo was used to promote the idea that polar bears are so desperately hungry due to climate change they’ve turned to cannibalism.  The problem with the photo is that male polar bears normally kill young and it’s no sign of desperate hunger or other stress. It’s with these questions in mind that I started working on an article about polar bears.  Then I talked to Andrew Derocher a PhD professor at University of Alberta, Edmonton and important polar bear biologist.  

I asked Dr. Derocher about polar bear’s role as icon of climate change and he explained it to me.  Of 19 known polar bear populations, there are 3 that show obvious signs of being hurt by climate change.  It turns out that we know more about polar bears than any other large mammal in the Arctic. It’s not that they’re the most iconic, narwhals and orcas are quite majestic.  Caribou and musk ox have plenty of appeal. Polar bears have been potentially threatened before and this is key to the reason they’ve become such an important image in the discussion on climate change.  

In 1965 there was a landmark meeting in 1965 at the University of Alaska Fairbanks, the discussion at hand was research and conservation of polar bears.  The meeting marked the first step towards the creation of the IUCN Polar Bear Specialist Group (PBSG).  The group was an international group of scientists collaborating on research and conservation of one species: Ursus maritimus, the polar bear.  

PBSG in turn lead to an international agreement between all the nations with polar bears.  In 1973, an agreement was made in Oslo Norway between the governments of Canada, Denmark, Norway, (the then) Soviet Union and the United States.  This unique agreement allowed the collection of an unprecedented amount of research in the Arctic. The result is that today scientists know more about the polar bear than any other large Arctic mammal.  This set the stage for polar bears to become the poster child of climate change. The other reason polar bears are center stage as icons of the destruction of a warming planet is their unique dependence on sea ice.

Polar bears are unique among bears.  Not only are polar bears the largest of bears but they also have a completely unique life among bears.  Black and brown bears live terrestrial lives, bound to solid land. Polar bears live lives on the sea, it’s even observed that polar bears although great swimmers walk awkwardly on land.  If you look at a map of the far northern part of our planet, where polar bears live, it it’s easy to see that the North Pole is mostly devoid of land, being dominated by the Arctic ocean north of the continents.  What isn’t so easy to see is that the sea in the polar region is dominated by ice floes that wax and wane with the seasons. Sea ice in the Arctic has played its own unique role in human history.

Through human history, much exploration has been pushed by the interest in global trade.  It was a hope of finding a trade route between Europe and Asia that Columbus first set out across the Atlantic and ended up in the Americas.  With North America and South America clearly hindering oceanic travel to the west from Europe towards Asia, a Northwest Passage became the new goal of explorers.  

The Northwest Passage north of the Americas, was sought for centuries and became a sort of El Dorado, a legendary objective for explorers seeking glory.  Roald Amundsen, the man who led the first expedition to the South Pole, made the first complete North West Passage in an expedition from 1903 to 1906. Still until 2009, ice made the passage impractical for normal, year round marine shipping.  The decline of sea ice has created new possibilities for shipping and international trade. What is good for human commerce isn’t good for polar bears though.

Polar bears hunt on the same pack ice that kept the Northwest passage closed to normal shipping for so long.  Polar bears depend almost entirely on seals for their diet. Bears wait patiently for long periods of time near holes (called aglu) in sea ice that seals use to get air.  In his book Arctic Dreams, Barry Lopez vividly described the hunting strategies of Polar Bears:

“It may take half an hour to patiently approach a seal resting on the edge of an ice floe, surfacing quietly to reconnoiter, then submerging again.  A bear may drift toward a seal like an innocuous piece of ice; when it reaches the floe edge it explodes from the water and smacks the seal dead all in one motion.  When it stalks seals over the ice, it flattens itself on its forequarters and slides along slowly on chest and forelegs, taking advantage of every piece of cover. It will scrape away the sea ice at a breathing hole until there is just a thin layer left, and then cover the ice with its body to cut off sunlight, so it looks to the seal below as if the thick crust of ice and snow is still present.  It will build a snow wall to hide behind while it waits at an aglu. And it will rise up suddenly in a resting seal’s own aglu.”

It’s clear that polar bears can be skilled, dedicated hunters but the ice is always part of their pursuit of seals.  It’s also well known that polar bears must work incredibly hard for the food they get. Inexperienced bears waste a lot of energy and bears have been known to regularly fast for up to eight months.  The fasting period is possible because of a seasonal extreme in food abundance. Dr. Derocher told me that for a bear, one seal is the caloric equivalent of 1,000 big mac meals. The number seems incredible but I did the math myself and it checks out.  Seals, like many marine mammals, especially those in cold climates are very fatty. The huge amount of calories from seal kills allow polar bears to survive seasons without pack ice to hunt on. The fat in polar bear’s diet poses another problem for their long term survival: pollutants.  

Many pollutants bond to fat.  Because polar bears are very large animals, pollutants in the fat of smaller animals that are in turn eaten by bigger animals and then seals and finally the bears become concentrated.  This means that the bears end up with a concentration of pollutants compared to say fish that seals eat. Some of these pollutants are pesticides from agriculture that travel long distances to reach the Arctic.  Andrew Derocher told me that there’s good evidence that pollutants are already causing bone development and immune system problems in bears. The fats that keep seals, polar bears and other marine mammals alive are also collecting toxins that hurt them.

In the end, it all comes down to the Arctic.  The cold is a defining characteristic of our pole and has partially set the niches of polar bears, seals, narwhals and anything else that lives in the far north.  This is why an animal like the polar bear is important to those concerned about climate change. Derocher said that scientists expect polar bears to live until the end of the century, he also tells me that as far as he can tell, the Arctic could get along without polar bears.  

As a scientist, Dr. Derocher’s role is to collect data, to show the cost of human enterprise, not advocate for bear survival.  When I think about places with dangerous creatures myself, I can’t help but think of them different. In an area with tigers, crocodiles or polar bears, we walk more softly, we feel our own humanity more acutely.  In my view, polar bears are part of the Arctic. As I finished up my conversation with Andrew Derocher, he told me that the Arctic is the most serene and beautiful place he’s been, and that as a scientist, he’ll run out of time before he runs out of questions.  I smiled to myself at the scientist’s curiosity and hoped quietly that I too will someday see a place of such northern beauty.

By Zach Fitzner, Contributing Writer

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