Is Global Warming Killing the Polar
Bears?
WSJ
By JIM CARLTON
Staff Reporter of THE WALL STREET JOURNAL
December 14, 2005; Page B1
t may be the latest evidence of global warming: Polar bears are
drowning.
Scientists for the first time have documented multiple deaths of polar bears
off Alaska, where they likely drowned after swimming long distances in the
ocean amid the melting of the Arctic ice shelf. The bears spend most of their
time hunting and raising their young on ice floes.
In a quarter-century of aerial surveys of the Alaskan coastline before 2004,
researchers from the U.S. Minerals Management Service said they typically
spotted a lone polar bear swimming in the ocean far from ice about once every
two years. Polar-bear drownings were so rare that they have never been
documented in the surveys.
But in September 2004, when the polar ice cap had retreated a record 160
miles north of the northern coast of Alaska, researchers counted 10 polar bears
swimming as far as 60 miles offshore. Polar bears can swim long distances but
have evolved to mainly swim between sheets of ice, scientists say.
The researchers returned to the vicinity a few days after a fierce storm and
found four dead bears floating in the water. "Extrapolation of survey data
suggests that on the order of 40 bears may have been swimming and that many of
those probably drowned as a result of rough seas caused by high winds," the
researchers say in a report set to be released today.
While the government researchers won't speculate on why a climate change is
taking place in the Arctic, environmentalists unconnected to the survey say
U.S. policies emphasizing oil and gas development are exacerbating global
warming, which is accelerating the melting of the ice. "For anyone who has
wondered how global warming and reduced sea ice will affect polar bears, the
answer is simple -- they die," said Richard Steiner, a marine-biology professor
at the University of Alaska.
The environmental group Greenpeace began airing a 30-second commercial
yesterday in New York, Los Angeles, Atlanta and other cities showing an
animated adult polar bear and a cub on a cracking ice floe. The two bears,
nowhere near land, slip underneath the water. "Polar bears may soon be extinct
because of global warming," the voice-over states. It ends with "Global
Warming: It's the Real Thing," a takeoff of a Coca-Cola Co. commercial
featuring polar bears.
Some experts say that climate change may indeed be shrinking the ice pack,
but they dispute that emissions are the main culprit or that significantly
cutting greenhouse gases would really make a difference. "Whether humans are
responsible for some, most, or all of the current warming trend in the Arctic,
there is no proposal on the table that would actually prevent continued warming
or reverse present trends," said Sterling Burnett, a senior fellow at the
National Center for Policy Analysis, a nongovernment organization based in
Dallas. "The question is how to adapt to future changes in climate, regardless
of the direction or the cause."
In addition to documenting polar-bear deaths, the Minerals Management
Service researchers, Chuck Monnett, Jeffrey Gleason and Lisa Rotterman, also
found a striking shift in the bears' habits. From 1979 to 1991, 87% of the
bears spotted were found mostly on sea ice. From 1992 to 2004, the percentage
dropped to 33%. Most of the remaining bears have been found either in the ocean
or on beaches, congregating around carcasses of whales butchered by hunters. In
the past, polar bears were rarely seen at such kill sites, because they spent
their time hunting their favorite meal -- seals -- on sea ice.
Marine experts consider the findings -- to be presented at a marine-mammal
conference this week in San Diego -- an ominous sign. Some have warned for
years that a rapid thawing of the Arctic from global warming could endanger
species like the polar bear. Already, a warmer Alaska over the past
half-century has been linked to increased erosion of rivers and streams, insect
infestations and the undermining of pipelines and roads as the permafrost
thaws.
Alarmed by the swift changes, the Alaska Inter-Tribal Council, a consortium
of the state's tribes, earlier this month passed a resolution urging that the
U.S. government enact a mandatory program to reduce global warming.
Some scientists predict polar bears could become extinct within the next
century because they have adapted over the millennia to only hunting on ice. If
they try to swim in disappearing ice conditions to catch seals, more are likely
to tire and drown, scientists say. Polar bears that stay onshore aren't adapted
to hunting land animals like caribou, which are preyed upon by more-aggressive
grizzly bears. Polar bears also require more fat intake than most food on land
offers them, experts say.
"As the sea ice goes, that will direct to a very great extent what happens
to polar bears," said Steven Amstrup, a polar-bear specialist with the U.S.
Geological Survey in Anchorage, Alaska.
Another study set to be released at the marine-mammal conference shows what
might happen to the Alaskan polar bears over time. Researchers from the USGS,
the University of Wyoming and the Canadian Wildlife Service found that the
population of polar bears in Canada's western Hudson Bay -- near the
southernmost habitat for the bears in the world -- fell to 935 in 2004 from
1,194 in 1987, a 22% drop. Researchers said the decline -- the first recorded
for these bears -- came in tandem with an extension by nearly a full month in
the time it takes for Hudson Bay to ice over after the summer.
"Our findings may foreshadow how more northerly populations will respond to
projected warming in the Arctic ecosystem," wrote Mr. Amstrup, a co-author of
the report.
Previous studies by the U.S. and Canadian governments support a link between
the decline in sea ice in the Arctic and the ways polar bears try to adapt to
their surroundings. For example, researchers say polar bears in the Beaufort
Sea off Alaska and Canada used to spend most of their lives jumping from ice
floe to ice floe in pursuit of seals. Only pregnant bears would occasionally
wander onto the mainland, in search of a den.
But weekly aerial surveys by the U.S. Fish and Wildlife Service show that,
over the past five years, an unusually large number of bears have congregated
along the beaches. Between the coastal town of Barrow, Alaska and the Canadian
border, about 300 miles east, researchers counted as many as 200 bears on land,
said Scott Schliebe, director of the Fish and Wildlife's polar-bear project.
Many bears could be seen gathered around whale carcasses near villages like
Kaktovik, which lies in the Arctic National Wildlife Refuge where the Bush
administration is pushing for drilling.
Scientists measured the distances from where the bears were gathered to the
nearest ice sheets at sea and found this correlation: The farther the ice was
from shore, the larger the number of bears were found on land.
Scientists estimate there are 20,000 to 25,000 polar bears world-wide,
including about 2,000 that frequent the Beaufort Sea off Alaska. The latest
population study by federal officials, in 1997, suggested the Alaskan bear
population wasn't endangered. An update is expected by the end of next
year.
Write to Jim Carlton at jim.carlton@wsj.com1
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