Science team placing radio collars on polar bears.
Ore. December 21, 2010. “When I first picked up the cub,
she was biting my hand,” explains wildlife biologist Bruce
Marcot. He was trying to calm the squirming cub while its sedated
mother slept nearby.
In the snowy spring of 2009, Portland-based
Marcot traveled with several colleagues onto the frozen Arctic
Ocean north of Alaska to
study and survey polar bear populations. From their base of operations
at the settlements of Deadhorse, next to Prudhoe Bay, Alaska, they
ventured by small plane and helicopter over a wide area of the Beaufort
Sea in a study to determine the bears’ health and to learn
the impact of warming Arctic temperatures on their population.
From the helicopter, we located radio-collared polar bears by their
signals. Then, swooping in like a cowboy after a bull, our lead
scientist would dart the bear with a tranquilizer dart,” explains
then landed, corralled any cubs, and made the sleeping mother comfortable
on the sea ice while we studied her health, weighed her, took measurements,
and changed her radio collar so she could be further tracked.”
a scientist at the Forest Service’s Pacific Northwest
Research Station, is a co-author on the recently published paper
about the impact of climate change on polar bears, in the journal
Nature. He was invited to be a member of the study team because
of his expertise in the analysis and modeling of wildlife population
viability. The study’s lead scientist, Steven Amstrup, of
the U.S. Geological Survey’s Alaska Science Center, had asked
Marcot several years earlier to join a polar bear science team
to advise the U.S. Fish and Wildlife Service. That team examined
and analyzed global polar bear populations, habitats, and climate
change. They presented their results in 2007 before several federal
agencies and the U.S.
Department of the Interior, in Washington,
D.C., and in 2008 the federal government designated the polar bear
as a globally threatened species.
The 2007 study projected that
about two-thirds of the roughly 25,000 polar bears in the world
would disappear by mid-century because
of the effects of climate change and the ice melting in the Arctic.
Now, in the December 2010 Nature study, Marcot and his colleagues
learned that decline of the bear could be mitigated if greenhouse
gas emissions are significantly reduced.
These findings may have
implications for citizens and natural resource managers in the
Pacific Northwest working to manage resources for
a warming climate, particularly in high mountain areas.
past several years, Marcot has collaborated with the U.S. Geological
Survey’s Alaska Science Center, the National Park
Service, the U.S. Fish and Wildlife Service, and others on studies
examining the impacts of climate change on wildlife and the environment.
The most recent study published in Nature, “Greenhouse Gas
Mitigation Can Reduce Sea-ice Loss and Increase Polar Bear Persistence,” was
coauthored by Amstrup; Eric DeWeaver, National Science Foundation;
David Douglas, U.S. Geological Survey, Alaska Science Center; Marcot;
George Durner, U.S. Geological Survey; Cecilia Bitz, University
of Washington; and David Bailey, National Center for Atmospheric
issue of Nature. It appears online at http://www.nature.com/nature/journal/v468/n7326/full/nature09653.html
study’s key findings says Marcot are:
- The results of modeling
regional polar bear populations indicate a potentially brighter
future for the species if global greenhouse
gas concentrations can be
kept under control at levels less than those expected under current conditions.
ice habitat for polar bears will likely not face a “tipping
point” of sudden catastrophic loss over the 21st century,
particularly under a mitigation scenario to reduce global greenhouse
- Even under relatively stringent mitigation reductions
in future greenhouse gas concentration, polar bears in two
of the four ecoregions,
constituting about two-thirds of all current polar bear numbers,
will still incur at least reductions in numbers and distribution.
However, the best future outcome for these populations would
result from a combination of mitigation control of greenhouse
with best on-the-ground management practices to control hunting
and human activities such as levels of shipping, oil and gas
- There will still be significant uncertainty
as to the future of polar bear populations from the combination
all sources of
stressors from climate change, direct human disruption, and other
The team’s study is significant. “It
demonstrates for the first time that—and how—a combination
of greenhouse gas mitigation and control of adverse human activities
in the Arctic
can lead to a more promising future for polar bear populations
and their sea ice habitat,” says Marcot. “It also provides
specific predictions of the future, couched in terms of probabilities
of polar bear population response that decisionmakers could use
in risk management.”
The PNW Research Station is headquartered in Portland, Oregon.
It has 11 laboratories and centers located in Alaska, Oregon, and
Washington and about 425 employees.