Predictions that global warming would wipe out polar bears are based on “scientifically unsound” computer models, according to a new study by a veteran zoologist at the University of Victoria.
Some scientists predicted that shrinking Arctic sea ice threatened to kill off significant numbers of polar bears in the coming decades. But those predictions were based on computer-modeled habitat loss; both models, released in 2006 and 2008, were produced by the International Union for the Conservation of Nature (IUCN) and the U.S. Fish and Wildlife Service (USFWS).
The University of Victoria study found data collected in 2008 contradicted prevailing dire predictions.
“Those mid-2000s survival assessments predicted significant population declines of polar bears would result by mid-century as a consequence of summer sea ice extent reaching approximately 3-5 mkm2 on a regular basis,” zoologist Dr. Susan J. Crockford, who wrote the study, said in a statement.
“Data collected between 2007 and 2015 by field biologists reveal that polar bear numbers have not declined as predicted and no subpopulation has been extirpated [destroyed completely],” Crockford said.
Polar bears became the first species to be listed under the Endangered Species Act (ESA) in 2008 over concerns of future global warming. USFWS predicted bear populations would decline 67 percent as the sea ice they rely on for hunting continued to shrink. But polar bears have only become more abundant, despite warming.
“The hypothesis that repeated summer sea ice levels of below 5 mkm2 will cause significant population declines in polar bears must be rejected,” Crockford wrote. “This result indicates the USFWS and IUCN judgments to list polar bears as threatened or vulnerable based on future risks of habitat loss back in 2006 and 2008 were scientifically unfounded and suggests that similar dire predictions for Arctic seals and walrus may be likewise flawed.”
Recent rumors about polar bear extinction underscore another time when scientists discovered the creatures possess higher resilience to changing levels of sea ice than previously believed. Another new study by Canadian scientists found “no evidence” polar bears are currently threatened by global warming.
“We see reason for concern, but find no reliable evidence to support the contention that polar bears are currently experiencing a climate crisis,” Canadian scientists wrote in their study, published in the peer-reviewed journal Ecology and Evolution.
Polar bears became an icon for environmentalists who claimed that melting Arctic sea ice could kill thousands of bears. Former Vice President Al Gore heavily promoted this viewpoint by featuring polar bears swimming for their lives and drowning in his 2006 film on global warming.
