Late last week, the state of Alaska announced plans to appeal a federal judge’s ruling to maintain polar bears’ listing as a threatened species under the Endangered Species Act. The lawsuit dates back to early 2008, when Governor Sarah Palin (at that time, blessedly obscure) challenged the Bush administration’s decision to list polar bears as “threatened,” arguing that the basis for the ruling—that climate change was destroying the bears’ habitat—couldn’t be relied upon. “In fact, there is insufficient evidence that polar bears are in danger of becoming extinct within the foreseeable future,” the future vice-presidential candidate wrote to an unsuspecting public in a January 2008 New York Times op-ed (really!). That judgment is still the basis for the state’s objection to the listing: Alaska’s current governor, Sean Parnell, argues that the bear population has quadrupled since the 1960s, and the state’s Attorney General says the decision relies on “uncertain predictions of future threats.” Is that true?
To put it lightly, scientists tend to have a different view. One 2010 paper by six geologists and biologists, to offer just one example, is bluntly titled “Climate change threatens polar bear populations.” (First things first: The scholars write that the claim the polar bear population has increased fourfold “has no basis in the scientiﬁc literature.”) And in tracking a polar bear population on the northern coast of Alaska, the scholars found troubling developments: The “ice-free period” in that region, they report, “increased by approximately 50% between 2001–2003 and 2004–2005.” Polar bears depend on ice for a habitat—they use ice to capture prey, for instance, and as ice disappears, they are required to swim unusually long distances (which can result in starvation or drowning). The authors conclude that “global warming is likely to have profoundly negative effects on future growth rates of polar bear populations.” And that claim is hardly an outlier. One 2007 study undertook an expert survey and found that “most experts project a substantial decline in polar bear range and population size across the Arctic,” as well as a decline in population size in several other regions, including the Chukchi Sea, which lies off the northwestern Alaskan coast.