In an 85-page opinion, U.S. District Court Judge Dana L. Christensen rejected as illegal a 2014 decision by the U.S. Fish and Wildlife Service to deny the wolverine protection under the Endangered Species Act.

Central to the case is a key, necessary ingredient for wolverine habitat: snow. Scientific research has shown that the famously tough creature relies on snow to survive, but temperature increases associated with climate change mean there is and will be less of it.

The judge’s opinion sharply questioned attempts by the federal government to challenge this basic premise.

“If evidence shows that wolverines need snow for denning purposes, and the best available science projects a loss of snow as a result of climate where and when wolverines den, then what sense does it make to deny that climate change is a threat to the wolverine simply because research has yet to prove exactly why wolverines need snow for denning?”

There are only an estimated 300 remaining wolverines in the continental U.S. This ruling could bolster their survival, while potentially setting the tone for future conservation decisions about species affected by climate change.

According to the court opinion, “The wolverine's sensitivity to climate change, in general, cannot really be questioned. In fact, many believe—similar to the polar bear—that the wolverine may serve as a land-based indicator of global warming.”

The Fish and Wildlife Service’s reasoning for refusing to list wolverines under the Endangered Species Act “borders on the absurd,” according to the court opinion. The judge went on to criticize the agency for buckling under political pressure from Western state agencies instead of basing its decision on the best available science.

“Of the numerous Western states which urged the service not to list the wolverine … not one provided any scientific evidence directly rebuffing the study's conclusions. On the contrary, internal service documents expose the likely motives—freedom from perceived federal oversight, maintaining the public's right to trap—behind the states' efforts against listing the wolverine.”

The opinion specifically rejected arguments made by the Montana Department of Fish, Wildlife and Parks. That state agency sought to prevent wolverine protection by attempting to discredit research by a team of scientists led by Kevin McKelvey. The team documented evidence of the dramatic effects of climate change on wolverine habitat.  Judge Christensen wrote:

“Montana's attacks against McKelvey (2011) and its authors, all scientists at the service's Rocky Mountain Research Station, are particularly weak and unsavory. Not only did Montana cavalierly dismiss the study as a ‘hypothesis,’ breezing right by its well-supported conclusions, but Montana Fish, Wildlife and Parks accused the service biologists of cooking the science in favor of listing with the intent of receiving additional funding.”

The opinion also rejected comments from Stephen Torbit, an assistant regional director at the U.S. Fish and Wildlife Service, who was critical of McKelvey’s scientific findings.

“The court views Torbit's comments as nothing more than an unpublished, unreviewed personal opinion, elicited by [U.S. Fish and  Wildlife Service Regional Director Noreen] Walsh in the eleventh hour to backfill her foregone conclusion to withdraw the Proposed Rule” that would have protected wolverines.

Judge Christensen dismissed Torbit’s arguments as weak and “insufficient” compared to the extensive scientific research presented in the McKelvey study. The judge termed the Fish and Wildlife Service’s reliance on Torbit’s comments “the essence of arbitrary and capricious decision making.”

Judge Christensen understood that protection under the Endangered Species Act is an existential issue for the wolverine.

“No greater level of certainty is needed to see the writing on the wall for this snow-dependent species standing squarely in the path of global climate change,” his opinion concluded.

“If there is one thing required of the [Fish and Wildlife] Service under the [Endangered Species Act], it is to take action at the earliest possible, defensible point in time to protect against the loss of biodiversity within our reach as a nation. For the wolverine, that time is now.”