Scientists hope new research linking polar bear deaths and climate change will help protect arctic wildlife

For 15 years, a federal standard has prevented regulators from considering planet-warming emissions when enforcing the Endangered Species Act, a federal law aimed at protecting species at risk of extinction.

But now, researchers at the University of Washington and Polar Bears International believe they’ve found a way to close that loophole. It's a finding that they hope will actually protect polar bears — the poster children for climate change — for real this time.

Scientists behind a recent study found that polar bears can go without food for hundreds of days. However, around 117 days of fasting, female polar bears face a decision to feed themselves instead of their cubs, making the future survival of polar bears more difficult.

"As the sea ice melts in the summertime, seals can still catch fish and other organisms that they feed on, while swimming around all summer long," said Steve Amstrup, a co-author of the study and chief scientist emeritus at Polar Bears International. "But polar bears can't swim as well as seals can, so that potential food source is unavailable when sea ice is unavailable."

By connecting greenhouse gas emissions to shrinking ice sheets, and those shrinking ice sheets to the loss of feeding opportunities for polar bears, Amstrup and his co-author, Cecilia Bitz, believe they've developed a methodology that clearly links new emissions and threats to endangered species.

“We now can parse the impact of the emissions from any particular action or a group of actions from the historic emissions,” Armstrup said.

That methodology would benefit other arctic animals threatened by climate change, such as penguins, which also depend on ice, he added.

In 2008, researchers and conservationists submitted a petition to designate polar bears as “threatened” under the Endangered Species Act. With arctic ice sheets disappearing due to greenhouse gas emissions, petitioners hoped the designation could require more scrutiny of new emissions-prone projects like gas pipelines.

"The law requires any federal agency that's going to carry out a project, or fund it or authorize it, to look at whether their project may jeopardize the continued existence of a species or adversely modify its critical habitat," said Kassie Siegel, senior counsel and the director of the Climate Law Institute at the Center for Biological Diversity.

"Usually, the Endangered Species Act doesn't actually stop projects, but it does make them much better and much less harmful through this important process," she added.

Siegel was an early proponent of designating polar bears as threatened by climate change. It was the first animal to receive such a designation.

The petition was approved — with one caveat.

In the “Bernhardt memo," named after Department of the Interior solicitor David Bernhardt, lawyers for the Department of the Interior agreed that polar bears were losing habitat due to a cumulative buildup of greenhouse gasses. However, scientists had yet to provide a framework proving a direct link between the emissions of new projects and that of historic emissions.

The memo became a guiding document for enforcement of the Endangered Species Act, and set a standard that the law couldn’t be used to measure or limit a project’s greenhouse gas production.

"For example, if you're going to approve a coal-fired power plant near the banks of a river that has an endangered fish, you're going to look at ways to try to minimize that harm," Siegel said. "But what the memo says is that greenhouse emissions are somehow different."

For their part, Amstrup and Bitz are optimistic that their new research will push the Biden Administration to rescind the Bernhardt memo, returning the power to consider emissions under the Endangered Species Act.

"In a sense, we're all sea ice dependent species in that if we allow the world to warm to the point where polar bears go extinct, it is going to be a bad thing for all of us," Amstrup said. "And conversely, if we save polar bears, it'll benefit the rest of life on Earth, including us."

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