Polar bears’ new peril: faster-moving sea ice

ANCHORAGE, Alaska — Rapid global warming has sped up the movement of sea ice off Alaska’s coasts, and already at-risk polar bears are paying a price, a new U.S. study says.

Most sea ice moves throughout the year and the bears are on a perpetual walk to stay within their preferred habitat, said U.S. Geological Survey research ecologist George Durner, lead author of the study.

He compares it to living on a treadmill that has picked up speed because ice is thinner, more brittle and moving faster because of wind and ocean currents.

“Increased sea ice drift rates likely exacerbate the physiological stress due to reduced foraging opportunity already experienced by many polar bears in the warming Arctic, adding yet another ‘straw to the camel’s back,’ ” Durner said.

Polar bears were listed as threatened under the Endangered Species Act in 2008 amid the alarming loss of summer sea ice in recent decades and climate models indicating the trend would persist. However, the government said the act would not be used to regulate greenhouse gas emissions.

The U.S. polar bear recovery plan says that without action to address climate change — the primary cause of diminishing sea ice — it is unlikely that polar bears could be saved.

The plan released in January noted positive signs such as emission goals in the Paris climate agreement. President Donald Trump, however, withdrew from the international pact this month, arguing it disadvantaged the U.S. “to the exclusive benefit of other countries,” leaving U.S. businesses and taxpayers to absorb the cost. Trump also has called for expanded petroleum development in polar bear habitat, including offshore Alaska waters and parts of areas the National Petroleum ReserveAlaska and the Arctic National Wildlife Refuge.