In this June 15, 2014, photo released by the U.S. Geological Survey, a polar bear dries off after taking a swim in the Chukchi Sea in Alaska. A polar bear has attacked and killed two people in a remote village in western Alaska, according to state troopers who said they received the report of the attack on Tuesday. Brian Battaile/U.S. Geological Survey via AP hide caption
Winter swimmers enjoyed an icy dip in Poland's Garczyn lake last February. Recorded air temperature was around 14 degrees Farenheit, and a large ice hole had to be cut to allow the lake bathing. NurPhoto/Getty Images hide caption
A polar bear attacked and injured a polar bear guard who was leading tourists off a cruise ship on the Svalbard archipelago between mainland Norway and the North Pole. The polar bear was shot dead by another employee, the cruise company said. Gustav Busch Arntsen/AP hide caption
The midnight sun shines across sea ice along the Northwest Passage in the Canadian Arctic Archipelago, July 23, 2017. David Goldman/AP hide caption
Climate skeptic Willie Soon has argued in the past that too much ice is bad for polar bears. An investigation into Soon's funding found he took money from the fossil fuel industry and did not always disclose that source. iStockphoto hide caption
A lone polar bear poses on a block of arctic sea ice in Russia's Franz Josef Land. iStockphoto hide caption
Arturo, the only polar bear in Argentina, lives in captivity at a zoo in Mendoza. The plight of the "sad bear" has spawned more than 400,000 signatures on a petition to get him moved to a "better life" in Canada. AFP/Getty Images hide caption
Siku on Dec. 8, 2011. Skandinavisk Dyrepark/AP hide caption