這項聲明終止了一個3年的法律爭議，這項爭議主要訴求是北極熊棲地在全球暖化衝擊下，北極熊是否應該列為「瀕危物種法案（Endangered Species Act）」中的生存受威脅物種。三個環保團體首先在2005年提出此項北極熊列冊保護的請願書。
美國漁業暨野生動物局（U.S. Fish and Wildlife Service）錯失在2008年1月份作出決議的截止日期，然而在法院命令下，仍必須在5月15日作出決議。
一項在2007年秋天由美國地質調查局（the U.S. Geological Survey, USGS）發表的關鍵性科學研究顯示，由於氣溫上升使海洋冰層融解的狀況加劇，包括美國境內在內的全球2/3北極熊將可能在2050年之前消失，因為北極熊必須仰賴海洋冰層來獵捕食物。
The Bush administration reluctantly declared the polar bear a threatened species today, concluding that the loss of Arctic sea ice has put the future of the iconic species in peril. But the administration also took steps to ensure the decision will not require new efforts to tackle global warming or put new restrictions on oil and gas development in polar bear habitat.
The announcement ends a three-year legal dispute over whether the polar bear should be listed as threatened under the Endangered Species Act because of the impact of global warming on its Arctic habitat. Three conservation groups first filed a petition requesting the decision in 2005.
The U.S. Fish and Wildlife Service missed a January deadline to issue a decision and was under a court order to finalize its decision by Thursday.
"I wish the decision could be otherwise," U.S. Interior Secretary Dirk Kempthorne told reporters, bemoaning the "restraints of the inflexible law that guides me."
Kempthorne said the growing body of evidence that the polar bear is at risk from melting sea ice left him with little choice but to list the species. The Endangered Species Act requires that the decision is supported by the best available science.
Although there are an estimated 22,000 polar bears spread across the Arctic, including some 4,700 within the United States, there are worrying signs that rising temperatures have put the species in jeopardy.
A key scientific study issued last fall by the U.S. Geological Survey, USGS, found that two-thirds of the world's polar bears, including all those within the United States, could disappear by 2050 due to increased sea ice melt caused by rising temperatures. Polar bears rely on sea ice to hunt for prey.
The USGS research came amid startling evidence that the Arctic is melting faster than predicted, as ice loss last year reached levels not predicted to occur until mid-century. Some scientists now predict the Arctic could be ice-free in the summer as early as 2012.
The loss of habitat puts polar bears at risk of becoming endangered in the "foreseeable future," Kempthorne said, and thus meets the criteria for the species to be listed as threatened.
Listing the polar bear requires federal agencies ensure that any action they authorize, fund, or carry out will not jeopardize the polar bears' continued existence or adversely modify their critical habitat.
In addition, the Fish and Wildlife Service must prepare a recovery plan for the polar bear, specifying measures necessary for its protection.
But the Interior chief immediately took steps to limit the impact of the listing and make sure it "isn't abused to make global warming policies."
He stressed that decision will not open the door to restraints on activities that produce carbon dioxide and other greenhouse gases.