The US government has opted¹ to retain a Bush-era rule that limits protection for polar bears from the effects of global warming.

美国政府选择保留布什时期因为全球变暖而对于北极熊采取的的有限保护措施。

The US listed polar bears as an endangered species last year

Environmental groups had been calling for the rule to be lifted, and the US Congress had given Interior Secretary Ken² Salazar the power to do so.

Mr Salazar said lifting the rule would create "uncertainty³ and confusion".

The rule means the government will act only against threats to polar bears that arise in their Arctic habitat.

'Industry pressure'

The US Environmental Protection Agency designated（指定的，特指的） polar bears an endangered species last year, because their habitats were disappearing as ice-caps melted.

Environmentalists seized on the ruling, arguing that endangered species were entitled to heightened protection under US law and that the government was therefore obliged to（不得不，必须） crack down on the carbon emissions⁵ causing global warming.

The Endangered Species Act bars federal agencies from "taking actions that are likely to jeopardise（使遭受危险） the species or adversely⁶（逆地，反对地） modify its critical habitat", and lays down civil and criminal penalties for people that kill or injure designated animals.

But the Bush administration passed a rule exempting⁷（免除） "activities outside the bear's range, such as emission⁴ of greenhouse gases" from prohibition⁸（禁止）.

It is this rule that the Obama administration has decided⁹ to let stand.

"The Endangered Species Act is not the proper mechanism¹⁰ for controlling our nation's carbon emissions," Mr Salazar said.

"Instead, we need a comprehensive energy and climate strategy that curbs¹¹（抑制，束缚） climate change and its impacts."

But the decision has angered environmental groups.

Mr Salazar's move "only serves to cement the Bush administration's legacy¹² of ignoring global warming science, thus putting the polar bear at further risk of extinction¹³", said Melanie Duchin, a Greenpeace campaigner in Alaska, in a statement.

"Regrettably, it seems to reflect an emerging willingness by the Obama administration to ignore clear scientific imperatives¹⁴（命令，诫命） on global warming in the face of industry pressure."