White House vs white bear: Judge says Bush must decide whether to save the polar bear as the ice melts

It's a classic stand-off between one of the world's best loved animals and one of its most unpopular leaders, between the planet's largest bear and its most powerful man. And it comes to a head this week.

On Thursday, by order of a federal judge, George W Bush must stop stalling on whether to designate the polar bear as a species endangered by global warming. The designation could have huge consequences for his climate-change policies; his administration would, by law, have to avoid doing anything that would "jeopardise the continued existence" of the mammal whose habitat is melting away.

Unsurprisingly, perhaps, the administration has sought to avoid the decision. It has delayed it for months, and was seeking to put it off for months more. But two weeks ago Claudia Wilken, the judge, ruled it had long been "in violation of the law", and ordered it to act by 15 May.

Polar bears depend on the sea ice for hunting, mating and moving around. Last summer, 200,000 square miles of ice – more than twice the size of Britain – melted for the first time, shrinking the frozen sea to an extent that the Intergovernmental Panel on Climate Change predicted would not occur until 2050. More and more scientists believe the Arctic could be ice-free in summer in little more than 20 years.

In February 2005, US conservation groups petitioned their government to list the polar bear as the first species to be endangered by global warming, starting a long battle with the White House. The conservationists have won the argument. A study commissioned by the Secretary of the Interior, Dirk Kempthorne, from the US Geological Survey concluded that two-thirds of the world's 20,000-25,000 polar bears would vanish by 2050.

In December 2006, the administration was forced by court action to propose designating the bear. This was meant to be finalised in January 2008, but has been delayed until now. In the meantime the administration has sold oil companies 448 rights to drill in prime polar bear habitat for a staggering $2.6bn (£1.3bn).

Kassie Siegel, of the Center for Biological Diversity – which has led the fight – says: "Polar bears need our help now, not whenever the Bush administration feels like getting round to it."