Arctic polar bears are becoming canaries in the mine, warning of the consequences of global warming. Even the Bush administration has been forced, grudgingly, to acknowledge this. Last week, it proposed to put the bears on the threatened species list because rising temperatures in the Arctic are depriving them of the ice platforms from which they hunt seals. But Interior Secretary Dirk Kempthorne acted only under pressure of a suit from environmental organisations, and has refused to admit that greenhouse gas emissions from vehicles and smokestacks are causing the ice loss and would have to be cut back to save the bears’ habitat. Bears have been seen cannibalising one another and have drowned during ever-longer swims. If the US does not quickly take a leadership role on this issue, polar bears will be only one of many species to suffer. So will human beings.

In 2000, the Intergovernmental Panel on Climate Change under the auspices of the UN reported on the strong evidence that global warming in recent decades has been “attributable to human activities.” The US National Academy of Sciences confirmed the UN panel’s finding. With all this evidence, it should not take polar bear cannibalism for the president to stop pretending that an environmental disaster is not in the making.