The environment itself is not the burning issue at the White House - but the price of gas is.

The pressure on the US president to do something on global warming along the lines sought by other world leaders comes not from traditional green activists, but from rising oil prices.

Every increase causes a flutter of concern among drivers on supermarket forecourts, where the larger bill for filling a tank means less money to spend on consumer goods - so threatening to put a brake on general economic growth.