The seeming impossibility of turning the supertanker of resistance to change in the world's greatest energy consumer has been the despair of many climate change campaigners.

A combination of lack of public awareness and powerful industry lobbying of already conservative federal authorities made the timelines needed to swing a real change in  consumption seem so long as to be pointless in the face of the predicted ticking up of global temperatures in the coming decades.

Even glimmers of hope such as energy-saving initiatives by individual states or the swing by parts of the religious right behind the moral rectitude of carbon cutting, gave little comfort in the face of that figure of 20 tonnes of carbon emitted every year by the average US citizen. (A study by students at the Massachusetts Insitute of Technology found that even the lowest consuming Americans, living rough and eating in soup kitchens accounted for a carbon load twice as heavy as the global average.)

In the past couple of days though, there has been a sign that things can change faster than expected and the juggernaut has taken a slightl nudge sideways with President Obama's edict to the auto industry that it is are going to have to meet existing fuel efficiency targets four years earlier than expected in 2016. This wasn't just the result of a new white-knight occupant of the White House sweeping all objections before him; Obama has shown himself at least partly susceptible to Washington realpolitik over the end of military trials for terror suspects held at Guantanamo Bay.

His ability to get the once overmighty auto industry to tow the line is directly linked to their economic woers and the fact that they are now dependent on the government's help for survival, so they have to take what is served up to them.

My point isn't that this means things are going to be rosy now, the prospects are still pretty bad for slowing anthropogenic climate change and it will still take a lot more action to shrink the carbon footprints of those in the US and other western countries. it's more that you would have got long odds 18 months ago on either of the two changes that have enabled this small improvement: the economic reversal and Obama's election.

It's an example of the way the landscape can change a lot faster than we allow for, and in the words of the Pet Shop Boys, sometimes "just when you least expect it, just what you least expect."

Louis