What's more surprising is that the US - historically, the world's biggest emitter - actually seems to be walking the walk. It is on track to meet Obama's 2009 pledge to cut US emissions by 17 per cent, from 2005 levels, by 2020. The target could even be exceeded, which may give a boost to the long-stalled international climate talks.

There's no realistic possibility of passing new laws to curb US greenhouse gas emissions - Republican control of the House of Representatives will see to that. So some pundits were scratching their heads at Obama's climate pledge in last week's inaugural address. But independent analyses paint an upbeat picture of the progress he can make simply by using existing laws.