So finally Bush has gone and Obama has arrived. For anyone watching yesterday’s inauguration, there was a real sense of history being made.

But as Obama made his inauguration address, everyone was looking for clues as to what an Obama presidency will really mean in practice.

For those of us who write on oil, energy and climate change, there was, not surprising evidence that Obama will steer a radically different course to Bush. After years of Bush’s refusal to do anything meaningful on climate, Obama pledged to “roll back the spectre of a warming planet.” Each day, argued the new President, “brings further evidence that the ways we use energy strengthen our adversaries and threaten our planet.”

For those who have despaired over the last eight years how the Bush Administration abused and misued the science of climate change amongst others, there was relief that Obama argued he would “restore science to its rightful place”.  Talking about his green revolution, he pledged to “harness the sun and the winds and the soil to fuel our cars and run our factories.”

The rhetoric is unrecognisable to that of Bush, and now we wait to see what specific policies will follow.   The first real measures aimed at dealing with climate change should emerge soon in Obama’s 825-billion-dollar economic stimulus package.

Michael Levi of the Council on Foreign Relations argues that “There is no question in my mind that there will be measures from the stimulus bill aimed at among other things cutting emissions. The stimulus package will have spending aimed at expanding renewable energy production, at improving energy efficiency in buildings and at reforming the electric power grid.”

But for all the hype will Obama deliver on climate? Press reports are all about how his “room to maneuver may be limited, cramped on one side by the US recession and on the other by the scant time before the December 2009 deadline for completing the new UN climate treaty.”

Elliott Diringer of the Pew Center for Global Climate Change argues that rather than work for a full treaty to be finalised by Copenhagen its “more practical to aim for an intermediary agreement. Maybe an agreement on the architecture of the post 2012 framework, not the specific commitment each country will have, but an overall architecture.”

That would be an unmitigated disaster. There have been too many delays already. Obama has to show true leadership and play his pivotal role in a radical final agreement at climate change.

Because when Obama said “On this day, we come to proclaim an end to the petty grievances and false promises, the recriminations and worn out dogmas, that for far too long have strangled our politics,” he  could well have been talking about the politics of climate change.