U.S. President Barack Obama came to office promising hope and change. But on climate change, he has followed in the footsteps of his predecessor, George W. Bush. Now, should the climate summit in Copenhagen fail, the blame will lie squarely with Obama.

The folder labeled "climate change" that George W. Bush left behind for his successor on the desk of the Oval Office in January likely wasn't a thick one. Although Bush once said that America is overly dependent on oil, he never got beyond that insight. He was too busy waging war on Iraq and searching for a legal basis for extraordinary renditions to pay much attention to the real threat facing humanity. "Forget the climate" seems to have been Bush's unofficial motto.

But few people expected that Barack Obama, of all people, would continue his predecessor's climate change plan. When he took office at the beginning of 2009, it was clear that the success of the U.N. Climate Change Summit in Copenhagen in December depended almost entirely on the U.S. - that America needed to take a clear leadership role on a problem that could shake civilization to its very core.

Only if the U.S. manages to reduce its excessive energy consumption, commit itself to mandatory CO2 emission reduction targets and help finance poorer countries' move away from oil is there still a chance that countries like China and India will do the same and that a dangerous warming of the Earth can be stopped. On the weekend, Obama announced that there would be no agreement on binding rules in Copenhagen. It was the admission of a massive failing - and the prelude to a truly dramatic phase of international climate policy.