For the first time in a long time, there’s almost a glut of good news flooding green media: not only did Obama commit last week to attend December’s crucial climate talks in Copenhagen (COP15), he’s also named a target US carbon reduction of 17% below 2005 levels by 2020. The announcements have been getting major airtime and print space in both public and private media. And no wonder – this is huge.

The world has been waiting with baited breath for answers to both the question of a US carbon reduction target and the question of who will represent the US at COP15. Many didn’t expect happy answers to either question. Obama’s decisions to attend COP15 and to announce a carbon target will serve as much-needed concrete evidence that America is serious about cracking down on climate change. We’re no longer the world’s biggest polluter – China has surpassed us – but per capita we still send up far and away more greenhouse gasses than any other nation. Developing countries are eager to see the US practice the CO2 reductions it preaches, and commit to playing a leading role in a global climate treaty.

Grist’s Bill Scher doesn’t want us all to forget that “control of Copenhagen’s outcome is far from being solely in Obama’s hands,” that “China and India, always using America as an excuse for irresponsible growth, need to step up on emissions targets,” or that “the EU, always crowing about its emissions targets, needs to step up on financial assistance to developing nations.” Well, true. But (as Scher also concedes) the firm stand Obama’s taking is a major step toward a global climate treaty, and cause for true thanksgiving.