With all the attention devoted to the elections, a remarkable story has been neglected: By 2009, China is now expected to be the world's leading emitter of greenhouse gases, surpassing the United States. This is a stunning finding, because even recent estimates had seen the United States as no. 1, and China as no. 2, as late as 2020 or 2025.
In terms of international controls on greenhouse gases, the explosive emissions growth in China raises enormous challenges. Both the United States and China have resisted such controls -- and apparently China's resistance has been even firmer than that of the U.S. It is certainly imaginable that the U.S. will accept an international accord of some kind within the next five years -- at least if China and other developing countries can be persuaded to participate. But will China participate? Its economic interest suggests otherwise. As China's economic growth becomes increasingly dependent on fossil fuels, the costs of stabilizing its emissions will remain very high, at least in the absence of some kind of technological breakthrough.
There are also important issues of equity in the background. The U.S. is, and will remain, the largest per capita emitter of greenhouse gases, and some people (including many Chinese officials) believe that what matters is per capita emissions, not aggregate emissions. Moreover, the U.S. has contributed far more than China to the existing "stock" of greenhouse emissions. It is conceivable that the U.S. would recognize the latter point in an international accord, but it is not conceivable that the U.S. would allow emissions rights to be allocated on a globally equal per capita basis.
The largest point is that while much of the world has focussed on the American reluctance to accept controls on greenhouse gases, China is now looming as the largest emitter on the planet. The problem is that the United States will not likely accept any agreement in which China does not participate; China is not likely to agree to any accord in which the United States does not participate; and in view of the different perspectives of the two nations, it is not easy to sketch an accord that both nations would find agreeable.