The Daily Telegraph is reporting (here) that China has voluntarily committed to a 40-45% reduction in greenhouse gas (GHG) emissions reductions per unit of GNP. It's very difficult to judge just what this means for total Chinese emissions; it's not even clear whether it would amount to a nominal reduction in emissions as against 2005, let alone 1990, given the rate of growth in the Chinese economy and its emissions. Moreover, like the Obama Administration's proposed reduction in emissions (which I posted about earlier), the commitment lacks credibility - there is no reason for any other country to believe that China will actually meet the commitment.
That said, it is worth recognizing that China is, at least, engaging with the rest of the international community on the need for GHG emissions reductions. As the world's largest emitter (though not per capita), Chinas's participation in international climate policy is absolutely essential. Today's promise to reduce emissions per unit of production is a very small step in a good direction. And getting the direction right on GHG emissions would be a very nice change in climate policy.