As the United National climate conference draws near (December 3-14 in Bali, Indonesia), it's worth considering some basic greenhouse gas emissions data that will inform the negotiations.

According to some estimates, China has just surpassed the US as the world's largest annual emitter of carbon dioxide. Neither the US nor China is covered by the Kyoto Protocol: the US because the Bush administration rejected the protocol; and China because the protocol does not cover developing countries, even rapidly industrializing countries such as China.

The administration rejected the protocol, in part, because it did not include commitments by China and other fast-developing countries to reduce emissions. China argues that mandatory emissions cuts would constrain economic development and that it should be allowed to use its energy resources -- including huge coal reserves -- to the maximum extent in order to achieve the prosperity enjoyed by industrialized nations.

However, the US and China will have to be brought into the fold if the international community hopes to develop an effective global climate regime to succeed Kyoto after 2012. The US might offer a better opportunity, particularly if the US Congress passes legislation in the next year or two mandating emissions reductions; and given the possibility that the next US administration would support mandatory reductions and a cap-and-trade system. That, in turn, could provide enough of an incentive, with energy efficient technology/financial sweeteners, for China to agree to limit the growth of -- although not actually reduce -- its emissions.

One of the guiding principles underlying the Kyoto Protocol, and the reason it doesn't cover developing nations, is that the industrial nations had to take the first steps to reduce emissions because they are responsible for most of the greenhouse gases currently in the atmosphere. Between 1850 and 2000, the US share of global total emissions was 30%; the nations that now comprise the European Union accounted for 27%; and China, 7%, much of that in recent years.

In 2004, the US accounted for 22% of global greenhouse gas emissions from energy use; fast-closing China accounted for 18%. (US per capita emissions were five times China's.) By 2030, China's emissions are projected to increase 119% from 2004 levels; US emissions are projected to increase 23%, according to EIA. Clearly, the success or failure of international efforts to combat climate change rests heavily on both countries.