The conversion of President George W. Bush to a "long-term goal" to cut emissions could be bad news for the international markets in trading carbon emissions, writes Fiona Harvey.

The White House made clear that Mr Bush's proposals would not include a global emissions trading system of the kind set up under the Kyoto protocol on climate change. Under the treaty, rich countries must cut their emissions by about 5 per cent compared with 1990 levels by 2012. But rather than achieving all these cuts themselves, governments and companies in the developed world can fund projects that cut emissions - such as wind farms or solar power - in developing countries. The projects are awarded carbon credits that can be bought by rich countries to count against their Kyoto targets.