But in reality there was never much chance the US would sign up to a Kyoto Protocol-style agreement in Gleneagles. It is for this reason that Britain, as chair of the G8, has brought proposals to the negotiating table designed to shift the approach in a new direction. And there is still potential for progress at Gleneagles.
One of the items on the agenda is a bundle of initiatives on maximising the developing world's use of "clean" energy. There is likely to be an agreement to encourage new technology that will minimise carbon emissions. The technology route to lower emissions is one for which Mr Bush has a particular enthusiasm. While this is no doubt because it is acceptable to his friends in the US oil industry, it is none the less welcome.
Many of the developed world's power stations are old and inefficient. New techniques such as carbon sequestering - which involves extracting and storing CO2 from power station gases - have the potential to affect the rate of global warming. So too does the development of a new generation of environmentally friendly cars. Hybrid cars are already available, as are vehicles powered by hydrogen fuel cells. The role of the G8 governments is to provide tax breaks for manufacturers leading the way in this technology. They should also provide incentives for consumers to buy such vehicles.
Another topic that will be discussed at Gleneagles is how to go about forming a partnership with the developing world with respect to global warming. Whenever the question of how to tackle the rising carbon emissions of countries such as China and India is raised, those countries become agitated. They regard it as an attempt by the West to curtail their development. But it need not be a zero sum game. A G8 deal with China to incorporate carbon sequestering technology on to its new power stations as soon as the technology becomes available could benefit the whole world.
The greatest potential stumbling block by far at Gleneagles is the mutual agreement on the science of global warming. It remains doubtful that the US will agree to recognise that there is a scientific consensus that man-made global warming exists and that it is a serious threat to life on earth. If agreement cannot be reached, the rest of the G8 leaders should not be afraid to isolate the US by endorsing the statement without the world's greatest producer of greenhouse gases. This would be preferable to adopting a meaningless verbal construction merely to keep the US on board.
Kyoto is almost obsolete, although not for the reasons put forward by the Bush administration. The problem with Kyoto is that it does not go far enough. The targets for reducing carbon emissions are too low to have a substantial impact on the process of global warming. And the protocol does not include developing countries. Any reductions would be more than equalled by increasing emissions from countries such as India and China.
This summit in Gleneagles has the potential to make progress. But the truth is that there will not be a great leap forward until the world develops - and agrees upon - a more rigorous and comprehensive successor to Kyoto. And that is not something that the world can afford to wait for very much longer.