The 5-Minute Briefing: America's 'Kyoto' pact with Asia

What is the significance of the new pact on climate change announced yesterday, linking the US and Australia with four leading Asian countries - China, India, Japan and South Korea?

The Asia-Pacific Partnership on Clean Development and Climate aims to use new technology to reduce emissions of greenhouse gases such as carbon dioxide (CO2) from power stations, without the necessity of the mandatory reduction targets set by the current international climate treaty, the Kyoto protocol, which the US and Australia have refused to ratify, claiming it would harm their economies.

What does the new treaty involve?

The signatories, led by the United States - the world's biggest polluter and emitter of CO2 - say that they will cut back their emissions of greenhouse gases while still allowing their economies to grow by the development of new technology for low-carbon energy generation, such as clean-coal-burning and carbon capture and storage (the trapping of CO2 from power station exhausts and storing it deep in the ground or under the seabed). This technology is being actively developed and is expected to come on stream in the next five years.

By how much will the six countries cut back their emissions under the new pact?

No one knows. There will be no mandatory targets.

What is the relationship of the new pact with the Kyoto protocol?

It is an alternative, offering a way forward diametrically opposed to that of Kyoto: the approach of business-as-usual and the technological fix, in place of "belt-tightening", the cutting-back on energy use which Kyoto demands.

Will it actually undermine the Kyoto treaty, as some environmentalists claim?

Their fear concerns what is known as the second commitment period of Kyoto, which begins in 2012 - the period in which the developing countries that have ratified the treaty, such as India and China, may be expected to take on emissions reductions targets of their own. At present, in the first commitment period, only the industrialised countries have targets - which was one of the principal US objections to the treaty. The fear is that the new pact may offer the developing countries an excuse not to come on board in Kyoto stage 2 - they can say that they are doing something to tackle the climate problem, and do not need mandatory targets.

But some analysts think that nations such as China and India do not need excuses, and will be governed in their actions by a hard-headed assessment of risks and costs. They will come into stage 2 if they think it worthwhile; if they don't think it is worthwhile, they will stay out anyway, and the current pact will make no difference.

What view do other governments take of the pact?

Most governments, including Britain's, are giving it a cautious welcome, and waiting to see what it actually leads to.