Leading article: A worthless gust of hot air

Taking part in a traditional Japanese Tanabata festival in Hokkaido this week, George Bush tied a piece of parchment to a bamboo tree. On the parchment, the President of the United States outlined his dearest wishes for the future of the planet. And there is evidence of yet more wishful thinking in the G8's communiqué on climate change from Hokkaido.

The leaders of the world's eight largest economies committed themselves to "avoiding the most serious consequences of climate change". They also set themselves a goal of halving global emissions by the middle of the century. It is hard to fault the target. But how is it going to be achieved?

There is no detail in the communiqué; no medium-term targets; no commitment to agreeing a legally binding successor to the Kyoto protocol at Copenhagen next year. There is not even agreement on the date from which CO2 cuts will be measured. The European Union is measuring its own targets from 1990 levels, but the Japanese Prime Minister spoke this week about using the considerably higher 2000 level as a benchmark. By far the biggest problem, though, is the lack of detail on the method. These leaders can set all the long-term goals they like, but without realistic means of achieving them, any document they produce will simply be a gust of hot air.

We know the roadblock to a serious deal on tackling climate change well enough. The Bush administration refuses to sign up to any successor to Kyoto without a requirement on China and India to begin cutting their emissions too. China and India, with justification, argue that since most of the greenhouse emissions in the atmosphere were put there by G8 nations, it is up to us to take a lead.

The latter is the only practical and moral way forward. Through a mixture of national taxation and international carbon trading, governments in the developed world must begin to reduce emissions steadily. The carbon-capturing and renewable energy technologies that will be developed as our economies decarbonise can then be transferred to the likes of China and India. The world will then have a possibility of achieving "green growth".

It is true that all nations must be included in a new global emission-cutting agreement. And all must accept their responsibilities. After all, the dire consequences of climate change will be felt universally. But unless those nations that are best placed to begin the difficult work of reducing emissions accept the role of leadership, catastrophic climate change is inevitable. Despite all the spin from Hokkaido, what we have had from the G8 is another staggering abdication of leadership.