Leading article: Kyoto is a hard, but not impossible, act to follow

The conference that opens today on the Indonesian island of Bali is one of the most important international gatherings of this year, perhaps the most important. Held under the aegis of the United Nations, it brings together representatives of 191 countries and its purpose is to start the process of agreeing a new treaty to carry on where the Kyoto Protocol on climate change leaves off in 2012. That the conference is taking place in Bali not only one of the most beautiful and welcoming of islands, but a place that would be among the first to feel the deleterious effects of climate change if the sea level rises should only underline for the delegates the seriousness of the task in hand.

The need for a new treaty should be far beyond dispute, as evidence of the gravity of the threat from climate change continues to mount. Today we report a study showing that the tropical climate zone is expanding towards the poles faster than any of the existing computer models had forecast. This trend is likely to make many regions that currently enjoy a temperate climate drier or more stormy in other words, into less hospitable places to live. The American south-west, Australia and swathes of the Mediterranean could be hit, with water supplies and agriculture jeopardised.

With or without new evidence, delegates to the Bali conference have their work cut out. While there may be a growing consensus about the nature and scale of the threat, there is much less agreement on how to tackle it. Increasingly, coming to the fore is the disparity between the interests of the industrialised world and those of countries, such as India and China, whose rapid development is accompanied by an equally rapid increase in carbon emissions. What measures can, or should, be taken to curb this rise, whether voluntary action could suffice, and how far the rich world would be prepared to underwrite the measures the poor world needs to take in order to cut carbon emissions globally, are all key questions that have as yet no answer.

The lack of ready answers is surely one reason why organisers of the Bali conference have been stressing that the purpose of the conference is not to agree specifics, but to set a realistic timetable and framework for further consideration. And the hardest bargaining is expected next week, when most ministerial-level delegates arrive. Still, there is no reason to write off this conference before it has begun. Indeed, there is some room for optimism. For this past year has witnessed major advances in the recognition of climate change as a threat that demands concerted international action.

Of course, we have to lament the cavalier way in which some governments have responded to climate change (most egregiously the US administration of George Bush) and the inadequacies of the measures taken even by those countries, such as our own, which have built combating climate change into their policies and say they understand the need to act. But there has also been much progress. Many US states are taking action at regional level. The European Union is making climate change a priority. The former US vice-president and climate-change campaigner, Al Gore, shared the Nobel Peace Prize with the UN's Intergovernmental Panel on Climate Change, for their efforts "to disseminate greater knowledge about man-made climate change". And Australia is on the point of signing up to the Kyoto protocol, having resoundingly voted out of office the climate-change sceptic, John Howard.

The Bali conference should be able to agree the framework for a new draft treaty and a timetable that would allow ratification in good time for 2012. With goodwill all round, we see no insurmountable reason why these ambitions should not be met.