Leading article: Will the world finally wake up to the scale of the challenge?

The Copenhagen summit must focus attention on an unfolding disaster

The Copenhagen conference is hugely important. Indeed, it is not far-fetched to say that it could mark a critical point in world history. In the words of Nicholas Stern, author of the 2006 report on climate change that Gordon Brown commissioned, Copenhagen may be the world's most important summit since the Second World War.

We agree, which is why we are giving our readers a new Met Office guide to climate change. Compiled by the world's most authoritative meteorological body, it is intended to explain the causes and implications of the rise in world temperatures and address the many myths now being circulated about how this phenomenon either is not happening, is not occurring on a scale that need worry us, or is happening but not as a result of man's activity.

The climate change sceptics and their allies in the oil industry have been noisier than usual recently, boosted by the controversy over the leaked email from the University of East Anglia. It is important to note that a single scientist appearing to suppress evidence on climate change does not alter the basic parameters of the question one jot. The overwhelming scientific consensus remains that if we continue to release carbon dioxide into the atmosphere at the same rate that we are today, the rise in world temperatures could be far higher than the 2 degrees that is seen as more or less tolerable, and might be as high as 6 degrees, which would doom human life in large parts of the world.

Yet, public opinion remains oddly somnambulistic about the horrifying consequences of this happening. Forget the rather silly climate change deniers. A bigger problem is the sluggish majority that accepts what is happening to the planet but doesn't want to pay more than a nominal price for taking any real action to prevent it. As the Energy Secretary, Ed Miliband, said yesterday concerning this public lethargy: "There is a mountain to climb on this, globally and nationally."

Western leadership on carbon emissions has not been inspiring. It is welcome that Barack Obama is going to Copenhagen bearing a pledge to cut America's 2005 levels of carbon emission by 17 per cent by 2020. This is a far cry from the America of the ill-fated Kyoto summit of 1997, which simply dropped out, denouncing the Kyoto targets as unfair. On the other hand, a pledge is all that President Obama is bringing – a bill on climate change remains stuck in the US Senate. Australia is in a similar position, with a helpful leader in the Prime Minister, Kevin Rudd, and a less than helpful legislature.

The financial imperative

On the plus side, some of the fastest-growing developing countries, which were not asked to do much at Kyoto, are coming round. China, which is now the world's biggest carbon emitter, has said it will cut its "carbon intensity" – the amount of carbon emitted per unit of GDP – which is a start. India, the fourth biggest emitter, is shifting its position in the right direction. If the developing giants abandon their old ideas about "business as usual" and accept that they can't take ringside seats when it comes to cutting carbon emissions, that will be a significant gain.

Two other things need to take place if the Copenhagen summit is to be judged a success in the minimum sense of the word. Without a legally binding agreement, it is vital that the developed countries reach a political agreement that paves the way towards a binding treaty, and which pledges ambitious cuts in carbon emissions by 2020. The IPCC, the UN body on climate change, says these cuts must be at least 25 per cent of 1990 levels.

Finally, without a financial deal, the verbal pledges at Copenhagen will not add up to much because the developing countries will not come on board. The industrialised countries have accepted they bear responsibility for most of the carbon dioxide that is already present in the atmosphere, and know that for any deal to work they will have to financially compensate developing countries that are being asked to slow their growth.

The big question is how much money, how it is to be raised and the criteria by which it will be distributed. As yet, we are barely at this point. Suffice to note that there is a predictably huge gap between the kind of money that the developing countries are seeking in compensation – hundreds of billions of dollars a year – and what the European Union, for example, appears ready to stump up.

So there are indeed mountains to climb. The scale of what is being asked of all of us is, frankly, dizzy-making and amounts to nothing less than a revolutionary change in all of our lifestyles. It calls for Churchillian reserves of nerve and willpower. Forget talk of "12 days to change the world"; what counts is what we all do after Copenhagen and whether the world unites to focus on an unfolding disaster. The consequences of collective failure to act are frightening to contemplate.