Nature Studies by Michael McCarthy: Cancun was a triumph for global co-operation

It is difficult sometimes, when one understands a situation but imperfectly, to make an accurate assessment of it; and such may be the case with some of those who have belittled the achievement of the United Nations climate conference which ended in Cancun, Mexico, a week ago.

I hope I may be forgiven for returning to the subject of climate change in a column dealing with the natural world, but I would repeat that Nature and all its works will be just as threatened by a climatic regime of soaring temperatures and extreme weather events as human society will be. So perhaps I may be allowed to look back on Cancun, which I covered from start to finish, and give my own assessment of what it achieved – which was considerable.

Discussion ends, of course, if you are a climate sceptic and you do not think global warming is real, man-made and a mortal threat to us, which must be tackled. In such a case – pah! – Cancun was all a waste of time and money, a giant and fatuous junket in the sun for government officials and ministers. Discussion may also be limited if climate change seems so far in the future that it is no concern of yours, and it may be difficult if you feel that addressing climate change is going to be prohibitively expensive. And it will be expensive, undeniably. Supplying the plant to decarbonise British power generation over the next 20 years is probably going to put something like £500 a year on our energy bills, which will be politically very difficult to sell.

But consider: who does think that it is real, man-made and a mortal threat which must be urgently addressed, as detailed in the most recent report of the UN's Intergovernmental Panel on Climate Change (IPCC)? The answer: all the governments of the world.

The synthesis of the IPCC's fourth report was endorsed at a meeting in Valencia on 17 November 2007, without qualification, by every government, including the administration of George W Bush, the US President and climate sceptic supreme (even he could not find the scientists to rubbish it) and since then, despite the tiny handful of errors dug out from the report's 2,500 pages and trumpeted by the sceptic lobby, no government has resiled from its endorsement.

So what do you say to that if you're a sceptic? That you're the one walking in step, while all the governments of the world have got it wrong? That's what they used to say about flying saucers. If we accept, then, the warming threat as real, man-made and urgent, what are we to do about it? The only thing we can do is cut the emissions of the greenhouse gases, principally carbon dioxide, which are causing it. How do we do that? Let everybody do as much or as little as they want, if they want? Or try to do it together in an organised, fair and scientifically appropriate way? There can surely be little argument that the latter course is preferable and that, in fact, is what has been happening since the signing of the UN's Climate Convention in 1992.

What is hardly appreciated at all, however, is just how maddeningly, exhaustively and impossibly difficult this process, the UN multilateral climate change negotiating process, really is. It is the most complex negotiation in human history, far overshadowing other such interchanges in its convolution. Congress of Vienna? Kid's stuff. Treaty of Versailles? Piece of cake, by comparison.

Here you have 194 countries all with vastly different domestic agendas and pressures, all with widely-diverging self-interests, who might have trouble agreeing on the colour of an orange, and you're asking them to shelve all that and sing from the same, vastly complicated song sheet. It is barely conceivable that it can be done at all, and in Copenhagen last year, essentially because of an argument between rich and poor countries about who should take on what, it fell apart.

Cancun put it back together. The negotiations which ran into the sand in Denmark were brought back to agreement in Mexico. Without that, the machinery for tackling climate change would be wrecked; now it is mended. There are now pledges to cut carbon emissions from all the major countries in the world, as part of the UN process. They're nothing like sufficient to halt the warming at the danger zone of 2C above the pre-industrial level – keep your hair on, we all know that, they only go about 60 per cent of the way – but they're there now, and they will be improved on.

There is a new deforestation treaty (deforestation alone being responsible for 20 per cent of carbon emissions), a new Green Fund to give climate-related aid to poor countries, a new agreement on monitoring and verifying countries' emissions pledges (which the Chinese angrily rejected as too intrusive last year in Copenhagen) and various other measures.

But most of all there was agreement itself, not another failure, which would have been terminal for the negotiating process. When it came, at 4am last Saturday, the delegates cheered, and this has been mocked by some commentators who clearly do not believe the process is necessary – call it the flying-saucers-have-landed syndrome – and who clearly do not understand its true difficulty. The delegates cheered because they, like few other people in the world, understand all too well both its necessity and its quite remarkable difficulty. I felt like cheering myself but, being a mere spectator, I cheered internally. And I'm still cheering.