Chris Huhne: Cancun needs realism, not blind hope

Progress towards an agreement to limit climate change is possible at talks in Mexico this week. But it will be slow

No one expects a binding deal on climate change in Cancun next month, but we can make real progress – just as we did in the past on key international agreements.

The Montreal Protocol on the ozone layer – the only international environmental agreement that every country in the world is party to – is more than 20 years old, and has steadily improved with age. It was described by Kofi Annan, the former secretary general of the UN, as the world's most successful treaty, and it is working. The concentration of ozone-depleting substances in the atmosphere is decreasing, and there are early signs that the ozone layer is recovering.

Over the next fortnight, much airtime will be given to sceptics – not just about climate change, but about the very process of international negotiations. Next time an armchair theorist holds forth on the impossibility of global agreements, remember the lessons of Montreal.

The UK's position on climate change is ambitious: a legally binding global deal is firmly in our national interest – and in the planet's interest too. It is our best chance of keeping global temperatures within two degrees Celsius of pre-industrial levels, without which we will increasingly face dangerous and extreme weather.

Achieving a deal will not be easy. Success will demand careful negotiation, compromise – and time. To properly judge progress, we need to put the negotiations into the historical context of other negotiations that were both complex and dealt with powerful economic interests.

In the European Union, when a process is particularly complicated, you must make incremental progress. Countries wishing to join the EU must clear a number of separate hurdles. You have to make solid progress on chapter after chapter, knowing that you are nowhere until everything has been agreed.

In their complexity, the climate change negotiations are similar to the trade agreements that have defined modern commerce and shaped the global system of trade. The General Agreement on Tariffs and Trade was agreed in 1949, yet it would take four and a half decades of evolution before the World Trade Organisation and its legally binding disputes procedures were born.

Of course, we do not have half a century to get to grips with climate change: the situation is far too urgent for that. But we should not expect an instant-coffee deal – just add water and stir. Rome was not built in a week, or even a year. It takes time to get negotiations right.

This time round, in Cancun, our expectations will be different. The search is for a renewed sense of momentum, not the finished product. But we are not starting from scratch.

Twenty years ago this week, the UN General Assembly commenced negotiations on what became the UN Framework Convention on Climate Change. It would be another seven years before the Kyoto Protocol was agreed, and a further eight before it came into force. Establishing a worthy successor to Kyoto – with a legal framework encompassing all – will be the culmination of a process that started just two months after the fall of the Berlin Wall.

Like the trade or environmental agreements that preceded them, the UN climate change negotiations are also complex, multilateral and deal with powerful vested interests. They will take a number of years to fully conclude. The key test of the negotiations is whether they are making enough progress each year, not whether they produce the polished, final deal this year or even next.

Progress toward a binding global agreement will be painstaking. Yet there are reasons to be confident that it will ultimately be successful.

First, concern about economic development and objections from industry are consistently overwrought – and over-reported. From the Clean Air Act of 1956 to the Montreal Protocol of 1987, there have always been voices willing to claim that the cost of action far outweighs the benefits. Yet, in a recent paper for the Institute for Economic Modelling, the Oxford economist David F Hendry argues that "in no case has there been a notable impact on any country's gross national product from solving these problems".

My own department commissioned a study to examine the risk of a competitive threat to our businesses under an emissions trading scheme. Contrary to popular belief, it found a tougher EU emissions reduction target would have a minimal effect on output.

Second, we have to see the flexibility needed today alongside agreements we have already made.

The commitment we seek on the measurement, reporting and verification of progress on cutting carbon emissions does not infringe on national sovereignty as much as Article IV of the International Monetary Fund agreement, which provides for detailed annual surveillance of the economies and finances of member states.

If we accept that economic success is collective, surely we should also accept that global climate change is a threat to us all?

The Montreal Protocol showed that, when credible scientific evidence identifies a common threat, the international community can come together to secure an equitable agreement that restricts pollution and protects a common natural resource.

We are realistic about prospects for Cancun. We seek progress, but don't expect finality. The difficult political conditions and the complexity of the task cannot be underestimated, but the Mexicans who are leading the process have learned lessons from Copenhagen last year. Ministers will have a shorter and more manageable list of decisions to take.

From deforestation to long-term climate finance, we can reach our destination in the only way anyone ever did: one step after another. We can regain momentum, and send a clear and vital signal to the world that international environmental agreements are achievable, workable and effective. They just need a little time.

Chris Huhne MP is Secretary of State for Energy and Climate Change