Few people outside Japan would have heard of Kyoto prior 1997, its Katsura palace or famous spring blossom. Mention the city now and it is immediately associated with the closest thing we have to an adequate global response to the global climate problem.

As delegates meeting in Copenhagen this month well know, the Kyoto protocol set legally binding requirements for developed economies to achieve emissions reductions by 2012.

But the deficiencies of the protocol are also well known. To name only three: the reductions required are small when compared to what climate science is now telling us; the most rapidly developing economies are not required to achieve any measurable emissions reductions, and it provides no real guidance to business needing to plan for the long term.

It isn't as if the world has been blind to these deficiencies. Since the United Nations climate conference in Bali in 2007, over the past two years climate negotiators from more than 190 countries have been meeting to overcome these constraints and establish a more effective global climate treaty. And this task is meant to conclude in less than 10 days at the UN climate conference in Copenhagen.

Already the Scandinavian city made famous by Hans Christian Andersen is becoming shorthand for the success or failure of our collective efforts to combat climate change. If Copenhagen ends in "success" then we will have succeeded in avoiding the danger of global warming and climate destabilisation; if it is a "failure" then we too will have failed to address this most wicked of problems.

If only it were so simple. If only tools such as text and agreement actually achieved the measureable, reportable and verifiable emissions reductions that all economies must achieve over the coming years. For Copenhagen can only be a beginning: the start to investment in modern low emissions technology and infrastructure and the imposition of costs on the old, polluting industries of the past.

The stakes at Copenhagen are high. The peer reviewed science has only firmed since Kyoto. There is now a consensus that the level of carbon dioxide and other greenhouse gases that the atmosphere can bear before warming triggers unpredictable and potentially catastrophic changes to the global climate system is considerably lower. Climate scientists who only a decade ago would have argued that the amount of greenhouse gas should be 550 parts per million, now argue that even 450pmm may be too much.

Our understanding of the climate problem and our experience of developing effective climate policy have progressed enormously over the past twelve years. The world is now a lot clearer about the policies and incentives that can reduce emissions, maintain economic growth and get our carbon cycle into greater balance. Prior to 1997 no one could refer to the learning from an emissions trading system in Europe, or the rapid move to renewable energy in Germany.

And perhaps more important than all of this is how public sentiment, and with it our politics, has shifted. Kyoto was before An Inconvenient Truth , the Stern review, hurricane Katrina, the 2003 European heatwave and Australia's worst drought on record. In many countries climate change is now an issue which bridges the standard political divide. Some of the most progressive leaders on the issue come from the right of politics: Angela Merkel, Nicolas Sarkozy and even an actor turned politician not known for his warm hearted roles: Arnold Schwarzenegger. Climate change is now a fixed agenda item for any meeting between heads of state: how to maintain economic growth, energy security and reduce emissions. And no longer is the President of the United States sceptical of the problem: in Barack Obama the White House is occupied by a man who has made tackling climate change a core part of his political narrative.

In accounting for Kyoto's ineffectiveness, in 1997 one could easily cite the lack of public understanding; a lack of clarity in the science; a lack of effective politics or an immaturity in our experience of effective climate policy. None of these excuses now apply.

Whether the final chapter in a story that started in Bali two years ago is one of resolution and joy, or confusion and despair, remains unknown. An unambiguous political agreement establishing how the new binding international rules can be agreed may still mean that Copenhagen becomes shorthand for describing when a new and powerful approach to tackling this most wicked of global problems was begun. That would be cause for celebration by this and all future generations.

• Erik Rasmussen is the founder of the Copenhagen Climate Council.

Professor Tim Flannery is chairman of the Copenhagen Climate Council and author of The Weather Makers