When we focus on news that reinforces our environmental challenges, of which there’s no shortage, we forget just how exciting the opportunities in fixing them are and how fast these solutions are now accelerating. Every story about melting icecaps or raging floods brings a smarter, cleaner world closer. My favourite example at the moment is electric cars. While they had a bad start, we are now on the verge of the breakthrough we’ve been waiting for, with around 30 models coming into the market from the major car companies and new start-ups over the next 3 years.

If we get this right, it’s hard to overstate the significance of the upside. This is a real game changer for our transport and energy systems. Forget any old ideas you have about niche markets, limited range and slow cars. There are some very exciting cars on the way and some business concepts that could change not just personal transport but the whole electricity sector. How will this unfold?

Throughout my 35 years in sustainability it has always seemed odd that while so-called economic rationalism reigned over our political, economic and business worlds, rational thought wasn’t applied to issues like climate change. The risks were always clear, as defined by rational science, while a logical analysis of the economics showed acting early was cheaper than acting late. Yet a strange kind of religious and ideological zealotry took hold, as otherwise sensible, educated people ignored rational thought. It was a failure of reason.

While Copenhagen failed to deliver any agreement however, it may well mark a return to rational thought and with it some profound shifts in markets, politics and our approach to sustainability. Perhaps historians will mark this point and refer to the world BC and AC – Before Copenhagen and After Copenhagen.

What will historians say changed at the end of 2009? And if we could read their conclusions now, would it change our present responses – not as historians but as the creators of that history? Perhaps they will write something like this:

There will probably be some kind of agreement at Copenhagen. It’s hard to imagine all those world leaders walking away without one. However I’m not spending any time at all wondering what the result will be. Why? Because it just doesn’t matter.

You see we’re not ready to fix climate change, not yet. We have not accepted the scale of the problem. Nor have we established the political conditions necessary to fix the problem when we do. However Copenhagen does signify the shift between two eras and if you watch carefully you can see the new world emerging. That is the interesting thing happening at Copenhagen.

But before I move on to that, let me go back, because most of you are probably stuck on my statement that the result at Copenhagen doesn’t matter. Isn’t this the most important meeting in history? Surely failure here will set us back a decade? Surely having a global agreement of any type would be an important first step? No, no and no. Here’s why.

Amidst the noise of the day-to-day debates, we have lost sight of the simple logic of the advice coming from the world’s top climate scientists. Despite the uncertainties in the details, the science carries one underlying message from which we can draw only one rational conclusion.

It is time to declare a global emergency and mobilise all available resources, political will and human ingenuity towards one task – to reduce the risk of catastrophic climate change to an acceptable level.

Today, we are releasing a paper detailing our response to this conclusion. ‘The One Degree War Plan’ began to take form a few years ago, the product of a challenging conversation between myself and Professor Jorgen Randers. Jorgen, a lifelong advocate for action on sustainability, rose to prominence in 1972 as one of the original authors of the Club of Rome’s famous “Limits to Growth”, the bestselling environmental book of all time – over 30 million copies in 37 different languages.

Jorgen and I had both accepted the scientific reality and were discussing the question it posed – what would a rational response to the climate science look like? If you stripped away all the politics and debate and took a fresh look, what would be the logical action plan?

Regular readers may be a little surprised by this column. I am regularly arguing that the science shows we are inevitably approaching, or may have past, a tipping point where widespread, rolling ecological and economic crises take hold.

But there’s another critical tipping point, of a very different character – where the world’s political and business leaders turn firmly towards action. Here’s the surprise – I think we may be at this tipping point already.

Scientists have become increasingly alarmed in recent years, as climate change reality has raced ahead of the political response. They point to countless examples of accelerating feedbacks, such as the reduction in the ocean’s ability to absorb CO2 and rapid Arctic melting. While they regularly point these out to our political masters, many of them express despair at the slow response.

So on what basis do I think the global political system has started to turn?