James Murray

On Wednesday night, more than 100 senior executives from a wide range of sectors braved torrential rain and puddles you could get lost in to attend BusinessGreen.com's evening of lectures on the impact of the Copenhagen summit.

Delivered in association with Citrix GoToMeeting, it was a hugely successful and engaging evening featuring presentations from some of the UK's leading green business experts and providing a great example of how significant the business community regards the forthcoming events in the Danish capital.

However, one particular incident stuck in the mind which hammered home quite how much is at stake over the next few weeks. Chairing the question and answer session that followed the presentations, I wrapped up the evening by asking the panel to give a one-word assessment of whether or not we would get a satisfactory deal from Copenhagen.

Tom Burke, the former executive director of Friends of the Earth and an environmental policy adviser to Rio Tinto, went first with "don't know", and was quickly followed by Craig Bennett of the Corporate Leaders Group on Climate Change, who offered the same response.

Jeremy Leggett at Solarcentury and Iain Watt of Forum for the Future were similarly non-committal, admitting only that they doubted an effective deal would be delivered.

I accused the panel of sitting on the fence, to which Tom Burke quite correctly replied that an admission of ignorance was not the same as fence-sitting. As he pointed out, he genuinely did not know one way or the other.

And that, in a nutshell, is why Copenhagen simply has to deliver. Our panel of experts is not alone. For two long years, businesses' green plans have been undermined and diluted by this crippling lack of clarity. Executives can manage good news, they can even cope with bad news, but they cannot handle uncertainty.

I am not of the opinion that a failure to deliver a robust deal will completely derail the transition to a low-carbon economy. Too many countries are committed already, the clean tech sector has too much momentum, and the climate risks associated with current business models are too high for things to stop. But that does not mean, as some have suggested, that Copenhagen is insignificant. The entire transition to a low-carbon economy becomes much easier with a deal, partly because it will enable improved and consistent environmental legislation, partly because it will pump money into climate-related projects, but mainly because it will give investors and businesses the certainty they crave.

Imagine for a moment waking up on the morning of 20 December and hearing on the news that a robust and ambitious deal has been signed, containing detailed emission targets from rich nations, verifiable action plans from emerging economies, clear funding commitments, and an immovable deadline to sign a binding treaty by summer 2010.

Suddenly all those green ideas, products, business plans and investment strategies that had looked marginal or were facing resistance would become significantly more viable. The actual economic or business case for pursuing a greener strategy may not change overnight, but the political and commercial backdrop that informs these types of decisions will have done. It is impossible to quantify the impact of that change, but it would be both real and sizable.

Plenty of people in and around the clean tech sector, the City, and Silicon Valley are convinced that there are huge sums of money just waiting for that clear signal to invest in greener business models.

It is deeply concerning that on the eve of the summit, experts who have closely observed the entire negotiating process genuinely have no idea how it will end, but it is critical that we find out soon and that the talks do not drag on into next year. Thankfully, we should not have too much longer to wait.