The recent UN Climate Change meeting in Durban, South Africa was in many ways the marmite of such events. Opinions are polarised on whether to love or hate the outcome.
For optimists, it was a breakthrough that saved the Kyoto Protocol and paved the way for a new global deal. The future involvement of both developed and developing countries- notably the US, China and India - creates a whole new political landscape which augers well for coordinated action to reduce emissions.
For pessimists, it was too little too late and a wholly inadequate response to the scientific evidence. Agreeing to do a deal by 2015, which will not come into force until 2020, will not be nearly enough to keep the world below the dangerous threshold of 2˚C warming. Politicians kicked the can down the road again, and we're running out of tarmac.
Clearly, there is truth in both of these assessments. Failure by politicians to agree a form of words that they could all live with would have led to a dramatic last-minute collapse of the talks after 72 hours of straight negotiation. This would have dented international confidence, which is already battered, and sent a bad signal to the markets of the likelihood of coordinated global action on climate.
It would have widened the gaps between the climate-can-dos and the climate-blockers and entrenched a hostility and blame-culture inimical to any sort of cooperation and progressive action.
The fact that negotiators were able - and willing - to overcome significant political obstacles and agree a text that commits them to clear timelines and future legally-binding emission reduction targets is a shot in the arm for global climate diplomacy. For business it means they might get the regulatory certainty they need to invest and innovate.
That said, there is of course, much more that can and must be done to set the world on a low-carbon, sustainable development course. If all sufficient action is delayed until 2020 - the proposed date by which a new agreement will come into force - then bringing emissions down quickly enough is likely to be somewhere between impossible and ruinously expensive.
That's why almost 400 global companies have signed the the 2˚C Challenge Communiqué from the The Prince of Wales's Corporate Leaders Group on Climate Change, which urges governments to urgently work on a global deal, but also to take the appropriate actions now at a national level that can drive down emissions and pave the way for a more effective and ambitious global deal.
The alternative is unpalatable: not only will the world miss the target that governments have set themselves of keeping warming below a global average of 2˚C, but in fact we will be firmly on track for 4˚C warming or more, and the consequent unpredictable climate-related disasters, disruption and costs.
In the debate over whether or not Durban offers the prospect of a new comprehensive global agreement a lot of commentators have missed the concrete policy outcomes that many businesses welcome.
The decision to bring Carbon Capture and Storage (CCS) into the Clean Development Mechanism (CDM) for example is a clear signal that governments recognise CCS as a technology that can help reduce carbon emissions.
But given the ongoing weakness of the CDM and other channels for funding action in developing countries, businesses are interested in hearing how governments intend to channel the $100billion a year they agreed in Copenhagen. The agreement to establish the Green Climate Fund offers potential for progress on this - although there is still a long way to go to show how the fund will engage the private sector and raise funds.
These questions go to the heart of why the member companies in The Prince of Wales's Corporate Leaders Group on Climate Change support coordinated and concerted government action on climate change. Actions, like those the companies are calling for, represent the possibility of unlocking new economic opportunities. Failure to act, on the other hand, represents rising unmanaged and unmanageable risks to their businesses, is a grave threat to all of our futures.
The companies in the Corporate Leaders Group are sending a clear message: Durban was a step forward, but this is only the beginning. They are saying that unless we collectively rise to the challenge posed by climate change, and chart a common course that better manages the environmental threats and values scarce resources, we will all suffer.
Governments could do a lot more to give business the confidence and incentives needed to mobilise investment in a sustainable future without undermining competitiveness. Members of the CLG, and business more generally, is increasingly showing what is possible - but they need further leadership from politicians to chart an effective course towards a more prosperous, safer and brighter future.