The largest academic conference that has yet been devoted to the subject of climate change finished yesterday in Copenhagen. Between 2,000 and 2,500 researchers from around the world attended three days of meetings during which 600 oral presentations (together with several hundred posters on display) were delivered on topics ranging from the ethics of energy sufficiency to the role of icons in communicating climate change to the dynamics of continental ice sheets.

I attended the Conference, chaired a session, listened to several presentations, read a number of posters and talked with dozens of colleagues from around the world. The breadth of research on climate change being presented was impressive, as was the vigour and thoughtfulness of the informal discussions being conducted during coffee breaks, evening receptions and side-meetings.

What intrigued me most, however, was the final conference statement issued yesterday, a statement drafted by the conference's Scientific Writing Team. It contained six key messages and was handed to the Danish Prime Minister Mr Anders Fogh Rasmusson. The messages focused, respectively, on Climatic Trends, Social Disruption, Long-term Strategy, Equity Dimensions, Inaction is Inexcusable, and Meeting the Challenge. A fuller version of this statement will be prepared and circulated to key negotiators and politicians ahead of the 15th Conference of the Parties (COP15) to the UN Framework Convention on Climate Change to be held in December this year - also in Copenhagen.

The conference, and the final conference statement, has been widely reported as one at which the world's scientists delivered a final warning to climate change negotiators about the necessity for a powerful political deal on climate change to be reached at COP15. (Some commentators have branded it The Emergency Science Conference'). The key messages include statements that 'the worst-case IPCC scenario trajectories (or even worse) are being realised', that 'there is no excuse for inaction', that 'the influence of vested interests that increase emissions' must be reduced, and that 'regardless of how dangerous climate change is defined' rapid, sustained and effective mitigation is required to avoid reaching it.

There is a fair amount of 'motherhood and apple pie' involved in the 600 word statement - who could disagree, for example, that climate risks are felt unevenly across the world or that we need sustainable jobs. But there are two aspects of this statement which are noteworthy and on which I would like to reflect: 'Whose views does the statement represent?' and 'What are the 'actions' being called for?'

The Copenhagen Climate Change Conference was no IPCC. This was not a process initiated and conducted by the world's governments, there was no systematic synthesis, assessment and review of research findings as in the IPCC, and there was certainly no collective process for the 2,500 researchers gathered in Copenhagen to consider drafts of the six key messages or to offer their own suggestions for what politicians may need to hear. The conference was in fact convened by no established academic or professional body. Unlike the American Geophysical Union, the World Meteorological Organisation or the UK's Royal Society - who also hold large conferences and who from time-to-time issue carefully worded statements representing the views of professional bodies - this conference was organized by the International Alliance of Research Universities (IARU), a little-heard-of coalition launched in January 2006 consisting of ten of the world's self-proclaimed elite universities, including of course the University of Copenhagen.

IARU is not accountable to anyone and has no professional membership. It is not accountable to governments, to professional scientific associations, nor to international scientific bodies operating under the umbrella of the UN. The conference statement therefore simply carries the weight of the Secretariat of this ad hoc conference, directed and steered by ten self-elected universities. The six key messages are not the collective voice of 2,500 researchers, nor are they the voice of established bodies such as the World Meteorological Organisation. Neither are they the messages arising from a collective endeavour of experts, for example through a considered process of screening, synthesizing and reviewing of the knowledge presented in Copenhagen this week. They are instead a set of messages drafted largely before the conference started by the organizing committee, sifting through research that they see emerging around the world and interpreting it for a political audience.

Which leads me to the second curiousity about this conference statement. What exactly is the 'action' the conference statement is calling for? Are these messages expressing the findings of science or are they expressing political opinions? I have no problem with scientists offering clear political messages as long as they are clearly recognized as such. And the conference chair herself, Professor Katherine Richardson, has described the messages as politically-motivated. All well and good.

But then we need to be clear about what authority these political messages carry. They carry the authority of the people who drafted them - and no more. Not the authority of the 2,500 expert researchers gathered at the conference. And certainly not the authority of collective global science. Caught between summarizing scientific knowledge and offering political interpretations of such knowledge, the six key messages seem rather ambivalent in what they are saying. It is as if they are not sure how to combine the quite precise statements of science with a set of more contested political interpretations.

Which brings us back to the calls for action and the 'inexcusability of inaction'. What action on climate change exactly is being called for? During the conference there were debates amongst the experts about whether a carbon tax or carbon trading is the way to go. There were debates amongst the experts about whether or not we should abandon the 'two degrees' target as unachievable. There were debates about whether or not a portfolio of geo-engineering strategies now really needs to start being researched and promoted. And there were debates about the epistemological limits to model-based predictions of the future. There were debates about the role of behavioural change versus technological change, about the role of religions in mitigation and adaptation, and about the forms of governance most likely to deliver carbon reductions.

These are all valid debates to have. And they were debates that did occur during the conference. Experts from the natural sciences and social sciences, from engineering and policy sciences, from economics and the humanities, all presented findings from their work and these were discussed and argued over. These debates mixed science, values, ethics and politics. This is the reality of how climate change now engages with the worlds of theoretical, empirical and philosophical investigation.

It therefore seems problematic to me when such lively, well-informed and yet largely unresolved debates among a substantial cohort of the world's climate change researchers gets reduced to six key messages, messages that on the one hand carry the aura of urgency, precision and scientific authority - 'there is no excuse for inaction' - and yet at the same time remain so imprecise as to resolve nothing in political terms.

In fact, we are no further forward after the Copenhagen Conference this week than before it. All options for attending to climate change - all political options - are, rightly, still on the table. Is it to be a carbon tax or carbon trading? Do we stick with 'two degrees' or abandon it? Do we promote geo-engineering or do we not? Do we coerce lifestyle change or not? Do we invest in direct poverty alleviation or in the New Green Deal?

A gathering of scientists and researchers has resolved nothing of the politics of climate change. But then why should it? All that can be told - and certainly should be told - is that climate change brings new and changed risks, that these risks can have a range of significant implications under different conditions, that there is an array of political considerations to be taken into account when judging what needs to be done, and there are a portfolio of powerful, but somewhat untested, policy measures that could be tried.

The rest is all politics. And we should let politics decide without being ambushed by a chimera of political prescriptiveness dressed up as (false) scientific unanimity.