Some members of the climate science community are gathered this week in Exter, UK at a meeting titled, “Avoiding Dangerous Climate Change.” Is this meeting for scientists to inform policy makers on a range of possible goals for climate stabilization and a range of means to achieve those goals, or is it a strategy of political advocacy designed to support adoption of a particular goal over others? There is evidence to support both sides of this question, and the presentations, press reports and conclusions from the meeting later this week should allow for a more definitive answer to this question.

Some background

The Exter meeting was first announced in a speech last summer by British Prime Minister Tony Blair, in which he called for the meeting to address two “big questions.”

“We have to recognise that the commitments reflected in the Kyoto protocol and current EU policy are insufficient, uncomfortable as that may be, and start urgently building a consensus based on the latest and best possible science. Prior to the G8 meeting itself we propose first to host an international scientific meeting at the Hadley Centre for Climate Prediction and Research in Exeter in February. More than just another scientific conference, this gathering will address the big questions on which we need to pool the answers available from the science: -What level of greenhouse gases in the atmosphere is self-evidently too much?; and What options do we have to avoid such levels?”

The phrase “dangerous climate change” used in the meeting’s name is a direct reference to the phrase “dangerous interference” which comes from the Framework Convention on Climate Change which states its overall objective in its Article 2,

“The ultimate objective of this Convention and any related legal instruments that the Conference of the Parties may adopt is to achieve, in accordance with the relevant provisions of the Convention, stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system. Such a level should be achieved within a time-frame sufficient to allow ecosystems to adapt naturally to climate change, to ensure that food production is not threatened and to enable economic development to proceed in a sustainable manner.”

In recent years advocates for emissions reductions have increasing organized around the phrase “dangerous interference” under the assumption that if they can demonstrate that some threshold of dangerous interference has been or will be exceeded, then given the broad range of signatories to the Climate Convention (including the United States) it will necessarily compel political action to reduce greenhouse gas emissions. And the threshold that many emissions reductions advocates have organized around is that a human-caused climate change of more than 2 degrees Celsius would represent “dangerous interference.” (For those wanting more background on this subject, have a look at this paper (PDF) by Dessai et al.)

Of course, a challenge exists in that definition of “dangerous interference” is subjective and different people will view the concept quite differently. The IPCC noted as much in its 2001 Summary for Policymakers that definition of “dangerous interference” is a political challenge, and not a scientific exercise.

“Natural, technical, and social sciences can provide essential information and evidence needed for decisions on what constitutes “dangerous anthropogenic interference with the climate system.” At the same time, such decisions are value judgments determined through socio-political processes, taking into account considerations such as development, equity, and sustainability, as well as uncertainties and risk.”

The organizers of the Exter conference wisely have chosen not to organize their meeting around the Prime Minister’s first question and instead have focused on a set of questions to clarify options. Here are the questions that are to be addressed by the conference:

“1. For different levels of climate change what are the key impacts, for different regions and sectors, and for the world as a whole?

2. What would such levels of climate change imply in terms of greenhouse gas stabilisation concentrations and emission pathways required to achieve such levels?

3. What technological options are there for achieving stabilisation of greenhouse gases at different stabilisation concentrations in the atmosphere, taking into account costs and uncertainties?”

So if the conference reports scientific understandings and uncertainties for emissions stabilization scenarios related to (a) a magical instantaneous ending of CO2 emissions, (b) unrestrained emissions (a maximum scenario), and (c) everything in between, then it would clearly give policy makers a sense of what science can say about stabilization scenarios and their consequences. This information would allow policy makers in the the UK, or any other country, to debate and discuss the concept of “dangerous climate change” and, if desired, work towards a political consensus. Such a perspective would be a valuable outcome of the meeting.

But if the meeting results in a recommendation for stabilization at one particular concentration level over others, and increasingly we hear calls for a 2 degree/400 ppm target, then the meeting will have devolved into an exercise in political advocacy under the cover of the authority of science and scientists.

In looking over the abstracts for the meeting there is evidence to support both approaches to the meeting. Given the number of prominent IPCC officials participating, this is a good chance for the IPCC to either reassert its role as honest broker or confirm its tendency towards political advocacy. Lets see what happens.

A last observation, surely the media present will be able to cherry pick from the presentations to support a particular agenda, and some of this appears to have begun. Consider this report from Agence France Presse,

“The three-day conference, running from Tuesday to Thursday in the southwestern English city of Exeter, is bound to have a wide political impact. It will add the objective weight of science to the political pressures on Washington to help curb carbon pollution.”

And the BBC also has characterized the meeting’s expected outcome in political terms by claiming that scientists will define how dangerous interference “should” be defined, “But Avoiding Dangerous Climate Change, a three-day meeting at the Met Office in Exeter, is mainly about the science. The participants, more than 200 in all, will try to agree how to define what is a danger level, and what it should be.”