Myles Allen has asked me to post this response to the thread in which we discussed his Communicate 2011 lecture.
I do think it is sad for democracy that so much energy in the debate on climate change has been expended on pseudo-debates about the science, leaving no room for public debate about the policy response. In the run-up to Copenhagen, public discussion of effective alternatives to a global cap-and-trade regime (which I would personally view with as much scepticism as most of the readers of this blog) was remarkably absent. It still is, and it always will be as long as the public are kept distracted by a debate over the Medieval Warm Period, which has only ever featured in one of the lines of evidence for human influence on climate (and not, in my view, a particularly strong one). The data we primarily rely upon is the instrumental temperature record, which, as I explained in the talk, emerged from the CRU e-mail affair pretty much unscathed (and I stand by the assertion that one would not have got this impression from media coverage of the issue).
My fear is that by keeping the public focussed on irrelevancies, you are excluding them from the discussion of what we should do about climate change should the decade-to-decade global warming trend observed since the 1970s continue and turn out, as current evidence suggests, to be largely caused by the increase in atmospheric greenhouse gas concentrations. Already, I find people arguing that so much has been invested in the emission cap-and-trade approach that it is too late to consider any alternative. In twenty years time, we may find people arguing that it is too late for any alternative to global geo-engineering, which seems even harder to reconcile with democracy. I believe there are effective alternatives that would represent much less of an intrusion into individual lives and the operation of the economy: for example, http://www.nature.com/ngeo/journal/v2/n12/full/ngeo709.html — but they aren't going to happen unless we start talking about them.
To be clear, "good for the planet" in the final line of the talk does not, of course, mean "good for us (or our grandchildren)". That is the whole point. I sincerely hope we do not end up in a situation where governments feel justified in taking highly anti-democratic measures to stabilise global temperatures, however effective they might be. I still believe this is a problem we can solve without compromising fundamental democratic principles, but the longer we leave off talking seriously about it, the harder this will be.