Global warming balance

Last night's Dispatches report on the Great Global Warming Swindle brought some welcome balance to the climate-change debate. Not because the programme itself was balanced - it was completely one-sided in favour of the sceptics - but because the other side of the argument (the alarmists) has been given almost all of the air-time for the past few years. We are constantly told by politicians, publicists and much of the media that there is scientific consensus, that the debate is over, and that it is somehow morally wrong to question the science. Well, there is clearly not consensus, the debate is not over, and suppressing debate is a whole lot more morally contemptible than trying to raise it (stand up and take a bow, all you Royal Society representatives, for your ignoble role in the effort to suppress debate).

Having said that, some climate-change sceptics are as inclined to grasp any evidence as complete refutation of global-warming theory, as the alarmists are inclined to interpret any data as further evidence to support their beliefs. So in the interests of balance, here is a link to the best-informed article I could find that provided counter-arguments to those in the programme.

I don't know what anyone else thinks, but I find quite weak the arguments in that post (and those linked from it) regarding the lag in the long-term historical data for CO2 and temperature rises (the former follows the latter by around 800 years, which is back-to-front on a simplistic interpretation of climate-change theory). I can understand that it is conceivable that something else caused the warming effect for the first 800 years, and that feedback from rising CO2 then continued the trend for the next 4,200 years. But there is a difference between conceivable and probable. If something caused the warming for 800 years, why do we assume that after that time that effect shut off and the rest of the rise in temperature is attributable to forcing from increased levels of CO2? And what about at the end of the rising trends? Temperature starts to fall while CO2 levels are still rising. Why did the forcing effect of the CO2 suddenly shut off?

Perhaps there are explanations for these discrepancies, but does Occam's Razor not apply? It is relatively simple to explain the lag in terms of temperature causing the CO2 increases, but quite complex to explain it in terms of a delayed effect combined with some other unknown factor.

Then again, Occam's razor is not proof but a guide to choice between two alternatives. It does not eliminate the possibility that the more complex explanation is the right one. And even if the simple explanation is correct, it does not eliminate the possibility that natural and anthropogenic global warming may both occur and that what we have seen recently is a man-made trend even if previous swings (over a longer timescale) have been natural and caused by factors other than CO2.

My bet, for what it's worth, is that the man-made effect is real but overstated (probably significantly) by the current models. But while I'd put a tenner (or a bit more) on that bet, I wouldn't gamble the earth. And I certainly wouldn't expect other people to accept that my bet was right. I'd prefer it if politicians and scientists would show the same respect for others' freedom to make their own judgments.

I don't want someone to decide for all of us what the risk is and what we are going to do about it. I want a way of putting a price on that risk (and allowing that value to change over time as science improves and people's perceptions change) so that each of us can make and vary his own decision (sorry for the masculine generic third-person) about what sacrifice they are prepared to make (better?) in order to mitigate the risk.

It is a good sign of a bad climate-change policy if it locks in the current assumptions. Another good indication of bad policy is where specific means are mandated for specific contribution to those current assumptions. A good policy would be designed so that broad incentives reacted to perceptions of the risk and the likelihood of being able to combat that risk. At the moment, we have only bad policies. The announcements from the EU today did not improve the situation.