Idly browsing, I came across a Horizon programme (still available on iPlayer) in which Paul Nurse bemoans the lack of public trust in science, basing his discussion on the case of global warming. I seem to have written about global warming only peripherally – Climategate and wind energy). So perhaps it is worth summarising my views.
My major conclusion is that the debate about whether human output of CO2 is significantly raising global temperatures is a waste of time.
For the first 20 years or so that people focussed on global warming, there were two major problems. Theoretically, it was obvious that CO2 emissions were likely to raise global temperatures. The snag was that for a 30 year period (1940-1970) we had rapidly rising emissions accompanied by slight global cooling. The second problem was that all the data prior to the satellite data (which only became available in the second half of the twentieth century) was riddled with problems. Going back in history over the last couple of thousand years it was almost impossible to get data which was remotely accurate enough. The claimed effect is measured in small fractions of a degree per decade averaged over the globe, so to test it one needs highly accurate data for a large fraction of the globe. Such data was simply not available prior to the satellites.
These difficulties were compounded by three factors. The first was that, going back further into history, it was clear that the climate had been subject to large variations before there was any question of a human effect. In particular, we had had the ice ages, followed by massive melts. So it was clear that the climate was far from stable. It was capable of large changes without any human intervention. Then each particular source of data seemed to have its own complexities and reasons why it might be an unreliable guide. Finally, it was disconcerting that so much of the climate work seemed to take the form of elaborate computer projections that were clearly based on an inadequate understanding of how the climate actually worked.
The effect of all that was to make the whole thesis highly speculative. Unfortunately, many campaigners and many scientists made light of these difficulties, insisted that human actions were causing global warming, and abused those who disagreed or reserved judgment as “deniers” or worse.
That changed when the period of rapidly rising emissions accompanied by slight global cooling was explained. It turned out to be due to human sulfate emissions which had a substantial cooling effect. Those emissions were controlled (because of other adverse effects, notably acid rain) and we got several decades of significantly rising temperatures. So the basic theoretical prediction (CO2 emissions should cause rising temperatures) was now confirmed.
Meanwhile the public debate has been almost entirely about how to reduce human output of CO2. That seems to me completely daft.
There are three problems. One is that it is completely unrealistic to expect people to reduce their energy usage significantly. Even if those in the developed world could be persuaded not to increase, or even to reduce their per capita usage, those in the Third World are determined to increase their usage in order to gain the same standard of living that they see in the developed world. Plus world population is remorselessly increasing.
The second problem is that there is only one technology available for roll-out on a large scale with low CO2 emissions – nuclear. Unfortunately, that has historically been seriously mishandled by politicians, scientists and engineers. Despite being a reasonably safe and reliable method of generating electricity, they politicians failed to grasp that the inevitable association in the public’s mind with nuclear weapons was going to result in quite different standards being applied to it. The current situation is that we now have largely unnecessary, but hugely expensive, gold-plating in the form of regulations on disposal of nuclear waste, coupled with poor reactor design which makes the plants less safe than they could be whilst they are operating. This lack of safety is not bad enough to kill people in significant numbers, but it is bad enough to cause periodic scares which force up operating costs.
The third problem is that even if we immediately stopped all human CO2 production, the CO2 remains in the atmosphere for so long that temperatures would continue to rise for another hundred years. In other words, even action far more drastic than that envisaged by the most optimistic campaigners would not do much to ameliorate the effects of too much CO2.
What we need is to shift our focus to coping with the effects of global warming, rather than trying to stop it. There is clearly substantial scope for such action – the Netherlands dike building programme was effective and not prohibitively expensive. Of course, it is also worth continuing to develop alternative energy sources and to research climate mechanisms. But it will take decades to develop new energy sources and more decades to roll them out on a large scale, whilst the effects of more research on climate are unpredictable.
In passing, I find Nurse’s programme irritating. He is just bleating that the rest of the world is not treating scientists with more respect. But in this case scientists have hardly deserved it. In the early decades they hopelessly over-egged their case. Moreover, much of the work was shoddy and made life easy for those who disagreed with it. More recently, they have too readily lent their support to such manifestly daft projects as switching from gas power stations to wind power.
I also find it amusing to find him complaining about amateurs forming opinions irrationally, paying attention to fashion or emotion, instead of carefully reviewed data and carefully analysed arguments. Has he not noticed that scientists frequently do the same! Take a field with which I am reasonably familiar – cosmology. It is rife with highly speculative theories, which are widely supported simply because they are fashionable.
He concludes by demanding that in this case we focus on the science. By that he seems to mean his view of the debate with those who believe that human CO2 emission is not causing global warming. But that debate is irrelevant. What we need are practical solutions that will help to deal with the consequences of global warming.