There are many interesting questions one can raise about how climate scientists and economists model both climate change and the human contribution to it. But I’m not going to discuss any of those here. I’m going to take as a given that global warming does exist and has many accepted, worrying effects – and try to argue that we should not be attempting to prevent it, but instead be looking to adapt to it.

It is interesting to enquire initially just whose job is it to tell us how to respond if we believe climate change is happening and materially human-induced. When various clever non-scientists raise concerns about climate change models they are waved away by specialists in the area, told that these are proper scientific questions for proper scientists. Yet all too often scientists fail to apply the same rules to themselves. The issue over whether there is global warming and what the human contribution to it might be is – at least to a material extent – a scientific question. But whether we should do anything about it and, if so, which of the available technical options is best to adopt, is emphatically not a question for scientists. Instead, it is a question for economists, which then puts you very much in my world.

For any ongoing event, there are at least five kinds of potential policy responses: ignore, accelerate, prevent, reverse or adapt. Assuming we do not wish to accelerate or ignore global warming, the three relevant options are reversal, prevention (called “mitigation” in the climate change jargon) or adaptation.

For 25 years the main approach politicians have discussed has been prevention. Margaret Thatcher led the way, with her November 1989 speech to the UN General Assembly. Later we had Kyoto and Al Gore and the Stern Review and David Cameron with the huskies, and now Philip Hammond and Ed Miliband arguing about who sees climate change as the greater “national security threat”.

In the late 1980s and early 1990s it seemed plausible that prevention (or even reversal) was a genuine option. We had great successes with limiting sulphur emissions causing acid rain, chlorofluorocarbons (CFCs) destroying the ozone layer and (earlier) smoke that had caused the famous fogs of London.

Yet the past 25 years have taught us that our scope, capacity and will to prevent climate change by limiting CO2 emissions is much less than was the case for these other pollutants.

These decades of devising fabulously expensive mitigation schemes are hoped, at best, to take a few tenths of a degree centigrade off global warming during the 21st century, compared with a likely rise of two to four degrees. The low-end estimates of the cost of such futility is put at 1pc to 3pc of GDP, with some models suggesting the actual cost is much higher.

Those of a scientific bent respond by saying we must enormously increase our efforts, doing far more to prevent warming proceeding. But the Chinese and Indians and Americans will never agree, and in economically depressed Britain the public appetite for even the sacrifices we make at present has all but evaporated, let alone asking for more.

Even if prevention were feasible, standard policy analysis suggests it would be a terrible idea. Already, according to UK government criteria, it is rare to find a global warming mitigation policy that comes anywhere near having benefits that match costs.

For example, the renewable energy strategy was found to have a 20-year cost of £57bn to £70bn but benefits of only £4bn to £5bn. This problem is so endemic that a few years ago the guidance for ministerial sign-off of policy impact assessments had to be changed so that ministers no longer declare that they are satisfied that benefits exceed costs. Nowadays they sign to say they merely believe that benefits “justify” costs. Even those few assessments that did find positive net benefits, such as the 2008 UK Climate Change Act, assumed international agreement that has never come through.

Given this, it is preposterous to suggest that the UK’s doing 10 or 50 times as much to prevent global warming could possibly be a good policy, even if it could work. The economics of trying to prevent global warming has simply never added up.

David Fuller's view

I would not want to tell many of those living in the USA, and enduring their coldest winter in decades, that they face global warming.  Similarly, I would not say to the unfortunate people with flooded homes and farms in Somerset, UK that this amount of rain was not unprecedented. 

We know from the Earth’s history that climate change has always been a random factor, occasionally traumatic and often stable for lengthy periods, at least in human terms.  We also know that temperatures during our lives have been well within the extremes that our continents have endured, often for centuries.  Against that background, it is appropriate to think ahead and prepare for some of the more likely reoccurring events that cause hardship.

For instance, floodplains seldom have that name by chance.  If we inhabit floodplains as many people do, it is sensible to have some reasonable flood defences which can reduce risks when the weather is less than ideal, as it inevitably will be at some point, almost certainly during our lives. 

If we live in regions prone to drought but which also support agriculture, such as California, as many people do, it is surely in the national interests of that country to develop emergency sources of water, including desalinisation plants near costal regions.  The alternative is either to do nothing, hoping the dice will continue to roll in the region’s favour, or to provide disaster insurance.  This is better than no policy but may be more expensive in the long run, especially where much of the produce comes from orchards.

Wealthier countries are obviously in a better position to plan ahead, rather than relying on temporary luck.  However, they can become victims of comparatively short-term election cycles.  Therefore, alliances of governments, businesses / agricultural communities and university research departments are necessary to address the challenges of periodic climate change.  These alliances can also reduce the risk of political grandstanding, where future generations are committed to costly long-term ‘solutions’ which have little practical value.