Politicians and ‘opinion leaders’ claim that damaging climate change is in prospect unless drastic centralised action is taken.

The prevailing view about climate change action is part of the ‘conventional wisdom’, gaining its authority more from its constant repetition than from its intellectual content. Supporters of the doomsday view of climate change have become a semi-religious movement, using the slogan ‘the science is settled’ and regarding as heretics anyone who questions their view.

But the basis of their forecasts is flimsy. Establishing a link between greenhouse gas emissions and global warming is extremely difficult, given the many factors that influence the earth’s climate.

Despite constantly rising emissions, warming has so far been confined to two periods in the twentieth century (1920-1940 and 1975-1998) with no further warming in the last ten years. And to calculate what warming lies in the future involves modelling both prospective climate change and its economic and social effects.

Since climate scientists are ignorant about many aspects of climate and economists are ignorant about the relevant economic and social linkages, there can be little confidence in the results of integrating these models, particularly since they look ahead for periods that in any other type of modelling would be regarded as ludicrous.

Yet despite the high level of uncertainty, our political leaders want big investment programmes to cope with future warming. In many countries, renewables and energy ‘conservation’ are subsidised and new nuclear power programmes are contemplated (possibly again subsidised) to reduce carbon emissions. But these government-sponsored investment programmes are essentially a reversion to the ‘picking winners’ approach of an earlier age, in the face of experience that government-backed ‘winners’ usually end up as losers.

A further, neglected problem is that, even if there was genuine evidence of climate change and the direction of change was clear, governments might not act effectively. Previous experience, for example in the ‘energy crisis’ of the 1970s, suggests that their priority might be to give the appearance of acting.

There is a great deal of political posturing going on about climate change action. EU summits make grand declarations about emission reduction targets, but at the same time country leaders undermine these targets by trying to make their countries or some of their industries ’special cases’.

All the genuine action is voluntary. Both producers and consumers have responded to the belief that damaging global warming is under way by demanding and being supplied with ‘green’ goods. Much marketing now centres on green claims. No doubt some claims are exaggerated or even false, but the response is proceeding through the pursuit of profit (which is a surer way of getting things done than political action).