Are this winter's extreme weather, with rain and floods across Southern England, down to global warming? If so, it's been going on for some time. Remember the devastating floods of 1953, or exceptionally cold winter of 1946, followed by an extremely hot summer. Or if you want a real (pre-industrial) extreme, reflect that in the 1680s, the Thames was frozen solid for two months.

The fact is that exteme weather has never been all that unusual. It's just that today, every episode is used to justify the existence of climate change and its allegedly human cause. Melting ice? We're burning too much carbon fuel. Floods? Our warmer atmosphere carries more moisture. Hurricanes? They're created by warmer seas. Droughts? That's warming too. Snow? The Gulf Stream is shifting. Heatwaves? Do you need to ask?

Of course, much of this is based on questionable evidence: global temperature rises have stalled in the last decade; Pacific hurricane intensity has been low since the mid-1980s; Antarctic ice is increasing; atmospheric moisture levels  are no higher. But the real problem is that a theory that supposedly predicts anything in fact tells us absolutely nothing. As the Scientific Alliance puts it:

Overall, the impression is that some people are taking whatever opportunities they see to find examples of what global warming may be doing, which by inference is then due to our carbon dioxide emissions. The purpose is presumably to stiffen political backbones and keep policies aimed at radical decarbonisation on track.

But there is a deeper agenda among some campaigners. The first element of it is to suggest that industrialisation and economic growth are our problem. In fact, they are the solution. The economist Andrew Lilico points out that, even if we assume that global warming is a reality, it is far cheaper and more practical to adapt to it than to try to reverse it. And economic growth makes us rich enough to make those adaptations. For future generations, it will be even easier.

The second element is that, when any sort of problem occurs – and not just some weather event –  people are inclined to say 'the government should do something about it'. So the more problems that campaigners can create, the more pressure there is for government expansion. And, indeed, for political intervention into markets. One can already see the insurance companies being lined up for a beating. Can it be long before they are told they have to provide cheap flood cover to everyone, no matter how often their riverside homes have been inundated before? The result, of course, will be that more people are encouraged to build and live in flood-prone areas – or that insurers simply leave the market and nobody can get bad-weather coverage at all.