But I am also an empiricist; and I observe that something appears to be up with our winter weather, and to call it “warming” is obviously to strain the language. I see from the BBC website that there are scientists who say that “global warming” is indeed the cause of the cold and snowy winters we seem to be having. A team of Americans and Chinese experts have postulated that the melting of the Arctic ice means that the whole North Atlantic is being chilled as the floes start to break off — like a Martini refrigerated by ice cubes.

I do not have the expertise to comment on the Martini theory; I merely observe that there are at least some other reputable scientists who say that it is complete tosh, or at least that there is no evidence to support it. We are expecting the snow and cold to go on for several days, and though London transport has coped very well so far, with few delays or cancellations, I can’t help brooding on my own amateur meteorological observations. I wish I knew more about what is going on, and why. It is time to consult once again the learned astrophysicist, Piers Corbyn.

Now Piers has a very good record of forecasting the weather. He has been bang on about these cold winters. Like JMW Turner and the Aztecs he thinks we should be paying more attention to the Sun. According to Piers, global temperature depends not on concentrations of CO2 but on the mood of our celestial orb. Sometime too bright the eye of heaven shines, said Shakespeare, and often is his gold complexion dimmed. That is more or less right. There are times in astronomical history when the Sun has been churning out more stuff — protons and electrons and what have you — than at other times. When the Sun has plenty of sunspots, he bathes the Earth in abundant rays.

When the solar acne diminishes, it seems that the Earth gets colder. No one contests that when the planet palpably cooled from 1645 to 1715 — the Maunder minimum, which saw the freezing of the Thames — there was a diminution of solar activity. The same point is made about the so-called Dalton minimum, from 1790 to 1830. And it is the view of Piers Corbyn that we are now seeing exactly the same phenomenon today.

Lower solar activity means – broadly speaking – that there is less agitation of the warm currents of air from the tropical to the temperate zones, so that a place like Britain can expect to be colder and damper in summer, and colder and snowier in winter. “There is every indication that we are at the beginning of a mini ice age,” he says. “The general decline in solar activity is lower than Nasa’s lowest prediction of five years ago. That could be very bad news for our climate. We are in for a prolonged cold period. Indeed, we could have 30 years of general cooling.”

Now I am not for a second saying that I am convinced Piers is right; and to all those scientists and environmentalists who will go wild with indignation on the publication of this article, I say, relax. I certainly support reducing CO2 by retrofitting homes and offices – not least since that reduces fuel bills. I want cleaner vehicles.

I am speaking only as a layman who observes that there is plenty of snow in our winters these days, and who wonders whether it might be time for government to start taking seriously the possibility — however remote — that Corbyn is right. If he is, that will have big implications for agriculture, tourism, transport, aviation policy and the economy as a whole. Of course it still seems a bit nuts to talk of the encroachment of a mini ice age.

But it doesn’t seem as nuts as it did five years ago. I look at the snowy waste outside, and I have an open mind.