Is the climate-crisis campaign trying to undermine its own credibility? Are its exponents deliberately fomenting scepticism about their own arguments with absurd hyperbole? Or have they, out of sheer ill temper, just given up on persuasion and decided to resort to wild claims that arouse suspicion and hostility?

Consider two possible instances of this, both of which occurred within the past week. The secretary general of the United Nations, Antonio Guterres, stated without any qualification that, “The era of global warming has ended; the era of global boiling has arrived.” Boiling? What is it exactly that is boiling? The oceans? Freshwater lakes? The mains water in your pipes? Given that we are talking about supposed scientific fact here, what is the empirical basis for the use of the word “boiling”? And – a genuinely factual question – what effect is the use of that word, which has no basis in observable reality, likely to have on the discussion of global-warming policy, which is now becoming seriously contentious?

The second notable example: an official statement issued by the Meteorological Office attacking a widely reported article in the scientific journal Nature, which claimed that the Atlantic Ocean current system, which maintains mild weather in Europe, could collapse in two years. This claim was, said the Met Office (which generally supports the climate-change thesis), “overdramatised” and simplistic, and it went on to warn, in what I believe to be quite unprecedented terms, that such overblown theatrical pronouncements could undermine the public perception of climate science. You bet they could. 

In fact, these statements are peculiarly irresponsible: if they are believed, they are (as the Met Office went on to point out) likely to induce despair and resignation in a population that is being urged to become ­­proactive. If they are disbelieved, they could lead to cynicism and a refusal to take seriously whatever threat there may actually be. 

Coincidentally, these histrionic claims, and the crucial critical examination of them, occurred only days after environmental policy had a spectacular political setback in the Uxbridge by-election. In what was the first clear-cut democratic test of whether people will be prepared to accept the real cost of all this, they made their judgment clear enough to throw Government and Opposition policy on the environment into chaos. Party leaders are now falling over one another to insist that they fully understand the considerable popular concern about adding to the cost of living, blah-blah. 

The power of free people to exercise their democratic will has suddenly shifted the parameters of the whole debate. So it is time to have a grown-up discussion, rather than what has prevailed until now: endless recriminations followed by demands that we dismantle the modern era and accept an existence that is not just pre-industrial but pre-agrarian, since the breeding of animals for food, which replaced the primitive hunter-gatherer model of survival, is also to be forbidden. Basic rule of political communication: do not suggest pauperising your electorate except under very temporary circumstances with clear objectives, such as fighting a war. Tony Blair, who knows a thing or two about winning elections, has been quick off the mark with this theme. In fact, no government, elected or otherwise, would survive for long on such a prospectus, for sound reasons: it is morally unacceptable to advocate a return to a time when life was truly nasty, brutish and short. 

But there is more at risk in the zero-sum solution of destroying prosperity and economic growth than mere electoral unpopularity. The new proper conversation will have to address another of last week’s developments. The wildfires in southern Europe, which may in part have been caused by arson and an exceptional jet-stream pattern, were almost certainly exacerbated and prolonged by what was an extreme (but not necessarily record-breaking) heatwave. 

Most people accept that there is considerable evidence for the measurable rise in global temperatures to be attributed at least in part to increased carbon emissions, even though the traditional means of proving a causal relation between two phenomena – repeating an experiment in order to replicate the original result, while eliminating other variables – is obviously impossible in this case. 

But even on this moderate global-warming thesis, in which carbon in the atmosphere increases the effect of extreme dangerous events, there is certainly a rational case for addressing the problem. And as everybody is now saying, the answers must lie with human ingenuity and resourcefulness, which have proved over the millennia to be virtually limitless. 

The first stage of the argument must be about priorities: choosing between adaptation and innovation. Do we accept that there will be changes in the conditions of life on earth that require the migration of populations, as there have been in countless earlier eras, with all the political and economic upheaval that will entail? Or do we try to interfere with those changes in ways that might involve drastic reinvention and use of resources, which will have to be universally accepted and enforced, perhaps by quite new international authorities? 

Both of these options, or any combination of the two, are going to be very expensive. The world is going to need to create wealth on a spectacular scale in order to cope with mass migrations, or to conduct the sort of innovative research and instrumental application of that research that the new conditions will require. The engineering and manufacture of whatever is needed will demand investment, economic confidence and courageous foresight – the direct opposite, in other words, of self-imposed poverty. 

If the climate campaigners are anywhere near being right, there are huge questions with profound implications for democratic governments, which must – even in the most dangerous circumstances – take people with them in willing consent. This is not the moment for hysteria, or for insulting the intelligence of ordinary people, or alienating them with accusations of selfishness and ignorance. Problem-solving is a function of rational thinking. It’s time to get on with it.