Let us agree that man-made climate change presents a serious challenge to humanity which should be urgently addressed by every government.

Set aside the protestations of the relatively few climate change sceptics who either deny the world is warming significantly or assert that, even if it is, carbon emissions are not responsible.

The non-scientists among us — and even the scientists who know nothing about climate change — would be rash to ignore the consensus among the thousands of experts who have studied the issue. Climate change is taking place.

But that doesn’t mean we should meekly swallow all the latest crystal ball gazing by the Intergovernmental Panel on Climate Change (IPCC). This United Nations body has just published some blood-curdling warnings.

The IPCC pronounces that global carbon dioxide emissions must virtually halve within 12 years to avoid a calamitous loss of coral reefs and Arctic ice, as well as intense floods and droughts.

The IPCC pronounces that global carbon dioxide emissions must virtually halve within 12 years to avoid a calamitous loss of coral reefs

Since there isn’t the remotest possibility that these emissions can be halved in so short a period of time — global emissions have been increasing, albeit slightly, though Britain has cut its own by 43 per cent since 1990 — one might be tempted to curl up in bed with a cup of cocoa and wait for Armageddon to arrive.

Except that the IPCC and other supposedly knowledgeable international bodies have produced dire warnings in the past which have not borne fruit. They specialise in making the hairs stand up on the back of our necks.

For example, in 2005 the WWF — formerly the World Wildlife Fund — exceeded even the IPCC’s pessimism at the time, and suggested that all Arctic ice might melt within five years. It’s still there.

In the same year, the United Nations Environmental Programme forecast that within five years some 50 million ‘climate refugees’ would be fleeing large areas of the globe which would have been rendered uninhabitable by the effects of climate change. This hasn’t happened yet.

Previous false predictions did not deter the International Energy Agency from informing us in 2011 that we had five years to start slashing carbon emissions, or give up the game. They weren’t cut, and now the IPPC says we have another 12 years.

I could go on. The point is that numerous expert bodies have forecast an imminent catastrophe, but it hasn’t happened.

And yet these thwarted soothsayers pop up again without any hint of apology for having got things wrong, as usual invoking the unchallengeable authority of science.

Meanwhile, laymen cheerfully jump on the bandwagon of doom. In March 2009, Prince Charles stated that we had ‘only 100 months to act’ before damage caused by climate change became irreversible. Those 100 months have passed, but no one seems to think the damage can’t be undone.

Prince Charles once stated that we had ‘only 100 months to act’ before damage caused by climate change became irreversible

No less hysterically, Gordon Brown proclaimed as Prime Minister in October 2009 that ‘we had 50 days to save the world’.

This was shortly before the Copenhagen summit on climate change. It did not change the world any more than any subsequent conferences on the same subject have done. And yet life still goes on.

Isn’t the lesson of all this that it is a perilous business predicting the future — particularly the short-term future — because one can so quickly be demonstrated to have been up the spout?

The danger, of course, is that if self-appointed clairvoyants produce too many spine-chilling prophecies, sooner or later the general public won’t believe anything they say. That would be a great pity, since climate change is a reality.

Gordon Brown proclaimed as Prime Minister in October 2009 that ‘we had 50 days to save the world’

I imagine the thinking of the IPCC and other similar organisations is that the best way to jolt governments and people into action is to exaggerate like mad. In fact, like all those who are seen as habitually crying wolf, they risk ending up being disbelieved.

What is needed, I submit, is a bit more candour and humility on the part of these presumptuous scientists.

Because they are fallible human beings rather than all-knowing gods, they can’t know for sure the magnitude of the risks that face us. And they shouldn’t pretend to.

This week’s IPCC report judged that global warning must be kept to a maximum of 1.5c warmer than pre-industrial levels, rather than the 2c ceiling previously envisaged. How can scientists be so sure that the lower figure should become the new goal?

I ask because it carries enormous extra costs. The IPCC estimates that new energy infrastructure — wind, solar and electricity storage — as well as technologies that can capture CO2 from the atmosphere, could cost a jaw dropping £1,800 billion.

This will be paid for by the likes of you and me. Indeed, it is already being met in the form of ‘green levies’. In 2015, these were estimated to amount to an extra £112 a year in energy bills. They are sure to go on rising.

And then there other costs, such as those advocated by the Institution of Engineering and Technology, reported in today’s Mail.

It envisages a deep ‘retro-fit’ with solar panels and triple glazing for 25 million homes. The cost would run into tens of billions of pounds, though there would be considerable savings in energy bills.

Shouldn’t there be some acknowledgement that Britain has done more than almost any other country in the world to bring down its carbon emissions?

The Government must not jettison good sense, nor accept the exorbitant shopping list presented by IPCC scientists guilty of over-egging the pudding.

My own patience snapped when I heard one of them saying that we should eat little or, ideally, no meat; drive as little as possible; and avoid travelling by plane. This same person had just flown to the IPCC conference in South Korea with hundreds of colleagues, generating a sizeable amount of carbon dioxide.

Any such small measures we might take pale into irrelevance when one considers the sins of the world’s major producer of carbon, China — which accounts for more than a quarter of global carbon dioxide output.

A Greenpeace analysis based on Beijing’s own data suggests that China’s carbon emissions are soaring at their fastest rate for years. According to a recent analysis of satellite imagery, hundreds of Chinese coal-fired power stations are under development.

Al Gore - who warned of global warming dangers - is accused using more electricity in his mansion in a month than the average US house does in one year

Show me a climate change fanatic, and I can often show you a hypocrite.

Former vice-president Al Gore, whose powerful film warned of the terrible dangers of global warming, stands accused of consuming more electricity in his magnificent mansion in a month than an average U.S. household uses in a year.

That climate change zealot Prince Charles thinks nothing of jumping on a plane of the Royal Flight.

Weeks after telling us that we had 50 days to save the world, Gordon Brown chartered a 185-seat Airbus to take him and 20 aides to the climate change summit in Copenhagen.

The truth is that many extreme proponents of man-made climate change, whether scientists or public figures, are not always as transparent about their own carbon footprints as they are censorious of other people’s.

More of us would respect exhortations to cut out beef, and mothball the family car and go by train instead of plane, if we could be sure that those who love to lecture us were prepared to make sacrifices of their own.

And I also suggest that the public would respond more favourably to warnings about climate change if they were balanced and measured, and avoided sensational and unprovable claims.

Before instructing us how to live our lives, scientists should concede they don’t know all the answers. Isn’t this blindingly obvious when one unfulfilled apocalyptic prophesy is swiftly followed by another?