Climate change is real, predominantly man-made and more urgent a threat than ever before, claims the latest report from the Intergovernmental Panel on Climate Change.

“Science has spoken. There is no ambiguity in their message. Leaders must act. Time is not on our side,” said the UN Secretary General Ban-Ki Moon at the launch of the report yesterday in Copenhagen, Denmark.

“Those who choose to ignore or dispute the science so clearly laid out in this report do so at great risk for all of us and for our kids and grandkids,” said US Secretary of State, John Kerry.

What neither appears to have realised is that the report contains no new “science” whatsoever. That is because it is a political document not a scientific one. It merely synthesises the three (heavily criticised) reports released over the last 13 months by the IPCC’s three Working Groups, cherrypicks the scariest bits, turns the hysteria up to 11, then asserts on this basis that drastic measures must be taken if disaster is to be averted.

Again, what is going here most definitely isn’t science. It’s pure propaganda.

Here, as summarised by the BBC’s Environment Reporter Matt McGrath, are some of the synthesis report’s key claims:

1. Warming is “unequivocal” and the human influence on climate is clear

2. Since the 1950s the observed changes are unprecedented over decades to millennia

3. The period from 1983 to 2012, it says, was likely the warmest 30 year period of the last 1,400 years

4. Warming impacts are already being seen around the globe, in the acidification of the oceans, the melting of arctic ice and poorer crop yields in many parts

5. Without concerted action on carbon, temperatures will increase over the coming decades and could be almost 5C above pre-industrial levels by the end of this century

None of these statements holds up to serious scrutiny.

1. Is so trivial as to be meaningless. Everyone agrees – dependent on timescale – that warming is unequivocal and that humans have an impact on climate, from the farts of beef cattle to the localised warming effects of cities.

2. Is a flat out lie. There have been several recorded instances of temperature rises at least as steep as the one post 1950. The most recent of these was the one between 1910 and 1940.

3. Dishonestly attempts to write off the Medieval Warm Period which – as even Michael Mann once admitted before he fully embraced the alarmist cause – saw average temperatures higher than in the late Twentieth century.

4. Is a litany of half-truths and straw men. Ocean acidification is little more than an urban myth. Arctic melting (or refreezing, as it is doing at the moment) tells us nothing about anthropogenic influences. The crop yields claim is misleading since the one thing we do know about the effects of growing CO2 levels is that they have contributed significantly to the greening of the planet.

5. Is a spectacularly arrogant assertion, giving the paucity of the evidence provided so far to justify it. As for that “5 degrees C by the end of the century” claim: not one of the computer models making such extravagant predictions has had any of its doomy prognostications to date validated by real world evidence.

None of this, of course, will prevent the report being enthusiastically trumpeted by the usual suspects across the mainstream media from the Guardian and the BBC to the New York Times as representing incontrovertible truth that climate change is the most serious issue of our time and that we must act now.

But this is how mass hysteria works – and how it always has worked, as the French author Gustave Le Bon observed in his influential 1895 work The Crowd: A Study of the Popular Mind.

One of the key methods by which demagogues work their magic and sell their snake oil to the delusional masses is through the medium of repetition, which acts on people’s brains like a virus.

“When an affirmation has been sufficiently repeated and there is unanimity in this repetition…what is called a current of opinion is formed and the powerful mechanism of contagion intervenes. Ideas, sentiments, emotions, and beliefs possess in crowds a contagious power as intense as that of microbes.”

This is why, when you read all today’s hysterical reports in the mainstream media on the IPCC’s latest bout of junk-science scaremongering and feel an odd sense of deja vu (or deja lu) – that you’ve read it all before – it doesn’t mean that your mind is playing tricks on you.

Rather, it’s because you have read it all before – many, many times. The endless repetition is the point. You are not being informed – but brainwashed.