The well-known environmental scientist James Lovelock (of "Gaia" fame) has conceded that some of his past pronouncements on the consequences of global warming were "alarmist".  Given that in 2007 he stated: "Before this century is over, billions of us will die and the few breeding pairs of people that survive will be in the Arctic", that might be felt to be putting it mildly – though he is far from the only person that was claiming a figures of billions of deaths at that time; the Archbishop of Canterbury had notably made the same claim the year before.

That same year (2007) I was arguing that: "Climate change will have an impact, but I believe that we should place zero weight on truly disastrous scenarios for that impact".  Rational considerations suggest that mine should always have been thought the serious opinion whilst "billions will die" claims should have been the preserve of crackpots.  But in fact fashionable opinion had that precisely reversed – respectable folk like the Archbishop held sway and were followed by almost all mainstream thinkers.  Opinions like mine were restricted to a large group (probably the majority) of economists (at least as relevant experts in this field as climate scientists, because all the key models depended totally on economic assumptions about growth and innovation – a point that seemed totally to be by-passed in public discourse at the time), a minority of climate scientists, a few journalists and some crack-pot conspiracy theorists.

On the fact of it, this might seem odd.  Why should the opinion that the world might go on pretty much as before be considered wacky?  But pondering just a little further we begin to understand.  For the past decade or so has seen many different of "billions will die" prophecies: the millenium bug; pandemic bird-flu or SARS; meteor impacts; and others.  Our culture seems to have an embedded instinct that some terrible disaster is just around the corner; the only question is quite what; and the only answer obviously wrong is that the world might go on with only minor bumps and detours.

Why?  As a first iteration – and I think there is a lot in this – we can see ourselves as recovering from the certainty of death in nuclear holocaust.  When I was a little boy, I was taught at school in my science classes that there would almost certainly be a nuclear war in my lifetime (presumably towards its end…).  Science shows like Carl Sagan's Cosmos told us there was only a tiny percentage chance (if I recall correctly, much less than 1%) that humanity would survive for a century after a nuclear war.  The books we read at school were things like John Wyndham's The Chrysalids, imagining life in a world of mutants thousands of years after a nuclear war.  Must-see television drama was shows like Threads and The Day After.  A topic of debate with other boys my age was whether it would be better to go out in a flash under the first bomb to fall or to survive the initial attacks and try to keep humanity going in a new and terrible world (I inclined to the latter).

With the end of the cold war, the imminent threat of nuclear destruction passed, but it is hard to eradicate the certainty, held since childhood, that global destruction is imminent.  We are certain of this, deep in the core of our being; the confidence that the end of the world is just around the corner is part of our cultural identity.  So when anyone tells us that the world is about to end – that "billions will die" – we know this to be true.  Anyone telling us that it is not true is attacking a part of our childhood, a part of our being so deep that we have forgotten it is there.

That much seems right to me, but it is incomplete.  For the notion that the world as we know it is about to end goes back much earlier.  During the 1930s people believed that if there were a European war there would be mass gas attacks on civilian targets.  They were wrong about that, but they were right about a change in everything, involving mass death and destruction, lying just around the corner.  The world as people understood it was overthrown in the First World War – albeit with much less death than imagined from nuclear holocaust.  And with our society's unhealthy fixation with the Nazis and thus the history of the 1930s, we forget that the period immediately after World War I saw the greatest pandemic disease outbreak for centuries (Spanish 'flu), communist revolution, and economic contraction in the UK on a far greater scale than anything of the 1930s (nominal GDP fell 28% between 1920 and 1923).  Through the twentieth century, people were familiar with the notions (a) that the overthrow of all they knew, often involving mass death and destruction, was less than a generation away; (b) each time it happened it got worse.

These events played into an older deep-seated feature of our culture, so far in there that, like the nuclear war beliefs of my childhood, we can fail to notice it: ours is a post-Christian culture.  Christianity preaches that there will one day be a Day of Judgement.  There are also extensive Bible passages – particularly in Revelation and Daniel, but also in more prosaic books such as Matthew (e.g. chapter 24) – that talk of "end times" and great wars or earthquakes or other destruction.  Orthodox Christianity teaches that we live in the end times, awaiting the Second Coming of the Messiah, but that this is an intrinsic feature of our world (sometimes referred to as "the eighth day") from now until the end of time.  But many Christians, reading their Bibles for themselves, have been tempted, through the centuries, to interpret the events of their days as indicating that their own generation is special, different from that only perhaps fifty years before, and the signs of the Lord's Return can be seen around them.

Such Millenarianism can take extreme forms, whereby pseudo-Christian cults go off on to mountain tops and have mass orgies (a common endgame for European Christian cults in the Middle Ages, often partnered with banditry).  It is not a feature of all religions.  Some forms of Hinduism, for example, regard the earth as evolving in eternally-repeating long-lasting cycles.  But Christians believe and prepare themselves for The End.

In a classical Christian setting the faithful and regenerate welcome (indeed, hope for) the end – the benign moment of God's own choosing when our Father rights all injustices, rewards everyone according to her deeds, and all death and sin end, with the swords beaten into ploughshares and the lion lying down with the lamb.  The end cannot be a bad thing - we have the promise of the rainbow that God will never again send a Flood to cleanse the Earth.  By contrast, in a post-Christian culture we retain, deep down, our belief in the end-times, but lose our notion that they are controlled benignly by God.  Instead, we hope that Paradise could be created by Man but fear and expect that Man will fail and instead create Hell.

This seems to me really be at the root of the "billions will die" meme of climate change alarmism.  Our post-Christian culture over-interprets the signs of the times, from a deep ingrained cultural expectation that the end is nigh, believing that it was (and, we hope against hope, still is) in our power to create Utopia, but we know deep down that we will fail and create our own Hell and we are shamed and hate ourselves for it.  When the Green Millenarians tell us of our environmental sins, we already knew we were sinners – they merely explain for us why.  And when they tell us the world is about to end, we knew that too – they merely explain for us how.