"How is it you cannot interpret this fateful hour?" In Luke 12:56 Jesus gives a glimpse of his frustration with our difficulty seeing, and acting on, the obvious. Two thousand years later, his words make an apt teaser for the recent film "Don't Look Up".

At the start of the movie, a young astronomer (Jennifer Lawrence) discovers a huge comet which is hurtling towards Planet Earth. She and her colleague (Leonardo DiCaprio) calculate that it will hit in about six months' time, and they set off to alert humanity (starting, naturally, with the US president, an oddly Trumpesque character played by Meryl Streep) in the hope that the comet can be deflected and life on earth saved. No spoilers here: just watch the film.

The film is a brilliant satire on climate change. Faced with a planet-scale threat, will we take urgent action? Will we dither and cross our fingers? Will we go for full-blown denial? What are the vested interests seeking to influence us? What are our internal conflicts? What, as Christians, do we believe that the Bible and the Holy Spirit have to say about it?

In a sense, this film is too generous to us. The comet is not of our making and although, in the story, we have a good chance of deflecting it, we didn't start it. Climate change is worse, in the sense that it is a problem of our own making. And we have had decades, not six months, to do something about it.

With noble and notable exceptions, the church's reaction to climate change could hardly be called prophetic. We are finally, belatedly, throwing our (still considerable) weight behind efforts to address it, but we cannot claim to have led the way. There's much still to do, and much doublespeak, but addressing the climate crisis is now a mainstream concern, including for Christians.

But what if climate change isn't the only existential threat facing us? As a part of the Christian Campaign for Nuclear Disarmament I could not help feeling like the two astronomers in the film. There is a threat there which is not getting the seriousness, attention, and action which it deserves. Nobody wants a nuclear war, and most people would gladly be rid of the weapons, but our attention is elsewhere.

If climate change is 'morally worse' than a comet strike, then nuclear weapons are worse still. The use of fossil fuels was, at least at first, intended to do good and build a better, modern world. Nuclear weapons (like the "thief" in John 10:10) can only kill and destroy.

Jesus offers us "life in all its fulness". Ninety-five per cent of the world's countries seem to believe they can have that without possessing nuclear weapons. Those of us in the other five per cent should be looking up, not down: at a world where this threat has been permanently removed – before it's too late.

The risk's greater than ever, with the Doomsday Clock set at just 100 seconds to midnight experts judge that humanity has never been closer to catastrophe. We know what to do: will we do it?