Having long complained that movies aren’t engaging with the most vital issue of our time – the climate crisis – it’s perhaps churlish of me not to be glad when one comes along that does exactly that. But Adam McKay’s laboured, self-conscious and unrelaxed satire Don’t Look Up is like a 145-minute Saturday Night Live sketch with neither the brilliant comedy of Succession, which McKay co-produces, nor the seriousness that the subject might otherwise require. It is as if the sheer unthinkability of the crisis can only be contained and represented in self-aware slapstick mode. With knockabout hints of Dr Strangelove, Network and Wag the Dog, Don’t Look Up is about two astronomers discovering that a Mount Everest-sized comet is due in six months’ time to hit planet Earth and wipe out all human life. The scientists urgently present their findings to the White House, but find that the political and media classes can’t or won’t grasp what they are saying: too stupefied with consumerism, short-termism and social-media gossip, and insidiously paralysed by the interests of big tech. Leonardo DiCaprio plays nerdy, bearded astronomer Dr Randall Mindy, nervous of human interaction and addicted to Xanax. Jennifer Lawrence is his smart, emotionally spiky grad student Kate Dibiasky. Meryl Streep is the panto-villain president, Jonah Hill her son and chief-of-staff, and Mark Rylance is the creepy Brit tech mogul Sir Peter Isherwell. The comet stands for the climate catastrophe, but the metaphor isn’t the problem. The clear danger of global heating means that it is no longer such a stretch to compare it to an Uluru-sized chunk of blazing rock heading our way. This is not like Mimi Leder’s 1998 thriller Deep Impact, which had a comparable story – it’s more conscious of its loftier satirical importance. But the pointed wackiness means that, with interesting exceptions, it’s not really working at its own chosen level of megaphone comedy, which is presented as the only workable medium for its politically serious and (justifiably) unfunny message. Having said this, the pure, bizarre spectacle of the opening act is startling and based on fact. It really is official US government policy to deflect incoming asteroids by launching missiles at them, a point made by Werner Herzog in his recent documentary Fireball: Visitors from Darker Worlds. This policy is not in itself disturbing but, as this film suggests, what is worrying is that the erosion of our ability to react in time, to understand that something awful could happen is happening – right now. You get a sense of Randall and Kate’s suppressed delirium as they prepare to go on a TV show and find everyone chattering about a pop star’s failed relationship. They have taken the red pill. Time is running out for everyone else to take theirs. There are some sharp political points to be made. Jonah Hill’s obnoxious political bro addresses his Trumpite base, describing what he sees as the three estates in today’s world: “There’s you, the working classes; there’s us, the cool rich, and there’s them …” and here he gestures vaguely at the woke left, whining about something as stupid as the end of the world. Don’t Look Up finally upshifts into a mode of exaltation and transcendance, and I couldn’t help thinking of Lars von Trier’s 2011 planet-collision film Melancholia, which is similar. But for all its faults, Von Trier’s film chose a more interesting and disquieting mode of dark comedy (and I’m sorry that, in 2011, I didn’t see the connection with climate change). This film could have done something more convincing with that mode of reverse-vertigo hinted at in its title: that fear and willed blindness about what looms over us. But if the movie helps to do something about climate change, such critical objections are unimportant. Don’t Look Up is in cinemas from 10 December and on Netflix from 24 December.