It’s early, but “Greenland: Migration” is already a candidate for worst movie of the year. I don’t say that because I have some knee-jerk aversion to Gerard Butler movies. I’ve been reviewing about one of them per year for longer than I can count (usually in January, the dumping-ground release period that’s become the Butler zone), and a few of them, like “Plane” and “Den of Thieves” and its sequel, have a pleasing pulp flair. When Butler plays bruiser cops or underworld dogs, he’s got a gruff charisma. But “Greenland: Migration” is one of the soggiest excuses for a sequel in memory. The first “Greenland,” released at the end of 2020, was an environmental disaster movie. The new one is a post-disaster slog. It should have been called “Rubble.”

The end-of-days scenario of “Greenland,” about a comet getting ready to hit the earth, rhymed, in a coincidental but resonant way, with the pandemic. It was like “Deep Impact” made on a B-movie budget, with a calamitous mood that was effective in a vérité way. But it was also a banal family-splits-apart-and-comes-together movie.

So now that that comet — or, in fact, a collection of rock fragments — has hit the earth, what is there left for “Greenland: Migration” to show us? I figured that the director, Ric Roman Waugh, returning from the first film, would find a contrived way to stage another extinction-level event. But no. “Migration” starts off in a bunker, where Butler’s John Garrity is waiting out the apocalypse with his wife, Allison (Morena Baccarin), and teenage son, Nathan (Roman Griffin Davis). Most of the planet has been destroyed; America, Canada, Iceland — all gone. The earth’s cities are wastelands (we see the twisted bottom of the Eiffel Tower sticking up out of the ruins), and if you go outside the radiation can kill you. 

Yet there’s a place that awaits in Western Europe, an oasis of green salvation like that Whole Foods commune in the last “Mad Max” film. It’s called the Crater, and once the bunker is destroyed by a cosmic storm, that’s the destination that Garrity and his family head for. This means they will journey, with a handful of comrades, from the bunker to a small metal covered tugboat that takes them across the ocean (it’s like a bunker on waves), until they reach Liverpool (which is covered in water). Then they find dry land and hook up with a Nigerian van driver who tells them, “The world is a dangerous place now. People are so desperate they will kill you for scraps of food.” They wind up in the ruins of London in a cramped apartment full of Alzheimer’s patients that’s like one more bunker.