TROMSO, Norway — Just days before the German icebreaker Polarstern sets sail on the largest and most ambitious climate-change research expedition the Arctic has ever seen, an air of quiet p andemonium prevails aboard ship.

Crates of scientific equipment — more than a million pounds in all — are stacked on deck and in passageways, scattered seemingly at random among spools of hose, gas cylinders, duffels filled with survival gear and even a spare blade for the ship’s twin propellers.

Scientists scurry about, sorting through supplies and making sure equipment is working and strapped down in the research ship’s permanent laboratories and more than a dozen portable ones in modified shipping containers, above and below deck.

The crew is performing its own last-minute tasks, including lifting four gleaming new snowmobiles aboard with a crane. Dangling high in the air, the machines look like insects against the hulking 400-foo t -long ship.