To get a better handle on the timeline, scientists are spending one year in a German icebreaker that has been trapped within the sea ice at the top of the globe. On that mission, which I joined for six weeks in September and October, they are monitoring the Arctic in order to better quantify the ice-albedo feedback loop, as well as a number of other Arctic unknowns. The hope is to use the on-the-ice measurements to calibrate remote data, such as satellite images, and to more deeply understand the complexities of pack ice so as to make climate models even more precise.

“It isn’t just an intellectual exercise,” said Perovich, who pointed to the huge disruptions happening right now in Inuit communities. “We’re trying to understand things that are having consequences on people today.”

The New Arctic

We entered the edge of the ice pack on the evening of September 26. The thin ice first appeared as an oily sprinkle of crystals that sparkled in the sunlight. It gradually thickened until it formed a thin black film. At this point, it could still bend, allowing waves from a passing ship to ripple through it. The ice continued to grow as we motored north until it became hard and white⁠⁠. Here, waves tossed the ice around — grinding it into round plates called pancake ice or pushing thin sheets on top of one another to create an interlocking pattern, a phenomenon known as finger rafting. One dictionary floating around the ship included descriptions and drawings of 99 different types of sea ice.

By the next morning, we started to pass giant floes, as though we were breaking through a vast, white continent that was crisscrossed by polar bear tracks. I was onboard a Russian icebreaker, the Akademik Fedorov, which was helping with the initial setup of the mission (known as the Multidisciplinary Drifting Observatory for the Study of Arctic Climate, or Mosaic). Together, the Akademik Fedorov and the German icebreaker, the Polarstern, sailed from Tromsø, Norway, in mid-September and headed toward the central Arctic. The first task was to find a floe so strong and so thick that the Polarstern could steer into it and the captain could kill the ship’s engines — entombing the vessel within the ice for a full year.

It should have been relatively straightforward. In late September, at our latitude, the sea ice should be around 1.6 meters thick, according to predictions made by the National Oceanic and Atmospheric Administration. Yet for days we searched in vain for an ice floe just 1 meter thick. Helicopter reconnaissance missions analyzed more than a dozen floes, but every one of them was less than 0.5 meter thick. Mooring a ship to a floe so thin would be dangerous — strong winds would shove the ship through the ice, destroying any research stations.

The difficulties threw into stark relief the lack of multiyear ice within the central Arctic Ocean. “The old ice is almost entirely gone,” Tsamados said. “That’s not alarmist — that’s a fact.” Over the past three decades, the oldest and thickest ice has declined by a stunning 95%. That much can be garnered from satellite observations, but satellite observations can be imperfect. Satellites typically measure ice thickness with a special radar, which is supposed to penetrate snow. If it doesn’t, scientists can mistake snow for ice and overestimate the ice thickness.

Snow creates other complicating factors. At its simplest, snow acts like a blanket, preventing heat from the relatively warm water from escaping into the atmosphere. (Its insulating properties, after all, make it excellent material for an igloo.)

In 2012, Melinda Webster, a scientist at the University of Alaska, Fairbanks, set out to study how snow cover affects the growth of sea ice. In a small lagoon connected to the Chukchi Sea — a spot protected from the complicating factors of wind and ocean currents — her team found that thick snow stunts the growth of sea ice. The thinner the ice is, the more it’s sensitive to snow’s insulating effects.

Yet scientists can’t say whether snow is increasing or decreasing in the Arctic. On the one hand, open water releases more moisture into the atmosphere, which causes more precipitation. But because there is less ice, there is a smaller surface on which to accumulate snow.