For millennia, the Beaufort Gyre — a massive wind-driven current in the Arctic Ocean — has been regulating climate and sea ice formation at the top of the world. Like a giant spinning top, the gyre corrals vast amounts of sea ice. Trapped in this clockwise swirl, the ice has historically had more time to thicken than it generally does in other parts of the Arctic Ocean, where currents such as the Trans Polar Drift transport the ice into the warmer north Atlantic more rapidly. In this way, the Beaufort Gyre — located north of Alaska and Canada’s Yukon Territory — has helped create the abundant layers of sea ice that, until recently, covered large parts of the Arctic Ocean year-round.