Chunks of ice float past the hull of the Akademik Fedorov as the ship moves through the southern edge of the Arctic Ocean ice pack.

Ravenna Koenig/NPR

Arctic researchers just starting out face an intriguing but unsettling reality: much of the sea ice that’s covered the Arctic Ocean for thousands of years may rapidly melt away over their careers. In fact, some projections say the region may see its first ice-free summer in modern history by 2040.

A group of grad students got to see this reality in person on a recent expedition that set off in September from Tromsø, Norway. It took five days of traveling through open water to get to the sea ice in the middle of the ocean, longer than it likely would have taken decades ago.

It’s night when the ship finally gets there. After being…