Not so long ago, the polar ice sheet made it almost impossible to circle the North Pole by sea.
But in June, two boats set off to do just that. By mid October, both returned to port successful — the first ships to sail around the pole in a single summer season.
It’s likely the feat greatly tested the crews’ skill and endurance. But their achievement is no cause for celebration.
The Arctic is often called the “planet’s refrigerator” because of the role it plays in regulating the Earth’s climate. Now, it’s clear the refrigerator is breaking down due to global warming.