By the middle of this century, thanks to climate change, anyone with a light icebreaker can spend their Septembers going anywhere they want in the Arctic Ocean, including straight over the North Pole, according to a new study.

Ordinary vessels, which account for more than 99 percent of shipping traffic, could easily navigate the Northern Sea Route along the Russian coastline and, in some years, even find a route through the fabled Northwest Passage.

“That’s kind of crazy and, frankly, a little bit worrisome,” Laurence C. Smith, a geographer and sea ice expert at the University of California, Los Angeles, told NBC News. “It is not like these will be open blue seas and safe or open year round.”