When North Atlantic right whales went missing from waters in the Gulf of Maine, it was a red flag. With only about 340 animals left, the species is at risk of extinction. Many of the whales are swimming hundreds of miles farther to Canadian waters instead, putting them in new danger.

Now, scientists are linking that to deeper shifts in the ocean, brought on by climate change. The connection may reach all the way to the world's second-largest ice sheet, melting increasingly fast on Greenland.