New research from scientists at the Norwegian Polar Institute finds that Arctic sea ice has never made a full recovery since suffering a dramatic decline in 2007. The study published in Nature suggests that the sudden loss 15 years ago marked a fundamental change unlikely to be fixed this century…or ever. The Arctic is now in a “new regime” according to the researchers, in which ice cover is thinner and younger than it ever was. 19% of the sea ice in the Arctic was at least 13 feet thick in 2007, but now only about 9.3% of ice is at least that thick, and the average age of the Arctic ice has dropped by more than a third to just 2.7 years.

Rising ocean temperatures and a fast warming Arctic are to blame, and the thinning ice could cause problems for Arctic sea life, which rely on thick sea ice for hunting and habitats. Sea ice thickness matters to areas even thousands of miles away, according to study lead author Hiroshi Sumata. “It will affect the entire Earth because the north and south pole is something like a radiator of the Earth, the air conditioning system of the Earth,” Sumata told the AP. “And the situation we observed indicates the air conditioner is not working well.”

Relatedly, the sea ice on the other end of the Earth, around Antarctica reached the lowest extent ever observed since the start of the satellite record in 1979.

(AP, Nature, National Geographic $, Washington Post $; Antarctic: NASA)