Vital Arctic sea ice shrank to tie its lowest measured level for the winter, the season when ice grows, as a warming Earth shattered records across the continents.

Arctic sea ice levels, especially in the summer, are crucial to Earth’s climate because without the ice reflecting sunlight, more heat energy goes into the oceans. Ice of all kinds around the poles acts as Earth’s refrigerator.

Wildlife, such as polar bears and seals, also depend on sea ice. Lack of sea ice in the Arctic creates new shipping routes and in doing so causes geopolitical disruptions, making once-ignored places such as Greenland, more desirable.