The first summer on record in which practically all of the sea ice in the Arctic melts could occur much earlier than previously expected. In a new study, scientists warn that the ever-increasing greenhouse emissions may bring us closer to an ice-free Arctic by the end of the decade.

“The first ice-free day in the Arctic won’t change things dramatically,” said Jahn. “But it will show that we’ve fundamentally altered one of the defining characteristics of the natural environment in the Arctic Ocean, which is that it is covered by sea ice and snow year-round, through greenhouse gas emissions.”

A polar bear stands on floating sea ice in the Arctic. The bears rely on sea ice to move throughout their hunting grounds.