Scientists Jahn and Heuzé projected the first ice-free day using computer simulations. In most models, regardless of greenhouse gas emissions, the first ice-free day could occur within nine to 20 years. In the earliest model, it could be between 2027 to 2030.

“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.