Arctic could see its first ice-free day before the end of the decade: Study

The planet's northernmost ocean could experience its first day free of ice as early as 2027, a new study has found.

While the three-year possibility remains extreme, the study authors determined that this first pivotal day could occur within nine to 20 years after 2023, regardless of how humans alter their greenhouse gas emissions.

Such a time, defined as the first day on which nearly all of the Arctic's sea ice melts, would mark "an ominous milestone for the planet," according to the authors, who published their findings on Tuesday in Nature Communications.

“The first ice-free day in the Arctic won’t change things dramatically,” co-author Alexandra Jahn, a climatologist at the University of Colorado Boulder, or CU Boulder, said in a statement.

“But it will show that we've fundamentally altered one of the defining characteristics of the natural environment in the Arctic Ocean," she added.

That departure from full-time ice and snow will have occurred because of greenhouse gas emissions, Jahn explained.

To draw these conclusions, an international team of researchers from CU Boulder and Sweden's University of Gothenburg used more than 300 computer simulations to predict when that first ice-free day would occur.

Scientists generally consider the Arctic to be ice free when the ocean has less than a million square kilometers of ice, according to the authors.

Examining a range of climate scenarios, the researchers found that the earliest ice-free day — an extreme case — could occur within three years. But they also observed in a total of nine simulations that an ice-free day could occur in three to six years.

The scientists found that a series of extreme weather events could melt 2 million square kilometers or more of sea ice in a short time. Such circumstances, they explained, could occur if an unusually warm fall weakens the ice, followed by a warm winter and spring — which collectively would prevent ice from forming.

If the Arctic region experiences such a cascade of events for three years or more, that first ice-free day could occur in late summer, according to the study.

The knock-on effects could be substantial, as sea ice protects the Arctic from warming by reflecting sunlight back into space, the researchers noted. Less reflective ice and more absorption of heat from the sun could end up increasing temperatures around the world, they warned.

While the results of their research appeared to be dire, the authors also stressed that there is some good news: the fact that a significant cut in emissions could postpone the ice-free timeline.

“Any reductions in emissions would help preserve sea ice,” Jahn said.