Scientists warn Arctic’s first ‘ice-free’ day could happen within 3 years

By Stephen Beech

The first ice-free day in the Arctic could happen within three years, warns a new study.

The first summer on record that melts practically all of the Arctic’s sea ice may occur as early as 2027, say scientists.

An international research team used computer models to predict when the first ice-free day could happen in the northernmost ocean.

They say an ice-free Arctic could "significantly impact" Earth's ecosystem and climate by changing weather patterns.

Co-author Professor Alexandra Jahn, a climatologist from the University of Colorado, Boulder, said: “The first ice-free day in the Arctic won’t change things dramatically.

“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.”

She said sea ice in the Arctic has disappeared at an "unprecedented" speed of more than 12% each decade as the climate warms due to increasing greenhouse gas emissions.

In September, the National Snow and Ice Data Centre reported that this year’s Arctic sea ice minimum - the day with the least amount of frozen seawater in the Arctic - was one of the lowest on record since 1978.

At 1.65 million square miles, or 4.28 million square kilometers, this year’s minimum was above the all-time low observed in September 2012.

However, the research team says it still represents a "stark decline" compared to the average coverage of 6.85 million square km between 1979 and 1992.

When the Arctic Ocean has less than one million square km of ice, scientists say the Arctic is ice-free.

Previous projections of Arctic sea ice change have focused on predicting when the ocean will become ice-free for a full month.

Jahn’s previous research suggested that the first ice-free month would happen by the 2030s.

As the tipping point approached, Jahn wondered when the first summer day that virtually all of the Arctic sea ice would melt would occur.

Study co-author Dr. Céline Heuzé, from the University of Gothenburg in Sweden, said: “Because the first ice-free day is likely to happen earlier than the first ice-free month, we want to be prepared.

"It’s also important to know what events could lead to the melting of all sea ice in the Arctic Ocean."

This summer, during an expedition to the Arctic Ocean, Dr. Heuzé and her colleagues saw first-hand that the Arctic sea ice is already "very thin".

Where 20 years ago they would have encountered ice two meters or thicker around the North Pole, this year it was barely one meter on average.

Dr. Heuzé said: “The sea ice was so thin and 'rotten' that it felt like we did not need an ice breaker.

"It was actually very stressful to work in these conditions; with no sea ice to slow down our progression, we barely had time to collect our data and recover by the time we had already reached the next measurement point."

The team estimated the first ice-free Arctic day using output from more than 300 computer simulations.

They found that most models predicted that the first ice-free day could happen within nine to 20 years after 2023 - regardless of how humans alter their greenhouse gas emissions.

However, the earliest ice-free day in the Arctic Ocean could occur within three years, according to the findings published in the journal Nature Communications.

The researchers say it is an "extreme scenario" but a possibility based on the models.

In total, nine simulations suggested that an ice-free day could occur in three to six years.

The team found that a series of extreme weather events could melt two million square km or more of sea ice in a short period of time: an unusually warm autumn first weakens the sea ice, followed by a warm Arctic winter and spring that prevents sea ice from forming.

When the Arctic experiences such extreme warming for three or more years in a row, the first ice-free day could happen in late summer.

The research team points out that those kinds of warm years have already happened. For example, in March 2022, areas of the Arctic were 50°F warmer than average, and areas around the North Pole were nearly melting.

With climate change, the frequency and intensity of these weather events will only increase, according to Dr. Heuzé.

She said: “All these individual events have already taken place several times in the Arctic, just not in the right order within the same season.

"The risk for the right sequence only increases with climate change, as our results show.

"But it is not too late to save the Arctic sea ice – we just need to finally reduce our greenhouse gas emissions."

Dr. Heuzé explained that sea ice protects the Arctic from warming by reflecting incoming sunlight back into space.

With less reflective ice, darker ocean waters will absorb more heat from the sun, further increasing temperatures in the Arctic and globally.

Warming in the Arctic could also change wind and ocean current patterns, leading to more extreme weather events around the world.

But there’s also good news, according to the study, as a "drastic" cut in emissions could delay the timeline for an ice-free Arctic and reduce the time the ocean stays ice-free.

Jahn, who is due to present the findings on December 9 at the American Geophysical Union annual meeting in Washington DC, added: “Any reductions in emissions would help preserve sea ice."