Climate graphic of the week: First ice-free day in the Arctic Ocean may come before 2030, study shows

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The Arctic Ocean may have its first ice-free day before 2030, or sooner than previously expected, as rapid melting shows an increasing rate of loss in the polar region, a new scientific study concludes.

The north pole has lost half of its late summer sea ice cover since the early 1980s, and the latest findings bring forward the possible date for an ice-free Arctic.

The study by an international research team using satellite-based sea ice concentration measures and advanced climate models generated a number of projections that put the date within the next three to six years.

“While the fastest sea ice loss simulations are unlikely, what the models are showing us is that they could occur, just like 1,000-year flood events occur occasionally,” said Alexandra Jahn, a co-author and professor of atmospheric and oceanic sciences at the University of Colorado Boulder. 

The Arctic is considered to be ice-free when its waters have less than one million square kilometres of sea ice. At this level, the remaining ice is mostly limited to the north of Greenland and the Canadian archipelago.

“In any kind of climate projection there is a lot of uncertainty simply due to the natural variations in the weather,” cautioned Walter Meier, research scientist at the US National Snow and Ice Data Center, about the precise year of full melt, noting it would occur only in extreme seasonal weather conditions.

Nevertheless, the shift in the Arctic was stark, he said. “My main takeaway is that the fact that the Arctic sea ice cover has changed so significantly that [its loss in] 2030 is even a remote possibility shows how much change there has already been in the Arctic environment.”

The previous record minimum of sea ice cover was set in September 2012, when the sea ice shrank to an area of 3.4mn sq km, or about half of the 1981-2010 average.

Delays in the autumn freeze are also being observed, with 1.5mn sq km of sea ice — or an area about the size of Mongolia — absent this week compared with the long-term average at the same point in the season.

Ella Gilbert, climate scientist at the British Antarctic Survey, said: “We have seen plenty of recent examples of how extreme events can trigger dramatic changes in the polar regions over the course of a few days, for instance the atmospheric river in March 2022 that triggered the collapse of the Conger ice shelf in Antarctica.”

Sea ice loss can in itself further accelerate climate change in a feedback loop known as the Albedo effect — when the ice no longer reflects back the sun’s rays and the darker underlying surface absorbs the heat. This regional warming of the upper levels of the ocean may also trigger more extreme weather events in the mid-latitudes, scientists warn.

The authors of the study found that reducing the greenhouse gas emissions behind climate change as much as possible would delay it from happening, but would not prevent it.

“Even in the lowest emission scenarios, we would only be reducing global emissions, but not reach negative emissions [for the next decades], so atmospheric CO₂ will continue to increase and with it the global temperatures,” said Jahn.

The effects of a melting Arctic are already being felt by communities and wildlife across the region. Some species are being forced on to the land because of the increasing absence of sea ice as a base for hunting, while other marine animals are moving further north into waters previously too cold for their survival a few decades ago.

“Climate change is happening fast, especially in the polar regions,” said Gilbert. “The Arctic is warming four times faster than the rest of the planet, threatening important ecosystems, infrastructure and livelihoods for people living there.”