The Arctic is still warming, so why no new sea ice low record since 2012?
Despite the Arctic's worsening, ongoing warming, an unexpected trend has been uncovered: A 13-year streak of no new records for sea ice minimum. A climate scientist dives into the possible reasons why
With the Arctic sea ice maintaining its trend of declining, average extent since the 1980s, there is another side to the story with a unique, slightly more positive statistic to it.
The Arctic sea ice extent achieved its annual minimum on Sept. 10 at about 4.6 million square kilometres. Tied with 2008, it is the 10th-lowest value on record, according to NASA, with satellite data going back to 1979. It extends the trend towards values considerably lower than the average sea ice extent that was observed in the 1980s, 1990s and 2000s.
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According to Flavio Lehner, chief climate scientist at Polar Bears International (PBI) and assistant professor at Cornell University, sea ice is particularly low this year along parts of the Siberian coast and in the Beaufort Sea off the coast of Alaska.
But, what is "remarkable" about this year’s sea ice minimum is that it is the 13th year in a row when there hasn't been a new, record low––not since 2012--despite ongoing Arctic warming, Lehner told The Weather Network in a written response via email.
(Polar Bears International/Submitted to The Weather Network)
"I’m not too surprised that something like this can happen, though it is interesting to see it happen during a period of continued global warming. I’ve seen too many 'false trends' to be surprised by something like this," said Lehner.
"The climate system is noisy, and not every uptick or slowdown is meaningful. Still, we should keep an eye on this. It’s a great test for our models. Can they reproduce such a slowdown? If yes, do they do it for the right physical reasons? If not, what are we missing? So far, it looks like this slowdown is still within our understanding of the magnitude of variability in Arctic sea ice."
Reason for no new minimum record is 'outstanding'
As to why there has been no new record set for sea ice minimum extent since 2012, "a definitive answer is still outstanding," Lehner said.
The "most plausible hypothesis" right now is a relation to the natural variability of the climate system, which occurs on top of long-term trends driven by climate change. It can either slow or hasten the overall direction, he added.
"Natural climate variability is a hard-to-convey concept. A great analogy is a person walking a dog on a leash," said Lehner. "The dog can randomly roam around but is ultimately constrained by the person’s walking direction. In the climate system, the person represents the long-term sea ice downward trend due to greenhouse gas-induced warming, while the dog represents random sea ice variations around the long-term trend."
(Getty Images/Frank Gunther/2220213277-170667a)
Natural, or internal, climate variations occur all the time and are well-studied, he said, noting that sometimes the variations combine with climate change to speed up or slow the decline in Arctic sea ice, but they don’t have the power to reverse it.
"Such variations are akin to the daily weather we experience, [acting] on top of slower changes such as the season. For example, if you’re lucky this year, you still get to experience a nice, summer-like day in October even as you would expect the weather to be fall-like. At the same time, you know that winter is inevitable," said Lehner.
He cited findings from an August 2025 paper that mainly shows how periods of ice slowdown are unusual but not unexpected given the current understanding of climate variability.
However, there are several ideas in consideration that could explain this type of slowdown.
Among them are, according to Lehner:
"Sea ice thickness feedback: Around the year 2007, Arctic sea ice has gotten quite a bit thinner, as a lot of old, thick, multi-year ice disappeared. Thin ice can actually grow more quickly in subsequent winters, as it doesn’t insulate the ocean beneath as well, allowing it to cool during the polar night. Such enhanced growth in winter could have temporarily slowed the overall sea ice loss."
(Getty Images-899103038-170667a)
"Ocean heat transport: Ocean currents transport heat into the Arctic, and if those currents slow down for a few years, less warm water gets to the sea ice edge to melt it."
"Missing forcing: Recent years have seen many more boreal wildfires than scientists expected. Some studies suggest that the smoke aerosols from those fires can lead to a relative reduction of Arctic temperatures, and consequently, a slowdown of sea ice loss. I call this a 'missing' forcing because most climate model simulations do not yet include this recent increase in fires, so [it] would miss that effect. However, as anything involving aerosols, the magnitude of this effect is poorly understood. It might be important, or it might not be important, relative to random variations of the weather over a few years."
2012 was the last year of record sea ice minimum
According to Lehner, the current record for sea ice minimum occurred in 2012 when the extent was as low as 3.3 million square kilometres--substantially less than any year before and after. While the long-term trend in Arctic sea ice is still on the decline, the recent slowdown is decidedly visible in the record.
That year, in the summer, a potent storm that passed over the Arctic Ocean broke up sea ice, making it more prone to melting, Lehner said.
Arctic sea ice. (Kt Miller/Polar Bears International/Submitted to The Weather Network)
"Sea ice melts from above and below, but also laterally, so breaking it up increases the area exposed to warm ocean waters," said Lehner.
How the current slowdown compares to past occurrences
The length of the current slowdown of sea ice melt is the longest that has been documented in the satellite data record since 1979, the climate scientist said.
"We know from sea ice reconstructions going back centuries that Arctic sea ice can vary substantially on decadal time scales. Our evidence for why this current slowdown is unusual, but not unexpected, comes from long climate model simulations where such events occur about 20 per cent of the time, so a one-in-five chance to see something like this," said Lehner.
Arctic sea ice. (Kt Miller/Polar Bears International/Submitted to The Weather Network)
When can we expect Arctic warming to pick up again?
If there are any positive impacts on polar bears from the current slowing of the sea ice melt, they will only be in a "relative sense," Lehner said.
A slowdown may give the bears a break from the "relentless, year-over-year reduction" in their habitat, but it won’t restore the sea ice extent they were accustomed to living with from the 1990s and time before that, he added.
"The reprieve in ice loss is only a small piece of good news for polar bears that depend on sea ice as their habitat. Sea ice has also been thinning continuously, making ice, even if it’s there, less ideal for bears to walk on," said Lehner.
Polar bear. (Kt Miller/Polar Bears International/Submitted to The Weather Network)
As for when to expect the sea ice melt to accelerate again, that's still up in the air because a particularly warm or stormy summer can happen in any given year, Lehner stated.
However, as long as we continue to warm the Arctic from additional greenhouse gas emissions, the sea ice is bound to eventually melt.
"The longer the slowdown lasts, the more likely the inevitable continuation of the decline becomes. The England et al. study found climate model simulations with slowdowns that lasted more than 20 years. In an extreme case, it could take another five to 10 years before sea ice starts to decline substantially again," said Lehner.
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Thumbnail courtesy of Kt Miller/Polar Bears International.
