The Arctic Ocean could be practically free of sea ice for the first time in summer (specifically in September) in the 2030s, even in a low emissions scenario, that is, considering a significant reduction in greenhouse gas emissions that warm the atmosphere. This means that the frozen ocean would lose its ice pack a decade sooner than previously projected.
This is according to a simulation study published in Nature Communications. These findings once again highlight the significant impact of human activities in the Arctic.
It is now too late to save Arctic sea ice in the summer, scientists find.
Even if greenhouse gas emissions are significantly reduced, the Arctic will be ice-free by September for decades to come. The first ice-free summer could be in the 2030s, a decade earlier than previous projections.
Research shows that 90% of melting is the result of human-caused global warming, while natural factors explain the rest.
Arctic sea ice has been rapidly declining in all seasons and months for the past few decades, with further declines experienced since 2000.
To analyze the human contribution to Arctic sea ice decline and project its future trajectory, the researchers used observational data from 1979 to 2019 to project climate model simulations.
The study authors conclude that the Arctic can be free of sea ice in September between 2030 and 2050 under all emission scenarios, which is in contrast to previous assessments.
This is roughly a decade ahead of recent projections by the UN's Intergovernmental Panel on Climate Change (IPCC), notes Seung-Ki Min of South Korea's Pohang and Yonsei Universities, a co-author of the paper.
The sixth assessment report of the UN Intergovernmental Panel on Climate Change (IPCC) (2022) predicted that, on average, the Arctic would be practically free of ice in September on indeterminate dates around mid-century, but always in scenarios where those with intermediate and high greenhouse gas emissions; on the other hand, this was not expected to occur in low emission scenarios, as is considered in this work.
When experts talk about the absence of ice, they mean an area of less than 1 million km2, because there can always be residual ice along the coasts.
The Arctic Ocean covers an area of approximately 14 million square kilometers and is covered in ice for most of the year.
This new report uses an approach called "attribution analysis" and shows that a dominant influence of greenhouse gases on the Arctic sea ice area (detected with observational data in all months of the year but even underestimated) may accelerate this thaw.
The findings suggest that the human impact on the decline in Arctic sea ice can be seen throughout the year and can be largely attributed to increased greenhouse gas emissions.
"We project an ice-free Arctic in September under all the scenarios considered," they highlight.
Instead, the contributions of aerosols and natural factors (such as solar and volcanic activity) were much smaller.
About 90% of Arctic sea ice melt is caused by the former, versus 10% by natural forces.
Arctic sea ice cover is typically lowest in September, at the end of summer, before growing again in the colder, darker months of fall and winter, peaking in March. His loss has global repercussions.
An Arctic without sea ice would affect natural ecosystems both inside and outside the Arctic, alter marine activity, accelerate warming in the region, and change the carbon cycle.
In fact, this ice plays a very important role in summer, returning the sun's rays, allowing the Arctic to cool down.
It is the albedo effect, the ability of this surface to reflect radiation. The problem is that this mirror is now getting smaller and smaller, and therefore the Arctic is warming much faster than other regions.
As the temperature difference between the Arctic and lower latitudes narrows, the fluctuations in the jet stream will become more intense.
Likewise, a warmer Arctic will accelerate the melting of permafrost and release more greenhouse gases into the atmosphere and accelerate a dangerous feedback loop. Greenland's ice sheet would also likely melt more quickly, which would mean higher seas.
"If the Arctic sea ice melts faster than predicted, then what we can immediately expect is faster Arctic warming," Seung-Ki Min said.
