The Arctic’s fast-melting ice is even more than our strongest predictions for the future, and that is not in line with the past.
A new and improved model, based on the last warm period in the history of the Earth, now suggests shallow pools of rain and melt water could bring the end of the summer sea ice much longer than we thought.
If what is happening right now with the Arctic is something like the last interglacial period, scientists say there is a chance that in 15 years it will be virtually free of sea ice.
“The prospect of sea ice loss by 2035 should really focus all our minds on realizing a world with low carbon, as human as possible,” says Louise Sime, a paleoclimate model at the British Antarctic Survey (BAS).
Previous projections from the United Nations Intergovernmental Panel on Climate Change (IPCC) show that summer ice lasts over a million square kilometers until at least 2050 or even beyond 2100, but recently that timeline has begun to look far too optimistic.
Just this year, an analysis of numerous climate models found that even at best, Arctic sea ice would slide under this mark, leaving the region virtually “ice-free” by the middle of the century.
Of course, the debate does not end; There are still so many subtle factors to consider. But Sime says we can get a better idea of the future by looking back at the last warm period of the earth, which began about 130,000 years ago and was much warmer than it is today.
While earlier models of this era did not show ice-free summers in the Arctic, Sime and her colleagues found the opposite with improved model physics and the incorporation of subtle feedback systems into the climate.
Their model suggests that the Arctic may have been ice-free in the summers of the last interglacial period, and this was compounded by the presence of melting ponds – even more so than clouds or ocean currents, which have historically gained more weight in the warming Arctic.
Melting dams occur in the late spring and summer of the Arctic, as rain and melting ice and snow accumulate in shallow poles of blue. Somewhat darker than the ice that perished, these scattered bodies of water reduce the reflection of the surface and absorb significantly more solar radiation than the frozen ground.
Some studies have shown that melting ponds actually increase the surrounding ice milk and increase the potential of phytoplankton blossoms in the ocean below. It can also make sea ice unsteady and lead to fractures, the ocean below the public and contribute to further heat absorption.
(NASA Earth Observatory)
If something happened to melting ponds later than in the future, the authors predicted that summer sea ice would disappear from the Arctic in the next few decades – anywhere between 2035 and 2086.
And it’s probably on the earlier side.
Half of the models they looked at predicted conditions with sea ice between 2030 and 2040, and even in the worst case scenario, where we do nothing to reduce emissions and continue to grow populations and economies the authors the last disappearance of sea ice would come in 2066.
This study is obviously not a direct measure of the current melting of the sea ice, nor does it examine winter temperatures as seasonal changes in sea ice. It is a prediction, based on what happened in the hottest days of last year and what will happen in the future with our current understanding of the atmosphere, land, ocean and ice.
It’s an incomplete estimate, but the findings support more recent models that imply that sea ice is far on the way we had hoped, in large part due to overhauled feedback systems such as melting ponds.
“The ability of the [new] model to realistically simulate the very hot LIG Arctic climate provides independent support for forecasts of ice-free conditions by summer 2035, ”the authors conclude.
“This should be a huge concern for Arctic communities and climate scientists.”
The study was published in Nature Climate change.
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