You probably know that Arctic sea ice is melting, but have you ever wondered how the ice forms? The Arctic is a partially enclosed area of sea covered in sheets of floating ice, called floes. New Arctic ice forms beneath those existing floes.
As water underneath ice floes freezes, heat escapes by traveling up through the existing mass of ice and into the air. This bottom-up ice formation means that thick masses of ice form slowly, because it takes a long time for the trapped heat to make its upward escape.
Historically, Arctic sea ice follows a pattern of melting and freezing seasons. Some floes persist through the summer creating thicker sheets of ice as time progresses. However, since 1979, the length of the melting season has extended; ice is melting earlier and refreezing later. Evidence also suggests that fewer patches of Arctic ice are persisting for multiple years, which limits the potential for thicker ice to form.
Melting sea ice puts Arctic animals, like polar bears, seals and walruses, at risk. These species depend on ice for food, mating and migration. Less ice restricts their range, access to prey and reproductive success. It also impacts the indigenous people whose survival depends on Arctic animals. But it is not just Arctic inhabitants that experience the impacts of receding sea ice.
Arctic ice also plays an important role in regulating the Earth’s climate. It cools air, by forming a barrier between air and warmer water. As sea ice decreases, so does its cooling impact. Less snow and ice to reflect the sun’s solar energy also means that the dark ocean absorbs more heat, warming waters and further exacerbating the rate at which sea ice melts.
The Arctic ice that cools the planet is melting faster than it can be replaced. Some scientists even posit that Earth could see an ice-free Arctic summer by 2040, though some more conservative estimates say 2050 or 2070.
At least, one team of researchers is not willing to wait to find out. They are thinking up new ways to speed the production of Arctic sea ice, by turning the process on its head. Their top-down approach proposes placing wind-powered buoys fitted with pumps throughout the Arctic.
The pumps would siphon almost-frozen water from under an ice floe onto its surface where the water would freeze faster, because trapped heat would have a streamlined path of escape. In doing so, they estimate a single pump could build a meter-thick layer of Arctic sea ice 100,000 square meters wide.
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