08-05-2025
Scientists hope to halt climate change by REFREEZING the Arctic - here's how it could work
When it comes to curbing climate change, scientists will try almost anything.
And experts at the University of Cambridge are no exception – as they have been given funding to see if global warming could be slowed by refreezing the Arctic.
A team will explore whether the Arctic's rapidly diminishing sea ice could be artificially thickened by pumping seawater onto the surface in winter.
If successful, it could reduce summer melt and slow regional warming, they said.
For years, scientists have sounded the alarm over the Arctic's rapidly-shrinking sea ice cover.
Many expect the region to be ice-free in the summer in the 2030s, even if sharp cuts to emissions are made immediately.
Some researchers say the only way to stop this from happening is to artificially thicken the ice – which polar wildlife and Inuit communities depend on.
But how, exactly, would it work?
Sea ice forms naturally by water freezing on the bottom of existing ice which floats on the ocean's surface.
As the ice grows it becomes a thicker insulating layer between the cold Arctic air above the ice and the water below, so the rate of freezing slows down.
Any snow on the ice's surface also acts as an insulator, further slowing the rate of new ice growth.
One technique that Cambridge's Centre for Climate Repair is looking into is called surface thickening.
This aims to increase the sea ice thickness directly when there is no snow by pumping seawater onto the surface, so it is directly exposed to the cool atmosphere and thickens the ice from above.
Another method can be used when there is snow on the surface of the ice. It involves filling the voids of air within snow with seawater – eventually turning the snow into solid ice which then leads to more natural freezing at the ice's base.
Field trials are set to begin in Canada this year in collaboration with Real Ice, whose mission is to 'preserve and restore Arctic Sea Ice'.
Last year the company said tests have validated the idea, with a pilot borehole thickening the ice shelf by 50 centimetres compared with a control site between January and May.
Crucially, the results show that the technique triggered 25 cm of natural ice growth on the underside of the ice shelf.
The method was first proposed by Steven Desch at Arizona State University and his colleagues in 2016.
They estimated that deploying ice thickening over 10 per cent of the Arctic could more than reverse recent ice loss in the region.
'Our objective is to demonstrate that ice thickening can be effective in preserving and restoring Arctic sea ice,' Andrea Ceccolini, from Real Ice, previously told New Scientist.
'Every action we can take to make the ice last longer during the summer will give us extra weeks of solar radiation reflection back to space, which is less energy absorbed by the planet.'
The scheme is one of 21 geo-engineering projects that will receive a total of £57 million in UK taxpayer money to assess a range of controversial techniques to curb the effects of global warming.
The funding comes from the government's Advanced Research and Invention Agency (Aria).
WHY DO POLAR BEARS NEED ICE TO SURVIVE?
Loss of ice due to climate change has a direct impact on the ability of polar bears to feed and survive.
The bears need platforms of ice to reach their prey of ringed and bearded seals. Some sea ice lies over more productive hunting areas than others.
Arctic sea ice shrinks during the summer as it gets warmer, then forms again in the long winter. How much it shrinks is where global warming kicks in, scientists say. The more the sea ice shrinks in the summer, the thinner the ice is overall, because the ice is weaker first-year ice.
But the Arctic has been warming twice as fast as the rest of the world. In some seasons, it has warmed three times faster than the rest of the globe, said University of Alaska at Fairbanks scientist John Walsh.
In the summertime, polar bears go out on the ice to hunt and eat, feasting and putting on weight to sustain them through the winter. They prefer areas that are more than half covered with ice because it´s the most productive hunting and feeding grounds.
From late fall until spring, mothers with new cubs den in snowdrifts on land or on pack ice. They emerge from their dens, with the new cubs, in the spring to hunt seals from floating sea ice.
Simply put, if there isn't enough sea ice, seals can't haul out on the ice and polar bears can't continue to hunt.
In recent years the sea ice has retreated so far offshore that the bears have been forced to drift on the ice into deep waters - sometimes nearly a mile deep - that are devoid of their prey.
