Can you “refreeze” the Arctic?
Scientists from the UK are in the Arctic to test out a method of “refreezing” its ice. The Arctic is the northernmost region of Earth and it is extremely cold – but global warming is melting its ice. Over the past 30 years, the oldest and thickest parts have shrunk by as much as 95%. Arctic ice melting is worrying because it makes sea levels rise and it makes the planet warmer because the dark water absorbs the Sun’s warmth, whereas the white ice reflects it back into space.
Earlier this month, a team travelled to Cambridge Bay, in Arctic Canada. They cut a hole in the ice and used a pump to bring seawater from below the ice up to the surface. This spread out across the ice and froze, replacing the snow that usually lies there. Having a layer of fresh ice rather than snow on top reduces the temperature of the ice and means seawater under it freezes faster, making the ice thicker by natural means too.
The scientists’ pump is powered by green hydrogen, a gas produced using renewable energy (energy from sources that won’t run out, like the Sun or wind). This is to limit the environmental impact of the study.
The plan is for local people to measure the thickness of the ice over several weeks. The team hope to add around a metre of ice in order to stop it melting completely in summer, when the weather is warmer. However, even if the idea works and the ice gets thicker, it could take several million pumps to reverse the melting ice all over the Arctic. “That’s a lot of pumps but it’s not absolutely out of this world,” said Dr Shaun Fitzgerald, from the University of Cambridge, which is involved in the expedition.
Experts are exploring other ideas too. One is to sprinkle glass powder over the ice to reflect the Sun’s rays back, reducing heat and the rate of melting.