There is considerably less sea-ice in the Arctic than there used to be. Thanks to global warming, Arctic sea-ice is melting faster in the spring and taking longer to form in the autumn.
Scientists who use satellite data to track Arctic sea-ice estimate that we’ve lost around 12 per cent of summer ice coverage for each decade since measuring began in 1985. And this trend is set to continue: the United Nations Intergovernmental Panel on Climate Change (IPCC) predicts that the Arctic is likely to be ice-free in summertime at least once by 2050.
Less ice means that less of the sun’s energy is reflected back into space. Instead, it is absorbed by the dark surface of the Arctic Ocean, warming the water and leading to further melting. This will cause sea levels to rise dramatically, which will have devastating consequences.
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Climate experts agree that we need to drastically reduce greenhouse gas emissions if we’re to slow the rate at which Arctic sea-ice is melting and, ultimately, reverse the trend. But turning this ship around, even in the most optimistic of geopolitical contexts, won’t be possible right away.
In the meantime, research is taking place into how we might use so-called geoengineering to give Arctic sea-ice formation a nudge in the right direction. Shaun Fitzgerald, director of the Centre for Climate Repair at the University of Cambridge, is leading a project exploring whether pumping sea water on to existing sea-ice in the Arctic might lead to the thickening of that ice.
The hope is that thicker ice would take longer to melt in the summer. Recently awarded £9.9 million in public funding by the UK government’s Advanced Research and Invention Agency (ARIA), the project involves mathematical modelling as well as laboratory and small-scale field experiments into the effects of flooding Arctic ice with sea water.
This includes teaming up with the local Inuit community in Cambridge Bay, northern Canada who, says Fitzgerald, “are greatly concerned about the ever decreasing amount of sea-ice. They are supporting the work to explore whether it might be possible toreduce the rate of loss.” Fitzgerald hopes that at the end of the three-and-a-half-year project his team will have gathered sufficient data to help decide whether there should be more research into Arctic refreezing.
Other routes being explored to slow the rate of Arctic sea-ice melt include marine cloud brightening (MCB), where tiny particles of sea water are sprayed into clouds to make them better at reflecting solar energy back into space. This research draws on field experiments that have been using MCB to protect the Great Barrier Reef from heat stress.
Another sky-based research area involves injecting aerosol compounds high up in the
stratosphere – the second-lowest layer of the atmosphere, above where clouds form. It is thought they could reflect some solar energy back into space, thereby cooling the surface of the Arctic and slowing the melting of sea-ice.
This technology replicates the natural cooling effect of reflective particles that enter the stratosphere following volcanic eruptions. As with the other methods, this research is at an early stage, assessing whether it would be feasible and safe to release natural mineral dust into the atmosphere. Geoengineering isn’t without criticism, however.
A study published in Frontiers in Science in September reviewed five geoengineering
concepts and deemed them unfeasible and expensive, suggesting decarbonisation as an alternative to intervening in fragile polar ecosystems. Whatever the outcome of the studies, we won’t be refreezing the Arctic any time soon.