Sea ice across much of the Arctic is thinning twice as fast as previously thought, researchers have found.
Arctic ice is melting as the climate crisis drives up temperatures, resulting in a vicious circle in which more dark water is exposed to the sun’s heat, leading to even more heating of the planet.
The faster ice loss means the shorter north-eastern shipping passage from China to Europe will become easier to navigate, but it also means new oil and gas extraction is more feasible.
Calculating the thickness of sea ice from satellite radar data is difficult because the amount of snow cover on top varies significantly. Until now, the snow data used came from measurements by Soviet expeditions on ice floes between 1954 and 1991. But the climate crisis has drastically changed the Arctic, meaning this information is out of date.
The new research used novel computer models to produce detailed snow cover estimates from 2002 to 2018. The models tracked temperature, snowfall and ice floe movement to assess the accumulation of snow. Using this data to calculate sea ice thickness showed it is thinning twice as fast as previously estimated in the seas around the central Arctic, which make up the bulk of the polar region.
Robbie Mallett of University College London, who led the study, said: “Sea ice thickness is a sensitive indicator of the health of the Arctic – and, when the Arctic warms, the world warms.
“Thicker ice acts as an insulating blanket, stopping the ocean from warming up the atmosphere in winter and protecting the ocean from the sunshine in summer. Thinner ice is also less likely to survive during the Arctic summer melt.”