Sea-Ice Thickening Trials Increase Thickness and Delay Melt by Up to 10 Days, but Large-Scale Impact Remains Unclear
Two companies tested pumping seawater onto Arctic ice to increase thickness. One trial in Canada recorded slower melt; the Norway trial did not.
newscientist.comReal Ice pumped seawater onto sea ice at eight sites in the Northwest Passage just south of Cambridge Bay, Canada, between December 2024 and February 2025. The company flooded and froze the snow layer over 250,000 square metres and thickened some sites twice. 62 metres at three nearby control sites.
Temperature sensors at the Real Ice sites recorded an estimated seven to 10 extra days before melting began. Satellite imagery from June 2025 showed the treated patches as white spots surrounded by blue meltwater. Andrea Ceccolini of Real Ice said the work contributed to reducing planetary heating.
Arctic Reflections conducted a separate trial in April 2024 in a lagoon in the Svalbard archipelago. The team drilled through nearly a metre of ice, pumped seawater onto a 20-centimetre snow layer for a little over an hour on two consecutive days, and created a 1,500-square-metre slush puddle that froze within three days. 16 metres.
A camera left at the Arctic Reflections site recorded that the thickened ice melted on the same day as an untreated control area. Christian Haas of the Alfred Wegener Institute, who analysed the Norway results, said the thickening process heated the sea ice and made it saltier as brine drained through pores. Both trials found that the treated ice became brighter.
The Arctic Reflections study estimated that the cooling effect barely offset emissions from the pumps and vehicles used. 9 million UK government grant that also funds both companies. Real Ice envisions a future fleet of 500,000 underwater drones that could refreeze 1 million square kilometres of sea ice.
Arctic Reflections is examining a smaller approach focused on straits where ice flows south. Last year 42 scientists published an article stating that polar geoengineering methods including sea-ice thickening were unfeasible. Michael Meredith of the British Antarctic Survey said the technique might serve as a small-scale stopgap in limited areas but does not represent a practical large-scale solution.
Canada builds more than 7,000 kilometres of ice roads each winter by the same pumping method used on lakes.
