Sea Ice Thickening Trials in Canada and Norway Increase Thickness and Delay Melt by Up to 10 Days

Two companies conducted field trials in 2024 and 2025 to test whether pumping seawater onto Arctic sea ice could thicken it enough to slow summer melt. Real Ice operated eight sites in the Northwest Passage just south of Cambridge Bay, Canada, while Arctic Reflections worked in a lagoon in Norway’s Svalbard archipelago.

In April 2024, Arctic Reflections drilled through nearly a metre of ice and pumped seawater onto a 20-centimetre snow layer for a little over an hour.

16 metres. A camera left at the site showed the thickened ice melted on the same day as a control patch. Between December 2024 and February 2025, Real Ice drilled holes and pumped water at eight Canadian sites, flooding and freezing snow over 250,000 square metres and thickening some locations twice.

62 metres at three control sites. Long temperature-sensor wires at the Real Ice sites indicated the ice lasted an estimated seven to 10 extra days before melting relative to historical averages. Both trials produced brighter ice, with Real Ice sites appearing as white spots amid blue meltwater in June satellite imagery.

The Arctic Reflections study estimated that the cooling effect barely offset emissions from pumps and vehicles. Christian Haas at the Alfred Wegener Institute, who analysed the Norway results, said the ice got thicker but added that how this delays disappearance remains an open question and that quality matters more than thickness.

Andrea Ceccolini of Real Ice said the brine pores created during thickening could drain meltwater and slow disappearance, stating the company was contributing to reducing planetary heating.

9 million UK government grant that also funds both companies, said it can work locally but questioned scaling to 10 or 100 kilometres. Real Ice stated that 500,000 underwater drones could eventually refreeze 1 million square kilometres. Arctic Reflections is considering refreezing straits where ice flows south to melt.

Last year, 42 scientists argued in an article that polar geoengineering including sea-ice thickening was unfeasible and could distract from emissions cuts. Michael Meredith at the British Antarctic Survey, who was not involved in the research, said the technique might have limited use as a small-scale stopgap in localised regions but does not represent a practical large-scale solution.

1029/2025EF007894.