Geoengineering trials can thicken Arctic sea ice, but the climate value is unsettled
Field trials in Canada and Norway have shown that pumping seawater onto Arctic sea ice can make the ice thicker. What remains unclear is whether that added thickness can preserve ice long enough to matter when summer melt arrives.
The experiments revisit a practical technique already used in cold regions: drilling into ice and pumping water onto the surface so it freezes into a thicker layer. In Canada, similar methods help maintain winter ice roads. Researchers and companies now want to know whether that approach could be scaled to support sea ice that is otherwise expected to disappear completely in summer as early as the 2030s.
The stakes are global because Arctic sea ice reflects sunlight back into space more effectively than open ocean. As the ice retreats, darker water absorbs more heat, amplifying warming. Any intervention that could reliably slow that loss would attract serious attention.
Two trials produced thicker ice, but different summer outcomes
Both sets of trials cited in the supplied source text succeeded in thickening sea ice. The disagreement begins afterward. Researchers in Canada reported that the added thickness slowed summer melt, while the Norway team found that although the thickened ice started “rotting” later, it still disappeared on the same day as a nearby control site.
In Norway, the Dutch company Arctic Reflections ran a 2024 test in a lagoon in Svalbard. The team drilled through nearly a meter of ice, pumped seawater onto the snowy surface and created a large slushy layer that froze within days. The process increased total sea-ice thickness from 90 centimeters to 1.16 meters. Yet camera monitoring through June showed no ultimate extension in the ice’s survival compared with untreated ice nearby.
In Canada, the UK company Real Ice carried out trials between December 2024 and February 2025 at eight sites in the Northwest Passage south of Cambridge Bay. The group flooded and froze the snow layer across a total of 250,000 square meters, with some sites thickened twice. According to the source text, the researchers said the intervention did delay melting when summer came.
Why thicker ice may not always translate into longer-lasting ice
The mixed results highlight a central problem in climate intervention research: a physical effect at one stage does not guarantee a meaningful system-level outcome later. Ice can become thicker in winter and still vanish on roughly the same timeline if spring and summer conditions overwhelm the gain.
Christian Haas of the Alfred Wegener Institute, who worked on analyzing the Norway results, summarized the uncertainty directly in the source article: yes, the ice is getting thicker, but whether that meaningfully delays eventual disappearance remains an open question.
That caution matters because geoengineering proposals are often judged not only on whether they work in a narrow technical sense, but on whether they produce durable climate benefits at relevant scale. A trial that changes local ice thickness is scientifically interesting. A method that can reliably preserve large areas of sea ice through warming seasons is a much more demanding proposition.
The experiments are continuing, but the burden of proof is high
Both groups have continued their work, which suggests the idea has not been dismissed despite the conflicting results. Continued testing is logical. Arctic conditions vary, and techniques may perform differently depending on snow cover, timing, location and weather patterns. But the burden of proof is high, because scaling any intervention across vast polar areas would be logistically difficult and politically contentious even before its climate effectiveness was established.
There is also a broader governance issue. Techniques that alter ice conditions in one region may affect ecosystems, local communities and international climate politics in ways that are not captured by a simple thickness measurement. The supplied source focuses mainly on field performance, but the policy conversation would inevitably become larger if the method ever appeared ready for deployment beyond experiments.
For now, the main result is both promising and limiting. Researchers have shown that pumped seawater can increase Arctic sea-ice thickness. What they have not yet shown consistently is that this is enough to preserve ice through the summer in a way that changes the larger trajectory of Arctic loss. That leaves the concept in a familiar geoengineering position: plausible enough to keep studying, not proven enough to count on.
This article is based on reporting by New Scientist. Read the original article.
Originally published on newscientist.com
