Can Arctic sea ice be artificially thickened?

In the middle of the Arctic winter, employees of the company Real Ice pump seawater onto the surface of sea ice. At temperatures well below minus 20 degrees Celsius, the water freezes rapidly and forms an additional ice layer. What resembles the construction of an ice road is part of a field experiment driven by a fundamental question: can Arctic sea ice be deliberately thickened in order to slow its decline?

The starting point is well documented. Since satellite measurements began, the summer sea ice extent in the Arctic has decreased by around 40 percent. With the ice, the climate system also loses a key function: the bright surface reflects a large portion of incoming solar radiation, while dark ocean water absorbs heat and amplifies warming, a feedback mechanism known as the ice–albedo effect.

The decline of Arctic sea ice does not only alter the climate; it also disrupts an entire network of life and human use. For animals such as seals, walruses, and polar bears, a central habitat and hunting ground is disappearing. At the same time, Indigenous communities are losing a foundation for mobility, subsistence, and cultural practice, as sea ice increasingly becomes an unreliable platform for hunting, transport, and social life.

A field experiment in Canadian ice

Against this backdrop, the UK-funded program “Re-thickening Arctic Sea Ice” (RASI), together with the company Real Ice, is testing an experimental approach in Cambridge Bay, Nunavut (Canada).

The method is technically simple: seawater is pumped through existing ice to the surface, where it freezes again and strengthens the ice layer.

In a study area of around one square kilometer, initial measurements show a local increase in ice thickness of up to 50 centimeters. In addition, treated areas remain stable longer at the beginning of the melt season and melt more slowly than comparison sites.

One possible explanation lies in the structure of the newly formed ice: rapidly frozen water forms different crystal structures and traps air bubbles, which alters heat conduction and light reflection.

Local effect, global limits

The field experiment demonstrates a measurable local increase in ice thickness under experimental conditions. However, whether this can translate into an effect relevant at the scale of the Arctic climate system remains unclear.

Arctic sea ice spans several million square kilometers in winter. Scaling this approach to climate-relevant dimensions would require enormous logistical and energy inputs under conditions that are already extreme.

In addition, such interventions would not only be technical but also ecological, affecting a highly sensitive system. Sea ice is a habitat for microorganisms such as algae and bacteria that form the basis of Arctic food webs. Changes in structure or light permeability could influence these processes, with potential consequences extending far beyond the ice itself.

Systemic feedbacks further amplify these uncertainties. Ice thickness alone is not a reliable indicator of stability; salinity and microstructure play a crucial role. Artificially formed ice can have higher salinity, which may weaken its structural integrity and, in some cases, accelerate melting.

Alongside physical questions, there is a central ethical debate: the so-called moral hazard, the concern that technological interventions may be misinterpreted as a safety guarantee and reduce pressure to cut emissions.

Against this background, the project is primarily understood as a research tool: not as a solution, but as a way to better understand the responses of a highly dynamic system.

At the same time, it remains open how interventions should be evaluated in a system that is not only climatically significant but also a habitat for numerous species and the foundation of human livelihoods in the Arctic.

The project thus stands as an example of a new form of Arctic climate research: experimental, precise and confronted with the limits of what can be technically stabilized.

An experiment with an open outcome

The field experiment provides initial empirical data on a concept that has so far been discussed mostly in models. This is scientifically significant.

At the same time, the gap between local effects and global relevance remains substantial. Likewise, it remains unclear whether such interventions are ecologically justifiable or ever scalable.

Within climate science, rapid reductions in greenhouse gas emissions continue to be seen as the central lever for protecting Arctic sea ice. Technological interventions cannot replace this goal, they merely shift the boundaries of understanding.

PolarJournal, Lisa Scherk