Deep beneath Greenland’s vast white surface, something unexpected is happening. The ice, long assumed to behave like a slow-moving but essentially rigid mass, appears to be stirring from within.
For more than a decade, radar surveys have revealed strange, plume-like structures rising through the ice sheet in northern Greenland. These formations distort layers that were once flat, bending them upward in towering folds. Their origin remained unclear, a persistent puzzle at the heart of modern glaciology.
Now, a new study published in The Cryosphere suggests that these features are not anomalies but evidence of a hidden process: convection inside the ice itself.
According to researchers at the University of Bergen and their collaborators, the Greenland ice sheet may behave in places less like a solid and more like a slowly circulating fluid. Temperature differences between the base and the surface can create density contrasts that drive a gradual vertical motion, with warmer, softer ice rising and cooler ice sinking.
This phenomenon, known as thermal convection, is typically associated with molten rock deep within the Earth’s mantle. Its presence in an ice sheet challenges long-standing assumptions. “We typically think of ice as a solid material,” said geophysicist Andreas Born. The idea that it can undergo such motion, he noted, is “as wild as it is fascinating.”.
The research team reached this conclusion through numerical modelling rather than direct observation. Using software commonly applied to simulate convection in Earth’s interior, they recreated a simplified slice of the Greenland ice sheet. By adjusting variables such as ice thickness, snowfall and flow speed, they found that under certain conditions, convection naturally generates plume-like features similar to those seen in radar data.
The models indicate that several factors must align. The ice must be sufficiently thick, exceeding roughly two kilometres. It must be relatively undisturbed by heavy snowfall or rapid horizontal flow, both of which suppress vertical motion. And crucially, the ice at depth must be softer than previously assumed.
This softness is central to the new interpretation. The study suggests that in parts of northern Greenland, the effective viscosity of ice may be up to an order of magnitude lower than conventional models predict. Such conditions allow the slow, buoyancy-driven movement required for convection to take hold.
The distribution of the observed plumes appears to support this framework. They occur mainly in the northern regions of the ice sheet, where accumulation rates are lower and ice moves more slowly toward the coast. In the south, where snowfall is heavier and flow is faster, similar structures are largely absent.
For scientists, the implications extend beyond explaining an isolated phenomenon. Ice-sheet models used to project future sea level rise depend heavily on assumptions about how ice deforms and flows. If the ice is softer than expected, those models may compensate by misrepresenting other factors, such as friction at the base.
At the same time, the discovery does not directly imply more rapid melting. Researchers emphasize that while convection alters the internal dynamics of the ice, it does not necessarily accelerate its loss. “On its own, softer ice does not mean that the ice will melt faster or that sea level rise will be higher,” said lead author Robert Law.
Instead, the finding refines the picture of how the ice sheet behaves over long timescales. Convection mixes warmer basal ice upward and colder ice downward, subtly redistributing heat and mechanical stress. These processes may influence how the ice evolves, particularly in regions where it has remained stable for thousands of years.
The study also helps reconcile competing explanations for the plumes. Earlier hypotheses suggested that they formed through freezing of meltwater at the base or from shifting zones of sliding ice. While these mechanisms may still play a role, they fail to fully account for the size, spacing and geometry of the observed structures, especially in three dimensions.
Convection, by contrast, naturally produces repeating, plume-like patterns with vertical coherence. The resemblance between modelled plumes and those seen in radar imagery strengthens the case that this process is active beneath northern Greenland.
Even so, the researchers describe their conclusion as a step rather than a final answer. The models are simplified, and the real ice sheet is shaped by additional processes, including anisotropy in ice crystals, geothermal heat variations and interactions at the bedrock interface. Further work, including field measurements, will be needed to confirm whether convection operates as widely as suggested.
What is clear is that the Greenland ice sheet is more dynamic than once believed. Beneath its seemingly static surface lies a slow, hidden circulation, unfolding over millennia.
It is not a violent motion. There is no cracking or collapse visible from above. Yet deep in the ice, heat and gravity are at work, quietly rearranging the structure of one of Earth’s largest reservoirs of freshwater.
For scientists seeking to understand the future of the ice sheet in a warming world, this subtle movement may prove to be an essential piece of the puzzle.
References
Law, R., Born, A., Voigt, P., MacGregor, J. A., & Guimond, C. M. (2026). Exploring the conditions conducive to convection within the Greenland Ice Sheet. The Cryosphere, 20, 1071–1086. https://doi.org/10.5194/tc-20-1071-2026 [tc.copernicus.org]
University of Bergen. (2026, February). The ice on Greenland is acting strangely. Scientists believe they finally know why. [www4.uib.no]
