Thermal Convection Drives Deep Plumes Inside Greenland Ice Sheet

A long-standing question regarding the deep internal structure of the Greenland Ice Sheet has been resolved with the definitive identification of thermal convection as the mechanism responsible for plume-like formations observed within the ice mass. This research, published in the journal The Cryosphere in early 2026, challenges previous assumptions about the static nature of deep ice layers. The findings indicate that a process typically associated with the Earth's molten mantle is actively occurring within the ice structure, causing upwellings that distort layering previously mapped by radar imagery for over a decade.

Lead researcher Dr. Robert Law, a glaciologist at the University of Bergen, described the discovery as an "exciting freak of nature," noting that the presence of thermal convection in an ice sheet defies conventional intuition. Co-author Professor Andreas Born, also from the University of Bergen, offered a more descriptive analogy, comparing the phenomenon to a "boiling pot of pasta." The research team, which included collaborators from NASA's Goddard Space Flight Center and the University of Oxford, employed the ASPECT modeling package—a code generally used for simulating mantle dynamics—to test this hypothesis against observed radar stratigraphy.

A significant quantitative outcome of the study concerns the mechanical properties of the deep ice, particularly in northern Greenland. The research suggests that this deep ice may possess a consistency roughly ten times softer than prior glaciological models estimated. This softer rheology, with an effective ice viscosity potentially spanning 2x10

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The context for this finding is significant, as the Greenland Ice Sheet holds approximately 10% of the Earth's total fresh water, making its internal physics crucial for accurate sea-level rise predictions. The plume-like upwellings were first documented in a 2014 paper, with their origin remaining uncertain, as earlier theories favored mechanisms like the freezing of glacial meltwater. While the scientists involved caution that softer ice does not automatically equate to faster melting or higher sea-level projections, the finding fundamentally recalibrates the assumed mechanical behavior of deep ice masses.

This research marks a major methodological advancement by successfully applying geodynamics modeling tools like ASPECT, which simulate thermally driven convection, to ice physics. This links deep Earth heat flow, derived from radioactive decay and residual formation heat, directly to ice sheet dynamics. Professor Born emphasized that this new understanding is essential for reducing uncertainties in future ice sheet mass balance models, as further research will focus on isolating the influence of this softer basal ice rheology in comprehensive numerical models to refine global coastline projections.