Scientists Find a 'Freak of Nature' Churning Deep in the Greenland Ice Sheet
Radar images and new computer models point to slow, thermal convection deep inside the Greenland Ice Sheet, a discovery that reframes how researchers think the ice moves beneath the surface and why that internal physics matters for future studies of the ice mass.
Deep plumes first seen in radar now match convection models
Researchers revisited strange, plume-like structures first described in a 2014 paper that show large, upward-buckling features deep inside northern Greenland. The features distort long-buried layers of snow and ice picked up by ice-penetrating radar and were unrelated to the bedrock topography below, creating a puzzle scientists have worked to solve.
Modeling a 2. 5-kilometer slab shows 'pasta-like' churning
Using a geodynamics modeling package normally used for Earth’s mantle, the team simulated a slab of ice 2. 5 kilometers (1. 6 miles) thick and varied snowfall rate, ice thickness, softness and surface speed. Under conditions where the ice near the base was warmer and significantly softer than standard assumptions, the model produced rising columns of ice — plume-like upwellings that folded overlying layers in a pattern strongly resembling the radar observations.
Heat from the crust can explain slow internal motion
The model found the heat needed to drive those upwellings was consistent with the tiny but continuous heat flow from Earth — the radioactive decay of elements in the crust plus residual heat from Earth’s formation. That internal warming, trapped under a giant slab of insulating ice that covers 80 percent of the island, could be enough over time to produce the convection-like motion the team modeled.
Scientists call it a 'freak of nature' but urge caution on implications
Lead and co-authors framed the result in vivid terms. "Finding that thermal convection can happen within an ice sheet goes slightly against our intuition and expectations, " said Dr. Robert Law of the University of Bergen. "Ice is at least a million times softer than the Earth's mantle, though, so the physics just work out. It's like an exciting freak of nature. " Professor Andreas Born of the University of Bergen added that the motion resembles a "boiling pot of pasta, " language echoed in the new study.
The team includes researchers from the University of Bergen, NASA’s Goddard Space Flight Center and the University of Oxford. Their study makes clear that parts of the deep ice could be much softer than previously assumed, but that softness alone does not automatically translate to faster surface melting or a simple change in sea-level projections. The authors emphasized the need for further work to isolate how this internal churning affects ice-sheet mass balance.
The findings appear this month in the journal The Cryosphere, and they provide a new target for observational and modeling campaigns that aim to refine predictions about how the Greenland Ice Sheet will behave over time. Future studies, the researchers say, will need to test where these conditions exist in the real ice and how widespread such convection might be before its effects on ice discharge and sea level are fully understood.
