Far beneath the surface of the Greenland ice sheet, scientists have identified enormous swirling structures that resemble rising plumes. These strange formations have puzzled researchers for more than a decade. Now, scientists from the University of Bergen (UiB) believe they have finally uncovered an explanation by using mathematical models similar to those used to study how Earth’s continents slowly drift apart.
A new study proposes that the mysterious plumes are created by thermal convection. This process involves slow, circulating movement within the ice caused by temperature differences between deeper and shallower layers. Thermal convection is typically associated with the extremely hot material moving inside Earth’s mantle, not with ice.
“We typically think of ice as a solid material, so the discovery that parts of the Greenland ice sheet actually undergo thermal convection, resembling a boiling pot of pasta, is as wild as it is fascinating,” says Andreas Born, professor at the Bjerknes Centre for Climate Research and the Department of Earth Science at UiB.
Born has studied Northern Hemisphere ice sheets for more than 15 years and co-authored the new research.
A “Freak of Nature” Beneath Kilometers of Ice
The idea that convection can occur within an ice sheet may seem counterintuitive at first. However, the physics behind it make sense once the properties of ice are considered.
“Finding that thermal convection can happen within an ice sheet goes slightly against our intuition and expectations. 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,” says glaciologist and lead author Robert Law.
The research has been accepted for publication in the journal The Cryosphere, where editors selected it as a ‘highlight paper’ because of its scientific importance.
According to Born, the findings could help scientists refine predictions about the future behavior of the Greenland ice sheet.
“Our discovery could be key to reducing uncertainties in models of future ice sheet mass balance and sea-level rise,” he says.
Softer Deep Ice Does Not Automatically Mean Faster Melting
The study suggests that ice deep within northern Greenland may be roughly ten times softer than scientists previously believed. Even so, this does not automatically mean the ice sheet will melt faster.
“Improving our understanding of ice physics is a really major way to be more certain about the future,” says Law, “but on its own, softer ice does not necessarily mean that the ice will melt faster or that sea level rise will be higher. We need further studies to fully isolate that.”
Greenland often appears in global headlines because of topics such as mining, geopolitics, and climate change. Law emphasizes that the new findings do not predict catastrophic changes in Greenland or elsewhere. Instead, they highlight how complex and dynamic the ice sheet really is.
“Greenland and its nature is truly special. The ice sheet there is over one thousand years old, and it’s the only ice sheet on Earth to have a culture and permanent population at its margins,” he says. “The more we learn about the hidden processes inside the ice, the better prepared we’ll be for the changes coming to coastlines around the world.”
About the Study
Researchers from the University of Bergen (Department of Earth Sciences and the Bjerknes Centre for Climate Research) conducted the study in collaboration with NASA Goddard Space Flight Center, the University of Oxford, and ETH Zurich.
The team examined whether the plume-like structures detected deep within the Greenland ice sheet could be explained by thermal convection and what this might reveal about the softness and movement of the ice.
Their analysis indicates that these plume-like features are likely created by thermal convection, a slow churning motion inside the ice driven by temperature differences. The results also suggest that deep ice in northern Greenland could be about ten times softer than scientists previously assumed.
Because softer ice affects how the ice sheet flows, the findings may help researchers improve projections of future sea level rise.