A buried weak spot under Greenland’s ice sheet

What’s happening beneath Greenland’s ice may matter as much as what’s melting on the surface. New research shows that a hidden landform under the ice sheet could influence how fast Greenland loses ice, and how quickly sea levels rise.

A study published in Nature Geoscience earlier this month reveals that the little-known Prudhoe Dome may play an outsized role in how the ice sheet responds to warming. Located in northwestern Greenland, the 500-meter thick dome stretches 2,500 kilometers under the ice, roughly equivalent to the distance from the northern tip of Norway to the southern tip of Italy.

By drilling deep into the structure, collecting ice chips for analysis along the way, researchers found that this ice-covered dome acts as a structural and hydrological hinge, influencing how ice flows and how meltwater moves beneath the ice. These dynamics matter because they can affect how quickly ice is lost to the ocean, with consequences for increases in the sea level that extend far beyond the Arctic.

Key Findings:

• A buried landform with big influence: Prudhoe Dome is a topographic high, a raised area of the Earth’s surface that stands higher than the surrounding terrain, hidden beneath the Greenland Ice Sheet. The study shows it helps control ice flow direction and stability across a wide region of northern Greenland.
• Water movement matters as much as ice: Meltwater beneath the ice is routed around the dome in specific ways, affecting lubrication at the ice-bed interface, a key factor in how fast ice can slide toward the coast.
• A potential tipping point for ice dynamics: Changes in meltwater input or ice thickness could alter how the dome functions, potentially accelerating ice flow in nearby outlet glaciers.
• A warning from the past: The structure fully melted just 7,000 years ago. With human-caused warming accelerating, researchers say the ice cap may once again be at risk.
• Implications for sea-level rise projections: Because current ice-sheet models often smooth over small-scale bed features, the influence of Prudhoe Dome may be underrepresented, meaning some future sea-level rise estimates could be incomplete.
• Why the Arctic is uniquely vulnerable: As surface melting increases in Greenland’s north, regions once considered stable may become more dynamic due to interactions between bed topography and meltwater.

Why it matters beyond Greenland:

What happens beneath the ice can determine how quickly Greenland loses (LAND?) mass, and how fast global sea levels rise. This study shows that hidden features under the ice sheet can amplify change, underscoring the need for better subglacial mapping and more detailed ice-sheet models as the Arctic continues to warm.