Greenland's Hidden Subsurface Reshapes Sea Level Rise Forecasts

Got story updates? Submit your updates here. ›

A groundbreaking study published in Geology has revealed a previously unknown factor accelerating the melting of Greenland's ice sheet - the complex and dynamic landscape hidden beneath the surface. Using seismic waves, researchers from the University of California, San Diego mapped the subsurface, finding it is not a uniform block of rock, but a mosaic of different materials that significantly impact how quickly glaciers slide towards the ocean. This discovery challenges the conventional view that Greenland's ice simply melts from above, showing that the nature of the ground beneath the ice sheet plays a crucial role in its movement and discharge into the sea, potentially leading to faster-than-expected sea level rise.

Why it matters

Greenland's ice sheet has already contributed significantly to global sea level rise, and accurately forecasting its future melt is critical for coastal communities worldwide. This new research reveals that the complex subsurface landscape, including the interaction of temperature, meltwater, and underlying materials, is a key factor that must be incorporated into climate models to provide more reliable predictions of sea level rise.

The details

The UCSD team, led by researcher Yan Yang, used seismic waves generated by earthquakes to map the ground beneath Greenland's miles-thick ice sheet. They found the subsurface is not a uniform block of rock, but a mosaic of different materials, some rigid and stable, others more fluid and changeable. This diversity in the underlying terrain significantly impacts how quickly glaciers can slide towards the ocean. Where the base is smoother or less resistant, the massive weight of the ice sheet allows it to flow faster, feeding outlet glaciers that discharge vast amounts of ice into the sea. The researchers also discovered that temperature and meltwater can penetrate deep through vertical shafts called moulins, reaching the bottom of the ice sheet and changing the pressure balance to further influence ice flow.

• The study was published in the scientific journal Geology in April 2026.
• The research was conducted by a team from the University of California, San Diego.

What they’re saying

What’s next

The researchers emphasize the need for a denser seismic network to capture the complexity of Greenland's subsurface more accurately, as localized changes in heat or water pressure can create differences over short distances, making long-term predictions challenging. Scientists are also combining seismic data with satellite velocity maps and topographic models to build a new generation of ice-sheet models that integrate what's happening both above and below the surface, in order to provide more reliable forecasts for policymakers and coastal planners worldwide.