Scientists have looked beneath the Greenland ice sheet

The authors built high-precision 3D models of the temperature distribution in the Earth's upper mantle beneath the ice sheet, which will help to better understand the geological past of the region and how the ice sheet has responded and will continue to respond to climate change. The work is published in the Proceedings of the National Academy of Sciences (PNAS).

Hidden heat beneath the ice

The study was done in collaboration with scientists from the University of Twente in the Netherlands and the Geological Survey of Denmark and Greenland (GEUS). The team used several independent satellite and ground-based datasets and ran hundreds of thousands of numerical simulations on supercomputing resources, including the facilities of the Digital Research Alliance of Canada.

"Our new regional temperature models show significant lateral (lateral) variations in the Earth's thermal structure beneath Greenland," explains the paper's first author, University of Ottawa PhD graduate Parviz Azhurlu. - These differences reflect Greenland's path over the Icelandic hotspot and help to better interpret the island's tectonic history and its influence on the geophysical properties of rocks at the base of the shield."

Project leader Glenn Milne, professor in the Department of Earth and Environmental Sciences at the University of Ottawa, adds that these data are critical to understanding how the ice sheet "interacts" with the underlying bedrock:

"Temperature variations directly affect the coupling between ice and bedrock. They need to be quantified in order to correctly interpret observations of land movement and gravity field changes. These observations, in turn, show how the ice sheet is responding to modern climate warming."

Why it matters for sea level

The scientists combined data on seismic wave velocities, gravity anomalies and heat flow to build a comprehensive three-dimensional temperature model of the upper mantle beneath Greenland. The results allow:

• more accurately reconstruct the geological past of the region and the trajectory of motion over the Icelandic plume;

• better assess the present state of the ice sheet and the conditions under which it "slides" and deforms;

• improve numerical models of future ice changes and their contribution to global sea level rise.

"This is a good illustration of how knowledge of the solid Earth helps to better understand the climate system," emphasises Ajurlu. - "The more accurately we describe the ice-crust-mantle interaction, the better we can predict and prepare for future sea-level rise."

In essence, more realistic data on the temperature and rock properties beneath Greenland means more accurate calculations of how quickly and in which scenarios its ice sheet will lose mass, and therefore how fast the oceans will grow.