Greenland's thick ice slabs may cause sea level to rise

Sea level may rise by 10 centimeters due to the presence of thick ice slabs in Greenland.

A new study, recently published in Nature, suggests that climate change not only affects Greenland's glaciers meltdown but it also increases the density of the remaining ice slabs.

Those ice slabs that may reach a thickness of 16 meters, have replaced thinner ice (which is porous and can re-absorb the melting snow) in the mainland of Greenland. As a result, a vast impermeable layer has been created and water flow from melted ice is directed into the sea. “As the climate continues to warm, these ice slabs will continue to grow and enhance other meltwater feedbacks. It’s a snowball effect: more melting creates more ice slabs, which create more melting, which, creates again more ice slabs,” Mahsa Moussavi, co-author of the study and researcher at the U.S. National Snow and Ice Data Center, stated.

The scientific team noticed this phenomenon for the first time in 2012 when they drilled boreholes and found dense ice layers below the seasonal snow. Since then, they have utilized ground-penetrating radars to measure their extent. They also used prediction models to evaluate their future growth.

According to the researchers, the phenomenon is currently exacerbating and the surface of Greenland may become a “runoff zone" that could eventually lead to a sea-level rise of about 10 centimeters by 2100. “We're watching an ice sheet rapidly transform its state in front of our eyes, which is terrifying,” Mike MacFerrin, lead author of the study and glaciologist at the University of Colorado, stated.

Data shows that this runoff zone covered a total area of 315,000 m³ back in 2000 and had increased by 65,000 m³ more by 2013. The study suggests that the zone may further expand by another 270,000 m³ or 695,000m³ under a modest or a high carbon emission scenario, respectively.