Scientists at the University of California at Irvine and NASA’s Jet Propulsion Laboratory have discovered one of the reasons for the rapid melting of ice in Greenland. According to results published in the journal Proceedings of the National Academy of Sciences (PNAS), climatologists may be grossly underestimating the magnitude of future sea level rise caused by the disappearance of ice sheets and glaciers.
The researchers analyzed radar interferometry data from the TanDEM-X, COSMO-SkyMed and ICEYE satellites to study the ground line migration of the Petermann Glacier (northwest Greenland), where the ice breaks away from the seafloor. It turned out that high-low tide cycles significantly affect the location of the ground line, causing migration of two to six kilometers. This allows warm seawater to seep under the glacier, causing accelerated melt. The highest rates of ice shelf melt have been recorded within the occurrence zone, with values ranging from 60 to 80 meters per year along pre-existing subglacial channels. So, between 2016 and 2022, the Petermann ground line receded by four kilometers, and a cavity about 204 meters high was formed in the lower part of the glacier due to the acceleration of melting from 40 to 60 meters per year. This cavity remained open throughout the entire tidal cycle Previously, scientists believed that ground lines did not migrate with the tides and did not undergo the melt associated with these cycles, and this traditional view was implemented in models of ice sheets predicting sea level rise. The results of the study indicate that the contemporary contribution of ice shelves to sea level rise could be as much as 200 percent greater.