LA JOLLA, Calif. — El Nino events are having a greater influence on ice melting in Antarctica than before, according to a joint study announced Thursday by the Scripps Institution of Oceanography at UC San Diego and Ohio State University.
Researchers were able to record substantial melting on the West Antarctic Ice Sheet during the 2015-16 El Nino episode with ground instruments for the first time. Prior melting was observed via satellite.
The ice sheet is larger than the land mass of Mexico, according to the scientists. They said melted snow was spotted over most of the Ross Ice Shelf, a thick platform of floating ice that channels about a third of the ice flowing from the West Antarctic Ice Sheet into the ocean.
One of the largest El Ninos in 50 years likely delivered to the region relatively warm air and clouds, which help seal in heat, according to the study, published in the journal Nature Communications.
“We were extraordinarily fortunate to be able to deploy state-of-the art equipment to West Antarctica just before this large melt event occurred,” said Dan Lubin, a research physicist at Scripps. “These atmospheric measurements will help geophysical scientists develop better physical models for projecting how the Antarctic ice sheet might respond to a changing climate and influence sea level rise.”
Scientists believe that climate change could result in more frequent El Ninos, which are characterized by an unusually warm mass of water in the Pacific Ocean. The phenomenon affects weather globally, and often brings wetter conditions to Southern California.
Warmer air gravitates toward Antarctica in El Nino, but are often counteracted by westerly winds, the scientists said.
“In West Antarctica, we have a tug-of-war going on between the influence of El Ninos and the westerly winds, and it looks like the El Ninos are winning,” said study co-author David Bromwich, professor of geography at Ohio State. “It’s a pattern that is emerging. And because we expect stronger, more frequent El Ninos in the future with a warming climate, we can expect more major surface melt events in West Antarctica.”
Scientists from Brookhaven National Laboratory in New York, Argonne National Laboratory in Illinois, Penn State University, the Australian Bureau of Meteorology and Los Alamos National Laboratory in New Mexico assisted with the study.
Funding was provided by the U.S. Department of Energy and National Science Foundation.