Warm water currents melting Antarctic glaciers?

(NaturalNews) An international research team has discovered that warming ocean currents are undercutting one of Antarctica's largest glaciers, with potentially catastrophic and irreversible consequences. The study, published in the journal Nature Geoscience, found that warm water is actually flowing underneath the glacier, melting it from the inside out.

"The Totten Glacier is the most rapidly thinning glacier in East Antarctica and this melt has the potential to drive substantial regional ice loss," Australian Antarctic Division glaciologist Jason Roberts said.

The research team involved scientists from the United States, United Kingdom, France and Australia.

Single glacier could raise sea levels 11 feet

The Totten Glacier, the largest glacier in East Antarctica, is 120 km (75 miles) long and more than 30 km (19 miles) wide. It has previously been observed to be melting more rapidly than other glaciers in the region. On a recent expedition, researchers discovered that the waters around the Totten Glacier were roughly 1.5 degrees Celsius warmer than those in other regions.

Up until now, most research on melting Antarctic glaciers has focused on the western part of the continent, in part because the water temperatures around East Antarctica were thought to be both cold and very stable.

The glacier contains enough ice that, if it melted entirely, it could raise global sea levels by 3.5 meters (11 feet). This may call for a revision in current projections based on specious climate change data that ocean levels will rise by about 1 meter per century.

"It's only one glacier, but it's changing now and it is significant for sea levels globally," said co-author Martin Siegert of Imperial College London. "The 3.5 metre rise may take several centuries to complete, but now the process has started it is likely irreversible. This is another example of how human-induced climate change could be triggering major changes with knock-on impacts that will be felt globally."

Change could soon be irreversible

From 2008 to 2013, the researchers sent aircraft equipped with radar, lasers and other sensing technology to map the ice thickness of the Totten Glacier, as well as the bedrock and sea floor beneath it. They found that, contrary to what was previously believed, an area toward the interior of the glacier does not sit directly on the continental bedrock. Instead, the glacier is undercut by a deep valley, three miles wide and dropping to at least a mile below sea level. This valley actually extends out into the ocean, forming an under-ice trough channeling seawater beneath the glacier.

"Now we know the ocean is melting ice in an area of the glacier that we thought was totally cut off before," said lead author Jamin Greenbaum, a PhD student at the University of Texas at Austin.

Alarmingly, the shape of this valley suggests that the melting could rapidly become irreversible. That's because, once the ice overlaying the valley melts enough, the entire ice formation above it could collapse and fall into the ocean. Indeed, studies have shown that, over the span of geological time, this seems to have happened numerous times.

"We've basically shown that the submarine basins of East Antarctica have similar configurations and coastal vulnerabilities to the submarine basins of West Antarctica that we're so worried about," researcher Donald Blankenship said.

Once the Totten Glacier begins melting from not just its edges but also its center, there is no telling how far-reaching the consequences could be.

"Once a certain region starts to change, the implications for the connected ice are potentially significant," Siegert said. "We are using computer modelling to understand whether changes in Totten Glacier could lead to changes in both adjacent and more distant places in Antarctica. While this work needs to be undertaken, the change at Totten Glacier itself is significant and concerning."

Sources for this article include:

http://www.france24.com

http://www.utexas.edu

http://www.nature.com

http://www3.imperial.ac.uk