The largest ice shelf in Antarctica is acting strangely

According to SciTechDaily, ice stream activity caused the Ross Ice Shelf in Antarctica to suddenly shift.

In Antarctica, giant glaciers are constantly shifting. Glacial streams, which act like conveyor belts, are pathways of accelerated movement that transport much of the ice and sedimentary debris from these vast glaciers toward the ocean.

According to new research from Washington University in St. Louis, one such ice stream pushed the entire Ross Ice Shelf out of position at least once a day. This discovery is very significant, because the scale of the Ross ice shelf is not small. This is the largest ice shelf in Antarctica , about the size of France.

The Ross Ice Shelf is a floating ice sheet, extending into the ocean from glaciers deep in Antarctica - (Photo: SciTechDaily).

"We found the entire ice shelf suddenly moved about 6cm to 8cm once or twice a day, due to caused by an ice stream flowing into the ice shelf. These sudden movements may play a role in triggering earthquakes and ice shelf rifts."

The Ross Ice Shelf is a floating sheet of ice, extending into the ocean from glaciers deep in Antarctica. Scientists are interested in the interactions between ice shelves and ice streams, partly because of concerns about the stability of Antarctic ice shelves in a world with warming temperatures.

The new study, published in the journal Geophysical Research Letters , focuses on movement caused by the Whillans Ice Stream, one of about half a dozen large, fast-moving glaciers that feed into the Ross Ice Shelf.

"Humans will not be able to detect the movement of the ice shelf just by feeling it. The movement occurs over a period of several minutes, so it cannot be detected without measuring equipment ," Wiens said.

"I have previously published several papers on sliding events in the Whillans Ice Stream, but until now I have not discovered that the entire Ross Ice Shelf also moves ," Wiens said.

Researchers don't think these slip events are directly related to human-caused global warming. One theory is that the phenomenon occurs due to dehydration of the Whillans glacial streambed, causing it to become "stickier" .

Sea levels will rise further when the ice shelf collapses

Ice shelves act as brakes for glaciers and ice streams, slowing their journey to the sea where they melt, thus allowing more ice to accumulate on the continent.

If an ice shelf collapses, the "brake" disappears and the glaciers are free to flow faster. Once flowing into the ocean, they contribute to rising sea levels.

Studies of glacial streams over the past 50 years show that some glacial streams are accelerating, others are slowing down. Scientists can use seismometers to detect sudden movements of ice streams, to help understand what drives this movement.