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Ocean Warming Triggers Rapid Melting Of World's Largest Ice Shelf

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A new study revealed that extreme ocean warming and solar heat are triggering the rapid melting of the world's largest ice shelf. The rapid ice melt can have a huge impact on rising sea levels.  ( NASA/University of California, Berkeley/Hazel Bain )

Extreme ocean warming and solar heat are the main culprits that trigger the rapid melting of the largest ice shelf in the world, a new study revealed.

Researchers from the National Institute of Water and Atmospheric Research in New Zealand found that Antarctica's Ross ice shelf is melting 10 times faster than average because of the solar heating of the ocean surface that surrounds it.

The study, which has been issued in the journal Nature Geoscience, reveals that Antarctica's Ross ice shelf is melting much more rapidly than previously thought.

In fact, although the Ross ice shelf appears more stable compared to other ice shelves, scientists believe it may actually be more vulnerable than thought so far.

Antarctica's Ross Ice Shelf Is Melting 10 Times Faster Than Average

For years now, scientists have been tracking the interactions between the northwest section of the Ross ice shelf and the Southern ocean.

In the new study led by Craig Stewart, the research team drilled a borehole several hundred feet into the ice and used an instrument-filled mooring in the ocean water inside the cavity of the ice shelf.

Stewart and his colleagues measured the salinity, temperature, ocean currents, and melt rates of the Ross ice shelf for four years. They also employed a custom-made radar system that tracks the changing thickness of the ice shelf.

Analysis revealed that during the summer, water heated by the sun flows into the cavity beneath the Ross ice shelf. This influx of warm water into the ice shelf causes the melting, which happened at a rate that tripled the average melt rate.

Stewart explained that climate change and higher surface ocean temperatures caused the melting of the sea ice. He said the findings suggest that melting in the region will increase in the future.

What Happens If The Ross Ice Shelf Collapses?

The interactions between the Ross ice shelf and the ocean have a direct impact on the sea level in the long-term. The Ross ice shelf blocks the ice that flows into the West Antarctic ice sheet from the world's largest glaciers, which in turn stabilizes the region.

Poul Christoffersen, a scientist from the Scott Polar Research Institute, explained that when ice shelves collapse, the feeding glaciers that melt can speed up by a factor of two or three.

"The difference here is the sheer size of Ross Ice Shelf, which over one hundred times larger than the ice shelves we've already seen disappear," said Christoffersen.

The Ross ice shelf's point of vulnerability lies in the fact that the heated surface of the warm ocean flows into the cavity near a stabilizing pinning point. This point can be undermined if basal melting further intensifies.

If the Ross ice shelf collapses, researchers said the flow of many other glaciers toward the Southern ocean would likely accelerate, and sea level would rise.

The good news is that the Ross ice shelf is currently stable, and the melting of warm water is still balanced by the inputs of ice from snow accumulation and feeding glaciers.

The balance in the West Antarctic ice shelf region depends largely on the Ross ice shelf pinning point, which has been identified as a point of future vulnerability.

Photo: NASA Goddard Space Flight Center | Flickr

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