Antarctic Ghost Mountains Throw Light on Global Climate Change

Miles beneath the surface of an ice sheet in Antarctica, “ghost mountains” are finally emerging that resemble the Cascades Range in the United States, scientists and researchers announced last month. The expedition over Antarctica’s ice-buried Gamburtsev Mountains was led by Dr. Robin Bell and her colleagues from the British Antarctic Survey (BAS). The discovery of the growth of ice sheets at the base is quite interesting and sheds light on how the Earth works. Environmental Graffiti spoke with Dr. Fausto Ferraccioli, co-author of the study, about this incredible research.

Ice sheet that grows from the bottomPhoto: Image courtesy Dr. Robin BellA radar image reveals that the bottom most ice was formed from below, not from above.

The discovery

When asked about his experience, Dr. Ferraccioli recalls: “First discovered about 50 years ago, the Gamburstev Sub-glacial Mountain’s remoteness and inaccessibility explain why the mountains have remained the least understood mountain range on Earth.”

“Our surveys of the range were challenging and adventurous and led to major new discoveries about the landscape, geology and ice sheet in East Antarctica,” he further explained. The discovery of numerous large ice structures within Antarctica is quite an unexpected one. Water is squeezed up the ice-covered river valleys and then reaches the end and freezes on to the bottom of the ice sheet.

“About a quarter of the ice sheet includes frozen-on ice. Frozen-on ice had been drilled before at Lake Vostok but nobody realized it was so extensive in the interior of East Antarctica,” continues Dr. Ferraccioli.

How important is water as a lubricating agent for the ice sheet dynamics?

Water under the ice sheet plays an important role. It promotes fast glacial flow, and many ice streams are lubricated by sediment and mud. Glaciers will sometimes surge when water is below them. But, it does not make a glacier speed up if it flows through a pipe or a river.

So far, over 300 sub-ice lakes have been detected, and more continue to be discovered. Scientists are only just starting to understand how these lakes are connected and how they fill, drain and interact with the overlying ice sheet.

“The discovery of freeze-on connected to sub-ice water systems in interior East Antarctica is an important new piece of the puzzle,” said Dr. Ferraccioli.

How does refreezing affect the margins of the Antarctic and Greenland ice sheets?

To explain this, Dr. Ferraccioli replied: “This is something researchers don’t know yet. Refreezing may well be important. However, detecting the process where ice is flowing very fast will be a challenge as the ice layers are more difficult both to map and interpret.” But, yes it will change the way the base of the ice sheet deforms, depending on how fast the ice will move.

Every day, new research is being carried out and our understanding is improving. The question that often comes to mind is what the biological effects of global warming in Antarctica could be? The answer is quite obvious. As the environment changes, polar ecosystem will shift too. No doubt, penguin populations and other arctic animals will also shift.

Now the time has come to change the model of existing ice caps and to include bottom-up freezing to predict the behavior of ice caps in the future.

My sincere thanks to Dr. Fausto Ferraccioli for taking the time to answer our questions.

Sources: 1, 2, and personal interview.