The floating portion of Totten Glacier in East Antarctica may be melting from warm seawater swirling beneath it, making it more vulnerable than previously thought to future melting.
That’s according to a new study by scientists at the Imperial College London and institutions in Australia, the US, and New Zealand, and published yesterday in Nature.
The study’s team found that a part of the Totten Glacier that floats on warm seawater is losing some ice, even while total ice cover in Antarctica continues to expand.
The team studied the history of the glacier’s advances and retreats and speculates that it could contribute 2.9 meters (9.5 feet) to global sea-level rise. If the Totten Glacier retreats 300 kilometers (186 miles) inland in the next couple of hundred years, it may release vast quantities of previously frozen water.
The East Antarctic Ice Sheet (EAIS) is relatively stable compared to West Antarctica, which sits on an enormous fault zone. However, the region of the Totten Glacier studied sits on ocean water heated from geothermal vents, which explains the possibility that it could progressively melt.
Antarctica’s ice cover has actually grown in size roughly 33 percent since satellite tracking began in 1979, making it much more difficult for researchers to gain access to the continent.
An then there’s the issue of plate tectonics. West Antarctica sits on an active 3,300-mile-long heat-emitting fault that includes a string of volcanoes, rifts, and hot springs. This fault line is constantly in motion, and this friction generates heat. Most of this geologic activity is buried beneath hundreds of feet of snow and ice.
The co-author of the Totten Glacier study, Professor Martin Siegert, says that it could take several hundred years for the Totten Glacier to retreat the necessary 186 miles inland to precipitate melting.
The research team studied sedimentary rocks below the glacier and aerial topographic surveys to recreate the history of the Totten Glacier, which they say has experienced large-scale retreats and advances, as indicated by inland bed erosion.
If the Totten Glacier has historically advanced and retreated at various times, and long before man-made carbon dioxide emissions increased globally, it’s logical to suggest that this is a natural phenomenon driven by geologic activity. As mantle heat warms the waters beneath the glacier, it makes the underside slippery.
In fact, geological forces are proving to have a significant effect on such diverse activities as glacial melting, animal migration, plankton blooms, and sea temperatures surrounding Antarctica.
That’s according to geologist James Kamis, who has for years been championing the idea that geological forces are an important driver of Earth’s climate and climate-related events, especially in Antarctica.
Geographical force serves as the main pillar in his Plate Climatology Theory, which he recently presented at the annual American Metrological Society Convention in New Orleans.
In an emailed statement, Kamis said, “Very powerful, geological forces in the form of proven sub-glacial heat flow from two major fault zones, one in West Antarctica and a newly discovered one in East Antarctica, plus significant amounts of recent volcanic activity in the oceans surrounding Antarctica, are further proof of geological drivers.”
He adds, “Clearly it’s time to alter our ‘atmospherically biased’ perception and give proper credit to the role that geological forces play in driving our climate. There is a well-established connection between the Totten Glacier’s underlying ocean being geologically warmed. Recreating the melting patterns of the Totten Glacier is just ‘icing’ on the cake.”
“Totten Glacier is only one outlet for the ice of the East Antarctic Ice Sheet, but it could have a huge impact,” Siegert says. “The East Antarctic Ice Sheet is by far the largest mass of ice on Earth, so any small changes have a big influence globally.” He says that the glacier has retreated more quickly over geologically unstable regions in the past.
There is further speculation that if the Totten Glacier retreated, Antarctica would see the same pattern again. And while much of this is based on what may or may not happen hundreds of years from now, they think the evidence shows the EAIS is “more vulnerable to global warming than previously thought.”
Last March, NASA announced the discovery of seafloor troughs beneath the Totten Glacier base that could allow warm ocean water to reach the ice sheet (see video).
Interestingly, researchers have downplayed the geological drivers that caused the Totten Glacier to retreat and advance for thousands of years and instead have made the debatable leap toward atmospheric global warming hundreds of years into the future.
Kamis says these global-warming relationships only exist in computer models, and not in reality. For now, it’s clear that geothermal activity contributes to both the movement and melting of the Totten Glacier, which is an important distinction from atmospherically induced warming.
Read rest at Examiner
