Image: Esmee van Wijk (CSIRO and ACE CRC)
This Melting Glacier in Antarctica Could Raise Sea Levels By 11 Feet
The Totten Ice Shelf is melting and it could have significant global impact.
by Grennan Milliken
December 17, 2016, 3:00pm
The Earth's climate, it seems, isn't listening to the politicians that are insisting it's not warming. The temperature continues to rise incrementally, and the globe's large glaciers—giant vaults of stored water—continue to melt, releasing into the oceans. The global sea level, due to thermal expansion and glacial melting, continues to rise, building up a head of steam like a train just beginning its descent down a steep hill.
Greenland's hulking glacier and the Arctic Sea ice are now marked by their rapid melting. And the western Antarctic ice sheet has garnered a lot of attention recently, too. But while scientists were fretting over the western side of Antarctica, the eastern Antarctic ice sheet has been melting too. Australian researchers braved treacherous sea conditions to collect data on the melting Totten Ice Shelf there, which holds up a body of ice that would cause over 11 feet of sea level rise, if it melted. Their findings are published in the journal Science Advances.
Scientists have concluded that ice shelves and glaciers in eastern Antarctica have been experiencing basal melt, where the bottom layer of a body of ice starts to melt away, but they've never directly observed how it's happening and what the main drivers of melting are until now.
The Totten Ice Shelf. Image: Esmee van Wijk (CSIRO and ACE CRC)
In Antarctica, the ice sheets covering the continent are so large that they extend beyond the land's edge. Picture a pool cover that's only covering half of an in-ground pool. Part of it lays on the patio nearby, and the rest of it slopes downward onto the water's surface where it floats. Where the glacier hits the water is a buttress of ice called a shelf, which keeps the land bound ice from draining into the sea. If the shelf melts then—well, you get the idea. Such is the Totten Ice Shelf.
Recovery of a mooring in heavy sea ice near the Totten Ice Shelf. Image: Steve Rintoul (CSIRO and ACE CRC)
With fair weather conducive to research, oceanographer and lead author of the study, Stephen Rich Rintoul, of the Commonwealth Scientific and Industrial Research Organization in Australia, directed a team of scientists to collect oceanographic data from the Totten ice front in east Antarctica. Previous expeditions were hampered by heavy sea ice conditions and ultimately unsuccessful. What they found was startling.
The RSV Aurora Australis at the front of the Totten Glacier. Image: Paul Brown (Australian Maritime College)
About 2,000 feet down, the team found a great trough—about 6 miles wide—worn into the side of the Totten shelf. Below 2,000 feet the gaping cavity narrows into two channels, and warm water flows through it, boring through the ice like sugar through the enamel of a tooth. The ice shelf, they measured, is melting at its base faster than all other ice shelves of similar size in East Antarctica. If it were to give way, enough ice would slide into the sea to raise global levels by over 11 feet.
Successful recovery of an oceanographic mooring near the Totten Ice Shelf. Image: Steve Rintoul (CSIRO and ACE CRC)
How the melting of these great bodies of ice will play out in the future remains to be seen, but regardless of any continuing work done to slow the effects of climate change, it's possible the damage is already done. Giants slabs of ice that give way 10 years from now, for example, could be the product of melting that started a decade ago. Climate scientist Kerim Nisancioglu, of the University of Bergen, told the New Yorker that
"In some cases, you have, in theory, this irreversible process. You set it off and it just goes. It drains." It's a wait and see.
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