Researchers at The University of Texas at Austin's Institute for Geophysics (UTIG) in the Jackson School of Geosciences have discovered two seafloor gateways that could allow warm ocean water to reach the base of Totten Glacier, East Antarctica's largest and most rapidly thinning glacier. The discovery, reported in the March 16 edition of the journal Nature Geoscience, probably explains the glacier's extreme thinning and raises concerns about how it will affect sea level rise.
Totten Glacier is East Antarctica's largest outlet of ice to the ocean and has been thinning rapidly for many years. Although deep, warm water has been observed seaward of the glacier, until now there was no evidence that it could compromise coastal ice. The paper shows that there are avenues for the warmest waters in East Antarctica to access the most sensitive areas of Totten Glacier.
"We've basically shown that the submarine basins of East Antarctica have similar configurations and coastal vulnerabilities to the submarine basins of West Antarctica that we're so worried about, and that warm ocean water, which is having a huge impact in West Antarctica, is affecting East Antarctica, as well", said a member of the research team.
Signal spotted by Anna Simpson
The result is of global importance because the ice flowing through Totten Glacier alone is sufficient to raise global sea level by at least 11 feet, equivalent to the contribution of the West Antarctic Ice Sheet if it were to completely collapse.
The ice loss to the ocean may soon be irreversible unless atmospheric and oceanic conditions change so that snowfall outpaces coastal melting. The potential for irreversible ice loss is due to the broadly deepening shape of Totten Glacier's catchment, the large collection of ice and snow that flows from a deep interior basin to the coastline.
Because much of the California-sized interior basin lies below sea level, its overlying thicker ice is susceptible to rapid loss if warm ocean currents sufficiently thin coastal ice. Given that previous work has shown that the basin has drained its ice to the ocean and filled again many times in the past, this study uncovers a means for how that process may be starting again.
Iain Watt, a climate and energy specialist at Forum for the Future, notes that the response to last year's findings - that the Amundsen Sea segment of the West Antarctic ice sheet has reached the point of inevitable collapse, an event that will raise sea levels more than a meter, possibly as soon as the next few hundred years - came to no more than a collective 'meh'.
"This likely means the end of Miami and most of Florida (just to pick one example) and still it hardly registered as a story", says Watt. "I can’t imagine that the new research will result in anything different…"
Over to you, dear reader...