Antarctica

New Video: The Trouble at Totten Glacier

http://climatecrocks.com/2015/04/14/new-video-the-trouble-at-totten-glacier/

The latest “This is Not Cool” video is the third in a trilogy of very important, and sobering, pieces I’ve posted over the last year. I didn’t start with a trilogy in mind, but the developments of the last few months have been jarring and momentous.

Chris Mooney wrote recently in the Washington Post, “A hundred years from now, humans may remember 2014 as the year that we first learned that we may have irreversibly destabilized the great ice sheet of West Antarctica, and thus set in motion more than 10 feet of sea level rise.”

He added, “Meanwhile, 2015 could be the year of the double whammy — when we learned the same about one gigantic glacier of East Antarctica, which could set in motion roughly the same amount all over again.”

The decades-long unfolding of this story – that vast areas of ice once thought to be invulnerable on time scales meaningful to humans, may in fact already be in the process of disintegration – is one that that the vast majority of humanity still does not understand, and that the media has been unwilling to track.  It’s a realization that, one top expert told us, even seasoned ice sheet veterans find “shattering”.

For this video I used in-person interviews from December’s AGU conference, as well as a skype chat with Jamin Greenbaum of the University of Texas, whose recent research on East Antarctic vulnerability has been widely reported. Jamin pointed me to some Australian research from the same area.  There was a huge volume of material, not all of which made it into this video, but which I’ll be posting in coming weeks to flesh out the picture.

The overriding message: we have a problem.

Australian Broadcasting Corporation:

Warm ocean water is melting one of the world’s biggest glaciers from below, potentially leading to a rise in sea levels, Australian scientists have discovered.

Australian icebreaker Aurora Australis recently returned to Hobart from Antarctica, with a team of 23 scientists who had used new technology to collect the first water samples near the Totten Glacier.

Steve Rintoul from the Australian Climate and Environment Cooperative Research Centre said the results indicated the glacier was being melted by the sea water beneath it.

“The measurements we collected provide the first evidence that warm water reaches the glacier and may be driving that melt of the glacier from below,” he said.

According Australian Antarctic Division estimates, the Totten Glacier holds enough water to raise sea level by six metres and scientists said it had been thinning over the past 15 years.

“We used to think the glaciers in east Antarctica were unlikely to be affected by the ocean because they were a long way away from the warm ocean waters,” he said.

“The fact that it’s changing is something new, we used to think that the glaciers in east Antarctic were very stable and unlikely to change.”

University of Texas:

AUSTIN,Texas — 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 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.

“We now know there are avenues for the warmest waters in East Antarctica to access the most sensitive areas of Totten Glacier,” said lead author Jamin Greenbaum, a UTIG Ph.D. candidate.

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.

“The catchment of Totten Glacier is covered by nearly 2½ miles of ice, filling a sub-ice basin reaching depths of at least one mile below sea level,” said UTIG researcher Donald Blankenship.

Greenbaum and Blankenship collaborated with an international team from the United States, Australia, the United Kingdom and France.

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.

“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,” Blankenship said.

Below, the first two videos in this trilogy. Together, they give a much clearer picture of emerging science than was available just a decade ago.