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15775 |
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Date: February 07, 2019 at 12:46:40
From: Akira, [DNS_Address]
Subject: Thwaites Glascier &Hidden Volcanoes Melt Antarctic Glaciers from Below |
URL: https://www.livescience.com/46194-volcanoes-melt-antarctic-glaciers.html |
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inspired from thread on Nat'l..
2014:
"Antarctica is a land of ice. But dive below the West Antarctic Ice Sheet, and
you'll find fire as well, in the form of subglacial volcanoes.
Now, a new study finds that these subglacial volcanoes and other
geothermal "hotspots" are contributing to the melting of Thwaites Glacier, a
major river of ice that flows into Antarctica's Pine Island Bay. Areas of the
glacier that sit near geologic features thought to be volcanic are melting
faster than regions farther away from hotspots, said Dustin Schroeder, the
study's lead author and a geophysicist at the University of Texas at Austin.
This melting could significantly affect ice loss in the West Antarctic, an area
that is losing ice quickly.
"It's not just the fact that there is melting water, and that water is coming
out," Schroeder told Live Science. "It's how that affects the flow and stability
of the ice." [Images: See an Antarctic Glacier Calve an Iceberg]
Antarctic heat
Researchers have long known that volcanoes lurk under the ice of West
Antarctica. This is a seismically active region, where East and West
Antarctica are rifting apart. In 2013, a team of scientists even found a new
volcano beneath the West Antarctic Ice Sheet.
West Antarctica is also hemorrhaging ice due to climate change, and recent
studies have suggested there is no way to reverse the retreat of West
Antarctic glaciers. However, the timing of this retreat is still in question,
Schroeder said — it could take hundreds of years, or thousands. It's
important to understand which, given that meltwater from the West
Antarctic Ice Sheet contributes directly to sea level rise.
Scientists use computer models to try to predict the future of the ice sheet,
but their lack of understanding of subglacial geothermal energy has been a
glaring gap in these models. Measuring geothermal activity under the ice
sheet is so difficult that researchers usually just enter one, uniform estimate
for the contributions of geothermal heat to melting, Schroeder said.
Of course, volcanism isn't uniform. Geothermal hotspots no doubt influence
melting more in some areas than in others.
"It's the most complex thermal environment you might imagine," study co-
author Don Blankenship, a geophysicist at UT Austin, said in a statement.
"And then, you plop the most critical dynamically unstable ice sheet on
planet Earth in the middle of this thing, and then you try to model it. It's
virtually impossible."
Hotspots melting
To unravel the complexity, the researchers built on a previous study they
published in 2013 that mapped out the system of channels that flows
beneath the Thwaites Glacier, a fast-flowing glacier that scientists say is
vulnerable to global warming.
Using data from airborne radar, the researchers were able to figure out
where these subglacial streams were too full to be explained by flow from
upstream. The swollen streams revealed spots of unusually high melt,
Schroeder said. Next, the researchers checked out the subglacial geology in
the region and found that fast-melting spots were disproportionately
clustered near confirmed West Antarctic volcanoes, suspected volcanoes or
other presumed hotspots.
"There's a pattern of hotspots," Schroeder said. "One of them is next to
Mount Takahe, which is a volcano that actually sticks out of the ice sheet."
The minimum average heat flow beneath Thwaites Glacier is 114 milliwatts
per square meter (or per about 10 square feet) with some areas giving off
200 milliwatts per square meter or more, the researchers report today (June
9) in the journal Proceedings of the National Academy of Sciences. (A
milliwatt is one-thousandth of a watt.) In comparison, Schroeder said, the
average heat flow of the rest of the continents is 65 milliwatts per square
meter.
"It's pretty hot by continental standards," he said.
The extra melt caused by subglacial volcanoes could lubricate the ice sheet
from beneath, hastening its flow toward the sea, Schroeder said. To
understand how much the volcanic melt contributes to this flow — and what
that means for the future of the West Antarctic Ice Sheet — glaciologists
and climate scientists will have to include the new, finer-grained findings in
their models. Schroeder and his colleagues also plan to expand their study
to other glaciers in the region.
"Anywhere in the West Antarctic Ice Sheet is going to be a candidate for
high melt areas," he said. "And we have radar data covering much of it."
Editor's Note: This article was updated to reflect the fact that airborne data,
not satellite information, was used in the study."
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Responses:
[15781] [15782] [15776] [15778] |
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15781 |
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Date: February 07, 2019 at 13:25:53
From: Akira, [DNS_Address]
Subject: recent NASA/JPL study... |
URL: http://advances.sciencemag.org/content/5/1/eaau3433 |
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Zero mention of volcanoes under Antarctica. I'm so confused. lol
Heterogeneous retreat and ice melt of Thwaites Glacier, West Antarctica
P. Milillo1,*, E. Rignot1,2, P. Rizzoli3,†, B. Scheuchl2,†, J. Mouginot2,4,†, J.
Bueso-Bello3,† and P. Prats-Iraola3,†
See all authors and affiliations
Science Advances 30 Jan 2019:
Vol. 5, no. 1, eaau3433
DOI: 10.1126/sciadv.aau3433
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Responses:
[15782] |
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15782 |
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Date: February 07, 2019 at 13:26:23
From: Akira, [DNS_Address]
Subject: or climate change(NT) |
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Responses:
None |
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15776 |
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Date: February 07, 2019 at 12:54:53
From: Akria, [DNS_Address]
Subject: Re: Thwaites Glascier &Hidden Volcanoes Melt Antarctic Glaciers from... |
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and the Counterpunch article Ryan posted below doesn't mention volcanoes
once. This study is 5 years old. Even nbc has a story on it. WTF? I like
Counterpunch in general, but this is bullshit.
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Responses:
[15778] |
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15778 |
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Date: February 07, 2019 at 13:07:08
From: pamela, [DNS_Address]
Subject: Re: Thwaites Glascier &Hidden Volcanoes Melt Antarctic Glaciers... |
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Been reading about the volcanoes under Antarctica for some years.
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Responses:
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