West Antarctic and Greenland ice sheets likely to completely melt

Started by jimmy olsen, July 21, 2013, 10:32:17 PM

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jimmy olsen

Lovely!

http://www.nbcnews.com/science/message-mud-east-antarctic-meltdown-could-cause-massive-sea-rise-6C10687020
QuoteMessage from the mud: East Antarctic meltdown could cause massive sea rise
John Roach NBC News

9 hours ago

The last time concentrations of the greenhouse gas carbon dioxide were as high as they are today, big chunks of the seemingly stable East Antarctic ice sheet melted and helped raise global sea levels more than 65 feet higher than they are now, a new study suggests.

Scientists have long known that seas were higher during the Pliocene, a geological epoch that ran from 5.3 million to 2.6 million years ago. At the time, atmospheric carbon dioxide levels were similar to today's 400 parts per million (ppm).

"Overall, it was a warmer climate than today, but similar to what we expect to reach by the end of this century," Carys Cook, a graduate student at the Grantham Institute for Climate Change at Imperial College London and the study's lead author, told NBC News in an email.

The West Antarctic and Greenland ice sheets were likely completely melted at the time, she added. The fate of the East Antarctic ice sheet has been less clear, though at least some of it must have melted to fully account for the highest global sea levels predicted by some reconstructions of the ancient Earth.

Cook and her colleagues studied the chemical composition of sediments drilled from the ocean floor near East Antarctica. They identified the signature of a specific type of rock "only found in large quantities hundreds of kilometers inland from the current ice sheet edge," Cook said.

The signature was strongest during the warmest phases of the Pliocene. "The only way it could have been eroded is by retreating the East Antarctic ice sheet inland, which means it must have melted significantly," she explained.

Cook and colleagues suggest that much of the ice that melted was in basins that were below sea level, putting it in direct contact with the seawater. As the ocean warmed, the ice was more vulnerable to melting.

That interpretation fits with recent airborne surveys that revealed large under-ice fjords in this part of Antarctica that appeared geologically young and carved by ice, and not as a result of plate tectonics, according to Duncan Young, a geophysicist at the University of Texas at Austin, who flew some of the surveys.

"This work reinforces that result," he told NBC News in an email. The new study is also "a shot in favor" of the argument that the East Antarctic ice sheet is less stable than previously believed, "which may be significant for future sea level change estimates," said Duncan, who was not involved in the new research.

Given the similarity between the Pliocene's estimated atmospheric carbon dioxide levels and those of today, scientists consider the epoch an analog for understanding how the present-day climate will evolve.

"What the study shows is that there is a clear record of rapid(-ish) sea level response to past climate shifts," Ted Scambos, an Antarctic ice expert at the National Snow and Ice Data Center in Boulder, Colo., said in an email to NBC News. He was not involved in the new research.

While the East Antarctic basins are covered in ice today, they might begin to melt as the oceans continue to warm, Scambos said. He noted that a mile-thick, Colorado-sized chunk of ice sloughing into the ocean would have a "big impact" on sea levels.

"And what we're seeing in other parts of Antarctica and Greenland today tells us that the transitions can be very abrupt by geologic standards," Scambos said. "They are mercifully more manageable by human standards, at least if we decide to start managing."
It is far better for the truth to tear my flesh to pieces, then for my soul to wander through darkness in eternal damnation.

Jet: So what kind of woman is she? What's Julia like?
Faye: Ordinary. The kind of beautiful, dangerous ordinary that you just can't leave alone.
Jet: I see.
Faye: Like an angel from the underworld. Or a devil from Paradise.
--------------------------------------------
1 Karma Chameleon point

Neil

I do not hate you, nor do I love you, but you are made out of atoms which I can use for something else.

CountDeMoney


jimmy olsen

It is far better for the truth to tear my flesh to pieces, then for my soul to wander through darkness in eternal damnation.

Jet: So what kind of woman is she? What's Julia like?
Faye: Ordinary. The kind of beautiful, dangerous ordinary that you just can't leave alone.
Jet: I see.
Faye: Like an angel from the underworld. Or a devil from Paradise.
--------------------------------------------
1 Karma Chameleon point

garbon

"I've never been quite sure what the point of a eunuch is, if truth be told. It seems to me they're only men with the useful bits cut off."
I drank because I wanted to drown my sorrows, but now the damned things have learned to swim.

jimmy olsen

Quote from: garbon on July 21, 2013, 11:19:39 PM
Quote from: jimmy olsen on July 21, 2013, 11:17:12 PM
Quote from: CountDeMoney on July 21, 2013, 11:08:42 PM
Nobody cares, Timmay.
They'll care if sea level rises 65 feet.

I'll be dead so why should I care?
I expect a significant rise within the next 30-50 years, so hopefully not.
It is far better for the truth to tear my flesh to pieces, then for my soul to wander through darkness in eternal damnation.

Jet: So what kind of woman is she? What's Julia like?
Faye: Ordinary. The kind of beautiful, dangerous ordinary that you just can't leave alone.
Jet: I see.
Faye: Like an angel from the underworld. Or a devil from Paradise.
--------------------------------------------
1 Karma Chameleon point

lustindarkness

Grand Duke of Lurkdom

fhdz

Quote from: jimmy olsen on July 21, 2013, 11:24:56 PM
Quote from: garbon on July 21, 2013, 11:19:39 PM
Quote from: jimmy olsen on July 21, 2013, 11:17:12 PM
Quote from: CountDeMoney on July 21, 2013, 11:08:42 PM
Nobody cares, Timmay.
They'll care if sea level rises 65 feet.

I'll be dead so why should I care?
I expect a significant rise within the next 30-50 years, so hopefully not.

Now Timmy's a climatologist.
and the horse you rode in on

jimmy olsen

Quote from: fhdz on July 21, 2013, 11:36:24 PM
Quote from: jimmy olsen on July 21, 2013, 11:24:56 PM
Quote from: garbon on July 21, 2013, 11:19:39 PM
Quote from: jimmy olsen on July 21, 2013, 11:17:12 PM
Quote from: CountDeMoney on July 21, 2013, 11:08:42 PM
Nobody cares, Timmay.
They'll care if sea level rises 65 feet.

I'll be dead so why should I care?
I expect a significant rise within the next 30-50 years, so hopefully not.

Now Timmy's a climatologist.
I'm not claiming any particular expertise in this matter.
It is far better for the truth to tear my flesh to pieces, then for my soul to wander through darkness in eternal damnation.

Jet: So what kind of woman is she? What's Julia like?
Faye: Ordinary. The kind of beautiful, dangerous ordinary that you just can't leave alone.
Jet: I see.
Faye: Like an angel from the underworld. Or a devil from Paradise.
--------------------------------------------
1 Karma Chameleon point

11B4V

"there's a long tradition of insulting people we disagree with here, and I'll be damned if I listen to your entreaties otherwise."-OVB

"Obviously not a Berkut-commanded armored column.  They're not all brewing."- CdM

"We've reached one of our phase lines after the firefight and it smells bad—meaning it's a little bit suspicious... Could be an amb—".

jimmy olsen

It is far better for the truth to tear my flesh to pieces, then for my soul to wander through darkness in eternal damnation.

Jet: So what kind of woman is she? What's Julia like?
Faye: Ordinary. The kind of beautiful, dangerous ordinary that you just can't leave alone.
Jet: I see.
Faye: Like an angel from the underworld. Or a devil from Paradise.
--------------------------------------------
1 Karma Chameleon point

Razgovory

I've given it serious thought. I must scorn the ways of my family, and seek a Japanese woman to yield me my progeny. He shall live in the lands of the east, and be well tutored in his sacred trust to weave the best traditions of Japan and the Sacred South together, until such time as he (or, indeed his house, which will periodically require infusion of both Southern and Japanese bloodlines of note) can deliver to the South it's independence, either in this world or in space.  -Lettow April of 2011

Raz is right. -MadImmortalMan March of 2017

11B4V

"there's a long tradition of insulting people we disagree with here, and I'll be damned if I listen to your entreaties otherwise."-OVB

"Obviously not a Berkut-commanded armored column.  They're not all brewing."- CdM

"We've reached one of our phase lines after the firefight and it smells bad—meaning it's a little bit suspicious... Could be an amb—".

frunk

Quote from: 11B4V on July 22, 2013, 03:02:11 AM
QuoteEast Antarctic meltdown could cause massive sea rise

You don't think an East Antarctic meltdown could cause a massive sea rise?  Where do you think that water would go?

Neil

Quote from: frunk on July 22, 2013, 07:04:35 AM
Quote from: 11B4V on July 22, 2013, 03:02:11 AM
QuoteEast Antarctic meltdown could cause massive sea rise

You don't think an East Antarctic meltdown could cause a massive sea rise?  Where do you think that water would go?
Who knows?  You can't reason with those gun nuts.
I do not hate you, nor do I love you, but you are made out of atoms which I can use for something else.