Scientists - Greenland Ice Sheet Irreversibly Lost W. 2C Increase - May Tip W/I 10 Years

[hatrack]

The entire ice mass of Greenland will disappear from the world map if temperatures rise by as little as 2C, with severe consequences for the rest of the world, a panel of scientists told Congress today. Greenland shed its largest chunk of ice in nearly half a century last week, and faces an even grimmer future, according to Richard Alley, a geosciences professor at Pennsylvania State University

"Sometime in the next decade we may pass that tipping point which would put us warmer than temperatures that Greenland can survive," Alley told a briefing in Congress, adding that a rise in the range of 2C to 7C would mean the obliteration of Greenland's ice sheet. The fall-out would be felt thousands of miles away from the Arctic, unleashing a global sea level rise of 23ft (7 metres), Alley warned. Low-lying cities such as New Orleans would vanish. "What is going on in the Arctic now is the biggest and fastest thing that nature has ever done," he said.

Speaking by phone, Alley was addressing a briefing held by the House of Representatives committee on energy independence and global warming. Greenland is losing ice mass at an increasing rate, dumping more icebergs into the ocean because of warming temperatures, he said.

The stark warning was underlined by the momentous break-up of one of Greenland's largest glaciers last week, which set a 100 sq mile chunk of ice drifting into the North Strait between Greenland and Canada. The briefing also noted that the last six months had set new temperature records.

EDIT

http://www.guardian.co.uk/environment/2010/aug/10/greenland-ice-sheet-tipping-point

[n2doc]

1. Hate to say it, but it has already tipped

Lots of pressure to say "we still have a chance", but little pressure to prepare for what is coming.

[aquart]

4. I cannot tell you how frightened I am.

I didn't much like the heat this summer.

[joshcryer]

9. Yep, given COP15 it's economically and politically impossible to do it.

We'll hit 2.0C easily.

[neverforget]

2. Just remember that the Earth is not warming and Al Gore is fat.

:sarcasm:

[hatrack]

3. Yeah, and remember when he grew a BEARD?!?!?!

Hahhahhahhahhahhah.

:eyes:

[n2doc]

5. He's got a huuuuuuge house too! n/t

[pscot]

6. What, Me worry?

[progressoid]

7. Blah blah blah. What about teh gays gettin married?

And the ground 0 mosque? Huh?

Thems the important things.

[jberryhill]

8. Can we buy real estate currently under the ice?

I could go for a nice 10 acre oceanfront spread in sunny Greenland.

[XemaSab]

10. Sorry for the late response.

[CHIMO]

11. Nice Theory

But we don't yet know how things will turn out or the rate of change.

There is only so much latent heat. It would seem to me that as the surface area of latent heat disappears the amount of latent heat consumed will remain the same. Except for increases in temperature.

So what is the rate of disappearance of ice that is floating plus other to the amount that is above land? Then include the increased methane production from exposed tundra?

My thoughts are that we can expect chaotic behavior. And it is not a general warming but an increase in energy excursions.

[Dead_Parrot]

12. Errr... What?

But we don't yet know how things will turn out or the rate of change.

No, but we have probabilities. I don't yet know what I'm going to have for lunch next Thursday, but the probability it'll be a toasted cheese sandwich is much higher than the probability it'll be your left foot and a hundredweight of Mongolian gravel.

There is only so much latent heat.

At any one time, yes.

It would seem to me that as the surface area of latent heat disappears --

What the fuck is the surface area of heat!?

--the amount of latent heat consumed will remain the same. Except for increases in temperature.

If you mean, "things get hotter when you heat them", then yes.

So what is the rate of disappearance of ice that is floating plus other to the amount that is above land? Then include the increased methane production from exposed tundra?

Practically all of the Greenland ice is above land. There is almost no tundra.

My thoughts are that we can expect chaotic behavior.

Yeah, especially when we loose all the land under 6m meters above sea level.

And it is not a general warming but an increase in energy excursions.

Please define "Energy excursions".

[CHIMO]

13. We

Don't know how things will turn out. Simple.

We know the past rate of change but not the future.

As ice melts there is less ice to melt.

The amount of latent heat per surface area of the material with latent heat.

Things do not get hotter when latent heat is involved. They change phase.

The artic ice is not on land. It is floating. Ice above land in Canada and Russia has tundra below it. When the perma frost is gone the organic material decomposes and the gasses are free to escape.

Chaotic behavour. Divide something by an ever decreasing number.

Energy excursions. Tornadoes. Excessive downpours. Drought. Forest fires. You can add to it.

[Dead_Parrot]

14. huh?

We don't know how things will turn out. Simple.

We know the past rate of change but not the future.

You may live your life constantly bewildered by the sun rising. I don't. Whilst I recognize there's a 0.0000000000000000000000000000000000000000000000000000000000000000000000001% chance a rogue black hole will destroy the sun overnight, I also recognize there's a 99.9999999999999999999999999999999999999999999999999999999999999999999999999% chance Monday morning will roll around as usual, and set my alarm clock accordingly.

As ice melts there is less ice to melt.

Well done.

The amount of latent heat per surface area of the material with latent heat.

That's not even English. I assume that's your definition of "surface area of heat", but I'm still puzzled as to how it fits in with the topic.

Things do not get hotter when latent heat is involved. They change phase.

Since we're dealing with plain, old-fashioned real heat from the sun, and a plain, old-fashioned 2C rise, they do both. And when they've finished changing phase, we'll all be building sandcastles in the Smithsonian carpark and eating fucking icecream. Hooray.

The artic ice is not on land. It is floating. Ice above land in Canada and Russia has tundra below it. When the perma frost is gone the organic material decomposes and the gasses are free to escape.

Look at the thread title. Then click here: Notice how "not Russia" and "not Canada" Greenland is? Now look at this photo:

Notice how "not floating" and "sort of land-ish" Greenland is? Good.

Chaotic behavour. Divide something by an ever decreasing number.

When I divide shit by a decreasing number, I eventually end up in more shit. This is not news, or indeed relevant.

Energy excursions. Tornadoes. Excessive downpours. Drought. Forest fires. You can add to it.

Power walking. Bubblebath. Cheese spoon on Joseph's albatros. Lemon waffle iron. Opal nosed goldfish.

Hey, I can add to it! Cool. Sounds like you meant "Extreme weather", though.

[Systematic Chaos]

15. You just about owed me a new keyboard with this.

Power walking. Bubblebath. Cheese spoon on Joseph's albatros. Lemon waffle iron. Opal nosed goldfish.

:rofl:

[The Croquist]

16. In unrelated news...

Press Release - Greenland Ice Core Team Reaches Bedrock

Bedrock has been reached Tuesday July 27 2010 at the deep ice core drilling site North Greenland Eemian Ice Drilling (NEEM) on the Greenland Ice Sheet at the depth 2537.36 m. The Eemian is the last interglacial period, when climate was warmer than today, and sea level 5 meters higher, and is our best analogue for future climate.

Further down:

The main goal of the NEEM project is to learn more about the warm Eemian climate period because it in many aspects can be seen to an analogue to the warming we will experience in the future. How reduced was the Greenland ice sheet 120.000 years ago when the global temperature was 2–3 deg C warmer than the present? And how much and how fast did the Greenland Ice Sheet contribute to sea level at that time? We expect that our findings will increase our knowledge on the future climate system and increase our ability to predict the speed and final height of sea level rise.

So let me get this straight. 120,000 years ago the global temperature was 2 - 3 degrees C warmer then today BUT there was still ice on Greenland. How does that square with the statement:

The entire ice mass of Greenland will disappear from the world map if temperatures rise by as little as 2C, with severe consequences for the rest of the world, a panel of scientists told Congress today. Greenland shed its largest chunk of ice in nearly half a century last week, and faces an even grimmer future, according to Richard Alley, a geosciences professor at Pennsylvania State University?

Maybe I just don't get it. How come 120,000 years ago the Greenland ice survived temperatures 2 to 3 degrees warmer then currently but Today they can't?

I would think the opposite. Since we are told that the rate of the temperature is "unprecedented" that would mean that the temperatures during the Eemian interglacial period should have been warmer for longer then the "sprint" we are supposed to be seeing yet somehow the Greenland Ice sheets survived. How is that possible? Maybe we should ask Professor Richard Alley. He seems to know what he is talking about. Maybe another funding grant will help.

[joshcryer]

17. Look at the ranges in the uncertainty.

For instance, it could be at the low end of 2.0C in the ice core, and in the middle of the 2-7C of the study. It's also necessary to look at where NEEM was done, higher latitude, higher altitude. The last big ice core (NGRIP) was done in a spot that has already seen significant surface melt.

Also, they're not saying "IT'LL ALL MELT AT 2.0C." They're saying that if we reach 2.0C and do not take measures to reduce global temperature, then the melting will continue on unabated.

The Eemian had sea levels 2 meters higher than now, but since I believe we had this discussion, you likely don't have an issue with that and will tell me it will take tens of thousands of years for a pithy 2.0C to cause that level of sea rise.

[The Croquist]

18. You are right

The sub headline (is that what they are called?) states it correctly.
Scientists warn that temperature rise of between 2C and 7C would cause ice to melt, resulting in 23ft rise in sea level

The first line of the Guardian story that I quoted however drops the 7C part.

I disagree however in saying that "they're not saying "IT'LL ALL MELT AT 2.0C." They're saying that if we reach 2.0C and do not take measures to reduce global temperature, then the melting will continue on unabated." The article says the exact opposite:

The entire ice mass of Greenland will disappear from the world map if temperatures rise by as little as 2C, with severe consequences for the rest of the world, a panel of scientists told Congress today.

The words entire ice mass of Greenland will disappear means that IT'LL ALL MELT.

Granted that the article contradicts itself elsewhere but this is the kind of crap that passes for journalism in the world today and frankly I partially blame the scientists. They should be writing letters demanding corrections but I don't recall a single one where the story exaggerates the risk of man-made global warming.

No sarcasm zone:
I may be wrong but don't glaciers melt at the bottom besides the top, sides and ends? I know in some cases it is caused by water seeping down but also I would think that the pressure of 2,537.36 meters (8,325 feet) has to create some amount of melting especially if it moves around. That would mean that there was even older ice down there that had melted, not from warmer temperatures, but from other natural forces.
End no sarcasm zone:

I also noticed the location chosen for the ice core. Sorry about not including a link on my previous post:
http://www.antarctica.ac.uk/press/press_releases/press_release.php?id=1266

It looks like they tried to find a place with the oldest ice on Greenland. They probably didn't but I'm willing to bet that they came pretty close.

From their website:
http://neem.nbi.ku.dk/about_neem/
The drill site
The choice of drill site is based on criteria giving the best possible conditions for retrieving the old Eemian ice:

•The ice must be thick, as large ice thickness implies more annual layers.
•The bedrock most be flat, because uneven bedrock causes irregular ice flow that can disturb the ice layering
•The precipitation should be moderately high. Large annual snowfall results in fast ice flow and thereby fast thinning of the lower, older parts. In contrast, low snowfall will mean that the annual layers become harder to detect and analyse.
•The dril site should be on an ice divide. The ice divide is the linie that separates the east-flowing part from the west-flowing part. The oldest ice layers are found near ice divides.
The NEEM drill site has been chosen based on radar profiling of the ice internal layers and the bedrock topography. The measurements show that the ice thickness is close to 2542 m.

The Eemian had sea levels 2 meters higher than now, but since I believe we had this discussion, you likely don't have an issue with that and will tell me it will take tens of thousands of years for a pithy 2.0C to cause that level of sea rise.

I don't know when we will have a 2 meter rise in sea level. It may take billions of years but if I had to bet I would say 600 to 700 years. At the current rate of sea level rise that is how long it will take. However if we look at the average sea level rise for the last 20,000 years it will take only about 300 years.

Just because we built cities on the coast doesn't mean that nature has to stop what it wants to be doing. For example, 3,260 years ago the city of Troy was just a brisk half a kilometer walk from the ocean where Helen used to catch rays (she was a babe you know). Today it is about 4 kilometers away which means she would probably want to take a cab. That isn't because of sea level change but the effects of two rivers that filled the bay with silt.

Today that doesn't happen. We build levees in New Orleans to prevent flooding that for tens of thousands of years dropped silt that kept the elevation of the city above sea level, dredge the harbor for the silt that the river does deposit and then blame the city sinking on global warming when the entire Mississippi delta has been sinking from the moment it was created tens of thousands of years ago. Other cities that are built on bedrock aren't in as big trouble but that doesn't mean they are safe. The Hudson river used to flow 200 miles past Manhattan to the Atlantic. Today Manhattan is on the Atlantic. There is no guarantee that a thousand years from now that Manhattan won't be a walled city with parts below sea level and pumps everywhere. Maybe, by then, They'll be able to stop dredging the harbor.