Donate Bitcoin

Donate Paypal


PeakOil is You

PeakOil is You

THE Glacier Thread (merged)

Re: Greenland ice sheet lowered six metres in just a month

Unread postby dohboi » Tue 01 Feb 2011, 00:32:49

Nice points. I wonder if the models and projections figure in melting going on right into the winter? I'm guessing NOT. Couldn't this accelerate the time for three meter rise considerably?
User avatar
dohboi
Harmless Drudge
Harmless Drudge
 
Posts: 19990
Joined: Mon 05 Dec 2005, 04:00:00

Re: Greenland ice sheet lowered six metres in just a month

Unread postby Serial_Worrier » Tue 01 Feb 2011, 01:19:11

Adelaidewonderer wrote:You got huge carriers (and millions of small leisure craft) being added to oceans each year (displacement). Permanent stutures like breakwaters etc being added. Volcanic fallout.


Pfffft. Ship displacement even for a fleet of aircraft carriers are NOTHING compared to the volume of the ocean. Try harder!
User avatar
Serial_Worrier
Heavy Crude
Heavy Crude
 
Posts: 1548
Joined: Thu 05 Jun 2008, 03:00:00

Re: Greenland ice sheet lowered six metres in just a month

Unread postby PrestonSturges » Tue 01 Feb 2011, 02:51:58

There's like an unexplained inch of sea level rise in the last hundred years, probably from groundwater that was drained into the sea. The whole state of Florida was a swamp, and they lowered the water level trenching between every field about 6 feet deep. It's like that in many coastal area that have been drained since colonial times. Settlers started trenching as soon as they got off the boat.
User avatar
PrestonSturges
Light Sweet Crude
Light Sweet Crude
 
Posts: 6052
Joined: Wed 15 Oct 2008, 03:00:00

Re: Greenland ice sheet lowered six metres in just a month

Unread postby dissident » Tue 01 Feb 2011, 14:15:13

I wonder if the models and projections figure in melting going on right into the winter? I'm guessing NOT. Couldn't this accelerate the time for three meter rise considerably?


Since the AOGCMs do a poor job with capturing the ocean response they will not see this extra heat acting on the ice sheet. But they don't have serious coupled ice models included so I wouldn't trust their predictions for ice loss whatsoever. The model consensus is that the sea ice would disappear completely by September after 2060. They are 40 years late and one of the main reasons is that they do not capture the right amount of heat flux into the Arctic Ocean basin.

If you were to evaluate these models on their forecasts of Labrador current strength and the temperature of the water in the Fram strait they would all fail miserably.

It looks to me like Hansen et al. are taking this into account in the 5 meter estimate since they identify a 10 year e-folding melt rate increase based on observations rather than models. But note that there will not be much ice loss by 2050 and all the action will be in the final decades of this century. Nice and long into the future so it can be safely ignored by policy makers :(
dissident
Expert
Expert
 
Posts: 6458
Joined: Sat 08 Apr 2006, 03:00:00

Re: Greenland ice sheet lowered six metres in just a month

Unread postby Hinterlander » Tue 01 Feb 2011, 15:25:25

Just as the theorists and models grossly underestimated the rate of loss of sea ice, my gut also tells me that the break up, not the melt-down, but the break-up of the greenland ice cap will happen far sooner than the dates being projected.

As is born out in the quotes below, there are non-linear processes at work. The ice cap does not simply melt like a monolithic ice cube, fissures and cracks cut into it, water lubricates the bottom, huge additional amounts are calved into the sea (see previous post).

Add to these non-linear processes the the impact of the glacial earthquakes, (info provided below) and something of dramatic import could happen within 20 years.

Dissident, I guess I'm posing this as a question to you: I would anticipate that you feel that there is a real possibility that there could be a significant break up (20% or more) of the Greenland ice sheet within the next 20 years.



by dissident » Tue Feb 01, 2011 1:15 pm

It looks to me like Hansen et al. are taking this into account in the 5 meter estimate since they identify a 10 year e-folding melt rate increase based on observations rather than models. But note that there will not be much ice loss by 2050




by dissident » Sun Aug 01, 2010 7:35 pm

It does not all need to all melt to be a big deal for at some point during the melting process you can bet that a big chunk (thousands of cubic miles) will suddenly slide into the ocean. [sorry for not citing the original poster here]


Exactly. .... The story of the last few years is that ice sheet dynamics is poorly understood. The default mode for human thinking be it scientific or not is implicit linearization. There is no sense of the rapid nonlinear processes that can develop in natural systems. .... Do they really have detailed finite volume codes that follow every crack in the Greenland ice sheet and are able to respond properly to the propagation of new cracks along with water flow from the surface? .




Glacial earthquakes rock Greenland ice sheet

http://www.newscientist.com/article/dn8889-glacial-earthquakes-rock-greenland-ice-sheet.html

12:36 24 March 2006

A rapid increase in "glacial earthquakes" - caused by sudden large movements of glaciers - over the past few years indicates that warmer temperatures will destroy the Greenland ice sheet faster than expected, a new study warns.

Surface meltwater is not dribbling away, as if from a giant ice block melting slowly, but is seeping through cracks to the bottom of the glacier. Once there it forms a layer that "helps lift the glacier up from the rock" so it flows faster to the sea, says seismologist Göran Ekström at Harvard University, US, who led the study.

He discovered the glacial quakes three years ago, when looking for unusual earthquakes, and traced them to slips within the ice. And the quakes can be substantial: a 10-metre slip of an ice slab roughly the size of Manhattan Island, and as tall as the Empire State building, causes a magnitude-5 quake on the Richter scale.

When the team analysed glacial seismic records back to 1993, they found a striking increase in the number of quakes recorded in recent years. All 136 of the best-documented slips were traced to glaciated valleys draining the main Greenland ice sheet. A handful of others occurred in Alaskan glaciers or on Antarctica.
Hinterlander
 

Re: Greenland ice sheet lowered six metres in just a month

Unread postby dissident » Tue 01 Feb 2011, 17:04:27

Dissident, I guess I'm posing this as a question to you: I would anticipate that you feel that there is a real possibility that there could be a significant break up (20% or more) of the Greenland ice sheet within the next 20 years.


To qualify my opinion I will say that ice loss from these massive ice sheets exhibits self organized criticality (link). So it is highly probable that the Greenland ice sheet will breakup in multiple "catastrophic" events rather than melt away over 1000 years. Catastrophic would not be a surge of all the ice into the sea at once but rapid glacier flow in the course of a few years. This process would stop and start with time gaps of possibly tens of years in between. Much like the distribution of earthquakes.

My feeling is that it is still too early to see major events since the Arctic temperature (ocean and atmosphere) has only changed noticeably in the last 30 years. But feelings aren't worth much and quantitative analysis with a detailed ice sheet model are needed. However, the state of the art of these models is not so great. Just like we have no models predicting earthquakes based on detailed crustal stress evolution we do not have ice sheet models that actually track each glacier as it slides down the slope. A central problem is that there are no observations at the rock/ice interface and in the ice sheet interior. And to model every crack is an enormous task that current computing resources are not sufficient for. So some sort of grid needs to be defined and then you have the ever-present problem of subgrid scale processes. But even with these limitations it is worthwhile to simulate the ice sheet in a way better than a giant ice cube slowly ablating at the air ice interface.

EPFL glacier model

Details slides (PDF)
dissident
Expert
Expert
 
Posts: 6458
Joined: Sat 08 Apr 2006, 03:00:00

Re: Greenland ice sheet lowered six metres in just a month

Unread postby Hinterlander » Tue 01 Feb 2011, 17:23:29

Thank you.
Hinterlander
 

Re: Greenland ice sheet lowered six metres in just a month

Unread postby Newfie » Wed 02 Feb 2011, 17:41:45

Not quantitative but interesting none the less.

http://www.cbc.ca/canada/newfoundland-l ... d-201.html

2 massive icebergs headed for Grand Banks
Last Updated: Tuesday, February 1, 2011 | 2:48 PM NT Comments18Recommend3The Canadian Press

An iceberg expert says there's a slim chance two gigantic islands of ice drifting south from the Arctic could reach Newfoundland's Grand Banks as early as August.

Luc Desjardins, a senior forecaster with the Canadian Ice Service, says the icebergs have a long way to go and they could break up or get stuck in some Arctic bay in the months ahead.

However, he says the unusually large bergs have a shallow draft, which means they could float over the Grand Banks.

He says there's a one-in-a-million chance one of the frozen slabs could hit the Hibernia offshore oil platform, but it's anybody's guess what path they will take.

One of the icebergs is 84 square kilometres, the other 65, making it about the size of Manhattan.

Both were once part of a gigantic slab that calved from a glacier in northwestern Greenland last August.


Read more: http://www.cbc.ca/canada/newfoundland-l ... z1Cq9NZp00
User avatar
Newfie
Forum Moderator
Forum Moderator
 
Posts: 18458
Joined: Thu 15 Nov 2007, 04:00:00
Location: Between Canada and Carribean

Re: Greenland ice sheet lowered six metres in just a month

Unread postby Hinterlander » Thu 03 Feb 2011, 15:23:47

The followng article is rather dated, from 2007, but its such a great piece, both on Konrad Steffen and the state of the Greenland Icecap, that I thought I would pass it along.


Konrad Steffen: The Global Warming Prophet


By Tom Clynes
Posted 07.03.2007

http://www.popsci.com/scitech/article/2007-07/konrad-steffen-global-warming-prophet?page=1


Arctic climatologist Konrad Steffen has spent 18 consecutive springs on the Greenland ice cap, personally building and installing the weather stations that help the world's scientists understand what's happening up there. And what's happening may be much worse than anyone thought possible



In the annals of polar science, Konrad Steffen will go down as one of the legends. Koni, as he is known by his friends and colleagues, oversees an annual budget of $50 million and a staff of 550 at the Cooperative Institute for Research in Environmental Sciences (CIRES) in Boulder, Colorado, a research center that is jointly funded by the National Oceanic and Atmospheric Administration and agencies like NASA.

But Steffen has had the most influence not as an administrator but as an icy-boots explorer. He has spent the past 32 summers in the high Arctic, working in Alaska and Canada before settling on Greenland, where his Greenland Climate Network serves as the eyes and ears for climate scientists worldwide. I

n this extreme environment, the on-the-ground reality was invisible until Steffen personally customized and deployed much of the instrumentation that tells the scientific world, hour by hour and year by year, the conditions on the Greenland ice sheet and how they're changing.
Hinterlander
 

Re: Peak ice

Unread postby jorgea » Wed 23 Nov 2011, 21:19:48

The Swiss government ought to be preparing for the future or this country is going to be facing mass destruction.


No Spam Please
jorgea
Wood
Wood
 
Posts: 5
Joined: Wed 23 Nov 2011, 21:10:51

Re: Peak ice

Unread postby kiwichick » Thu 24 Nov 2011, 00:12:21

devil

new zealand has approx 70% of electricity from renewables and will over time go to 100%

hydro
geothermal
wind

and in the future wave
User avatar
kiwichick
Intermediate Crude
Intermediate Crude
 
Posts: 2267
Joined: Sat 02 Aug 2008, 03:00:00
Location: Southland New Zealand

Re: Peak ice

Unread postby dolanbaker » Thu 24 Nov 2011, 01:16:42

You do realize that this thread is seven years old! :P
Religion is regarded by the common people as true, by the wise as false, and by rulers as useful.:Anonymous
Our whole economy is based on planned obsolescence.
Hungrymoggy "I am now predicting that Europe will NUKE ITSELF sometime in the first week of January"
User avatar
dolanbaker
Intermediate Crude
Intermediate Crude
 
Posts: 3855
Joined: Wed 14 Apr 2010, 10:38:47
Location: Éire

Re: Peak ice

Unread postby papa moose » Thu 24 Nov 2011, 02:45:33

dolanbaker wrote:You do realize that this thread is seven years old! :P

I'm not sure if he did or not, i actually got the feeling that jorgea may have been a new login for devil.
Certainly doesn't seem that she did. :roll:
It, was an interesting read and raised an interesting point that i had never even heard brought up before, ie: cost of maintaining/repairing & decommissioning dams.
"That really annoying person you know, the one who's always spouting bullshit, the person who always thinks they're right?
Well, the odds are that for somebody else, you're that person.
So take the amount you think you know, reduce it by 99.999%, and then you'll have an idea of how much you actually know..."
papa moose
Lignite
Lignite
 
Posts: 276
Joined: Wed 17 Nov 2010, 01:44:59
Location: Perth, Western Australia

Re: Peak ice

Unread postby meemoe_uk » Thu 24 Nov 2011, 06:48:45

Back in 2004 when this thread started I would have agreed, the world still seemed to be warming so ice was on the decline. But by 2006, things were turning colder, and I was figuring out this AGW scam.
Image
full image here
Still looks to be plenty of ice. Just what you'd expect for 12 million years into the current ice age, with at least another 40 million years to go.
Image
User avatar
meemoe_uk
Tar Sands
Tar Sands
 
Posts: 948
Joined: Tue 22 May 2007, 03:00:00

Re: Peak ice

Unread postby AgentR11 » Thu 24 Nov 2011, 11:24:57

meemoe_uk wrote:Still looks to be plenty of ice. Just what you'd expect for 12 million years into the current ice age, with at least another 40 million years to go.


Ya know, you're so close to understanding... When your mind takes that final step and you come to realize what we've done as a species, don't be concerned about being proven wrong, just pick a new nick and join the doom parade.
Yes we are, as we are,
And so shall we remain,
Until the end.
AgentR11
Light Sweet Crude
Light Sweet Crude
 
Posts: 6357
Joined: Tue 22 Mar 2011, 09:15:51
Location: East Texas

Iceberg bigger than Manhattan breaks from Greenland glacier

Unread postby Ferretlover » Wed 18 Jul 2012, 09:30:35

This can't be good:
Iceberg bigger than Manhattan breaks from Greenland glacier
A massive iceberg larger than Manhattan has broken away from the floating end of a Greenland glacier this week, an event scientists predicted last autumn.
The giant ice island is 46 square miles, and separated from the terminus of the Petermann Glacier, one of Greenland's largest.
The Petermann Glacier last birthed — or "calved" — a massive iceberg two years ago, in August 2010. The iceberg that broke off and floated away was nearly four times the size of Manhattan, and one of the largest ever recorded in Greenland. …
"The Greenland ice sheet as a whole is shrinking, melting and reducing in size as the result of globally changing air and ocean temperatures and associated changes in circulation patterns in both the ocean and atmosphere," Muenchow said.

NBC
"Open the gates of hell!" ~Morgan Freeman's character in the movie, Olympus Has Fallen.
Ferretlover
Elite
Elite
 
Posts: 5852
Joined: Wed 13 Jun 2007, 03:00:00
Location: Hundreds of miles further inland

Re: Iceberg bigger than Manhattan breaks from Greenland glac

Unread postby dinopello » Wed 18 Jul 2012, 10:22:54

As the article states, A berg 4 times the size of Manhatten broke off 2 years ago. I wonder what the protocol is for claiming these floating masses. I assume they track the location of these big bergs. Anyone know a website ? If they get down to a nicer latitude they would make a nice little retreat for someone. We need Superman to pick these things and put it down on the drought-stricken midwest prairie.

The article above states

“The freshwater stored in this ice island could keep the Delaware or Hudson rivers flowing for more than two years. It could also keep all U.S. public tap water flowing for 120 days,” Muenchow said.
User avatar
dinopello
Light Sweet Crude
Light Sweet Crude
 
Posts: 6088
Joined: Fri 13 May 2005, 03:00:00
Location: The Urban Village

Re: Iceberg bigger than Manhattan breaks from Greenland glac

Unread postby dorlomin » Wed 18 Jul 2012, 10:31:07

Peterman is melting from below. It is in a very very deep fjord, about 500 meters of water below it. About 50 km from where that breakaway happened Peterman becomes deep enough to touch the surface. Warmer waters are coming in from deep channels and melting Peterman at the base. Ofcourse the water that is melted is fresh and sits about the warmer waters so does not stop this warm channel slowly melting Peterman. There is a lip, a point where the land goes deeper not so far back from where the glacier meets the ground and when it melts back to this point gravity will start accelerating the forward motion of the glacier.

Link here. Peterman is only moving slowly about 1km a year. No one knows why this warm water has entered the region. But if you think of a huge sheet of ice about 3km high and Peterman (and nearby Humbolt) being two gaps in big amounts of land that hold back that ice. All the friction of the contact between Peterman and the walls of the Fjyord are what holds that ice back, 500 meter thick at its thickest and 50km long worth of friction.

But being erroded from below now begining to succumb to mechanical stress at its terminus and thinnest and also now the snow from the top is ablating sooner and we are begining to see melt water ponds form on the top over summer.

Image

You can get a great view of the meltwater on the top on this picture.

Peterman is likely going to be a long time awaking. Many years or even many decades before it starts to really accelerate. In petermans case it is possible (probible?) that the basal melt from the currents was unforced by human factors (perhaps, perhaps not). But the warming of the region and the rapid increase of surface melt means yet another of the great Greenland outlet glaciers is showing signs of having less friction holding back those 3kms of ice.
User avatar
dorlomin
Light Sweet Crude
Light Sweet Crude
 
Posts: 5193
Joined: Sun 05 Aug 2007, 03:00:00

Re: Iceberg bigger than Manhattan breaks from Greenland glac

Unread postby autonomous » Wed 18 Jul 2012, 22:04:47

This massive Antartic iceburg is due to break off soon:
Image

Pine Island is roughly the size of the state of New York.
User avatar
autonomous
Peat
Peat
 
Posts: 186
Joined: Mon 14 Nov 2011, 15:08:25

Re: Iceberg bigger than Manhattan breaks from Greenland glac

Unread postby Newfie » Thu 19 Jul 2012, 06:39:25

The Canadian Ice Service tracks these large ice bergs. Google Canadian ice service. Lots of historical data there about ice cover etc.
User avatar
Newfie
Forum Moderator
Forum Moderator
 
Posts: 18458
Joined: Thu 15 Nov 2007, 04:00:00
Location: Between Canada and Carribean

PreviousNext

Return to Environment, Weather & Climate

Who is online

Users browsing this forum: No registered users and 71 guests