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Researcher Finds Greenland Melt Accelerating

12 December 2007

The 2007 melt extent on the Greenland ice sheet broke the 2005 summer melt record by 10%, making it the largest ever recorded there since satellite measurements began in 1979, according to a University of Colorado at Boulder climate scientist.

The melting increased by about 30% for the western part of Greenland from 1979 to 2006, with record melt years in 1987, 1991, 1998, 2002, 2005 and 2007, said CU-Boulder Professor Konrad Steffen, director of the Cooperative Institute for Research in Environmental Sciences. Air temperatures on the Greenland ice sheet have increased by about 7° F since 1991, primarily a result of the build-up of greenhouse gases in Earth’s atmosphere, according to scientists.

Steffen gave a presentation on his research at the fall meeting of the American Geophysical Union held in San Francisco from 10-14 December. His team used data from the Defense Meteorology Satellite Program’s Special Sensor Microwave Imager aboard several military and weather satellites to chart the area of melt, including rapid thinning and acceleration of ice into the ocean at Greenland’s margins.

Steffen maintains an extensive climate-monitoring network of 22 stations on the Greenland ice sheet known as the Greenland Climate Network, transmitting hourly data via satellites to CU-Boulder to study ice-sheet processes.

Although Greenland has been thickening at higher elevations due to increases in snowfall, the gain is more than offset by an accelerating mass loss, primarily from rapidly thinning and accelerating outlet glaciers, Steffen said.

The amount of ice lost by Greenland over the last year is the equivalent of two times all the ice in the Alps, or a layer of water more than one-half mile deep covering Washington, D.C.

—Konrad Steffen

The Jacobshavn Glacier on the west coast of the ice sheet, a major Greenland outlet glacier draining roughly 8% of the ice sheet, has sped up nearly twofold in the last decade, he said. Nearby glaciers showed an increase in flow velocities of up to 50 percent during the summer melt period as a result of melt water draining to the ice-sheet bed, he said.

The more lubrication there is under the ice, the faster that ice moves to the coast. Those glaciers with floating ice 'tongues' also will increase in iceberg production.

—Konrad Steffen

Greenland is about one-fourth the size of the United States, and about 80% of its surface area is covered by the massive ice sheet. Greenland hosts about one-twentieth of the world’s ice—the equivalent of about 21 feet of global sea rise. The current contribution of Greenland ice melt to global sea levels is about 0.5 millimeters annually.

The most sensitive regions for future, rapid change in Greenland’s ice volume are dynamic outlet glaciers like Jacobshavn, which has a deep channel reaching far inland, Steffen said.

Inclusion of the dynamic processes of these glaciers in models will likely demonstrate that the 2007 Intergovernmental Panel on Climate Change assessment underestimated sea-level projections for the end of the 21st century.

—Konrad Steffen

Helicopter surveys indicate there has been an increase in cylindrical, vertical shafts in Greenland’s ice known as moulins, which drain melt water from surface ponds down to bedrock, he said. Moulins, which resemble huge tunnels in the ice and may run vertically for several hundred feet, switch back and forth from vertical to horizontal as they descend toward the bottom of the ice sheet.

Steffen and his team have been using a rotating laser and a sophisticated digital camera and high-definition camera system provided by NASA’s Jet Propulsion Laboratory to map the volume and geometry of moulins on the Greenland ice sheet to a depth of more than 1,500 feet.

We know the number of moulins is increasing. The bigger question is how much water is reaching the bed of the ice sheet, and how quickly it gets there.

—Konrad Steffen

Steffen said the ice loss trend in Greenland is somewhat similar to the trend of Arctic sea ice in recent decades. In October, CU-Boulder’s National Snow and Ice Data Center reported the 2007 Arctic sea-ice extent had plummeted to the lowest levels since satellite measurements began in 1979 and was 39% below the long-term average tracked from 1979 to 2007.

CIRES is a joint institute of CU-Boulder and the National Oceanic and Atmospheric Administration.

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Time to sell that beach front property.

Nick;

The pace seems to be accellerating. How long will it take to have a significant effect on sea level? One thing seems to be almost certain is that sea level will be higher 50, 100 or 150 years from today. Will it be 50 cm, 100 cm or 200 cm ... all bets are opened.

I doubt that we will see more than a few cm in our life time.

"a layer of water more than one-half mile deep covering Washington, D.C."

DC is 68.3 square miles in area. The world's oceans are 139,500,000 square miles in area. That amount of water will raise the ocean level by .0155 inches. Ho hum.

There is the equivalent of seven meters (23 feet) of sea level in the Greenland ice pack and it is growing where it counts: inland.

The current pattern of melting at the edges started in the 1880's. The claim that GHG has anything to do with it is spurious since most of the anthropogenic CO2 has been released since after 1940.

For links to the facts cited see:

http://epw.senate.gov/public/index.cfm?FuseAction=Minority.Blogs&ContentRecord_id=175B568A-802A-23AD-4C69-9BDD978FB3CD

>> There is the equivalent of seven meters (23 feet) of sea level in the Greenland ice pack and it is growing where it counts: inland. <<

Arthur you left out the important detail from the report, the glaciers are accelerating their flow out (volume) faster than the new snow is being dumped in the center.

That's bad.

Average temperature above the ice sheet increasing by 7 degrees since 1991.

That's bad.

Add to the fact that there is no reason to believe these changes will stop. Its not a good picture.

Arhur so this is ho-hum.
Nick, There is another seven meters waiting in the Antarctic?
Dont ask me but the risks are plain.

Scott, check the links provided. Even though the temperature on top of the ice pack has risen since 1991, it is still lower than it was in the 1930's. Climate fluctuates around established cycles. The ice pack survived higher temperatures in the 1930's, the Medieval Warm Period, and even the last interglacial.

Arnold, yes. An inch of sea level rise in 80 years, if things continue as they have for the last 125 years, isn't very exciting. Even if the main ice pack is going to melt for the first time in 100,000 years, it will take thousands of years for it to happen.

Do the outflow glaciers matter for the longevity of the ice pack? Good question. The experts think that a meltdown would take about 3,000 years if conditions were in place to cause it. If that estimate doesn't include outflow (requiring all the ice to stay put until it melted) then they should stop claiming to be experts.

Arnold, this link has the Greenland (23 feet) and the West Antarctic Ice Sheet (17 to 20 feet) data you wanted.

http://www.epa.gov/climatechange/science/futureslc.html

"The ice pack survived higher temperatures in the 1930's, the Medieval Warm Period, and even the last interglacial."

Arthur, check your facts. This is getting silly.

==The ice pack survived higher temperatures in the 1930's, the Medieval Warm Period, and even the last interglacial.==

According to the US National Academy of Sciences report published in 2006
“none of the large-scale surface temperature reconstructions show medieval temperatures as warm as the last few decades of the 20th century.”
http://greyfalcon.net/swindle3

_

He's probably just quoting Sallie Balinuas or S. Fred Singer.

Catch being that their papers were retracted for academic dishonesty, and it was so bad that 5 of the reviewing staff of the journal quit in protest.
http://www.heatisonline.org/contentserver/objecthandlers/index.cfm?id=4361&method=full

Snark, during the MWP, England had a thriving grape and wine industry, the Vikings plied the northern Atlantic and planted colonies in Greenland and Iceland, and Europe had such prosperous harvests that the Europeans could afford cathedral building. The little ice age, destroyed the English wine industry, destroyed the Viking colonies in Greenland, made Iceland inhospitable, and made Europe poor and sickly. Warmth is life and wealth and health.

My facts are solid. If you don't believe them, present proof to refute them. Scoffing is not productive.

Also while we're at it.
The recent IPCC synthesis report clearly stated that:

"The (sea level rise) projections do not include uncertainties in climate-carbon cycle feedbacks nor the full effects of changes in ice sheet flow, therefore the upper values of the ranges are not to be considered upper bounds for sea level rise."

http://gristmill.grist.org/story/2007/11/18/123840/77

==My facts are solid. If you don't believe them, present proof to refute them.==

Evidence? You got it.

The Greenland part is kinda wrong. Only the very southern tip of Greenland is just barely outside the artic circle. Greenlanders barely eeked out a meager living, until they were obliterated. Largely due to pissing off the native indians, and because they were barely making due when they got there. Only reason they went there in the first place was because this guy Erik the Red got banished there for killing a bunch of people.

And the Vineyards thing is just silly.

_

By the way, even Newt Gingrich thinks that Senator Inhofe doesn't know what he's talking about.

GreyFlcn, Thanks, that's much more constructive than simple scoffing. A couple additional items for you:

Dr. Craig Loehle found that the MWP was slightly warmer than today:
http://www.ncasi.org/publications/Detail.aspx?id=3025

The ice sheet contains evidence of considerable resiliency:
http://www.boston.com/news/local/articles/2007/07/06/greenland_ice_yields_hope_on_climate/

Note that the ice sheet doesn't have to melt to raise sea level, it only has to be un-grounded. We may live to see how quickly can it slide off the land mass.

Actually, the MWP Greenlanders did rather well agriculturally, since about 80% of their diet was from crops. The archeaological evidence is that they were driven out by a worsening climate not by hostile neighbors:
http://www.csmonitor.com/2007/1128/p13s01-stgn.html?page=1

Vast commercial English vineyards during the MWP were documented by author Geoffrey Chaucer (whose family's wealth was based on their vineyard ownership). Commercial vineyards have retreated 300 miles south of where they were in the MWP:
http://www2.sunysuffolk.edu/mandias/lia/little_ice_age.html

Our "unprecedented" modern temperatures aren't.

The data for this study obtained from the QuickScat satellite which attempts to measure large scale snow melt and refreeze - as yet unconfirmed by ground measurement. Apparently 90 percent of our fresh water is not melting:

"Antarctica has shown little to no warming in the recent past with the exception of the Antarctic Peninsula, but now large regions are showing the first signs of the impacts of warming as interpreted by this satellite analysis," said Steffen.

The silence is fascinating. I made some unorthodox comments without getting called a troll, a denier, or a hack (so far, this time). Okay, that’s good. Let’s consider some more what this news from the Greenland ice sheet means to us.

During the most recent Ice Age, geologists tell us that the world’s oceans were 300 feet lower than they are today. This can be seen off the coast of Australia in the fossilized remains of a Paleolithic Great Barrier Reef in deeper water beyond the modern one. As the current interglacial progressed, the ice sheets melted and the oceans rose (and the coral larvae founded new reefs in shallower water).

For a time after the ice sheets receded, it was possible to walk from Europe to England and from Asia to North America until the rising water cut off these land routes. This was not always a very smooth process as melt water was in some places dammed up behind unmelted ice and caused great scouring floods when the ice dams broke (google: Lake Missoula). Most of the rise must have happened in the first few thousand years of the present interglacial period since, for the most part, for the last 6,000 years the oceans have risen smoothly and gradually. A notable exception occurred between AD 350 and 550 when the North Sea rose 2 feet and flooded coastal Europe and created the Fens of England:
http://www.historynet.com/magazines/british_heritage/6890117.html

Where the water for this sudden sea level rise came from can only be inferred since this was before satellite technology. But we are talking about 2 feet of water over 139 million square miles of oceans just 1600 years ago, so “somewhere” lost a really big chunk of ice during a relatively cool time between the Mid-Holocene Warm Period (MHWP) and the Medieval Warm Period (MWP). No such sudden rise is known for either the MHWP or the MWP. From this, I infer two things: (1) Ocean levels can rise fairly quickly and (2) It doesn’t require a period of global warming for it to happen.

So, since ice cores show that the Greenland Ice Sheet has endured through past interglacial periods and recent warm periods, I’m not finding a compelling reason to worry about it now. But…

That West Antarctic Ice Sheet is looking a lot more interesting to me. Not just because it is warmer now than at the end of the Little Ice Age (LIA) about 150 years ago (though that could be a contributing factor) but because past events tell me that it would be prudent to have an understanding of what’s possible in such a large potential source of sea level equivalent water. So how much of it is floating harmlessly on the Ross Sea and how much is grounded between there and Siple Dome?

Inquiring minds want to know.

Arthur:
"NCASI was established in 1943 by the pulp and paper industry to provide technical assistance for the industry’s goal of lowering the ecological impact of its spent pulping liquors." as described from their website.
I am not sure that the papers from this organization have been peer reviewed for accuracy from scientists at universities or other noncommercial entities.
Secondly, some of the highest temperatures recorded happened in the last 7 years, yet this report published last month omits the last 7 years of data.
Do you have any other reports from reputable institutions not started from industrial sponsorships that corroborate these conclusions?
Thanks - JROJAI

Arthur:
Regarding the ocean levels increasing, I think the media are taking extreme positions on both sides. Current estimates from NASA suggest about a 5 - 7 mm increase per year at current rates which means that the rise will not be as noticable in our lifetimes unless you were born in the last 10 years and live a long life.

HOWEVER, levels rising at current rates has no meaning if the problem increases at an exponential or otherwise nonlinear rate. All of the most recent estimates from scientists keep getting revised upward because earlier estimates underestimated the melting rate. The average global earth temperatures keep breaking the previous year's record for the highest temperature.

I think the truth is somewhere in the middle, and that by 2050 we will have ocean levels rise enough not necessarily to flood dozens of coastlines due to just average sea level rising, but due to storm surges that flood levies and river banks to destroy properties that would normally not see flood damage.

JROJAI, That's a reprint from Energy & Environment, not a product of NCASI. E&E appear to offer a forum for both sides of this debate. See: http://www.multi-science.co.uk/ee.htm

I hear you about the media; they want to sell soap and are going to go for sensation as much as possible.

Anybody know a peer reviewed source for temperature results for the last 7-8 years? I read "temperatures flat" in some places and "new records every year" in others. I can't just assume I have straight data without sourcing it.

I live near Denver, CO, and I have trouble believing that snow or ice respond quickly to air temperature changes. Where the sun shines, though, we can have melt at well below freezing. The air temperature on the Greenland ice sheet is low enough to prevent melt so if it is getting blitzed, my natural impulse is to extrapolate what I see in my yard to the ice pack (i.e. blame the sun). I also follow what happens on Mt St Helens in Washington State and the crater glacier formed because the south rim shaded it from sunlight. Currently, the 2004 eruption is still going on at a slower pace and the glacier has been pretty pushed around by the new lava dome but continues to last in the shade. See:
http://vulcan.wr.usgs.gov/Volcanoes/MSH/Images/MSH04/

Goo and Drivel.

Notice that all this is on the Western side of Greeneland. The Reports DID NOT discuss the Eastern sideof Greenland. Why??

The Polar Ocsillation, every decade or so, changes the wind direction. When West Greenland warms, East Greenland freezes. When the Polar Ocsillation reverses then East Greenland warms, West Greenland freezes.

Vice Vera every ten years or so; as long as we have been taking observations.

Statsitics and figures don't lie; but Liars can figure. And give you only half of the story...

Now you've heard the rest of the story.

Hi Arthur:
My response in referencing NCASI was to your reference from this organization in your previous post. I am trying to address your point directly with information from your reference.

My point still stands: work from commercially funded organizations need to be peer reviewed before their information can be presented as accepted in the scientific community. Just publishing something in a blog, a magazine or a web page (even my comments) don't make statements facts.

An example of a non-commercial, peer reviewed source of temperature studies of the last few years is the IPCC.
These major press anouncements from this UN panel have emphasized how clear the data is. There is no flat temperature data in these reports. There is also no disagreement within the panel on the stated results. Refer to (Fourth Report, Section 1.1 in Topic 1).
The IPCC is peer reviewed and respected in the scientific community.

Here is another recent post on this web site that supports the temperature data reports:
Green Car Congress Post 12 12 2007

@stan,
Did you even go to the website? A picture tells a thousand words, and that picture shows erosion of the glacial pact all around Greenland and not just as you propose on one side.

As for the ice pack in Greenland surviving? The National Snow and Ice Data Center in September estimated the surface area of the Arctic sea ice nearly 23 per cent below the previous record set in 2005. It's shrinking. How does it survive when everything around it is getting warmer. The MWP was medeival europe and the north atlantic. If countries believed that this is a temporary situation, why are different countries starting to try to claim artic resources. The only way they are exploitable is if the weather warms in the area.

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