2010 spike in Greenland ice loss lifted bedrock, GPS reveals

Dec 09, 2011 by Pam Frost Gorder
This is a composite photograph of a GNET GPS unit implanted in the southeastern Greenland bedrock. Credit: Image by Dana Caccamise, courtesy of Ohio State University

(PhysOrg.com) -- An unusually hot melting season in 2010 accelerated ice loss in southern Greenland by 100 billion tons – and large portions of the island's bedrock rose an additional quarter of an inch in response.

That's the finding from a network of nearly 50 GPS stations planted along the Greenland coast to measure the bedrock's natural response to the ever-diminishing weight of ice above it.

Every year as the Sheet melts, the rocky coast rises, explained Michael Bevis, Ohio Eminent Scholar in Geodynamics and professor in the School of Earth Sciences at Ohio State University. Some GPS stations around Greenland routinely detect uplift of 15 mm (0.59 inches) or more, year after year. But a temperature spike in 2010 lifted the a detectably higher amount over a short five-month period – as high as 20 mm (0.79 inches) in some locations.

In a presentation Friday at the American Geophysical Union meeting in San Francisco, Bevis described the study's implications for climate change.

"Pulses of extra melting and uplift imply that we'll experience pulses of extra sea level rise," he said. "The process is not really a steady process."

The 2010 Uplift Anomaly (green arrows), superimposed on a map shows the 2010 Melting Day Anomaly (shaded in red). Produced by R. Simmon of the NASA Earth Observatory using data provided by M. Tedesco. Courtesy of Ohio State University

Because the solid earth is elastic, Bevis and his team can use the natural flexure of the Greenland bedrock to measure the weight of the ice sheet, just like the compression of a spring in a bathroom scale measures the weight of the person standing on it.

Bevis is the principal investigator for the Greenland GPS Network (GNET), and he's confident that the anomalous 2010 uplift that GNET detected is due to anomalous ice loss during 2010: "Really, there is no other explanation. The uplift anomaly correlates with maps of the 2010 melting day anomaly. In locations where there were many extra days of melting in 2010, the uplift anomaly is highest."

In scientific parlance, a melting day "anomaly" refers to the number of extra melting days – that is, days that were warm enough to melt ice – relative to the average number of melting days per year over several decades.

In 2010, the southern half of Greenland lost an extra 100 billion tons of ice under conditions that scientists would consider anomalously warm.

GNET measurements indicate that as that ice melted away, the bedrock beneath it rose. The amount of uplift differed from station to station, depending on how close the station was to regions where ice loss was greatest.

Southern Greenland stations that were very close to zones of heavy ice loss rose as much as 20 mm (about 0.79 inches) over the five months. Even stations that were located far away typically rose at least 5 mm (0.2 inches) during the course of the 2010 melting season. But stations in the North of Greenland barely moved at all.

From 2007 to 2009, GNET installed GPS stations in the bedrock that lay exposed around the ice sheet margins along the Greenland coast. The research team is using the earth's natural elasticity of to "weigh" the ice. As previous Ohio State studies of Antarctica revealed, ice weighs down bedrock, and when the ice melts away, the bedrock rises measurably in response.

GNET and similar networks around the world could thus allow scientists to continue to measure ice loss after the Gravity Recovery and Climate Experiment (GRACE) satellites are retired in 2015. (GRACE is a joint project of NASA and the German Aerospace Center.)

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NotAsleep
1.5 / 5 (8) Dec 09, 2011
"Greenland ice loss lifted bedrock"

"Hey, Barney, get the ice skates... you're not gonna believe this!"
"Alright, Fred. I'll grab the boots, too, else the engine might be a bit too cold to start!"
Nanobanano
3.1 / 5 (11) Dec 09, 2011
Melting and Calving events of the continental ice provides a false cooling signature in the ocean, partially masking some of the warming, because 0C or near 0C water/ice falls into a presumably slightly warmer ocean, if not warmer locally certainly warmer globally.

Thus the melting provides a FALSE "negative feedback" signature in the ocean temperature data and sea ice data.

The reality is that the running average of the SUM of continental ice loss plus sea ice loss deteriorates exponentially.

It appears that we have just set a new "record low maximum" for total global sea ice, therefore we may be approaching a point in the very near future where both northern and southern hemisphere sea ice will be in decline, and this in spite of the "false negative feedback" signature.

Melting rates this high, and even quite a LOT higher will become quite common over the next 5 to 10 years, and continue thereafter as positive feedbacks continue to compound one another.
Nanobanano
3.3 / 5 (6) Dec 09, 2011
The average annual loss of the sea ice over the past 5 years was 1000km. Most of this occured in the 2500km anomalies of both 2007 and 2010, with a rebound in 2008, but no rebound since then. Over the past 30 years the average was 400km per year, but heavily weighted by the past 10 years. 400km is also the exact amount lost this year.

The average annual loss of greenland ice cap is currently somewhere around 380 or 400km.

According to the exponential curves, we would expect the TREND in the 5 year running average to be as big as the 2007 and 2010 anomalies after just another 7 years of compounding of the feedbacks.

However, this curve will be difficult to measure exactly, because by 7 years from now we will expect the complete september meltdown to have already happened at least once, though some computer models delay this a few years.
Nanobanano
3.3 / 5 (9) Dec 09, 2011
Some of the models appear to take the false negative feedback into consideration, and assume it will take a full 10 years before the first complete september meltdown of the sea ice.

Apparently, about the time the sea ice gets below 2000km for annual minimum, (given as 5 years from now,) Greenland will probably be melting and calving fast enough to nearly replenish the sea ice, so it will take a further 5 years, according to the model, to put the nail in the coffin. That remains to be seen.

See Here:

neven1.typepad.com/blog/2011/10/september-2011-sea-ice-volume-looking-back-and-ahead.html

Shows 10 years to complete meltdown, a bit longer than extrapolation.

Personally, I see the existing trend in 5 year running average. I see the trend in Keeling Curve. I know the positive albedo feedback formula. I know there's CO2 bomb and Methane bombs in the tundra and permafrost...

I figure the trend is probably too big for any "normal" negative feedback to stop any time soon.
Nanobanano
2.9 / 5 (7) Dec 09, 2011
91 13.5

92 14.9 Pinatubo

93 12.2

94 13.6

95 11.2 13.1

96 13.7 13.1 0.0 Montserat

97 13.2 13.0 0.1

98 11.5 12.6 0.4

99 10.9 12.0 0.6

00 11.0 12.0 0.0 0.22

01 12.2 11.8 0.2 0.26

02 10.8 11.3 0.5 0.34

03 10.2 11.0 0.3 0.32

04 09.9 10.8 0.2 0.24

05 09.2 10.5 0.3 0.3

06 09.0 09.8 0.7 0.4

07 06.5 09.0 0.8 0.56

08 07.1 08.3 0.7 0.54

09 06.9 07.7 0.6 0.62

10 04.4 06.8 0.9 0.74

11 04.0 05.8 1.0 0.80

Hopefully, the formatting will be maintained.

1 is year.
2 is PIOMAS volume data
3 is 5 year running average
4 is annual change in 5 year running average
5 is 5 year running average of the annual change in 5 year average.

Since 4 is a rate of change, 5 is the average rate of change.

Notice, by 2011, averaged rate of change has roughly quadrupled compared to 2000, 11 years earlier.

The rebound peaks of notable volcanos are marked in the following year.
TegiriNenashi
2.5 / 5 (11) Dec 09, 2011
Why [junk] scientists are so paranoid for using proxy data? Did Greenland temperature stations indicate any warming? Did satellite radar measurements (<1M precision) prompt any ice loss? And no, I can't possibly believe that alleged ice melting somewhere at the ocean fringes can explain flat temperature curve recorded by Argo network.
Vendicar_Decarian
2.9 / 5 (12) Dec 09, 2011
"Did Greenland temperature stations indicate any warming?" - TegirlTard

Of course. Don't you know?

Are you that spectacularly ignorant?

http://www.nasa.g...ig09.jpg
Nanobanano
3.9 / 5 (10) Dec 10, 2011
no, I can't possibly believe that alleged ice melting somewhere at the ocean fringes can explain flat temperature curve recorded by Argo network.


Then you don't understand ice melting anyway.

Heat of Fusion of Ice is much higher than Specific Heat Capacity of air by mass. Try about 320 times higher.

It's possible for ice to melt without the air temperature even showing a significant rise, just so long as the air and run-off water is as warm or warmer than the ice.

The data isn't faked idjit.

There's too many different nations, and now even some corporations, who have space satellites for any of this to be a hoax.
Nanobanano
3.6 / 5 (8) Dec 10, 2011
Ya'll ain't seen NOTHING yet, kids.

The real sick stuff starts happening 5 to 10 years from now.

2012 : Will not be the end of the world.
P.S. Don't join ANY cults.

2013 : Scorcher. Hottest on record at that time.

2014 : Scorcher. Maybe hotter.

2015 : Hotter than 2011, but maybe not as hot as 2013 and 2014.

2016 : S. Hemisphere Sea Ice goes negative.
.....: Complete Arctic minimum Sea Ice meltdown possible.

2021 : S. Hemisphere Sea Ice has averaged negative for 5 years.
.....: Complete Arctic minimum Sea Ice meltdown 95% certainty.

2022 : Most Republicans and other ultra-conservatives finally admit something is wrong.
Skepticus_Rex
1.3 / 5 (15) Dec 10, 2011
I just happened to read the following today, so it seemed fitting to quote this in the place of an article on Greenland melting:

Greenland has been on the cusp of agriculture since the 16th century. Before this, agriculture was practiced by Viking settlers. Then came the Little Ice Age of the 16th century, wiping out Norse settlers and dooming agriculture in the region. But temperatures have been rising steadily since the 80s, and farming may soon be possible.

http://www.enviro...gain/392


Catch that last line in the quote? They are talking in terms of farming "possibly coming back" to Greenland. The Vikings already have been there and done that.

Wait! How could the Vikings have had agriculture when it nowadays is being discussed as only a "possibility"? How could this be even close to possible if today's temps are higher than they were in the days of the Vikings? They didn't have greenhouses in Greenland in their day.
WKern
5 / 5 (3) Dec 10, 2011
@Skepticus: Would you please please please please read Jared Diamond's Collapse? The Viking agricultural economy was a stupid idea. It barely supported less than 100 people iirc with help from summer imports when the temps were at the peak of the Milankovitch cycle. When the colder weather made the growing season shorter, it didn't pay to send ships there, and by the time things warmed up again, the folks there had all starved to death. Had they adopted Inuit ways, they would have survived. If anyone wanted to adopt the same stupid idea, they could have done it any time in the last 3 centuries. What the quote conveys, badly, is that Greenland temps have now risen so much beyond that of the past 2,000 years or so (not to mention probably the 5 million years before that) that farming (probably in the same two locations) may actually support enough people with enough of a cushion to make it not such a stupid idea.
Skepticus_Rex
1 / 5 (12) Dec 11, 2011
Perhaps you ought to take a look at H.H Lamb's work on climate in Greenland. Vikings dug in ground with hand tools to bury their dead in what now is permafrost.

A historical document also records a man swimming for an extended time in waters--and surviving without hypothermia--that now would kill would-be swimmers.

Diamond's work may not be as pertinent as you think.
Skepticus_Rex
1 / 5 (8) Dec 11, 2011
From Diamond:

Fishing was abandoned in the earliest years of the colony, and Greenlanders did not reconsider that decision during the four-and-a-half centuries of their society's existence.
* * *
In exchange for those imports, the same consideration of limited ship cargo capacity would have prevented Greenlanders from exporting bulk fish, as did medieval Iceland and as does modern Greenland, even if Greenlanders had been willing to fish.

(Collapse pp. 239-241)


Diamond mentioned the middens in these same pages. But, what gets me is that Diamond does not mention the bones of fish that were found in middens all over the colony. There were too many for this claimed abandonment of fishing. They may not have been able to ship much, it is true, but they still ate fish, and, thus, were willing to fish.

Ag. barely sustained less than 100 people? According to Diamond (p.262), there were not more than 4,000 people in Eastern Settlement alone. "...Self-sufficient in food..." (p.240).
Skepticus_Rex
1.4 / 5 (11) Dec 11, 2011
That the waters off west Greenland in the heyday of the Norse settlements were at least as warm as in the warmest periods of the present century is indicated by the abundance of cod which the inhabitants caught, the bones of which are found in their middens.

(Lamb, Climate, History and the Modern World, 159)

Other items point to a similarly great departure of the temperatures ashore in that area: for Old Norse burials took place deep in ground which has since been permanently frozen.

(ibid., 159)

The swimming incident is mentioned on the same page as the above citations. The water temperatures are postulated to have been at least 4 degrees C warmer at that time than they were at the time Lamb wrote his work.
Nanobanano
3 / 5 (4) Dec 11, 2011
You realize digging a grave in frozen ground really isn't impossible at all.

heck, people have been digging and mining in solid rock for thousands of years, and you act as if some frozen soil is somehow impenetrable?

The water could NOT have been 4C hotter just a millenium ago.

You want to know why, idiot?

Because Greenland would have been ice free, 10% of Antarctica would have melted too, and the Mean Sea level would have been a good 30 to 50 feet higher. It clearly has never been that high for at least many thousands years.

And all that ice would have had to be replaced since then to get the sea levels back "down" to what they are now...

I really don't even want to get into that.

If you think the arctic was 4C warmer for the Vikings, do you have an IDEA what the fricken weather would have been like?

At plus 4C, the heat potential from the top 100 meters of water GOES UP BY 168Kj/cm^2. This is more than the Gulf of Mexico's TCHP in August and September.
Skepticus_Rex
1 / 5 (9) Dec 11, 2011
The distance was well over two miles. Dr. L.G.C.E. Pugh of the Medical Research Laboratories, Hampstead, has given his opinion, from the studies of the endurance of Channel swimmers and others undertaking similar exploits, that 10 °C would be about the lowest temperature at which a strong person, even if fat, not specially trained for long-distance swimming, could swim the distance mentioned. As the average temperatures in fjords of that coast in August in modern times have seldom exceeded 6 °C (+3 to +6 °C being more typical), it seems that the water must have been at least 4 °C warmer than this limit in the year in which Thorkel swam it and brought home his sheep.

(Lamb, Climate, History and the Modern World, 159).

From the front matter of the book:

H.H. Lamb is Emeritus Professor in the School of Environmental Sciences and was the Founder and first Director of the Climatic Research Unit at the University of East Anglia.
Skepticus_Rex
1 / 5 (9) Dec 11, 2011
Nano,

Here is a temperature data chart taken from GISP2 data for you (from a paper dated 2011):

http://www.agu.or...350x.jpg

Here is the page for the abstract to access the article (also showing the chart in case the above link fails):

http://www.agu.or...44.shtml

Note: The authors of the article are AGW/AGCC believers.
Ethelred
5 / 5 (2) Dec 13, 2011
that 10 °C would be about the lowest temperature at which a strong person, even if fat, not specially trained for long-distance swimming,
This part is not likely correct. True the person in question was trained but self trained as in no one could teach her how to do it. Note that ONE person is supposed to have managed this in Iceland.

http://en.wikiped...ynne_Cox

Cox is perhaps best known for swimming the Bering Strait in 1987, from the island of Little Diomede in Alaska to Big Diomede, then part of the Soviet Union, where the water temperature averaged around 4 °C (40 °F).


The islands are 3.7 km (2.3 miles) apart. That 10C number makes no sense at all. It does not fit with the data you posted or any other data.

As for cod fishing, these were Norse we are talking about. Long distance sailors that even sailed to Newfoundland. Those could easily and rather more likely been caught from the Newfoundland Grand Banks and there is a Greenland Cod today.

Ethelred
FastEddy
not rated yet Dec 15, 2011
So, first the chicken, then the egg? Icelandic Volcanos of 2010 had nothing to do with this? Did the land rise before the ice melted or after?
Ethelred
5 / 5 (1) Dec 16, 2011
Greenland is not Iceland.

Ethelred