Greenland - What Do We Know, What Is The Long Term Future And Is There Any Evidence Of A Melt Out?

[knocker]

Intense melt over Greenland the last few days, especially in west bringing smb very negative

 

Cumulative SMB not yet as low as 2012, or other low years like 2010 but well below mean

 

 

[songster]

Where "intense" = "below average"?

http://nsidc.org/greenland-today/images/greenland_melt_area_plot_tmb.png

[knocker]

Well I did qualify it with:

 

Cumulative SMB not yet as low as 2012, or other low years like 2010 but well below mean

 

 

 But if we are going to be pedantic.

 

http://polarportal.org/en/greenland-ice-shelf/nbsp/surface-conditions/

Edited July 17, 2013 by knocker

[knocker]

New near realtime comparison of Greenland glacier fronts with past surveys by GEUS

 

http://polarportal.dk/en/greenland-ice-shelf/nbsp/glacier-front-positions/

[Polar Maritime]

Like butter: Study explains surprising acceleration of Greenland’s inland ice

16 July 2013
AGU Release No. 13-35
For Immediate Release

WASHINGTON, DC — Surface meltwater draining through cracks in an ice sheet can warm the sheet from the inside, softening the ice and letting it flow faster, a new study finds.

During the last decade, researchers have captured compelling evidence of accelerating ice flow at terminal regions, or "snouts," of Greenland glaciers as they flow into the ocean along the western coast. Now, the new research shows that the interior regions are also flowing much faster than they were in the winter of 2000-2001, and the study authors propose a reason for the speedup.

"Through satellite observations, we determined that an inland region of the Sermeq Avannarleq Glacier, 40 to 60 miles from the coast, is flowing about 1.5 times faster than it was about a decade ago," said Thomas Phillips, lead author of the new paper and a research associate at the time of the study with the Cooperative Institute for Research in Environmental Sciences (CIRES) at the University of Colorado, Boulder.

In 2000-2001, the inland segment was flowing at about 40 meters (130 feet) per year; in 2007-2008, that speed was closer to 60 meters (200 feet) per year.

"At first, we couldn't explain this rapid interior acceleration," Phillips said. "We knew it wasn't related to what was going on at the glacier's terminus. The speedup had to be due to changes within the ice itself."

To shed light on the observed acceleration, Phillips and his team developed a new model to investigate the effects of meltwater on the ice sheet's physical properties. The team found that meltwater warms the ice sheet, which then—like a warm stick of butter—softens, deforms, and flows faster.

Previous studies estimated that it would take centuries to millennia for new climates to increase the temperature deep within ice sheets. But when the influence of meltwater is considered, warming can occur within decades and, thus, produce rapid accelerations. The paper has been accepted for publication in theJournal of Geophysical Research: Earth Surface, a journal of the American Geophysical Union.

The researchers were tipped off to this mechanism by the massive amount of meltwater they observed on the ice sheet's surface during their summer field campaigns, and they wondered if it was affecting the ice sheet. During the last several decades, atmospheric warming above the Greenland Ice Sheet has caused an expanding area of the surface to melt during the summer, creating pools of water that gush down cracks in the ice. The meltwater eventually funnels to the interior and bed of the ice sheet.

As the meltwater drains through the ice, it carries with it heat from the sun.

"The sun melts ice into water at the surface, and that water then flows into the ice sheet carrying a tremendous amount of latent energy," said William Colgan, a coauthor and CIRES adjunct research associate. "The latent energy then heats the ice."

The new model shows that this speeds up ice flow in two major ways: One, the retained meltwater warms the bed of the ice sheet and preconditions it to accommodate a basal water layer, making it easier for the ice sheet to slide by lubrication. Two, warmer ice is also softer (less viscous), which makes it flow more readily.

"Basically, the gravitational force driving the ice sheet flow hasn't changed over time, but with the ice sheet becoming warmer and softer, that same gravitational force now makes the ice flow faster," Colgan said.

This transformation from stiff to soft only requires a little bit of extra heat from meltwater. "The model shows that a slight warming of the ice near the ice sheet bed—only a couple of degrees Celsius—is sufficient to explain the widespread acceleration," Colgan said.

The findings have important ramifications for ice sheets and glaciers everywhere. "It could imply that ice sheets can discharge ice into the ocean far more rapidly than currently estimated," Phillips said. "It also means that the glaciers are not finished accelerating and may continue to accelerate for a while. As the area experiencing melt expands inland, the acceleration may be observed farther inland."

The study's results suggest that to understand future sea-level rise, scientists need to account for a previously overlooked factor—meltwater's latent energy—and its potential role in making glaciers and ice sheets flow faster into the world's oceans. In 2007, the Intergovernmental Panel on Climate Change (IPCC) wrote that one of the most significant challenges in predicting sea-level rise was "limited" understanding of the processes controlling ice flow. The IPCC's next assessment is due out in 2014.

"Traditionally, latent energy has been considered a relatively unimportant factor, but most glaciers are now receiving far more meltwater than they used to and are increasing in temperature faster than previously imagined," Colgan said. "The chunk of butter known as the Greenland Ice Sheet may be softening a lot faster than we previously thought possible."

 http://www.agu.org/news/press/pr_archives/2013/2013-35.shtml

Edited July 19, 2013 by Polar Maritime

[be cause]

The chunk of butter in my kitchen ran away today .. Greenland tomorrow ?

[knocker]

Greenland ice sheet climate before summer 2013:

 

a climate of temperature and precipitation extremes.

 

Written by: Jason E. Box, Peter Lang Langen, Signe Bech Andersen
Date: 18 June, 2013

 

Key Statements

• [*]Greenland air temperatures have climbed sharply since the mid 1990s. The recent decade is probably the warmest since during the Medieval Warm Period, which ended approximately 860 years ago. 
    [*]There has been a modest (12% to 20%) increase in snowfall rates over Greenland since the 1840s, associated with increasing atmospheric temperatures.
    [*]A continuous net ice loss from Greenland has been observed since a period of stability and modest growth during the 1970s/1980s. Since the Little Ice Age ended in 1900, observation-based ice sheet reconstructions indicate accelerating ice loss. The largest ice loss rates since 1840 have occurred in the most recent decade. [*]The contribution to global sea level rise from the Greenland ice sheet in the period 2002 to 2010 was more than 6.1 mm. After the thermal expansion of the oceans, this makes Greenland the largest single contributor to observed global sea level rise.
    [*]In 2012 there was record ice loss from the Greenland Ice Sheet.
    [*]Surface air temperatures in spring 2013 were above normal with very little snowfall in all areas except the south east. Simultaneously, it was a cold spring in Northwestern Europe. The well-known opposite temperature pattern between Western Greenland and Northwestern Europe has been strong in both summer and winter since 2007.
    [*]In 2013, pre-melt season observations and atmospheric modelling indicate a more variable climate than has been usual for Greenland in recent decades, with extremes of snowfall and temperature, making the coming warm season climate difficult to predict. 
    [*]There is growing evidence that declining Arctic sea ice is influencing the Northern Hemisphere mid-latitude and North Atlantic climate, including the Greenland Ice Sheet, leading to persistent warm or cold, wet or dry weather.
  

 

http://polarportal.org/en/greenland-ice-shelf/

[knocker]

A fair melt in south Greenland.

 

http://polarportal.org/en/greenland-ice-shelf/nbsp/surface-conditions/

Edited July 22, 2013 by knocker

[knocker]

Too late now for 2013 to produce surface melting anywhere near as large as in 2012

 

We’ve made it to the middle of the melt season 2013.

 

It’s been a roller coaster for Greenland climate in 2013. The year started out with an astonishing low albedo from a snow drought that made huge melt possible. Yet this was punctuated by the return of snow late April and prolonged low temperatures as the North Atlantic Oscillation (NAO) shifted from persistent negative that had been causing west Greenland temperatures to be abnormally warm while Copenhagen thad its coldest late winter and early spring in decades. The dipole in temperatures between NW Europe and W Greenland has been recognized for more than a century and called the “seesaw†in temperature.

 

Like in 2012, melt came on strong by early June but was shut down again by abnormally low temperatures, accompanied by additional snowfalls [1, Ruth Mottram, Danish Meteorological Institute, personal communication] in some areas, that lasted until mid July. The key difference between 2013 and the previous 6 summers (2007-2012) is the absence of a persistent negative NAO that drove south air over Greenland, heating it while promoting clear skies that maximized the impact of surface darkening through the albedo feedback (Box et al. 2012).

 

With this much of a delayed start, the albedo feedback has not had enough time to produce strong melt. Given now that we are at the mid point of the melt season, it is too late now for 2013 to produce melting anywhere nearly as large as we saw in 2012. In spite of this, the NASA MODIS data still show that the 2013 Greenland mid melt season (mid-July) albedo is at its lowest in 4 years; behind 2009, 2010, 2011, and 2012.

 

 

http://www.meltfactor.org/blog/?p=1163

Edited July 22, 2013 by knocker

[knocker]

Quebec fires in NASA CALIPSO data, drifting to Greenland

On the lower limit of this 4 July NASA CALIPSO laser scan, between latitude 42.60 N, longitude -68.93 W, evident is a rising smoke plume. The plume seeds cloud formation toward Greenland, reaching the southwest of the island.

 

http://www.meltfactor.org/blog/?p=1148

[knocker]

Rollingstone on the Greenland melt with Jason Box.

 

http://www.rollingstone.com/greenland-melting

Edited July 25, 2013 by knocker

[Gray-Wolf]

I think this is a growing problem knocks , the tip of the iceberg in fact!, We have seen the russian permafrosts melt out and the vegetation above dry off allowing the scale of wildfires we see there. this darkens the surface allowing faster melt ,earlier in the year, below. This leads to a 'warmer' land which in turn impacts the still frozen lands further north. There is no 'switch off' mechanism. it is a climate fuse burning and unable to be stamped out.

[knocker]

25th Jul 2013 saw smb - 12.484 Gt w.e. max in 2012 was about -20 Gt

 

 

[knocker]

mid 2013 melt season average Greenland ice sheet reflectivity 5% above 2012 value

 

http://www.meltfactor.org/blog/?p=1144

Edited July 26, 2013 by knocker

[knocker]

Greenland ice melt at station 1850 m above sea level the past 3 days

 

http://www.promice.org/WeatherArchive.html?stationid=123

[loafer]

Yes, albit temperatures are similar/slightly lower than historical data for the same date, albeit the data is only available since 2009, so no really statistically significant conclusions can be reached.

 

Interestingly, the lower altitude stations seem to be reporting some materially lower temperatures this year, although all that could change as the summer continues.

[knocker]

I've put this in here as it might be of interest to some.

 

How a beer bottle helped reveal rapid past climate change

July 27, 2013 — andyextance

 

On Saturday June 21, 1952, in a garden in Copenhagen, Denmark, raindrops fell through the slim neck of a beer bottle, splattering and splashing as they hit its bottom. But the bottle wasn’t carelessly left behind – Willi Dansgaard had inserted a funnel into its neck so he could use it for an experiment. He was watching it closely, collecting rain to later measure in his lab. Each drop brought Willi closer to revealing the secrets of Earth’s history, by giving scientists a way to work out temperature from ancient ice. In doing so, he would help show how climate can change much faster than experts had thought possible.

 

 

http://simpleclimate.wordpress.com/2013/07/27/how-a-beer-bottle-helped-reveal-rapid-past-climate-change/?utm_source=twitterfeed&utm_medium=twitter

[knocker]

May be most negative year since 2010 - 2012, outlook for ice sheet from July 2013 report

 

http://polarportal.dk/fileadmin/Rapporter/July_ice_sheet_report_final.pdf

[BornFromTheVoid]

An interesting video...

 

 

 

[knocker]

Melt widespread over southern Greenland, also concentrated in West

 

 

[knocker]

Gone Fishing…Took IcePod!

 

http://blogs.ei.columbia.edu/2013/07/30/gone-fishingtook-icepod/?utm_content=buffer841f5&utm_source=buffer&utm_medium=twitter&utm_campaign=Buffer

Edited July 31, 2013 by knocker

[knocker]

Greenland set the temperature record

Tuesday saw the highest temperature measured by a Greenlandic DMI weather station - records dating back to 1958.

 

On 30 July 2013 at 16 o'clock in the afternoon measured DMI weather station Maniitsoq / Sugar Loaf 25.9 ° C. Maniitsoq is located a few hundred kilometers north of Nuuk, Greenland's southwest coast.

 

25.9 ° C, the highest temperature measured on a DMI station since records began in 1958. The previous record of 25.5 ° C was from 27 July 1990 at Kangerlussuaq, located in the same area of ​​Greenland.

 

http://translate.google.co.uk/translate?hl=en&sl=da&u=http://www.dmi.dk/&prev=/search%3Fq%3Ddmi%26client%3Dfirefox-a%26hs%3DNb%26rls%3Dorg.mozilla:en-US:official

[knocker]

Greenland high near-surface air temperature record set

 

Let me front-load that the large scale circulation, if (likely) delivering (excess, anthropogenic) heat via south air advection, is arguably a legitimate part of a climate change narrative.

 

The foehn effect may not be an aside if atmospheric humidity were enhanced by climate warming, yielding additional latent heat release in the downslope compression of the foehn effect…

 

http://www.meltfactor.org/blog/?p=1204

Edited August 4, 2013 by knocker

[knocker]

As Jason Box says it already is.

 

New research has shown surface ice melt will be the dominant process controlling ice-loss from Greenland. As outlet glaciers retreat inland the other process, iceberg production, remains important but will not grow as rapidly.

 

http://scienceblog.com/64494/greenland-ice-sheet-to-continue-push-of-sea-level/

Edited August 8, 2013 by knocker

[Polar Maritime]

Salad days in Greenland signal a warming climate

Read more: http://www.smh.com.au/environment/climate-change/salad-days-in-greenland-signal-a-warming-climate-20130326-2gsn1.html#ixzz2bVBlLJn4