Good news? Greenland is melting, but less quickly than predicted

Nov 09, 2012
Greenland is melting, but less quickly than predicted
Computer generated east-west cross-section of Greenland: certain ice sheet zones are more propitious to falls of snow than melting, and vice versa. At the summit, the ‘accumulation zone’ benefits from significant snowfall, whilst the ‘ablation zone’, lower in altitude, is consumed by melting and in ‘calving’ icebergs into the ocean.

The melting of the Greenland ice sheet is speeding up and 2012 already seems to be a record year in terms of this thawing. The potential consequences of this melt on the climate and on the rise of sea levels are such that the island of Greenland and its ice sheet have been the subject of close monitoring by researchers for a number of years. One of them, Xavier Fettweis, a climatology researcher at the University of Liège, has developed a mathematical model which studies different possible scenarios. Whilst this model confirms the acceleration of the thawing, it does not yet take into consideration a factor which has just been revealed in the journal Nature by American researchers working in part on the basis of venturing beyond the model designed by Xavier Fettweis.

In this publication, the American researchers (from the Universities of Colorado, Wyoming and Montana) stress the importance of what is called a 'percolation zone': the does not immediately join the oceans but infiltrates the empty spaces of the snowpack, then stays there and refreezes in the Winter. This does not contradict the predictions of Xavier Fettweis' models but put backs their coming into reality by some ten years or so at most. During this lapse of time Greenland's contribution to the rise of sea levels is, at least in part, compensated by the storing of water in the island's snowpack.

'In my model,' explains Xavier Fettweis, 'I consider that if the quantity of present in the snowpack is higher than 70%, the meltwater flows into the . Yet the Americans have demonstrated that certain zones of the ice sheet have much higher storage capacities.'

Whilst many remain, it is nevertheless certain that the Greenland ice sheet contributes significantly to the rise of sea levels. 'All these effects contribute to it,' continues Xavier Fettweis. 'In melting, the ice sheet loses and warms up, which accelerates the thawing. The snow which melts loses some of its whiteness and absorbs more energy, which also leads the melting to spiral.' It all contributes to the melting but it will nevertheless be spread over several centuries, or even over several thousands of years, before we will see the Greenland ice sheet disappear.

2012: a tipping point year?

For 4 million years, the permanence of the has been ensured by snow falls which accumulate in the centre of the island and become transformed into ice. Up until recently the ice sheet mass balance between gains (the falls of snow) and losses (the melting of the ice, icebergs breaking away) in overall mass has been close to zero and the ice sheet was in equilibrium. Despite the constant extension of the melt zone, the ice sheet has stayed in equilibrium thanks to the flow dynamics of the ice, which redistributes the snow mass accumulated in the centre towards the edges of the ice sheet.

Nevertheless the record thaws observed in recent months in 2012 (which have their origins not only in global warming but also modifications in Summer atmospheric circulation) have led to fears that the situation will be reversed. In August 2012 Greenland's surface ice sheet mass balance reached the absolute minimum recorded for at least fifty years. The equilibrium has been shattered, the ice melt and icebergs breaking away exceeding the arrival of snow. The weather conditions in the coming months will thus be decisive for the 2012 ice sheet mass balance, which could prove significantly imbalanced overall for the first time in Greenland's history.

Explore further: Mexico's Volcano of Fire blows huge ash cloud

More information: Harper, J., Humphrey, N., Pfeffer, W.T., Brown J. , X. Fettweis, Greenland Ice Sheet Contribution to Sea Level Rise Buffered by Meltwater Storage in Firn, Nature, doi: 10.1038/nature11566, 2012.

add to favorites email to friend print save as pdf

Related Stories

Greenland and Antarctic ice sheet melting, rate unknown

Feb 16, 2009

The Greenland and Antarctica ice sheets are melting, but the amounts that will melt and the time it will take are still unknown, according to Richard Alley, Evan Pugh professor of geosciences, Penn State.

Greenland ice cap melting faster than ever

Nov 12, 2009

Satellite observations and a state-of-the art regional atmospheric model have independently confirmed that the Greenland ice sheet is loosing mass at an accelerating rate, reports a new study in Science.

Warming and melting on top of the Greenland ice sheet

Aug 03, 2012

On top of the approximately 3 km thick ice sheet in Greenland the temperature is normally around minus 10-15 degrees C in the summer and about minus 60 degrees in the winter. This year, researchers from the ...

Recommended for you

Underwater robot sheds new light on Antarctic sea ice

1 hour ago

The first detailed, high-resolution 3-D maps of Antarctic sea ice have been developed using an underwater robot. Scientists from the UK, USA and Australia say the new technology provides accurate ice thickness ...

Damage caused by geothermal probes is rare

3 hours ago

Soil settlements or upheavals and resulting cracks in monuments, floodings, or dried-up wells: Reports about damage caused by geothermal probes have made the population feel insecure. In fact, the probability ...

Extreme shrimp may hold clues to alien life

4 hours ago

(Phys.org) —At one of the world's deepest undersea hydrothermal vents, tiny shrimp are piled on top of each other, layer upon layer, crawling on rock chimneys that spew hot water. Bacteria, inside the shrimps' ...

User comments : 20

Adjust slider to filter visible comments by rank

Display comments: newest first

Dug
1.7 / 5 (16) Nov 09, 2012
I thought Greenland was ice free in the recent past about 1500 years ago? As evinced by forests and Nordic tribe habitation with herd animal husbandry. Once again the "facts" don't match well or consistently.
SoylentGrin
4.5 / 5 (13) Nov 09, 2012
I thought Greenland was ice free in the recent past about 1500 years ago?


You gotta stop getting your climate information from Rush Limbaugh, dude.
Greenland has always had regions of habitability, but it's never been "ice free".
Claudius
2.1 / 5 (15) Nov 09, 2012
...less quickly than predicted...


Computer models... Sigh.
rubberman
3.9 / 5 (11) Nov 09, 2012
Measurements over the next 3-5 years will indicate if the sheet is out of equilibrium, if so, it is yet another piece of fruit off the climate change tree that we will have figure out how to prepare and eat....the branches are getting pretty low to the ground on that tree.
Tangent2
3 / 5 (10) Nov 09, 2012
Nevertheless the record thaws observed in recent months in 2012 (which have their origins not only in global warming but also modifications in Summer atmospheric circulation)...


Couldn't the modifications in Summer atmospheric circulation be a consequence of the global warming? Seems like they are trying to dismiss the cause once again and play it down.
Maggnus
3.4 / 5 (10) Nov 09, 2012
...less quickly than predicted...


Computer models... Sigh.


Willful obtuseness. **Sigh**
Maggnus
3.5 / 5 (11) Nov 09, 2012
I thought Greenland was ice free in the recent past about 1500 years ago? As evinced by forests and Nordic tribe habitation with herd animal husbandry. Once again the "facts" don't match well or consistently.


Wow. Talk about self deluded.

Eric The Red, a Viking, was the first European to come upon the frozen wastes of Greenland. He named it Greenland in hopes of attracting colonists to settle there. His reason--he made money off every one who did so.

They all died. Cause "Greenland" was, and is, a frozen wasteland.
ValeriaT
1 / 5 (12) Nov 09, 2012
In my theory the global warming is caused mostly with decay of radioactive elements in the Earth crust and oceans, which leads into heat content anomaly: the heat evolved with oceans is larger, than the heat formed with atmosphere. Which explains, why Greenland and Antarctica are melting in slower speed, than climatic models based on global temperature predictions.
omatwankr
2.8 / 5 (10) Nov 09, 2012
"Eric The Red, a Viking, was the first European to come upon the frozen wastes of Greenland. He named it Greenland in hopes of attracting colonists to settle there. His reason--he made money off every one who did so"

Eric the red was a visionary Kapitalist, and a bit to ahead of his time....

Greenland is Atlantis, it just hidden in plain sight under "frozen" water and will be the seat for the New Order One World Government when the Atlantien Illuminati finish unthawing it with factious Kabal Warmimg.

mrlewish
4 / 5 (6) Nov 10, 2012
"Eric The Red, a Viking, was the first European to come upon the frozen wastes of Greenland. He named it Greenland in hopes of attracting colonists to settle there. His reason--he made money off every one who did so"

Eric the red was a visionary Kapitalist, and a bit to ahead of his time....

Greenland is Atlantis, it just hidden in plain sight under "frozen" water and will be the seat for the New Order One World Government when the Atlantien Illuminati finish unthawing it with factious Kabal Warmimg.



You forgot the mention the Knights Templar and Freemasons with their black helicopters with the earths only hope being the flat earth society and birthers.
baudrunner
3 / 5 (5) Nov 10, 2012
I keep saying, one day Denmark will be the next great world power.
VendicarD
4.3 / 5 (6) Nov 10, 2012
You must have been reading denialist Claptrap.

"I thought Greenland was ice free in the recent past about 1500 years ago?" - Duq

Greenland hasn't been devoid of ice for hundreds of thousands of years.
VendicarD
4.4 / 5 (7) Nov 10, 2012
You don't have a theory unless you have some numbers to back it up, and it meshes with known science.

Your fantasy has/does neither.

"In my theory the global warming is caused mostly with decay of radioactive elements in the Earth crust and oceans" - ValeriaT
ValeriaT
1 / 5 (7) Nov 10, 2012
Look, I've nowhere to hurry, I'm just collecting an evidence. The faster melting of Arctic ocean and slower melting of Antarctica and Greenland makes no problem for my theory so I'll continue in its research.
VendicarD
4.5 / 5 (8) Nov 10, 2012
If you are still collecting evidence then you have no theory.

All you have is baseless speculation.

The same kind of idle speculation you can get from any drunk bum found sleeping it off in an back alley.

VendicarD
3.7 / 5 (3) Nov 10, 2012
Here is a Republican who is worthy of some respect.

http://www.youtub...e=fvwrel
VendicarD
4.3 / 5 (6) Nov 10, 2012
Friday, November 09, 2012

While there was little talk of climate change during the presidential campaign, the number of U.S. voters who see global warming as a serious problem is at an all-time high.

A new Rasmussen Reports national telephone survey finds that 68% of Likely U.S. Voters now say global warming is at least a somewhat serious problem, including 38% who think it's Very Serious. Thirty percent (30%) don't see global warming as a serious problem, with 12% who think it's Not At All Serious.
ubavontuba
1.6 / 5 (7) Nov 11, 2012
Wow. Talk about self deluded.

Eric The Red, a Viking, was the first European to come upon the frozen wastes of Greenland. He named it Greenland in hopes of attracting colonists to settle there. His reason--he made money off every one who did so.

They all died. Cause "Greenland" was, and is, a frozen wasteland.
Actually, Greenland was inhabited by Nordic Europeans for several centuries. And parts of it were surprisinly green:

"...there were considerable birch woods with birch trees up to 4 to 6 meters high..."

http://en.wikiped...ttlement

VendicarD
3.7 / 5 (6) Nov 11, 2012
During which they found the land unsuitable for agriculture, and unsustainable for living.

Their culture went extinct as a result.

"Actually, Greenland was inhabited by Nordic Europeans for several centuries." - UbVonTard

Conservative America is going the same way.
Shinobiwan Kenobi
1.4 / 5 (5) Nov 12, 2012
Their culture went extinct as a result.

"Actually, Greenland was inhabited by Nordic Europeans for several centuries." - UbVonTard

Conservative America is going the same way.


As a result of embracing the extremists. ...and the entire time I've been thinking the TEAbaggers had no use.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.