From the Helmholtz Association Greenland ice is melting — also from below
Heat flow from the mantle contributes to the ice melt
The Greenland ice sheet is melting from below, caused by a high heat flow from the mantle into the lithosphere. This influence is very variable spatially and has its origin in an exceptionally thin lithosphere. Consequently, there is an increased heat flow from the mantle and a complex interplay between this geothermal heating and the Greenland ice sheet. The international research initiative IceGeoHeat led by the GFZ German Research Centre for Geosciences establishes in the current online issue of Nature Geoscience (Vol 6, August 11, 2013) that this effect cannot be neglected when modeling the ice sheet as part of a climate study.
The continental ice sheets play a central role in climate. Interactions and feedback processes between ice and temperature rise are complex and still a current research topic. The Greenland ice sheet loses about 227 gigatonnes of ice per year and contributes about 0.7 millimeters to the currently observed mean sea level change of about 3 mm per year. Existing model calculations, however, were based on a consideration of the ice cap and considered the effect of the lithosphere, i.e. the earth’s crust and upper mantle, too simplistic and primarily mechanical: the ice presses the crust down due to its weight. GFZ scientists Alexey Petrunin and Irina Rogozhina have now coupled an ice/climate model with a thermo-mechanical model for the Greenland lithosphere. “We have run the model over a simulated period of three million years, and taken into account measurements from ice cores and independent magnetic and seismic data”, says Petrunin. “Our model calculations are in good agreement with the measurements. Both the thickness of the ice sheet as well as the temperature at its base are depicted very accurately. ”
The model can even explain the difference in temperature measured at two adjacent drill holes: the thickness of the Greenland lithosphere and thus the geothermal heat flow varies greatly in narrow confines.
What does this mean for climate modeling? “The temperature at the base of the ice, and therefore the current dynamics of the Greenland ice sheet is the result of the interaction between the heat flow from the earth’s interior and the temperature changes associated with glacial cycles,” explains corresponding author Irina Rogozhina (GFZ) who initiated IceGeoHeat. “We found areas where the ice melts at the base next to other areas where the base is extremely cold.”
The current climate is influenced by processes that go far back into the history of Earth: the Greenland lithosphere is 2.8 to 1.7 billion years old and is only about 70 to 80 kilometers thick under Central Greenland. It remains to be explored why it is so exceptionally thin. It turns out, however, that the coupling of models of ice dynamics with thermo-mechanical models of the solid earth allows a more accurate view of the processes that are melting the Greenland ice.
Petrunin, A. G., Rogozhina, I., Vaughan, A. P. M., Kukkonen, I. T., Kaban, M. K., Koulakov, I. & Thomas, M., “Heat flux variations beneath central Greenland’s ice due to anomalously thin lithosphere”, Advance Online Publication, Nature Geoscience, 11. 08. 2013, http://dx.doi.org/10.1038/ngeo1898)
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Salvatore Del Prete says:
August 12, 2013 at 11:28 a
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Wow, it appears you have a consensus of belief. That is so wonderful…
Now lets dance…
All this wondering this and wondering that. It is no coincidence that nearby Iceland, built from material flowing out of the Mid-Atlantic Ridge, is entirely a volcanic island and has fantastic volcanoes and hot springs. Iceland land surface is continually growing by accretion of offshore volcanoes. It keeps their surveyors busy mapping new land. It is one of the few places on earth where one has volcanic eruption under ice. The flat-topped volcanoes called tuyas are a result of this and are an interesting sight there.
http://en.wikipedia.org/wiki/Tuya
We’ve been recently treated to several “surprising” discoveries of active undersea volcanoes in a line going north of Iceland passing near Svalbaard and all the way up to 85N. Why would we think a feature that goes down the mid-Atlantic all the way past the southern tips of Africa and South America would not extend a few hundred km more north. In fact these are surprise new discoveries for non-geologists. I see this kind of knowledge “new” to climatologists all the time. Learning by doing can be rewarding but to report on it the way they do makes asses out of themselves. Here even Wiki has something on it. These egghead institutes should call up the geology department of a nearby university, first.
http://en.wikipedia.org/wiki/File:Iceland_Mid-Atlantic_Ridge_Fig16.gif
meemoe_uk says:
August 12, 2013 at 3:14 pm
“All continental plates are spreading out all the time. And all oceanic plates too.”
Really? So the Earth’s surface is growing?
I love this thread, i am always learning new things.
I thought only the Antarctic plate was the only plate that was growing all the time…
Gary Pearse says:
August 12, 2013 at 4:28 pm
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The article is about Greenland and wiki has no info on volcanoes there.
http://en.wikipedia.org/w/index.php?search=greenland+volcanoes&title=Special%3ASearch
Here is a nice profile of the temperature of the Greenland glacier from top-to-bottom at the Summit (GISP2) site.
http://www.iceandclimate.nbi.ku.dk/images/images_research_sep_09/Temp.jpg/
At the bottom of the ice in most of Greenland, the temperature is around -2.4C, which is just enough to melt the ice given the additional pressure of the ice above. The ice temperature is a balance of the “memory” of when the snow fell at -35C for example, got buried and is now deeper versus the heat coming up from the bedrock below. This means that throughout Greenland, they can’t really resolve any ice older than 115,000 years ago because it has mostly melted already and/or is too distorted to get an accurate age estimate.
The new NEEM ice core from northern Greenland, however, was just slightly colder at -3.0C and has allowed ice core data back to 130,000 years ago.
[just a personal comment about this temperature profile. It is used in borehole thermodynamic modelling to estimate the temperatures that might have existed at the surface when the snow fell. This model is then applied to the dO18 isotope data to arrive at the temperature history in Greenland going back to 130,000 years ago. I think this methodology is faulty. It comes up with a change in temperature from the last glacial maximum in Greenland of 25C while the global temperature change was only 5C. Antarctica is only 10C (given a realistic polar amplification factor of 2 times). I don’t believe polar amplification in Greenland is 5 times and this borehole thermometry modelling has led to incorrect estimates about Greenland’s temperature history. And this means it applies to the GISP2 temperature charts which you may have seen on the internet. Cut the temperature change by 2.5 times to reflect the real temperature in Greenland or cut it by 5 times to reflect the global temperature reality. Just a personal comment that a few other scientists agree with (as in all those assessing Antarctica ice cores) but most Greenland ice core scientists don’t agree with].
>Really? So the Earth’s surface is growing?
Yeah. Neal Adams has it right
And sometimes love sours…
Neal Adams; a comic book from the ’40s…
Isn’t it obvious? Without the ocean’s buffering mechanisms, the elevated atmospheric CO₂ and the sulfurous emissions from coal-burning North American power plants have combined for catastrophic Glacier Acidification!
The meltwater under the icecap must have eaten away the lithosphere!
And now that the lithosphere is so dangerously thin, Vuk’s graphs can now show an upcoming solar disturbance could rupture the crust under Greenland, leading to rapid icecap loss and Cataclysmic Global Flooding.
Hansen may have been right, burning all that coal may have been a bad thing after all.
what evidence do we have that the heat flux from the lithosphere has changed?
Kajajuk says:
August 12, 2013 at 4:35 pm
“All continental plates are spreading out all the time. And all oceanic plates too.”
Really? So the Earth’s surface is growing?
No, because an equal amount of area is sinking into the Earth in other places [called subduction zones -Google can explain what those are]
In any case, crustal heat flow doesn’t vary over time scales less than millenia. Whatever heat is coming up from under Greenland has been doing so throughout the last several glacial/interglacial cycles. There is no applicability to changes in melting over decades or even centuries.
Thanks Lief.
If you know, could you answer a question that no one has yet or any research binge has revealed:
Why is there no East-West subduction margins to balance the plate spreading of the Antarctic plate from South America to Africa? Is the Earth deforming into a split pear?
Kajajuk says:
August 12, 2013 at 8:30 pm
If you know, could you answer a question that no one has yet or any research binge has revealed: Why is there no East-West subduction margins to balance the plate spreading of the Antarctic plate from South America to Africa?
The Americas are, indeed, for now intruding into the Pacific Ocean floor. What happens next is anybody’s guess. Here is one such guess http://www.youtube.com/watch?v=uGcDed4xVD4 the Pacific seems to get the upper hand, and in 250 million years all continents might be collected in one large landmass, as has happened about 8 times over the history of the Earth.
Also, if you look at the floor of the Arctic one can see three ridges; a very pronounced one, Lomonosov, is 1800 km and i assume dormant. This suggests that that the top of the world has been spreading for a very long time. The gakkel ridge is the active one.
Where is the subduction to conserve the spreading.
http://geology.com/articles/arctic-ocean-features/arctic-ocean-seafloor-map.jpg
And all the plates are moving away from the Antarctic Plate:
http://www.fhwa.dot.gov/bridge/tunnel/pubs/nhi09010/images/ch13/fig_13_01.gif
Leif Svalgaard says:
August 12, 2013 at 8:55 pm
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Cool video.
If i could have afforded to go to University i would have wanted a time generous prof like you.
Thanks again!
Kajajuk says:
August 12, 2013 at 8:57 pm
And all the plates are moving away from the Antarctic Plate
Over the long haul all the plates will collect in a super landmass, then drift apart again, then collect, the split, then collect, then split, etc, so any specific tendency in one of the splittings will not survive into the next and all will wash.
Kajajuk says:
August 12, 2013 at 9:03 pm
If i could have afforded to go to University i would have wanted a time generous prof like you.
Thanks again!
You are welcome. Education is my pleasure and the internet [when you filter out all the nonsense] is a great tool for this.
Goldie says:August 12, 2013 at 6:16 pm
what evidence do we have that the heat flux from the lithosphere has changed?
Do we have evidence that it is constant?
This is an interesting article about the centre of the Earth.
http://www.nytimes.com/2012/05/29/science/earths-core-the-enigma-1800-miles-below-us.html?pagewanted=1&src=recg
Leif Svalgaard says:
August 12, 2013 at 8:55 pm
You are a scholar, teacher & gentleman for you patience. The video is fun, but its misuse of “era” for “period” & “epoch” is annoying.
Here is one scenario for the next supercontinent, assuming continued westward movement of North America, for further collision with Eurasia:
http://www.livescience.com/18387-future-earth-supercontinent-amasia.html
But it’s also possible that Atlantic seafloor spreading will stop & possibly reverse, leading to a replay of Pangaea. But in any case, Baja California & Alta California south of Point Reyes will in about 50 million years be a very scenic, long island off the coast of the Pacific Northwest.
Viewing of the Perseids spoiled locally by a thunderstorm tonight. Darn global warming! I mean climate change! I mean greedy humans!
David M. Hoffer,
I’m so glad you posted (esp. 10:59AM). I thought the same thing. Whether it intends to or not, the article refutes human-CO2 global warming. That would make it an article to applaud or at least give a little nod to, not to boo and hiss at. Glad someone else thought the same (and someone much more well-versed in science than I).
Janice
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@WWUT folks: PLEASE FORGIVE THE FOLLOWING NOTE — nowhere to post such things… Thank you, everyone —
Dear Kevin Knoebel,
I’m so sorry about the accident. God does whatever he pleases. He allowed a jerk to use his free will to ram into you. He has, nevertheless, promised to “work all things together for good for them who love Him… .” (Romans 8:28). You may hate God, but I love Him. I will keep on praying for you. In fact, I just prayed that He will give you a Chevy Suburban (in good condition, incl. AC and a nice step for your mom to help her get inside) to replace the Jeep. Lest this little note embarrass you, I pray for lots of WUWT people (no need to feel I’m trying to be too friendly, I mean).
And I won’t write notes like this anymore to you.
Well, take care, back there (lol, I thought you were in S. Cal or Texas!).
Your sister in the fight for Truth in Science,
Janice
Not new science. Geothermal heat average is 30W/m2 which will not melt much ice, and not caused by CO2. (before some idiot jumps onto that scenario)
[i]>If i could have afforded to go to University i would have wanted a time generous prof like you.[/i]
Leif is far from perfect. He’s a stubborn conservative of 20th century science who has no time for ideas that have been recently evidenced better than the older or more conventional theories. He’s the most knowledgable prof on solar oberservation I know of who is highly active in our community, but his models are outdated. Knowledge without correct interpretation is way short of understanding.
Here, wrt geology models he’s just grabed with blith faith the flawed current mainstream theory and I expect he’ll give it his full unquestioning support. Someone who does that has no business in science, but he should get a job with the church.
Well here’s a vid that does some weighing up evidence which conventional continental drift theory can’t explain.
From Janice Moore on August 12, 2013 at 10:22 pm:
It is a prerequisite for the exercise of free will to allow others to be acted upon. This ain’t a holodeck simulation.
Why would I do that?
Janice, I have lived a strange life, with large amounts of forced accidental spirituality. I could go on for several pages of what has happened, of what I have rationally and logically come to accept, by the preponderance of evidence that was not documented, is not reproducible, but which I know was real.
And this is not the place for it.
So let me say instead, that a young moron needed a wake-up lesson, I was available and could be in the right place, at the right time, in the right vehicle. And while I had plans to go elsewhere, I was there then. The lesson was taught, I am merely temporarily inconvenienced, there were no serious injuries or deaths, as there could have been with a different vehicle, and perhaps a different driver with possibly passengers.
I don’t mind doing my part when called.
I could no more hate God than I could hate the global atmosphere. I am surrounded, sustained, it is within me as I dwell within it, as I willingly breathe it in and into my being. I would perish without it. The analogy breaks down when I will inevitably be done with wearing the flesh, and I will be joined with only one for the transition.
Personally I don’t mind, the management and other patrons of this fine establishment may think otherwise.
On further examination, the gas tank wasn’t what was hit. That’s the spare tire well, which is now so pushed in the spare sticks up, the cover panel inside won’t sit flat to the floor. Frankly, I would consider buying a vehicle like that, and just pound out the well and live with the torn-up bumper plastic, for maybe a third of the cost.
As it is, the Jeep is drivable, it will be fixed on his insurance. Which is the best case possible, as I’d rather not get a rental even if his insurance is paying for it. As I’d have to get the rental insurance, as I don’t have collision/comprehensive, thus I’m not covered if I damage the rental, and I would pay for the rental insurance, not him.
BTW, are you watching the national news? The mystery of the priest who showed up at the car wreck, said comforting things, then disappeared into thin air without appearing on virtually all of the photos, has been solved. He’s come forward, his name is Dowling.
And so goes another Father Dowling Mystery.
You should use quotes or a blockquote format to indicate what you copied from the Internet.