Researchers Find Major West Antarctic Glacier Melting from Geothermal Sources

June 10, 2014

AUSTIN, Texas — Thwaites Glacier, the large, rapidly changing outlet of the West Antarctic Ice Sheet, is not only being eroded by the ocean, it’s being melted from below by geothermal heat, researchers at the Institute for Geophysics at The University of Texas at Austin (UTIG) report in the current edition of the Proceedings of the National Academy of Sciences.

The findings significantly change the understanding of conditions beneath the West Antarctic Ice Sheet where accurate information has previously been unobtainable.

The Thwaites Glacier has been the focus of considerable attention in recent weeks as other groups of researchers found the glacier is on the way to collapse, but more data and computer modeling are needed to determine when the collapse will begin in earnest and at what rate the sea level will increase as it proceeds. The new observations by UTIG will greatly inform these ice sheet modeling efforts.

This map shows the locations of geothermal flow underneath Thwaites Glacier in West Antarctica that were identified with airborne ice-penetrating radar. The dark magenta triangles show where geothermal flow exceeds 150 milliwatts per square meter, and the light magenta triangles show where flow exceeds 200 milliwatts per square meter. Letters C, D and E denote high melt areas: in the western-most tributary, C; adjacent to the Crary mountains, D; and in the upper portion of the central tributaries, E. Credit: University of Texas Institute Geophysics.

Using radar techniques to map how water flows under ice sheets, UTIG researchers were able to estimate ice melting rates and thus identify significant sources of geothermal heat under Thwaites Glacier. They found these sources are distributed over a wider area and are much hotter than previously assumed.

The geothermal heat contributed significantly to melting of the underside of the glacier, and it might be a key factor in allowing the ice sheet to slide, affecting the ice sheet’s stability and its contribution to future sea level rise.

The cause of the variable distribution of heat beneath the glacier is thought to be the movement of magma and associated volcanic activity arising from the rifting of the Earth’s crust beneath the West Antarctic Ice Sheet.

Knowledge of the heat distribution beneath Thwaites Glacier is crucial information that enables ice sheet modelers to more accurately predict the response of the glacier to the presence of a warming ocean.

Until now, scientists had been unable to measure the strength or location of heat flow under the glacier. Current ice sheet models have assumed that heat flow under the glacier is uniform like a pancake griddle with even heat distribution across the bottom of the ice.

The findings of lead author Dusty Schroeder and his colleagues show that the glacier sits on something more like a multi-burner stovetop with burners putting out heat at different levels at different locations.

“It’s the most complex thermal environment you might imagine,” said co-author Don Blankenship, a senior research scientist at UTIG and Schroeder’s Ph.D. adviser. “And then you plop the most critical dynamically unstable ice sheet on planet Earth in the middle of this thing, and then you try to model it. It’s virtually impossible.”

That’s why, he said, getting a handle on the distribution of geothermal heat flow under the ice sheet has been considered essential for understanding it.

Gathering knowledge about Thwaites Glacier is crucial to understanding what might happen to the West Antarctic Ice Sheet. An outlet glacier the size of Florida in the Amundsen Sea Embayment, it is up to 4,000 meters thick and is considered a key question mark in making projections of global sea level rise.

The glacier is retreating in the face of the warming ocean and is thought to be unstable because its interior lies more than two kilometers below sea level while, at the coast, the bottom of the glacier is quite shallow.

Because its interior connects to the vast portion of the West Antarctic Ice Sheet that lies deeply below sea level, the glacier is considered a gateway to the majority of West Antarctica’s potential sea level contribution.

The collapse of the Thwaites Glacier would cause an increase of global sea level of between 1 and 2 meters, with the potential for more than twice that from the entire West Antarctic Ice Sheet.

The UTIG researchers had previously used ice-penetrating airborne radar sounding data to image two vast interacting subglacial water systems under Thwaites Glacier. The results from this earlier work on water systems (also published in the Proceedings of the National Academy of Sciences) formed the foundation for the new work, which used the distribution of water beneath the glacier to determine the levels and locations of heat flow.

In each case, Schroeder, who received his Ph.D. in May, used techniques he had developed to pull information out of data collected by the radar developed at UTIG.

According to his findings, the minimum average geothermal heat flow beneath Thwaites Glacier is about 100 milliwatts per square meter, with hotspots over 200 milliwatts per square meter. For comparison, the average heat flow of the Earth’s continents is less than 65 milliwatts per square meter.

The presence of water and heat present researchers with significant challenges.

“The combination of variable subglacial geothermal heat flow and the interacting subglacial water system could threaten the stability of Thwaites Glacier in ways that we never before imagined,” Schroeder said.

For more information, contact: University Communications, Office of the President, 512 471 3151;  Anton Caputo, Geology Foundation, Jackson School of Geosciences, 512-232-9623.

24 Comments to "Researchers Find Major West Antarctic Glacier Melting from Geothermal Sources"

1.  Helainous Maxima said on June 10, 2014

So let me get this straight - "geothermal heat" cannot be MAN-MADE global warming as the last time I looked those evil coal-fired power plants cannot impact and certainly not "control" the earth's underground/underwater geothermic heating up!! That my children would make humanity a "Stage 1" civilization - i.e., it could actually control all major weather, emissions, geologic and other forces on a planetary level. So we're "stuck" at still being a "Phase Zero" civilization or one that's not far removed from living in trees and eating bananas!!!

2.  Mary Ellen Lyons said on June 10, 2014

I am very interesting in reading any further updates.
Thank you

3.  ReduceGHGs said on June 10, 2014

Rising seas are on the way. We can and should do more to decrease the odds of having to deal with the more dire effects of human-caused climate change. We need to reduce emissions as soon as possible. Please join the efforts to get Congress to act. Currently there are too many obstructionists holding seats. The reject the reality and cater to vested fossil fuel interests or some political agenda. ENOUGH!


4.  Bob Maginnis said on June 10, 2014

"...According to his findings, the minimum average geothermal heat flow beneath Thwaites Glacier is about 100 milliwatts per square meter, with hotspots over 200 milliwatts per square meter. For comparison, the average heat flow of the Earth’s continents is less than 65 milliwatts per square meter....."

Note that human caused CO2 forcing is much more, about 1,500 milliwatts per square meter.

5.  NancySmyth said on June 10, 2014

humanity is slow to change, much like our planet. we are connected, yet some think humans have dominion over it and the other critters. sadly, we are finding that is all a heap of dung, with the vast majority failing to move and adapt to reality. we plant our hopes on the easy shores of verdant lands, scraping all value into a few civilized regions, leaving the greater world barren and lifeless, of all other species.

6.  Paul said on June 10, 2014

I guess I missed it.... I did not notice the article mentioning or remotely attempting to attach their scientific findings on "global warming". However I was looking for it! Because the ever moving, redefining, and infinitely-loose and broad-based way "climate change" is "defined"... enables one to blame anything on everything; and still call it "science". I would take them more seriously if only I could trust that they can acknowledge decent and good scientific truths, even if it is contrary. But again, maybe tis I who is blind, to... "geothermal change"...

7.  Mike Ward said on June 10, 2014

ReduceGHG - but what do you do about the volcano that's melting the ice sheet...? Seems to me that's the most pressing issue.

8.  Fred realist said on June 10, 2014

How is this even remotely linked to greenhouse gas emissions? This is caused by geothermal heat generated from underwater volcanic activity. Please refrain from the spin!!

9.  Paleo said on June 10, 2014

This makes perfect sense. Subglacial volcanic activity, (very hot temperature) melting ice. Seems like some great research.

Unless congress can stop subglacial volcanic activity, (which they can't and I wouldn't want them to use my money to try) then give it a rest. The Earth has been around for 13.8 THOUSAND, BILLION years. Humans will not destroy earth. Earth has survived much worse in its history and it is absolutely ABSURD to think we can change the course of the earth.

It is conceded, and fool-hearted to believe in such fantasy.

10.  Heidi Morgan-Finger,Jr. said on June 10, 2014

I love this!!! Not only are we going to die, but we are going to die from something completely unexpected!!!! How funny!!! Going extinct without knowing why!

11.  SureBuddy said on June 10, 2014

If you take the time to actually read the article, you can realize that acts of Congress will and cannot have any effect.

12.  FactsoverFaith said on June 10, 2014

How can we believe this article? It makes it sound like the ice is melting because of magma under the ice? How can we band together to ensure that we all focus on fossil fuel and stop this un-ethical reporting that ice melting can be due to Volcanic activity. Next you will hear that Mt. Pinatubo released more that 100 years of human created green house gas when it erupted. If that was true - then human-caused climate change might not get the science boost that we all know is true

13.  mike white said on June 10, 2014

for two years I have been preaching about thermal vents causing the ocean to warm. With the frequent earthquakes the position of these vents can change. we have had warm periods in the eons before according to scientist did man cause these? But, I should be quiet because this is not politically correct and those who believe that man has caused this do not tolerate anyone who disagrees with them.

14.  mike said on June 11, 2014

I read an article about the heating of the continent beneath the 2mi. thick glaciers above. It said that the melting of the ice above has exerted less pressure on the continent and has caused the land to begin to rise. The rising of the land has caused fissions and releasing the heat below.

Scientists have said that the Antarctic ice has been melting far greater than they originally have thought and their model program to predict the melting process is no longer applicable.
When it goes it's going to go in a very short period of time and we can't do a thing about it. A little scary. I think WE really screwed up our only planet and it isn't going to be pretty.

15.  DEW said on June 12, 2014

Nature bats last

16.  Tim said on June 13, 2014

AGW is nonsense. The whole solar system is heating up. And, it appears the whole solar system may be heating up from the inside out. We simply don't really understand much of anything that drives these major cyclical factors. But, I could easily see a causative or correlative effect of the sun becoming weak and the planet's heating up from the inside out to compensate. Because that is exactly what is happening.

But, the science is settled. Humans cause AGW. lol. Too bad 500,000 years of ice core samples prove CO2 is a lagging indicator to climate or a dependent variable. The science on this was settled long ago. It's not CO2 and it's not humans.

17.  garhighway said on June 13, 2014

Those who want to use this to cast doubt on global warming are missing the point: the fact that geothermal is making a mild contribution to warming under the ice doesn't mean that AGW isn't also contributing to ice melt, and the ratio of their contributions is heavily weighted towards AGW.

18.  Luke Anderson said on June 13, 2014

You people realize that there are two separate references to 'a warming ocean,' in the article? You do also realize that the effect of geothermal heat on this glacier is in no way evidence that the overall global climate isn't changing?

I have a microwave in my home. Sometimes I use it to make pizza rolls. When I bite into one and it's too hot I don't turn to my wife and say, "The Sun didn't heat these pizza rolls up! Our microwave did! The Sun doesn't exist!"

19.  John Christian said on June 15, 2014 matter what others might believe or feel, this news story is still fantastic, and it doesn't take away from all the good, solid, and worthy that many researchers, et al., in different fields. Believe it or not such a phenomenon as evolution does exist -- we evolve the minute we are born -- we and our wonderful planet evolves constantly and in many ways -- everything and every creature are effected. Its happening right here in our own backyard -- I invite you to come take a ride with me and my adorable wife and well-behaved hard studying magnificent children on our wonderful Miami-style power boat on Lake Travis and we can stop for yummy fish tacos at one of the shoreline cafes...we have plenty of sun block (ugh!)....

20.  Robert V. said on June 16, 2014

I am so happy to see research results like this. My concern is for the natural life systems that exist and depend today on the Antartic Glacier System. Bob McGinnis raises a very valid point, and that is the contribution that the contaminants spewing into the Earth's atmosphere are raising the retained power due to the sun's radiation at a rate much faster than certain geological developments. The Earth is a system, and life on Earth continues to adapt to the changing elements if such changes do not occur so rapidly that the Earth's system has time to react. We know life, as it is today, because the Earth has built a natural factory to produce the CO2 that protects our surface and helps to retain the water from evaporating into space. Large areas of ice are great reflectors and help to reflect unwanted radiation back into space further helping to mitigate rising thermal conditions that could accelerate the evaporation of our water system that sustains life. Losing the large areas of reflective ice systems along with opening "holes" in our CO2 blanket may cause the Earth surface to heat up in a way that we may experience a "tipping" point and observe that our water system will disappear much faster than the life system of the Earth can adapt to. Research such as this is critical to our understanding of how to mitigate the loss of these vast reflective surfaces and help to sustain or accelerate life system changes required to adapt to the changing environment. We can all take short-term action by finding ways to lower our consumption of the resources and getting policy around the world that protects our CO2 natural factories while finding new ways to restore and maintain our reflective surfaces in efforts to mitigate the rising heat of our Earth's surface.

21.  Bob Colvin said on June 16, 2014

Since a given number of molecules of water ice take up a greater volume than the same number of molecules of liquid water, and since it seems that the majority of the glacier ice is below sea level, if this glacier melts, world sea levels SHOULD GO DOWN.

22.  Al Stlouis said on June 20, 2014

The estimated rise in sea levels, 1-2 meters, is astounding, and cause for alarm. Look at NOAA's models for what 1-2 meters rise in sea levels does to the East and Gulf Coasts.

23.  Bruce Farber said on June 27, 2014

Any ice already floating on ocean water or displacing ocean water will not affect ocean surface elevation when it melts. Float ice cubes in a glass of water, mark the water surface, wait until the ice is completely melted, note that the water level has not changed. Only land based ice melting can add to ocean level rise. This is based on physics, not politics or religion.

24.  Murray Jackson said on July 6, 2014

Some commenters seem to be trying to mitigate the effect of geothermal heatflux by juxtaposing their perceived effect of CO2. Firstly, geothermal heat flux is magnified by multiples in areas of significant subglacial topography ( C. J. van der Veen, T. Leftwich, R. von Frese, B. M. Csatho, J. Li 2007). Secondly, the effect of submarine and subglacial volcanism extends from the tip of the Antarctic peninsula through to the south end of the Ross sea. This is the area of destabilization in Antarctica (West Antarctic Ice Sheet) and the rest of Antarctica that is only exposed to theoretical CO2 modelling is cooling and the ice is thickening. So safe to say the primary influence on glacial destabilization in west Antarctica is geothermal heatflux.