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Tuesday, June 10, 2014

Geothermal flux, West Antarctica and deniers at WUWT

Sou | 6:34 PM Go to the first of 10 comments. Add a comment

Anthony Watts has a headline about a new paper on the West Antarctic Ice Sheet (WAIS). He wrote (archived here):
Uh oh: Study says ‘collapsing’ Thwaites Glacier in Antarctica melting from geothermal heat, not ‘climate change’ effects
Remember the wailing from Suzanne Goldenberg over the “collapse” of the Thwaites glacier blaming man-made CO2 effects and the smackdown given to the claim on WUWT?
Well, never mind. From the University of Texas at Austin  and the “you can stop your wailing now” department, comes this really, really, inconvenient truth.
Researchers find major West Antarctic glacier melting from geothermal sources
Anthony then pastes a press release that he copied but didn't bother to read. If he had read it, he would have noticed the following:
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 "being eroded by the ocean" refers to the warmer ocean melting the ice in West Antarctica.  West Antarctic melting been discussed in recent articles on several occasions - here and here and here and here and here and here for example. Many slightly older articles too, such as this one. The geothermal heat is adding to this effect, not replacing it.

So for Anthony to write "you can stop your wailing now" is dumb on two counts. Firstly that global warming is melting WAIS. Secondly that if WAIS is also being melted from below by geothermal heat, that could mean that seas will rise sooner rather than later, which will cause a lot of "wailing". I don't know if the effects from warmer oceans and geothermal activity are additive or not. What I would say is that the combined effect has to be greater than either one on its own.

Of course it's easy to see why Anthony wants to pretend that WAIS isn't melting from global warming. The facts, like all global warming facts, threaten his ideology and his blog business. Anthony writes purely for science deniers, not for the general public.

Anthony Watts has already written a lot of wrong articles about melting ice and rising sea level (eg he was wrong about the Suzanne Goldenberg article he referred to above). Anthony effectively argues that ice doesn't melt as earth gets hotter. He usually extrapolates past sea level trends as measured by tide gauges to "prove" his point that ice won't melt in the future.  Anthony can be regarded as a sea level rise denier.

Once again, Anthony didn't even link to the press release, let alone the paper itself. So I will. The paper is by Dustin M. Schroeder, Donald D. Blankenship, Duncan A. Young, and Enrica Quartini. You can read the early release of the full paper at PNAS.

The front page of the paper has a text box describing the significance of the work.
Thwaites Glacier is one of the West Antarctica’s most prominent, rapidly evolving, and potentially unstable contributors to global sea level rise. Uncertainty in the amount and spatial pattern of geothermal flux and melting beneath this glacier is a major limitation in predicting its future behavior and sea level contribution. In this paper, a combination of radar sounding and subglacial water routing is used to show that large areas at the base of Thwaites Glacier are actively melting in response to geothermal flux consistent with rift-associated magma migration and volcanism. This supports the hypothesis that heterogeneous geothermal flux and local magmatic processes could be critical factors in determining the future behavior of the West Antarctic Ice Sheet.

Scientists have known that there are geothermal heat sources under the West Antarctic ice sheet. This research has pinpointed them and finds they are less homogenous and warmer than previously thought. From the press release as published at ScienceDaily.com:
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.
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 Earth's crust beneath the West Antarctic Ice Sheet.

The fact of geothermal fluxes in West Antarctica isn't a new discovery. For example, there's a 2004 paper by  Hermann Engelhardt on the subject. What is new in this paper is that it provides more insight into the spatial layout and the size of the geothermal flux. The scientists have deduced that it is not equally spread out and that in parts the flux is considerably higher than previously thought. All of which means more meltwater under the ice sheet, which is already fragile.


From the WUWT comments


Since I started this article, a few more comments have appeared (archived here), not all of which are related to the topic.


Marcos says the news apparently reported the science better than WUWT did, (although I don't know if the effects are additive or not) and says:
June 9, 2014 at 6:48 pm
The article I read about this paper (on Fox News I think) made it sound like things were extra bad because the geothermal heat was combining with the effects of CAGW to make the ice shelves collapse super fast…


Chris Marlowe says those scientists are just trying to scare him (the "scare" factor is one of the main things that cause deniers to deny - something to do with the amygdala) - excerpt only:
June 9, 2014 at 8:13 pm
This is definitely a useful contribution because it explains why the rate of movement of the Thwaites Glacier is faster than what would be expected if the base of the glacier were locked to the bedrock and the movement is the result only of shear within the glacier.
This study, combined with others, explains [the] rate of movement from purely natural causes and not from accelerated warming caused by man.. .
However, the article contains an unscientific alarmist statement:
“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.”
This statement is obviously calculated to inspire fear. It is unscientific because there is no time period, no indication if the rate of rise of sea level is faster or slower than now or in the past.

latecommer2014 wonders if warming can increase volcanic activity and says:
June 9, 2014 at 9:12 pm
Brings to mind chicken little. Does an increase in CO2 cause volcanic activity. If I can suggest it’s even worse than we could imagine can I get some grant money? ……..100K sounds about right. Does anyone know a good financial expert who can hide the money?

I don't know the answer to that one. However it's quite feasible that massive flooding in fragile areas or the rapid depletion of massive ice sheets or large water reservoirs would have an impact on the stability of the crust and maybe cause earthquakes. The filling of the Thomson Dam in Victoria caused earth tremors.


michaelwiseguy is another one who thinks/hopes that global warming is from a whole bunch of newly active undiscovered underwater volcanoes, presumably rather than the greenhouse effect, and says:
June 9, 2014 at 9:40 pm
A better question might be; To what extent is Earth’s liquid molten magma iron core heating the worlds oceans, and what is that contribution to climate change?


Caleb mistakes ice sheets for sea ice and says (excerpt from a long rant about scientists only in it for the money):
June 9, 2014 at 10:06 pm
Considering nine-tenth of an iceberg lies under water, and a tenth protrudes upwards, then, if the ice extends down 2 km to rock below sea level, 0.X km of the ice extending above sea level is due to expansion, and could melt, along with the ice beneath, without effecting sea level at all.
There. Even a member of the “general public” can understand that.
Of course, it isn’t so simple. Further study, funding, and trips to sunny Antarctica during dark northern winters are needed to determine if the ice flows the same speed at the surface as at the bottom, and at the middle as at the sides. If the top of the ice flows off leaving the bottom in place it might lift sea levels.
The “general public” can also understand that, especially the word “funding,” when it concerns their tax dollars in a time of economic hardship.
The “general public” is not as stupid as some here think. Call them “sheeple” if you will, but you cannot fool all of the people all of the time. Furthermore, once a minority produces definite evidence of dishonesty, awareness of the dishonesty spreads through the “general public,” and sometimes the awareness achieves a sort of critical mass and “goes viral,” (and this happened even before computers were invented.)...



Dustin M. Schroeder, Donald D. Blankenship, Duncan A. Young, and Enrica Quartini. "Evidence for elevated and spatially variable geothermal flux beneath the West Antarctic Ice Sheet." PNAS, June 9, 2014 DOI: 10.1073/pnas.1405184111

10 comments:

  1. Mmmh. Should I risk an immediate snipping and banning with a simple reminder on WUWT : geothermal flux do not appear overnight, or even in 50 years ? (well, except when a volcano erupts right under the ice, but that kind of events is not exactly what I would call "barely visible")

    Maybe I should invest in TOR just for this case.

    ReplyDelete
    Replies
    1. forgot this gem in the comment : "trip to sunny Antarctica during dark northen winters".
      Monthly mean at McMurdo in January is -3°C. With winds able to make equipment fly around. Such nice working conditions ....

      A**hole.

      Delete
    2. on second thoughts, I was unfair and wrong. If a dyke system is appearing right under the target, geothermal fluxes may change significantly in 50 years in most cases.

      I don't expect Mr Watts to enlighten me about that possibility, though.

      Delete
  2. Judith Curry also weighs in on this, and rather disappointingly implies that it's geothermal which is responsible, without pointing out that there's no evidence that geothermal is either very significant, or that it's changed with time.

    ”Climate models don’t simulate correctly the ocean heat transport and its variations, and they certainly don’t simulate geothermal heat sources”.

    http://judithcurry.com/2014/06/09/asymmetric-responses-of-arctic-and-antarctic/#comment-591690

    The numerology of the post before, though is really quite special. Even Judith's commentators find it hard to stomach, a very high bar indeed.

    Dumb:"I come to this avenue of research unencumbered by any formal education in climate science or meteorology... "

    ...and dumber "...Being unencumbered by such education means that I have a whole lot less to un-learn"

    http://judithcurry.com/2014/06/09/climate-data-and-financial-data-part-i/

    ReplyDelete
  3. latecommer2014 seems to believe $100k is a lot of money -- after overheads it would pay a student for a year, plus equipment and travel, with maybe a bit left over for summer funding.

    ReplyDelete
  4. Surprise, surprise, the first comment I've seen on the weather forum which I use was, "West Antarctic glacier being melted by magma not GW", proving some have slipped the net and escaped from WUWT.

    On another matter I've been doing some research on the global affects of the Tambora eruption and unfortunately came across an old article at WUWT by 'wandering ' Willie on the summer of 1816. I have to say it hasn't been my privilege to read so much garbage for many a year.

    ReplyDelete
  5. Hi Sou,

    You don't seem have mentioned the latest WUWT Arctic sea ice prediction post as yet, so this seems like a suitable icy repository. What's up with this recently "snipped" comment of mine?

    https://twitter.com/jim_hunt/statuses/476405196570886144

    ReplyDelete
  6. from the Judith Curry thread about the Antarctic glacier, from stefanthedenier :
    "CO2&H20 molecules NEVER go into the stratosphere!!! Troposphere is as far up as there is oxygen&nitrogen, which is up to 27km; CO2&H2O go up to 10km max, but most of them are at about 4-8km altitude (that’s why aircraft go higher, to avoid clouds"
    Wow. I ... wow.

    ReplyDelete
  7. The paper’s upshot is:
    We estimate a minimum average geothermal flux value of about 114 mW/m^2 with a notional uncertainty of about 10 mW/m^2 for the Thwaites Glacier catchment with areas exceeding 200 mW/m^2 (Fig. 3). These values are likely underestimates due to the low uni-form geothermal flux value used in the ice sheet model (9) and the compensating effect of enhanced vertical advection of cold shallow ice in high-melt areas….
    Alright, let’s do some basic physics. Let’s assume, for the sake of argument, geothermal flux of 200 mW/m^2 over the entire Thwaites catchment, and also that all of that heat goes into melting the overlying ice (as opposed to, say, heating it to the melting point). The Thwaites catchment has an area of ~189,000 km^2. Water ice has a heat of fusion of 333.55 kJ/kg. A 200 mW (=0.2 J/s) flux is 6.3 MJ/yr (0.2*3600*24*365). That flux will, thus, melt 18.9 kg of ice/yr. Since the flux is distributed over a m^2, the melt rate will be 18.9 kg/m^2/yr, or 3.6 Gt/yr for the entire catchment.

    The actual melt rate for the Thwaites, exclusive of calving, is ~70 Gt/yr (Depoorter et al, doi:10.1038/nature12567, http://www.staff.science.uu.nl/~lenae101/pubs/Depoorter2013.pdf , at Fig. 1).

    So, even assuming a geothermal flux almost 2x that in Schroeder, and that all of it melts ice, geothermal flux contributes, at most, 3.6/70=5.1% of Thwaites’s meltwater, and probably much less.

    - See more at: http://www.realclimate.org/index.php/archives/2014/06/unforced-variations-june-2014/comment-page-4/#comment-550983

    ReplyDelete
    Replies
    1. HINT the comment was from someones cat
      JB

      Delete

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