ice sheet collapse

This is a repost from

http://news.sciencemag.org/climate/2014/12/antarctic-ice-shelf-being-eaten-away-sea#comment-1739567369

only the discussion between John Reid and cONTRARIAN are included.

Antarctic ice shelf being eaten away by sea

By
Carolyn Gramling
4 December 2014 4:15 pm

 

John Reid • 8 days ago
Why are subaqueous volcanism and/or subglacial volcanism being ignored in this dicussion? See:

http://www.livescience.com/46194-volcanoes-melt-antarctic-glaciers.html

cONTRARIAN John Reid • 6 days ago

So what are you saying? It’s not climate change, it’s volcanoes?
“Why are… volcanism being ignored?”
1. Ocean warming and surface ice loss are greatly more significant factors.
2. Do the math: Volcanic heating estimated at 200MILLI watts per m2. That’s enough to melt 7 inches of ice in one year, or a mere 1/4 cubic km of ice if the extra heating covers an area of 500 square miles. (except I forgot to subtract out the 65mW/m2 everywhere else in the world)
3. They’re not being ignored. You just posted an article about it.
4. The article which you linked acknowledges the “hemorraging of ice” due to anthropogenic global warming.
5. There’s nothing anyone can do about this volcanism.

John Reid cONTRARIAN • 6 days ago

So you are saying that 1 Watt per square metre at the top of the atmosphere (e.g Trenberth) plays a major role in heating the deep ocean whereas heat fluxes as large as 10,000 Watts per square meter through the ocean floor (e.g. as observed at the TAG Hydrothermal Vent Field) can be ignored in the interests of keeping climate models smooth, deterministic and manageable. See

http://www. blackjay.net/pause-for-thought/index.html

You also appear to be saying that scientists should ignore those forcings which we can do nothing about.

cONTRARIAN John Reid • 5 days ago

You didn’t answer the question.
TYPICAL!
And really, linking to your own blog-posted amateur article? NOT a credible source. Got some glaring errors in there. (You like the word “stochastic” a lot. What’s with that??)
“Ice age temperature of -18C”. First, “-18C” that’s Greenland only. Second, that’s -18C relative to the reference value – a “temperature anomaly”, not relative to zero C.
Global temperature in the depths of the ice age was only -9C temperature anomaly, with the reference level being the current interglacial. Global average temperature today is 14C (that’s degrees above freezing). Subtract 1C to get to the Holocene average maybe, so 13C minus 9C, still above zero. It is IMPOSSIBLE that global average temperature was anywhere near -18C.

This is very basic and you got it nails-on-chalkboard wrong. You are WAY out of your element!

John Reid cONTRARIAN • 5 days ago

I had hoped my blog reference would provide a better understanding of the point I was trying to make. It appears that I failed.

cONTRARIAN John Reid • 5 hours ago

You haven’t really produced any evidence showing that these hidden volcanic sources are in fact significant. This is such “low hanging fruit” that I suspect it was considered long ago and thrown aside as immaterial.
S/scientists estimated the average energy output of the volcanism you mention under the Antarctic ice and my calculations show it’s impact is trivial. Skepticism isn’t just saying “I don’t believe it”. If you think this volcanism is significant, then prove it. Show us YOUR calculations. Show us YOUR energy estimates. Convince us!

John Reid cONTRARIAN • 16 minutes ago
In my original question I only asked why it had not been considered in the present article or discussion? Not exactly “low hanging fruit”, though. See:

http://www.livescience.com/46194-volcanoes-melt-antarctic-glaciers.html

Scientists use computer models to try to predict the future of the ice sheet, but their lack of understanding of subglacial geothermal energy has been a glaring gap in these models. Measuring geothermal activity under the ice sheet is so difficult that researchers usually just enter one, uniform estimate for the contributions of geothermal heat to melting, Schroeder said.

Of course, volcanism isn’t uniform. Geothermal hotspots no doubt influence melting more in some areas than in others.

“It’s the most complex thermal environment you might imagine,” study co-author Don Blankenship, a geophysicist at UT Austin, said in a statement. “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.”

It seems it is much easier to attribute ice-sheet melting to global warming and just leave it at that. Just about anything can be attributed to global warming it seems – heat waves, cold spells, droughts, floods, hurricanes. And now melting ice sheets.

  • The parentage of the “glaring gap” statement is unclear due to sloppy punctuation. I believe it is the author’s opinion, who is not qualified to make such a value judgement!

    To quote YOUR article “WEST ANTARCTICA IS ALSO HEMORRHAGING ICE DUE TO CLIMATE CHANGE”. Is this text invisible to you? YOUR OWN ARTICLE attributes ice-sheet melting to global warming YOU &$%@#, the very same article which you use to insinuate that it could really be volcanism.

    Skeptics are blind, they see only what they want to see.
    AGAIN, you fail to present any evidence that volcanism could possibly be accountable for more than a trivial amount of the 100s of cubic kilometers of ice being lost by global ice sheets every year.
    There are NO volcanoes in Greenland, NO geothermal hot spots that anyone is aware of and yet estimates of ice loss for Greenland are up to 375 cubic kilometers in 2014. That would require some MAJOR volcanic activity of which there is not a trace.

    You have doubts about Antarctica? Explain Greenland then!

    • The statement between <quote> and </quote> are statements by scientists quoted in the article in Live Science. In that article the “hemorrhaging ice due to climate change” statement was made by the journalist not by a scientist

      Regarding Greenland, just Google:

      “gakkel ridge volcanic activity”

      I should point out that such volcanoes do not necessarily melt any ice themselves. It could be more complex than that. They create deep ocean circulation so bringing warmer water to the surface. Water has maximum density at 4 degrees Celsius.

      Why are you so angry? Why do you write in capital letters as if you are shouting? Why do you use pejoratives like “insinuate”? All I did was suggest there might be another explanation and that the author of the article could have mentioned it. Rather than discuss this in the manner of a research scientist along the lines of – “that’s an interesting idea but what about … ” – you react as if your fundamental belief system is under attack. Are you trying to suppress heresy? You are not alone. Many people on blogs adopt a similar attitude. This is why I think to some people Science is more like a religion or an ideology.