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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.

Matt Ridley Comments

The Times recently ran an article by Matt Ridley:

(Published at 12:01AM, December 8 2014)

It began:

Environmental researchers are increasingly looking for evidence that fits their ideology, rather than seeking the truth

As somebody who has championed science all his career, carrying a lot of water for the profession against its critics on many issues, I am losing faith. Recent examples of bias and corruption in science are bad enough. What’s worse is the reluctance of scientific leaders to criticise the bad apples. Science as a philosophy is in good health; science as an institution increasingly stinks

Some of the comments ran as follows:

Mr D J Noble 1 day ago

Let us just review a few undisputed facts, not contested opinions, but verifiable facts.

1) Carbon dioxide is a greenhouse gas. That means it absorbs heat more easily than the oxygen and nitrogen that forms most of our atmosphere.

2) If the concentration of carbon dioxide increases more heat will be absorbed and less reflected into space, so the earth will warm up.

3) There has been a considerable increase in carbon dioxide concentration in the atmosphere over the last 200 years and particularly over the last 50 years.

4) Whatever other effects may be going this increase in concentration will result in the earth being warmer than it otherwise would be.

5) Human beings have been adding vast quantities of carbon dioxide to the atmosphere over the last 200 years and particularly over the last 50 years.

6) Whatever other effects may be going this human activity will increase the concentration to more than it otherwise would be.

It follows from these 6 facts that human activity is raising the temperature of the earth. There is no possible alternative. There can be discussions and disagreement about “How much”, and “How fast” and, of course, some measurements and forecasts may be inaccurate for this or that reason. But you cannot get away from the simple truth that human activity is causing the earth to be warmer than it otherwise would be.
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John Reid 20 hours ago

@Mr D J Noble I would dispute some of your “undisputed facts”, as follows:
1) agreed.
2) No, because the primary mechanism for the transport of heat through the lower atmosphere is convection not radiation. Surface heat is transported by convection into the stratosphere where it is radiated into space in accordance with the Stefan-Boltzman law.
3) True.
4) Not necessarily, see #2 above,
5) Not “vast” quantities – the total human production of CO2 since the beginning of the Industrial Revolution is abut 320 Gigatonnes (James Hansen’s congressional testimony) whereas the total CO2 in the ocean-atmosphere system is estimated to be 32,000 Gigatonnes (IPCC TAR). Hence humans are responsible for about one percent, a negligible proportion. Furthermore there is a continuous interchange between the oceans and the atmosphere. The present relatively high levels of CO2 in the atmosphere have more to do with the vagaries of ocean currents and upwellings than with human activity.
6) Technically true but unimportant – our contribution is “lost in the noise”.

In addition I would also like to point out that there is nothing at all remarkable about the climate of the last century.

For further discussion see http://www.blackjay.net/pause-for-thought/index.html

ATNT 16 hours ago

@John Reid @Mr D J Noble Correct me if I am wrong but I would like to dispute your disputes to the points above:

Point 2. Carbon dioxide is a greenhouse gas which means that infrared light from the sun can pass through it and heat up the earth’s surface however the heat that escapes the earth surface via convection is trapped in between the troposphere and the earths surface by greenhouse gasses – which in turn creates a positive feedback which gradually increases the temperature under the troposphere.

The majority of greenhouse gasses are made up of water vapour but as carbon dioxide is now at over 400 ppm (higher than anytime in measurable history (ice core measurements that are thousands of years old) there is a very strong argument that says that the addition of carbon dioxide to the atmosphere will contribute to changes in the earth’s climate.

I think this answers your retort to point 4 too. As to point 5, as briefly mentioned above, measurements from ice cores point to the fact that the highest historical (measurable) amounts of CO2 in the earths atmosphere prior to the 1870s was around 270 ppm. In 2013 there were 400 ppm up from 200 ppm in 1904. If this was to do with the vagaries of the ocean currents then we could have expected levels of up to 400 ppm in the past – that has not happened so we have to look elsewhere, and that leads us to burning fossil fuels and the man-made release of CO2 in to the atmosphere.

Point 6 – you say technically unimportant – this is where the argument rages, The question remains as to whether these changes will have any measurable effect to us and the earth is something that I am sure will be disputed for many many years.

My personal view is that there is a correlation between right wing political ideology and climate change doubt and left wing political ideology and Climate Change acceptance. In the past the right wing approach (which more often than not has worked and has been the correct approach) is to use market forces to lift a beleaguered nation out of debt, of save a company or what ever needs to be done to benefit society as a whole. It is an approach which is tenable, understandable and has a history of working, spend more, buy more, make more in order to get out of trouble. Up against the spectre of climate change where cut back is called for in almost every area there is a fairly typical and understandable push back from the established right wing politically minded. I am not saying that this small personal anecdote proves or disproves Climate Change I am just positing a hypothesis on why some people are apt to deny Climate Change and others are more willing to accept it.

John Reid
pending

@ATNT @John Reid @Mr D J Noble
Heat is not “trapped in between the tropopause and the earth’s surface”. The convective transport of heat from the surface to the stratosphere leads to the well known decrease of temperature with height known as the “adiabatic lapse rate” which is measured many times daily using radio-sond balloons. The lapse rate can be calculated theoretically from the thermodynamic properties of gases and the observed lapse rate fits rather well. If there were any trapping of heat as you suggest it would distort the lapse rate but this is not observed.

The 400 ppm of CO2 is a spot reading, an instantaneous value, whereas the proxy atmospheric concentrations of this and other gases in ice cores are effectively averaged over centuries due to the squeezing of ice under pressure. Averaging removes the highs and the lows. It is the dubious practice of plotting recent spot readings on the same graph as these much older averages which leads to the characteristic “hockey stick” curve. It is also possible that CO2 diffuses though ice. Other methods of estimating ancient CO2 concentrations, such as counting stomata density in fossil leaves, indicate that CO2 has indeed been as high in the past.

I certainly agree with you about the correlation between Left or Right vs Warmer or Sceptic but it does not apply in my case. I was a member of the Australian Labor Party for many years and once served on the State Executive. I also have a PhD in Upper Atmosphere Physics and a lifetime of research experience in various aspects of environmental physics. For me the physics of AGW just does not stack up for reasons I have outlined. I am saddened by the way in which this interesting branch of science has become corrupted by political ideology and by an “integrity deficit” within the scientific community as Matt Ridley points out.