Glaciers Cause Global Warming?

Guest post by David Middleton

Rice

Rice University

Torres, who joined the Rice faculty in July, is lead author of a paper in the Proceedings of the National Academy of Sciences. He wanted to know how and when chemicals released by weathering of the land reached the atmosphere and ocean, and what effect they have had.

The study shows that glaciation, through enhanced erosion, probably increased the rate of carbon dioxide released to the environment.

The researchers determined enhanced oxidation of pyrite, an iron sulfide also known as fool’s gold, most likely generated acidity that fed carbon dioxide into the oceans and altered the carbon cycle. The oscillation of glaciers over 10,000 years could have changed atmospheric carbon dioxide by 25 parts per million or more. While this is a significant percentage of the 400 parts per million measured in recent months, present anthropogenic carbon dioxide release is occurring at a much faster rate than it is naturally released by glaciation.

Over long timescales, they found, glaciers’ contribution to the release of carbon dioxide could have acted as a negative feedback loop that may have inhibited runaway glaciation.

[…]

The researchers acknowledged that glaciers are equal-opportunity weathering agents, as they also break down silicates in rocks. Silicates release alkalinity that removes carbon from the atmosphere. Still, they believe the net effect of glaciation could be to supply carbon dioxide to the atmosphere rather than to remove it.

The results support a couple of interesting additional theories. One is that billions of years ago in the Archean eon and Paleoproterozoic era, when the atmosphere contained little oxygen, Earth may indeed have been a “snowball” as oxidative weathering in glaciated regions and the subsequent release of carbon would have been less active.

Another is that the growth of a sulfide reservoir in Earth’s crust over time may have helped to stabilize the climate, which is important for maintaining Earth’s habitability over geologic timescales.

[…]

This looks like some very interesting research.  Unfortunately, the paper is behind the PNAS paywall.

The only problem is that glaciers have been the exception rather than the norm over the Phanerozoic Eon.  There’s very little evidence of significant glaciation outside of the Neogene-Upper Paleogene, Permo-Carboniferous and Ordovician periods.  There is also some evidence of ephemeral glaciation during the Late Jurassic to Early Cretaceous; which is the only “ice age” associated with a contemporary peak in atmospheric CO2.

phanerozoicco2vtemp

Featured image source: Rice University and Paul Quackenbush.

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53 thoughts on “Glaciers Cause Global Warming?

    • True.
      Also, as soon as the [distinguished?] professor attributed the warming as a result of the CO2 connection I knew it was pure BS.

    • So pyrite “most likely generated acidity that fed carbon dioxide into the oceans?” This may be a faux pas on behalf of the press release writer, but acidity does not lead to feeding CO2 into ocean waters. Just the opposite.CO2 is less soluble in acidic waters.

  1. Mr. Torres may be onto something; last night, I made a mixed drink with about 8 ice cubes – after about 3 minutes, the liquid seemed to be getting hotter instead of colder.
    Also, I’ve had picnics and the guests always complained that the ice in the coolers never seemed to cool the cans/bottles.
    I now understand that ‘snowball earth’ was the primary source to create our nice climate of today.

    • I’ve had picnics and the guests always complained that the ice in the coolers never seemed to cool the cans/bottles.

      I had that very same problem myself. It turned out that the trouble was from the Pemanent, Everlast ice cubes I bought from a traveling salesman, which were made of Styrofoam. While it is true that the Everlast Ice Cubes last a good long time, they did not work very well.
      Eventually, one guest suggested that I put water in the freezer until it turns solid, and use that instead. As it turns out, that actually worked pretty well.

      • Removing the insulating air from the cooler will make either type of ice cube much more efficient at cooling the cans/bottles. Procedure: stock cooler with cans/bottles, pack in the ice cubes, and then pour in enough water to just cover the cans/bottles. The water will transfer the cold from the cubes into the beverages about 30 times faster than the cubes alone. Five minutes in the ice & water mixture is equivalent to hours in the ice & air configuration. Once again, convection rules over radiation in our local environment.

  2. I think it is unfortunate otherwise interesting studies are contaminated by the CO2 is all concept. In another era maybe that scientist might have looked for another theory and made a finding.

    • Bingo!

      Climate scientists have CO2 syndrome or the grant awarding orgaizations do – take your pick.

    • I would love to know how he separates the effects of glaciation from the effects of mountain building. There was a study years ago that attributed large fluctuations in atmospheric CO2 to mountain building exposing huge amounts of rock that then absorbed CO2 during subsequent weathering.

      Of course, none of this changed the climate in the first place, but it is interesting where things go.

      • Well the floating Arctic Sea Ice is not exactly glaciation; and it apparently is disappearing rapidly.
        So if it all melts as a result of all the heat conveyed up there by the gulf stream and its clones, it would of course lower the sea level since (virtually) all of the latent heat required to melt the ice must come from the sea water under which 9/10 or 10/11 of the ice mass resides and salt water has a positive Temperature coefficient of expansion all the way down to its freezing point.

        So what if ALL of the arctic ocean floating sea ice melted, leaving open water.

        The water surface would be much warmer than the subzero former ice surface was, and water is a quite good near BB thermal radiator of LWIR radiation peaking somewhere around 10 micron wavelength.

        So we would have an Arctic ocean sans ice, which would be a much higher efficiency thermal radiator than is the way sub zero (maybe 50 below) ice that is presently there.

        Now the Antarctic highlands ice sheets aren’t about to melt, so they would continue to be a pitiful contributor to the cooling of planet earth, but the Arctic would surely do a better job.

        Yes I know that an open ocean surface would absorb a greater amount of solar energy during the arctic daytime; but there isn’t much of that anyway; unless you have some other explanation for why the heck all of that ice is there in the first place.

        Yes I’m assuming that ocean might all melt, but all the freshwater ice won’t fall out of the Greenland Ice bowl..

        G

    • The study shows that glaciation, through enhanced erosion, probably increased the rate of carbon dioxide released to the environment.

      The central assumption is that CO2 is the control knob. That’s when I quit reading. The whole thing is built on a false assumption.

    • Glaciation, through enhanced erosion put more iron in the oceans, which spurred phytoplankton growth.

      This sequesters CO2 in the deep ocean and leads to increased cloud cover. Phytoplankton produce cloud condensation nuclei.

  3. What evidence is there that an increase of 25 PPM of co2 would have any significant effect on temperatures even if the the study is accurate, which seems very unlikely.

    • Not only that, but that’s 25 PPM over millions and millions of years. How would the signal from weathered rock be evident from the background signal of either internal natural variability?

    • You can also just paste any DOI into sci-hub.cc and as long as someone has provided the key to the paper already, it magically opens. Nice to have the freedom to academic papers (i.e. knowledge) without having to always pay for it.

  4. Someday, climate scientists will be paid to look for something else besides CO2 to explain climate change. When that happens, they will probably find the things that really are important to global climate. Until then, they will be just like the alchemists who were paid to find a chemical way to change lead into gold. They may find some interesting things along the way, but they will never find that CO2 is the primary driver of climate.

  5. As I have previously mentioned before – the warmist will show a photo of a glacier from the late 1880’s through the 1920;s along side a current photo with the intention of implying that the glacial melt has been very recent.
    Rarely do the warmist show a series of photos (by decade) which show that a significant amount of the glacier melt occurred in the 1920/1930/1940 time period vs the impression that most of the melt occurred in the last few decades.

  6. Here’s the abstract:

    Connections between glaciation, chemical weathering, and the global
    carbon cycle could steer the evolution of global climate over geologic
    time, but even the directionality of feedbacks in this system remain to
    be resolved.
    Here, we assemble a compilation of hydrochemical data
    from glacierized catchments, use this data to evaluate the dominant
    chemical reactions associated with glacial weathering, and explore the
    implications for long-term geochemical cycles. Weathering yields from
    catchments in our compilation are higher than the global average,
    which results, in part, from higher runoff in glaciated catchments.
    Our analysis supports the theory that glacial weathering is characterized
    predominantly by weathering of trace sulfide and carbonate minerals.
    To evaluate the effects of glacial weathering on atmospheric
    pCO2, we use a solute mixing model to predict the ratio of alkalinity
    to dissolved inorganic carbon (DIC) generated by weathering reactions.
    Compared with nonglacial weathering, glacial weathering is more
    likely to yield alkalinity/DIC ratios less than 1, suggesting that enhanced
    sulfide oxidation as a result of glaciation may act as a source of CO2 to
    the atmosphere. Back-of-the-envelope calculations indicate that oxidative
    fluxes could change ocean–atmosphere CO2 equilibrium by 25 ppm
    or more over 10 ky. Over longer timescales, CO2 release could act as a
    negative feedback, limiting progress of glaciation, dependent on lithology
    and the concentration of atmospheric O2. Future work on glaciation–weathering–carbon
    cycle feedbacks should consider weathering
    of trace sulfide minerals in addition to silicate minerals

    The problems I see with this is that (a) there’s an assumption that glacial weathering was over a significant enough land mass to impact global pCO2 levels, (b) they rely on a solute mixing model, and (c) a scientific journal submission actually headlines it’s talking point with the words “back-of-the-envelope calculations”. If the public is losing its trust in science and the scientific process, it’s because of garbage like this making into the news.

    • Just quickly looking at this study is says increased rock weathering from sulfuric acid increase sodium, and calcium levels. When these levels increase more carbonates from in the ocean. Which he equates to increased CO2 levels. It appears he is saying more carbonates in the ocean means higher CO2 levels

      The problem is that carbonates don’t release CO2 levels. In fact the formation of charbonaes pulls CO2 out of the air they do the opposite.

  7. Ummmm… No. The headline starts off by saying, “Glaciers …warm…” but the paper talks about the rate of release of carbon dioxide into the atmosphere. Current evidence is the level of atmospheric CO2 has little, if any, effect on global temperature, and in fact a rise in temperature precedes a rise in CO2. i.e., temperature controls CO2 levels, not vice versa. So the headline is just plain wrong. Is the paper still worth something? Could be, we can’t tell.

    • Well they have done some back of the envelope calculations and hypothesised even the directionality of feedbacks in this system remain to be resolved so clearly the paper is worth something- i.e. we can instantly tell more grants are needed. Don’t you understand how this sciencey climate stuff works?

  8. characterized predominantly by weathering of trace sulfide and carbonate minerals

    Their hypothesis asserts that trace amounts of sulfides will weather into acid and acidify the world’s oceans to such an extent that the oceans will outgas CO2.

    I wonder if they know that trace anything is not going to have that effect. The oceans are buffered, after all.
    *sigh*

    • TonyL,

      I think you misunderstand. The premise is that the mechanical weathering of glaciation (comminution) increases the surface area and promotes oxidation of sulfides, which produces sulfuric acid, which in turn will release CO2 from carbonates such as limestone. This is one aspect of chemical weathering. One problem, though, is that while the glacial till is entrained, it is pretty much isolated from oxygen, and kept at a low temperature. It is only after the glaciers recede and expose the till that the trace pyrite/marcasite can oxidize and be dissolved in liquid water. Thus, the warming would seem to have to precede the release of CO2. Also, as to the efficacy, silicates are pretty much ubiquitous, where as carbonates may be very localized, and the sulfides even more so. At least in North America, the glaciated Canadian Shield is predominantly silicates. So, this does seem to be yet another study with a solution in search of a problem.

      • Ah, I see, now.
        Yet, now we need sulfur bearing minerals in some proximity to carbonate minerals. As the origins of these two types are very different, it does seem rather unlikely.

      • TonyL,
        Heavy metal sulfides, such as are usually ore minerals, usually occur in or in proximity to silicate intrusives such as ‘granite.’ On the other hand, pyrite and marcasite are fairly common in shale, limestone, and coal, where the organic materials provide sulfur to create the sulfides. However, even if the sulfides are not in close proximity to carbonates, once the iron sulfate is dissolved in water, the water can easily travel long distances before encountering and dissolving the carbonates and releasing CO2.

      • @ Clyde

        On the other hand, pyrite and marcasite are fairly common in shale, limestone, and coal

        I did not know that.
        Thanks for the clarifications.

      • My understanding is rock is mostly Si,Ca,Mg,Na, and oxygen all melted together in the form of a mixed metal oxide. There is very little carbon in it and no carbonates in it.. When sulfuric acid comes in contact with it a reaction occurs that converts the rock to silicon dioxide, some Ca, Mg, and Na sulfates with some Ca, Mg, and Na oxides. These oxides quickly react with air to form Ca, Mg, Na carbonates. In short the weathering of rock with sulfuric acid pulls CO2 out of the air.

      • These guys pull weathering out of their hindquarters of whichever sign suits their current need. What caused the Cenozoic temperature decline? Budofcourrsse, silicate weathering of the Himilayas. Never mind the Tethys carbonates. Never mind the stupendous MOR volcanism to hurl India.

        What busted the planet out of the mythical snowball earth? Volcanism, never mind the weathering.

  9. I’ve noticed that when the global warming supporters hear or read the word “weathering”, they automatically go into an hypnotic state and will believe anything said or written afterward.

    But weathering contributes just 0.05 billion tons to the 240.00 billion tons per year Carbon Cycle. As in meaningless to even count it at all. 0.02%.

  10. Why make it so complicated.
    Glaciers grind up rock, it washes out at the bottom of them where they melt and the ground up stuff is pure Ambrosia for plant life.

    It is ‘Processed Food’ and just like any other life-form we know, they lap it all up. Hey look in the mirror, that critter loves processed food and it’s lying through its teeth if it says ‘no it doesn’t’

    In doing so, the plants suck CO2 (an atmospheric coolant) out of the air, the air becomes a better heat insulator than it was, heat stored in the oceans cab thus travel further inland and the places warms up. Simple.

    The feedback is reinforced due the the water retentive properties of the live plants and also the resulting dead ones buried in the dirt. (Sorry Warmists and other muddle-heads, still NOT positive feedback, it’s just the volume control of a negative feedback amplifier being tweaked)
    The extra water, due to its epic heat properties, (there really is NOTHING comes close of water) moderates the weather and by some magic means, turns into climate.
    BTW, what is today’s Climate Average Number/result/value. We are supposed to be at the very height of England’s summer here and it’s pouring rain and quite/very chilly at night. That must put a dent into ‘The Climate

    No radiation, no Planck, no Tyndall, no Boltzmann, no microwave ovens in the sky, no downwelling guff, no cosmic rays, no clouds keeping you warm (just how crazy is that?), no Milankovich.

    Just a few weeds, a bit of ground up rock and elementary-school physics.

    There will be some ‘ground up rock’ when all the Castles in the Sky built around this climate thing come crashing down – mind your heads.
    ha ha

    • Peta from Cumbria, now Newark

      Damn, at last, science I can understand!

      I can’t read a graph to help myself, but plain common sense like this is what we ignorant sods need to understand what’s going on.

      Brilliant Peta, thanks for that, more please.

  11. The main problem with this paper is that it is based completely on the solute weathering cycle in (interglacial) rivers, but glacial erosion very largely delivers the erosion products as IRD (ice-rafted debris) directly to the oceans with a very different chemistry. This is particularly true during glaciations.

  12. I just finished reading the original article. The ‘Significance Box’ has the statement, ” We show that this effect COULD contribute to changes in CO2 during glacial cycles of the past million years.” Geologists are famous for hand waving when waxing eloquent about past events that no one was around to witness. I’d be happier if even some “back of envelope” calculations were presented to show just what the magnitude of the changes to CO2 were.

    The authors state, ” Here, we assemble an expanded compilation of glacial weathering data and use this compilation to identify characteristic features of PRESENT-DAY glacial weathering, including the relative roles of sulfide-carbonate vs. silicate mineral weathering compared with rivers not dominated by glacial processes.” Lest one overlook the obvious, they are looking at the chemical characteristics of alpine glaciation runoff POST continental glaciation! That is, they may be making a case that glaciation may enhance CO2 production after the peak of glaciation; however, it is not a compelling case that during the maximum glaciation the same conditions prevailed!

    They claim, “Higher dissolved ion yields and higher SO4:Na and Ca:Na ratios together suggest that sulfide and carbonate dissolution rates are enhanced in association with [past!] glacial weathering.” After glaciers have pulverized the rocks, released them to the atmosphere in a warmed environment, and provided water to disperse the sulfates [H2SO4], CO2 production may be increased over that which would have occurred without glaciation. But, nowhere do I find a compelling argument that the process contributed to global warming and the demise of the glaciers.

    Personally, I’d be a little embarrassed to hinge a speculation on correlation coefficients of ~>0.2 to ~10^5 y.” It should be evident that while the rock flour and other particles with high surface-to-volume ratios are entrained in ice, there is little opportunity for direct oxidation or microbial oxidation. During the advancing and stagnant phases of continental glaciation, there is little till or outwash exposed. It is primarily in the waning, declining phase that the terminal and ground moraines are exposed to oxygen and microbial attack. Thus, it would seem to me that we are seeing yet another example of how warming after glaciation increases the release of CO2 into the atmosphere.

    • WordPress seems to have corrupted what I wrote. The last paragraph should read as follows:

      Personally, I’d be a little embarrassed to hinge a speculation on correlation coefficients of ~>0.2 to ~10^5 y.”

      It should be evident that while the rock flour and other particles with high surface-to-volume ratios are entrained in ice, there is little opportunity for direct oxidation or microbial oxidation. During the advancing and stagnant phases of continental glaciation, there is little till or outwash exposed. It is primarily in the waning, declining phase that the terminal and ground moraines are exposed to oxygen and microbial attack. Thus, it would seem to me that we are seeing yet another example of how warming after glaciation increases the release of CO2 into the atmosphere.

  13. I give up! WordPress has again truncated the end of the second paragraph and deleted a direct quote from the paper that should have been immediately before that new last paragraph. Basically, they acknowledge that my position is a working hypotheses, but that the process could not last more than 10^5 years.

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