Study claims: Ancient tectonic activity was trigger for ice ages

From the MASSACHUSETTS INSTITUTE OF TECHNOLOGY and the “thank goodness we have plenty of free CO2 in the atmosphere today” department comes this claim:

Continental shifting may have acted as a natural mechanism for extreme carbon sequestration

ice-age-scene

Ice ages may be related to tectonic carbon sequestration

For hundreds of millions of years, Earth’s climate has remained on a fairly even keel, with some dramatic exceptions: Around 80 million years ago, the planet’s temperature plummeted, along with carbon dioxide levels in the atmosphere. The Earth eventually recovered, only to swing back into the present-day ice age 50 million years ago.

Now geologists at MIT have identified the likely cause of both ice ages, as well as a natural mechanism for carbon sequestration. Just prior to both periods, massive tectonic collisions took place near the Earth’s equator — a tropical zone where rocks undergo heavy weathering due to frequent rain and other environmental conditions. This weathering involves chemical reactions that absorb a large amount of carbon dioxide from the atmosphere. The dramatic drawdown of carbon dioxide cooled the atmosphere, the new study suggests, and set the planet up for two ice ages, 80 million and 50 million years ago.

“Everybody agrees that on geological timescales over hundreds of millions of years, tectonics control the climate, but we didn’t know how to connect this,” says Oliver Jagoutz, associate professor of Earth, Atmospheric and Planetary Sciences (EAPS) at MIT. “I think we’re the first ones to really link large-scale tectonic events to climate change.”

Jagoutz and his colleagues, EAPS Professor Leigh Royden, and Francis McDonald of Harvard University, have published their findings in the Proceedings of the National Academy of Sciences.

Putting the squeeze on

The two tectonic collisions that the team studied stemmed from the same event: the slow northward migration of Gondwana, a supercontinent that spanned the Southern Hemisphere from 300 million to 180 million years ago and eventually broke up to form Antarctica, South America, Africa, India, and Australia.

Around 180 million years ago, tectonic activity began to push fragments of Gondwana up toward the northern supercontinent of Eurasia, which slowly squeezed and eventually closed the Neo-Tethys Ocean, an ancient body of water lying between the supercontinents.

In previous work, Jagoutz and his colleagues developed a model to simulate the tectonic shifting that occurred in and around that ocean as Gondwana fragments were crushed against Eurasia. Through analysis of ancient rocks in today’s Himalayas, the team determined a sequence of events as the continents merged.

They found that 90 million years ago, the northeastern edge of the African plate collided and slid under an oceanic plate in the Neo-Tethys Ocean, creating a chain of volcanoes. At 80 million years ago, as Africa continued advancing north, the oceanic plate was pushed further up and over the continent, exposing ocean rock to the atmosphere, while simultaneously terminating the volcanoes. Then, 50 million years ago, India merged with Eurasia in a second collision in which a different region of the oceanic plate was pushed up onto that continent.

Both collisions took place in the Intertropical Convergence Zone (ITCZ), an atmospheric region hovering over the Earth’s equator, in which trade winds come together to generate a region of intense temperatures and rainfall.

A weathering trigger

For this new paper, the researchers wondered whether the tectonic collisions in this extremely tropical region may have played a part in pulling huge amounts of carbon dioxide out of the atmosphere and triggering the ice ages.

Certain types of rock, if exposed to high heat and heavy rain, undergo chemical reactions and effectively absorb carbon dioxide, a process known as silicate weathering. These rocks include basalts and “ultramafic” rocks, which are often found within oceanic plates. If these rocks are exposed to the atmosphere in a tropical region, they can act as very efficient carbon sinks.

The team hypothesized that the two collisions, involving Africa and then India, brought basaltic and ultramafic rocks up from the oceans and onto land, creating carbon sinks 80 and 50 million years ago. Both collisions also effectively turned off carbon sources by burying volcanoes that had been emitting carbon dioxide and other gases into the atmosphere.

To know whether such a sequence of events directly reduced carbon dioxide in the atmosphere, the researchers looked to weathering rates of different rock types, including granites, basalts, and ultramafics. These rates, which have been calculated by other researchers, describe the way rocks erode and take up carbon dioxide, given exposure to a certain amount of rainfall.

They then applied these weathering rates to their model’s estimates of the amount of oceanic plate that was pushed up onto Africa and India, at 80 and 50 million years ago, respectively. After determining the amount of carbon dioxide sequestered by these rocks, they calculated the total amount of atmospheric carbon dioxide through time, from 100 million years ago to around 40 million years ago.

The team found that carbon dioxide dipped dramatically at precisely the time the two collisions occurred. The levels of carbon dioxide also mirrored the temperature of the oceans during this interval.

Jagoutz says one reason these two collisions had such an extreme effect on atmospheric carbon dioxide may have been the fact that each continent continued moving north, exposing new basaltic and ultramafic material, “like a bulldozer that brings fresh rock to the surface.”

Interestingly, a similar process is taking place today, albeit at a smaller scale, near the island of Java. The same tectonic activity that shifted Gondwana northward more than 100 million years ago is today pushing the Australian plate north, and as a result, is piling up basaltic material on Java within the ITCZ, which Jagoutz says is “a huge carbon sink.”

“What nature shows us is, if you put a lot of these rocks in the tropics, where it’s hot, muggy, wet, and rains every day, and you also have the effect of removing the soil constantly by tectonics and thus exposing fresh rocks, then you have an excellent trigger for ice ages,” Jagoutz says. “But the question is whether that is a mechanism that works on the timescale that is relevant for us.”

###

Additional background

ARCHIVE: India drift

ARCHIVE: Newly discovered flux in the Earth may solve missing-mantle mystery

ARCHIVE: India joined with Asia 10 million years later than previously thought

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107 thoughts on “Study claims: Ancient tectonic activity was trigger for ice ages

  1. Or did the Sun’s activity trigger the earthquakes during a solar minimum that pushed things into an ice age?

    Sort of like what is going on right now.

    • It’s also possible that lowering temperatures caused the oceans to absorb more CO2.
      (Or is it now CP2, I’m so confused.)

      • So, more CP/CO2/Plant Food in the ocean made the water heavier and pushed the continental plates?

        Got it. I think.

      • It is also likely that the tectonic activity and subsequent Volcanic Activity dumped particulate material into the upper atmosphere over the course of the 10 million year period from the beginning of the African Plate striking and slipping under the Neo-Tethys Oceanic plate 90 million years ago to the end of the volcanism period 80 million years ago.
        Think of Mt. Tambora and the year without a winter on a scale of about 100 Tambora Volcanos simultaneously erupting for 10 million years. This would cause the oceans to cool and we all know that colder water absorbs and holds more CO2.

        Same mechanism would occur when the India Plate struck the Asian Plate and formed the Himalayas

      • Holy F**k this is bad! I suppose when your null hypothesis (actually null conclusion) is that CO2 is the control knob, then this is the warped mutant-science result.

        1st, the current ice age started 30 million years ago, not 50.
        2nd, what ice age 80 million years ago? 80 million years ago happened to be one of the hottest periods in Earth history.
        3rd ““Everybody agrees that on geological timescales over hundreds of millions of years, tectonics control the climate, but we didn’t know how to connect this,”
        Uh, no, we have had theories on how to connect tectonic cycles to climate for awhile. The continental arrangement on Earth dictates ocean and atmospheric currents. The closing of the Isthmus of Panama seperated the Atlantic and Pacific basins, highly altering ocean circulation and heat distribution, then the ice age began as Antarctica became glaciated. The overall volcanic activity on Earth (especially at the mid-ocean ridges) shows very strong correlation to marine chemistry and global climate.

        http://scholar.princeton.edu/sites/default/files/styles/os_files_xxlarge/public/agothman/files/thesis_secularvariationsfig.png?itok=OEf91-Py

        4th, When your study looks at just two variables in a very complex system, ignoring everything else, and you find an exact fit with the two variables and the data you were trying to fit it to, then you should probably ask why did all other events taking place at the time (Laramide Orogeny, Andes Orogeny, closing of an entire ocean basin, etc.) not show up in the data. Well how about those Deccan Traps that revisionist scientists are trying to blame as the culpret behind the last global extinction? That was an enormous volume of mafic basalt being exposed to the atmosphere, yet it occurred directly between the periods they claim that CO2 drop occurred precisely as mafic basalt was exposed.

        Here is a simple and more plausible explanation based on science that I know all of you here already know, decreasing temperature of the atmosphere caused more CO2 to dissolve into the oceans.

      • Furthermore, if exposing oceanic basalt to the atmosphere is the first order control on ice age/hot age conditions on Earth, then why did CO2 continue to fall after the Indian Plate collision slowed considerably and less basalt was being exposed? It must have been a ‘tipping point’.

      • *And that should be…decreasing temperature of the OCEAN caused more CO2 to dissolve into it.

      • I agree with RWTurner.
        This is really bad when they claim 80 Mya ice ages in the Cretaceous and T-Rex was just getting going and eating everything in sight in the Earths hothouse jungles.

      • I can’t be certain, but they seem to have confounded “ice age” and the odd, very long span “Ice house/Hot house” or “Ice House/Greenhouse” patterns. The former are the patterns of periodic glacial advance and retreat such as we note in the Pleistocene – the “Ice Age.” The latter is a much longer term pattern in which during “ice house” periods there is evidence of glaciation (scoured rock surfaces, moraines or sedimentary rock from moraine material, and isolated rocks in marine formation dropped by melting ice bergs. The Ice House/Hot House pattern is a climatic pattern of shifts at intervals of tens to hundreds of millions of years. There have only been six – three of each – in the entire Phanerozoic and the present falls within a current Ice House state, which apparently began roughly around the time of the terminal Cretaceous – though
        Wikipedia implies that it began about 30 MYA. Greenhouse periods LACK geological evidence of terrestrial or marine ice. More recent discussions suggest or assert a correlation between low atmospheric carbon and Ice States, but aside from the terminal Permian no other period matches the present. Such sites also often indicate a much smaller number Ice House states. One of the realities of the pattern, regardless of – ah – political views is that the majority of the planet’s climate history is considerably warmer than the present, and another is that extinction events are followed by recovery of atmospheric carbon. The clear conclusion is that living biomass, over geological time spans fixes carbon faster than natural sources can replenish it. At least one extinction, that of the Permian, may very well have due to low atmospheric carbon..

      • Forgot to say that an Ice House state does not preclude intervals of extremely hot climate. The early Eocene by some measures, which was extremely warm, falls within an Ice House period. A good deal of more recent geological literature that addresses climate events seems to be arguing for more numerous Greenhouse and Icehouse intervals, but critics point to an extreme reliance on computer models to support more frequent changes. Observation geology does not support them and they are often in direct conflict with empirical evidence. It is probably clear that I prefer the empirical evidence of actual ice action over an emphasis on modeled arguments.

    • How do you ” identify a likely cause ” ??

      Seems to me, that you have either identified a cause or you haven’t.

      If you have identified it, then it isn’t a likely cause, it is a cause.

      Making a list of possible causes is NOT identifying a cause, likely of not.

      G

    • Why is everything in climate ‘dramatic’ or ‘massive’, and why does everything ‘plummet ‘

      My idea of plummet, is falling 2,000 meters off the north face of the Eiger. That is a plummet, not a ten deg. C drop in Temperature !

      These writers must lead awfully boring lives if every little happenstance scares the BG’s out of them.

      ” Wherefore art thou? Romeo” That’s dramatic; unless it’s “Wherefore art thou, Romeo ?”

      G

      • “Why is everything in climate ‘dramatic’ or ‘massive’, and why does everything ‘plummet ‘”

        To get attention.

        “My idea of plummet, is falling 2,000 meters off the north face of the Eiger.”

        Wrong. That should be “”My idea of plummet is falling 2,000 meters off the north face of the Eiger.” No comma after the subject.

        “These writers must lead awfully boring lives if every little happenstance scares the BG’s out of them.”

        Well, yes.

        ” Wherefore art thou? Romeo” That’s dramatic; unless it’s “Wherefore art thou, Romeo ?”

        Neither of them is dramatic. They just don’t make sense. Juliet is asking why he is called Romeo, not why he exists.

  2. What is CP2 ??

    ” From the MASSACHUSETTS INSTITUTE OF TECHNOLOGY and the “thank goodness we have plenty of free CP2 in the atmosphere today” department comes this claim:”

  3. What about all the basalt left by volcanoes? I would think the lava would cover far more area than that revealed by continental drift. Not that I buy their ‘it’s all CO2’.

  4. And this explains the 100,000 year cycling of glacial periods? I think not. Seems like a lame attempt to blame CO2. From what I recall seeing, the CO2 typically remains high for thousands of years at the end of each of the last several interglacial warm periods while global temperature is dropping rapidly. It looks more like cooling ocean temperatures reduced the CO2. This study is just more CO2 nonsense and a poor excuse for science targeted at getting more funding.

    • I have to agree. Shifting ocean currents due to continent placement explain some of the major climate shifts. However, this presupposes CO2 is to blame for everything.

      • Yep. CO2 is all-powerful and all-mighty. Here in the UK, we’re seeing that Brexit is also all-powerful, and will cause terrible things, like tornadoes and heatwaves. Every child will be born without hair, and animals will commit suicide…if we leave the EU. It’s amazing what CO2 and Brexit can do.

      • Don’t have the references handy, but the Panama Gap between N and S America closed about 2 million years ago. That coincides with the beginnings of the current iceage. The closing would have interrupted an equatorial current carrying heat from the tropics and turned it into the Gulf Stream. The closure also interrupted heat flow across the Pacific and set up a much more complicated ocean circulation with loops in the Pacific and the Atlantic interacting south of India and transmitting more heat into the Antarctic circulation. Having two large ocean basins with partially connecting currents makes possible multiple oscillations in both circulation and heat flow.

      • Phil, that fits with what I learned on PBS before global warming was a thing–that continental drift changes ocean currents, leading to atmospheric changes. The latest being the interruption caused by the connection of South to North America.

        The only part of this that is new is the CO2 connection, which, for obvious reasons, I am dubious of.

      • benofhouston —

        CO2 causes climate change and can bring both hot and cold weather. Certainly it is not much of an extension to claim it can fry all life on earth and create ice ages? It is really just a question of “degrees” (pun)

        Eugene WR Gallun

      • Reply to Phil Cartier,

        The consensus had been that the Panama isthmus fully closed by arounf 3 Mya.

        However a more recent Science paper where a group studied sediments from ancient river beds found strong evidence the Isthmus closed as much as 10 Mya.


        Middle Miocene closure of the Central American Seaway

        C. Montes1,*, A. Cardona2, C. Jaramillo3, A. Pardo4, J. C. Silva5, V. Valencia6, C. Ayala7, L. C. Pérez-Angel1, L. A. Rodriguez-Parra1, V. Ramirez8, H. Niño8
        Science 10 Apr 2015:
        Vol. 348, Issue 6231, pp. 226-229
        DOI: 10.1126/science.aaa2815

        ” The Central American Seaway, which once separated the Panama Arc from South America, may have closed 10 million years earlier than is believed. Montes et al. report that certain minerals of Panamanian provenance began to appear in South America during the Middle Miocene, 15 to 13 million years ago (see the Perspective by Hoorn and Flantua). The presence of the minerals indicates that rivers were flowing from the Panama Arc into the shallow marine basins of northern South America. One interpretation of this finding is that large-scale ocean flow between the Atlantic and Pacific had ended by then. If this is true, then many models of paleo-ocean circulation and biotic exchange between the Americas need to be reconsidered.”
        http://science.sciencemag.org/content/348/6231/226

        The 3 Mya closure hypothesis was liked because it seemed to coincide with the onset of the glacial cycles we are now in; that is, the drastic ocean circulation and atmosphere coupling was greatly altered coupled with Milankovitch started NH glaciations.

        With a 13 Mya isthmus closure, who knows? Pure Speculation. Orbital and planetary shifts? 10 Mya and before was also a time when Mars was tilting its obliquity by 40deg (or so) every 5-10 My. Were the planets doing something we don’t know? We don’t know.

      • Michael, I do believe that tectonics play a major role over very long time periods through forcing changes in distribution of albedo at different latitudes relative to sun angle and through modification of ocean currents, but not through modulation of CO2 levels and related radiative forcing effects. I am puzzled about their reported ice ages at 80 and 50 million years ago, because all the paleoclimate reconstructions I have found show these as relatively warm periods compared to our current ice age that started with the Pleistocene about 2.6 million years ago.

    • oz4caster “And this explains the 100,000 year cycling of glacial periods?.”

      For decades now I’ve often wondered what geological change initiated the quasi-cyclic ice ages every 80,000 to 120,000 years over the last approximate 1M+ years. It must have been “big” geologically. I considered what could have caused this and have since concluded that the widening of the Atlantic Ocean with the creation of the Gulf Stream circulation might be the initiating mechanism. An important “pump” for the Gulf Stream would be the higher density cold fresh water melt from the Arctic region. (The significantly lower temperature of this fresh water–cooled further by evaporation in pools of fresh water melt at the surface over the salt water through which it sinks–explains it’s higher density.) Once this pump becomes less effective, due perhaps to reduction in the available ice melt as the temperature warms and melts the North polar region, the Gulf Stream reduces and may shut off and stay off as the resulting colder Arctic reduces ice melt further. This initiates a cycle of bowl shaped Ice Ages separated by warmer interregnums such as the one we are in now as follows.

      As the ice age progresses with the absence of the Gulf Stream, the Southern extent of the Northern ice sheets reach into what is now the United States, and similar latitudes in Europe and Asia. But it’s warmer down here, and the melting rate of the ice sheet increases in these more Southern latitudes cranking up the Gulf stream again. The renewed Gulf Stream increases the melt rate of the Northern ice sheets causing their slow retreat. This process continues to be driven by the renewed Gulf Stream until a new interregnum is reached.

      The question remaining is, “What effect does CO2 have on this process IF ANY?”

      • The most likely candidate for this change is the joining of the American Continents, which broke up the east-west oceanic flow and creating two separate circulation currents. The timing’s about right and the result, two strongly varying oscillations, could go in and out of sync, resulting in large fluctuations

      • Dan Harrison, I like the hypothesis that ralfellis discusses in the link he posted: that the consistently rapid end of the recent glacial periods is likely caused by increasingly massive dust storms induced by the drier climate associated with colder oceans, but also by lack of adequate CO2 for vegetation which expands the deserts even more. So, it does appear that CO2 has an effect at least for ending the glacial periods, but mainly through it’s effect on vegetative health and not from any possible minor radiative forcing effects. I’m not sure we have a very good handle on how the interglacial warm periods end, which is a lot more inconsistent than how they begin. This is where it would be useful to have GCMs that really are accurate, unlike the ones we have now. Here’s what I mean about the varying interglacial terminations:

      • Oz4

        Interglacials end when the precessionary Great Summer turns into a Great winter, which cools the northern latitudes. The longer interglacials occur during periods of low eccentricity, when the precessionary cycle is weak and there is no strong Great Winter. On these occasions, the weaker obliquity cycle can maintain and extend the interglacial. We are in just such an extended cycle now.

        R

    • Yes, I thought that also : jolly decent behaviour of those tectonic events to occur with such lovely regularity.

    • Well, if you don’t believe that CO2 production does damage, all you need to do is look at the US Congress and House of Representatives. Those 541 people pump out enormous amounts of CO2 at every meeting which has done devastating damage to the economy

      • “stupid don’t have money and power”

        Are you sure?

        I mean, look at the moneyed powerful in the gummints and hollyweird today. :-(

  5. The hypothesis assumes too much about how the climate is regulated. CO2 has some effect, but the absorption curves I have seen put most of the effect in the first 40 ppm, and even ice age levels were higher than that.

  6. But the question is whether that is a mechanism that works on the timescale that is relevant for us.

    “us” ? Depends on the definition of what us is. I think, though, that I am not in the set.

    • Yes, it could be, for example, that WAIS collapses in 400 years, not really something relevant to us.

      The question, the big question, is whether there exists any plausible, significant enough risk mitigateable by CO2 emissions reductions that are plausibly implementable physically, economically and politically by this generation.

      I don’t quite think so.

    • Maybe it was building the Panama canal, that brought on the modern heating, and not CO2 at all.

      And they say that CO2 can’t do it alone, it takes water vapor to do most of the atmosphere heating.

      And guess what, water vapor can do all of that even without any CO2 at all, so CO2 is just a red herring or maybe just a sardine. And yes CO2 does absorb some LWIR radiation, water absorbs much more.

      G

  7. I have not read the publication, but given this summary the authors would appear to have accepted as a premise that Carbon Dioxide sequestration cools the planet sufficiently to induce an ice age. I have to wonder if their analysis addresses the impact of changes in ocean circulation resulting from the closure of the Neo-Tethys Ocean. Could a competing theory be developed that explains the ice ages as a result of significant changes in ocean circulation which would result? For example, should the Atlantic Ocean be lost in the geological future due to a reversal of plate tectonics, the Gulf Stream would disappear and with it the warm temperatures currently experienced in Europe, etc. Could this induce another ice age?

    Another question that immediately arises is the cause or causes of ice ages predating the two addressed in this publication. If I recall correctly there has been an ice age approximately every 80,000 to 120,000 years–very roughly every 100,000 year–for just over 1M years now. Can the paper’s arguments be extended to address these earlier ice ages? If not, what caused the earlier ice ages and couldn’t these–perhaps unknown–mechanisms operate as completing theories as well?

    • Actually, those 100k-year cycles began about 2M years ago, and are called glacials and interglacials. We are currently in an ice age called the the Pliocene-Quaternary, which began about 2 1/2 mya. Our current interglacial, the Holocene, could end anytime between now and about 9,000 years from now.

      • Bruce,

        Human life span is so short on glacial time scales we wont recognize it. It wont likely be binary switch, but many centuries of slow walking back and forth into the darkness and cold, to occassional centuries of warmth. The LIA could very well have been the first of many lingering multi cntury long descents to a cold climate.

  8. This is just another paper trying to reinforce the weathering hypothesis for reducing CO2 60 million years ago believed to drive the 60 million year cooling trend. There are 2 competing theories for the cooling of the climate and the initial formation of the Antarctic ice cap. Proponents of CO2-causes-everything required a mechanism to pull CO2 out of the atmosphere in order for lower CO2 . The weathering argument is often invoked but there is no consensus and many disagreements

    The competing theory is tectonics opened the ocean gateways to allow the Antarctic Circumpolar Current to form which then inhibited the flow of tropical heat to the southern oceans. As discussed here in the Antarctic Refrigeration Effect, http://landscapesandcycles.net/antarctic-refrigeration-effect.html , this set the stage for cooling the deep ocean. The Gateway evidence is also supported by the close timing of tectonics and climate. The reduction of CO2 is tied to the change in upwelling and a shift in plankton from the coccolithophores that formed the Cretaceous chalk deposits and released CO2 to evolving diatoms that more efficiently export CO2 to depth and the increased upwelling.

    Antarctic ice cap formed 30 million years before the Arctic ice caps formed suggesting the initial cooling was a regional effect, not global. That supports the isolation and cooling of Antarctica as the driver and the drawdown of CO2 as a result, not a cause

    • Further to Jim Steele. Not only not new, not likely to be main cause. The weathering sink hypothesis was explored, for example, in a long 2013 paper from Univerity of Cambridge. Geochemica et Cosmochemica Acta 103: 11-25 (2013).
      At least with respect to the 50mya event, it is also clear that there was a great deal of biological sinking, as this is the time frame for formation of the vast Green River formation, which comprises more than half of the worlds kerogen shales. Unquestionably from the fossil evidence marine phytoplankton sourced. Tectonics and biology much more likely than tectonics plus weathering.

  9. Bollocks. CO2 has little effect on temps (it’s the reverse). Ice ages are probably caused by solar and orbital cycles and certainly by whether there is land at the poles. You can’t make 2 mile thick ice sheets over water. Academia has become obsessed with the nutty idea that CO2 is a control knob for temps, which only exists in the fantasy world of their computer models. It’s nowhere in the climate record.

  10. Another thought… I see a lot of basalt, living near Basalt, CO. Chunks that are buried in dirt, just below the surface, accrue a white layer on the stone faces closest to the surface of the dirt. I assume this is calcium carbonate. This doesn’t build up more than a foot or two in the earth, nor does it build up on exposed surfaces. And it also builds up on any other rocks mixed in with the basalt. If it is a carbonate deposit, there is a lot of carbon sequestered this way, which I’ve never seen mentioned.

    • skeohane, this article is referring to oceanic rock being exposed. That’s basalt. So the weathering is the same chemical reaction which you’re describing in Colorado. I’m sure that it actually does happen on exposed surfaces, but the altered material washes off so you are not seeing much of it on the “exposed surfaces”.

      • I thought it was about basalt being exposed by tectonic movement. It seems too slow except when catastrophic. Seems like it could easily be outproduced by the occasional volcano. Anyway my comment is about deposition in the top couple of feet of soil, not erosion. Unless there are a lot of snail shells in the soil, the deposits must be coming from the atmosphere. Since we get 18″ of rain a year, there aren’t any snails living on south-facing rocky slopes where plenty of the white material is on basalt boulders.

  11. Assuming the weathering hypothesis for reducing CO2 and acting as a primary driver for climate change for a moment, one would expect relatively strong alignment between extreme vulcanism–flood basalt, supervolcano eruptions, etc.–such as the tectonic collisions described and climate variations. It might be a good weekend project to map that data to see if we find any alignment between the volume of basalt associated with such events and paleoclimate studies.

  12. Sorry MIT geologists, in the last 2 billion years, Earth’s atmosphere has become a product of biological activity. Look it up. To be fair, the biology needs the oceans and the sun.

    • Probably from the warming of the atmosphere. The glacier ice core records seem to show pretty conclusively that the CO2 starts increasing after the temperature.

    • Most studies show that at the end of the Ice Age warming around the Antarctic initiated an increase in the Antarctic Circumpolar Current (ACC) and intensified upwelling. Again the warming was initially regional not global, and rising CO2 lagged Antarctic warming.

      The intensified upwelling and latitudinal shift in the ACC tapped a reservoir of deep CO2 mostly of from the biological pump, raising atmospheric concentrations in the same way upwelling does today on a seasonal basis.

      The warming in the Arctic followed much later raising the question if CO2 was the cause or if both Arctic warming and higher CO2 were again the result of natural Antarctic warming.

  13. Something seems a bit off, here. Generally continental crust is lighter than oceanic crust. One generally does not see a lighter continental crust subduct under a heavier oceanic crust and thrust the oceanic crust upward. It usually works the other way around. The lighter north American plate, for example. rides over the subducting Pacific and Gorda plates along northern Japan, far eastern Russia, Alaska and the Pacific Northwest. I don’t see the mechanism whereby the Africa would collide with an ocean plate and push what is generally thought to be heavier basaltic crust up and over the lighter continental crust. What DOES fit generally in the time frame here are the Deccan Traps formation around 70 million years ago where huge flood basalt formations would be exposed to atmosphere. This would have likely increased the acidity of local rainfall and increased erosion and accelerated carbon dioxide scrubbing. The Columbia River flood basalts of 15-20 million years ago might have been an additional factor. I would think events such as these would have exposed more basalt to atmosphere than some mysterious levitation of a basaltic ocean crust over a lighter continental crust but I’m only going on gut instinct here.

  14. What nature shows us is, if you put a lot of these rocks in the tropics, where it’s hot, muggy, wet, and rains every day, and you also have the effect of removing the soil constantly by tectonics (erosion) and thus exposing fresh rocks,..

    ..it all ends up in the oceans just like it always has

  15. There is a strong correlation between mountain building (orogeny) and lowering CO2 levels. This is not new info. The Himalayan orogeny continues to this day.
    (Ruddiman and Kutzbach 1991)

  16. I can’t believe that this kind of absurdity is being published by people who call themselves scientists! What part of ‘CO2 always LAGS warming for all of the Ice Ages’ don’t they understand? “The dramatic drawdown of carbon dioxide cooled the atmosphere, the new study suggests, and set the planet up for two ice ages, 80 million and 50 million years ago.” ???? There was no Ice Age 80 or 50 million years ago–the climate was considerably warmer then than during the Ice Ages. The last Ice Age didn’t “swing back into the present-day ice age 50 million years ago,” it began 2.3 million years ago.

    Oh, I just saw “published their findings in the Proceedings of the National Academy of Sciences”–that explains everything. Just another propaganda paper. Maybe MIT now stands for Many Idiots There!

      • And I have a hunch that the authors will not respond to Don Easterbrook’s critique, too—or to anyone else’s here. Isn’t science supposed to require a dialogue?

        /Mr Lynn

    • Actually there was a minor ice age (the Campanian-Maastrichtian Boundary event, CMBE) about 71 million years ago, and the ongoing ice-age actually started with the Oi-1 glaciation about 34 million years ago.

      Both were largely confined to Antarctica, but there was montane glaciation at least in Alaska, Greenland; Iceland and Norway by the Pliocene, and Antarctica has been completely glaciated for about 14 million years. That 2.3 (actually 2.6) million year figure is actually for when large-scale lowland glaciation at middle latitudes in the Northern Hemisphere started.

    • the various estimates of CO2’s equilibrium sensitivity seem to be converging back to the original estimates of ~1-1.5deg. C. That is about 1/10th the variations in temperature between the highest and lowest estimates of temperature from the paleo records. So CO2 has a minimal effect on the climate. It certainly isn’t a significant driver. If it was or the CIMP5 models had any validity current estimated temperatures would not be bouncing around at the -95% lower bound of the coldest models.

  17. The scenarios sound plausible. Not irrefutable, but not crazed. However, I’m having a bit of difficulty with the dates. 80 million years bp would be the Upper Cretaceous, right? Glaciation? There were tropical seas in the Dakotas and Alberta. 50 million years ago? Early Eocene. I was under the impression that time period was quite warm also although there was cooling from then until the Oligocene (34 million years ago and even more thereafter.

    Apparently there is something here that I’m not following

    • >>Glaciation?

      Yeah, likewise confused. In my post below about albedo cooling, I assumed they were correct about these ice age timings. But this simplistic Wiki temperature graph might suggest they are not. But the same mechanism would apply, whatever the era.

      Ralph.

  18. Thank you Don Easterbrook^^+100. This fallacy of “Icehouse” and “greenhouse” climate state is something the AGW jihad has worked into the language for years now. As Don states, there were no glacial episodes 80 mya (late Cretaceous Period) or 50 mya (early Eocene), but the “climate language police” place the “icehouse” label to make one believe that the earth was suffering from severe cold temperatures. Sorry, geologic evidence does not support that conclusion. The Antarctic ice sheet may have started to develop during the late Eocene to early Oligocene (38-33 mya), but that does not constitute a glacial period, The Pleistocene (2.56 mya) constitutes a glacial climate with ice sheets developing on both poles and impacting global scale climate. Don’t go along with the numbnut scientists that prefer to use the icehouse/greenhouse language to wrongly simplify a ‘climate’ state that supposedly lasts for 10’s of millions of years without any detailed data to support the assertion. P.S., there is no ‘continental drift’, the correct term is plate tectonics and is much different and significantly more complex than the original and very simplified idea of continental drift….

  19. The implicit assumption underlaying this idea is that CO2 is the most important climate driver. It is not, except when you start at very low concentrations (10% of pre industrial, for instance). Under those conditions, however, there would have been no plant life left. That clearly hasn’t happened.

  20. Someone forgot to update these guys with the modern confirmation that “the science is settled”.
    That’s it folks. The debate is over. All the results are in and the earth’s climate has been conclusively described in fullness (on Skeptical Science, of course, and also now on Wikipedia).
    So, no more new theories, or lousy guesses, or “just-so stories” or wild imaginings, or hapless hand flailing, or searching for the missing pieces. Since no pieces are missing and nothing needs to be explained.
    Consensus climate science certainly has no need for these kind of attempts to re-explain the very most fundamental principles of climatic process and documented shifts in the earth’s climate over eons.
    What are these people trying to achieve?
    There attempts to explain basic things suggest that we humans don’t know what the hell is going on!!!
    This tomfoolery will not be tolerated!!!
    (some sarc.)

    • Apologies typo: “there attempts” should read “these attempts” or “their attempts”, obviously.

  21. Didn’t they forget something, like establishing a link between the level of CO2 in the atmosphere and the amount of warming.

    There were times in the past when it was cold and the CO2 levels were high.

  22. This ‘study’ is beyond stupid. The simple truth is painfully obvious: all ice ages begin and end suddenly and come at a fairly even pace and the only thing able to do this is the sun. Turning on and off the level of heat has immediate impact.

    If the cooling was all one way, this story might be slightly plausible but periodic cold/warm cycles: no way.

  23. The trouble with assuming that CO2 is ALWAYS responsible, is that you may ALWAYS be wrong. Sometimes it is better to have a few eggs in another basket, otherwise your theory becomes a creed, and your science becomes a religion.

    .

    In this case, it is equally likely that albedo was responsible for these ancient ice age eras, not CO2.

    Continental collisions result in continental uplift,
    And continental uplift results in surface cooling, at 6.6oc/1000m,
    And surface cooling results in massive ice sheets,
    And ice sheets result in higher albedo, from 0.3 to 0.9.
    And high albedo results in less much insolation absorption,
    And reduced insolation absorption means global cooling.

    Many decades ago, before CO2 became the devil that controlled everything on the planet, people made other suggestions and theories. One of those suggestions was by Matthias Khule, who suggested that the change from obliquity regulated ice ages to precessionary regulated ice ages – at the Mid Pleistocene Transition (MPT) 1 million years ago – was caused by Himalayan uplift. If the Himalaya plateau rose by 500m to 1000m, the Himalaya ice sheet would grow substantially and reflect much more insolation. And because of its southerly location and high altitude, Kuhl reasoned that it would reflect up to four times as much annual insolation as the northern ice sheets do (per unit area). And this great blob of cooling near the tropics, would be enough to drag down global temperatures and cause the MPT – the sudden shift from smaller ice ages to large ones.

    Well exactly the same could have happened 50 and 80 million years ago. The continental collision-uplift caused ice sheets, high albedo, and global cooling. And the cooling climate caused lower CO2 levels, through the natural increased solubility of colder oceans. And since this is a much faster process that waiting for continental erosion to take effect, and reduce CO2 and temperatures, it is a much more reasonable and likely theory.

    So CO2 is merely following temperature, not regulating it. And once again, this may well suggest that everything that has been said about CO2, may be completely wrong. And so everything within modern climate science may also be wrong – every last drop (or molecule) of it.

    Ralph

  24. Isn’t the term “weathering” wonderful. All one has to do is use the word “weathering” and everyone on the pro-global warming side of the debate enters some type of trance where any explanation for any phenomenon becomes believable.

    Weathering is only about 0.5% of the annual Carbon Cycle flux and thus, can be completely ignored. It is tiny compared to plants or the oceans annual flux.

    • Just an update, weathering is only 0.2% of the annual Carbon Cycle so the math just does not work in this case or any other “weathering” case.

      Climate scientists are just very, very bad at basic math (it is almost a pre-requisite to get into the profession) and I think they migrate into the profession from Environmental Science or whatever because it is just accepted in this scientific field.

  25. A couple of things:
    1 – Change in CO2 lags change in temperature. link Do they have an explanation for that? It’s hard to say CO2 changed temperature if the temperature change happened first.
    2 – They say Java has the right conditions to absorb CO2 the same way they say happened 80 million years ago. As far as I can tell, Java has a high CO2 concentration. It doesn’t look like much of a sink. link I’ll bet they don’t deal with that either. If Java was a CO2 sink, you would expect it to have low CO2 levels.

  26. The fly in the ointment for all ideas about the cause of the last ice age, is “why did the climates of North America and northern europe become the extreme cold events they did. The only reason that l can see why that would happen is if the cause was due to the weather.

  27. They got it wrong because adding CO2 to the atmosphere does not cause warming. More CO2 in the atmosphere causes a slight decrease in the lapse rate in the troposphere which is evidence of cooling not warming. It is the colder temperatures that caused CO2 to decrease in the atmosphere. There is no real evidence that CO2 has any effect on climate. Changes of CO2 with climate are an effect of climate change and not a cause. If a greenhouse gas was responsible then climate change then H2O has got to be the primary culprit but that is not part of their theory. The real effect on climate that the moving continents had is how they affected ocean currents.

  28. “I think we’re the first ones to really link large-scale tectonic events to climate change.”

    No you are not. You are just the most recent ones to be wrong.Tectonic activity PRODUCES CO2 and water. Check out a modern Carbon cycle. Weathering is lunch money.

  29. It’s almost embarrassing reading this stuff. They seem to be taking credit for identifying patterns of plate tectonic activity that have long been known and documented. Then they seem to be creating “ice ages” where none existed before and stretching the concept of ice ages to include a long slow cooling period with no NH glaciation. And they start from the assumption that the “ice age” must have been caused by lower CO2 rather than fairly well established patterns of oceanic circulation (and oh, yes, let’s not forget the sun). And they use a model instead of actual observations, which (if their proposed events actually took place) might have been noted by some of the geologists who still go out and look at rocks

    If their concept is right (almost certainly not) and if they’re looking for basalt to suck CO2 out of the air, there have been some stupendously huge volcanic events in the Cenozoic that put millions of cubic kilometres of basalt right on surface, with no need to invoke subduction or underplating. Don’t these people even read geology textbooks? Oh I forgot, volcanism emits CO2, doesn’t it. Oh well, there must have been that much more to sequester. (/sarc)

    I can’t take much more of this armchair arm-waving masquerading as “research”.

    • I agree with you. With so many variables and over such a long geological period how they build carbon dioxide into the equations is magical. These guys knew the answer they wanted and constructed the narrative to provide it.

      The massive tectonic changes were just an aside to the carbon dioxide that controlled all the planet’s climate zones.

    • “and stretching the concept of ice ages to include a long slow cooling period with no NH glaciation.”

      Actually there was fairly large-scale NH glaciation during this “long slow cooling period”. Greenland has had tidewater glaciers at least since the Oligocene (possiby Eocene) and by the Pliocene there were tidewater glaciers in Alaska, Iceland and Norway as well,, while in East Greenland the large fiords already existed by the Pliocene.

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