New insights emerge on what drives long-term climatic trends

Sources and sinks

From the UNIVERSITY OF CALIFORNIA – SANTA BARBARA

For the entire history of our species, humans have lived on a planet capped by a chunk of ice at each pole. But Earth has been ice-free for about 75 percent of the time since complex life first appeared. This variation in background climate, between partly glaciated and ice-free, has puzzled geologists for decades.

Now a team of scientists led by UC Santa Barbara’s Francis Macdonald has published a study suggesting that tectonic activity may be the culprit. They found that long-term trends in Earth’s climate are set by the presence or absence of collisions between volcanic arcs and continents in the tropics. The results appear in the journal Science.

“There’ve been a few hypotheses but no agreements as to why we have warmer or colder climates on these very long timescales,” said Macdonald, a professor in the Department of Earth Science.

And when Macdonald says “long timescales,” he’s talking about 10 million-year periods, at a minimum. These are broad climatic trends, the backdrop against which natural and human-made fluctuations play out. Scientists have a relatively good understanding of what factors influence the climate on a thousand-year timescale, according to Macdonald.

On any scale, though, the primary agent of climate change is carbon dioxide (CO2). The question is what factors influence the amount of CO2 in atmosphere. Some processes produce CO2, while others absorb it. Scientists call these sources and sinks.

The debate among geologists is whether sources or sinks affect the climate more. “Some have argued that CO2 sources, like volcanism, have driven climate change on long timescales, while others have argued that, no, it’s the sinks that have caused climate change on these timescales,” said Macdonald.

He believes it’s mostly the sinks, specifically vast deposits of rock that absorb CO2 through chemical reactions. But these carbon sinks are not distributed evenly across the surface. For instance, greater Indonesia is only 1-2 percent of the Earth’s exposed land area, but accounts for roughly 10 percent of the current geologic carbon sink.

The activity of these sinks depends on a number of factors. Water is important for the chemical reactions and also washes the end results away into the oceans, where they consume CO2. Mountain-building increases the reactions by uplifting and exposing new rock. In flat terrain, the soil shields the underlying rock.

Rock type also plays a key role. Stone rich in iron and magnesium has simpler chemical bonds that are more easily broken down. This makes these mafic rocks, like basalt, better carbon sinks than rocks such as granite, which have more complex bonds.

Plate tectonics is what drives this geologic carbon cycle. When one tectonic plate slides under another — usually a dense ocean plate under a continent — the melting rock fuels a row of volcanoes on the top plate called a volcanic arc. The Cascade Range of the Pacific Northwest is one example of this.

Macdonald and his colleagues reckoned that when these volcanic arcs collide with another continent, the collision uplifts mafic rocks. These rocks are readily eroded, particularly in warm, wet, tropical latitudes, and the sediment is sent out to oceans where it consumes CO2. So, he reasoned, when these collisions happen in the tropics, they drive the climate toward cooling.

“The tropics are where the rocks weather best because it’s the warmest and wettest,” explained coauthor Lorraine Lisiecki, an associate professor also in UC Santa Barbara’s Department of Earth Science.

To test their hypothesis, the team used reconstructions of the continents and mountain-building events that scientists had built up over the past decades. This gave them an idea where and when arc-continent collisions happened. They limited themselves to the last 500 million years, since the geologic record is much less complete, and reconstructions less certain, before that time.

Temperature is harder to get a read on than geography, so the team used a simple metric: Was there ice on the poles at a given time or not? They reconstructed this information from the literature by looking at data on rocks that form only in the presence of ice. What they found was that Earth had significant ice cover during only four periods in their time window.

Combining the geographic and temperature data, the team found that over the last 500 million years, glacial climates occurred during periods of extensive collision between continents and volcanic arcs in the tropics. There was less than a 1 percent probability that the match was due to chance.

“Given how many things are changing on Earth at the same time, it’s amazing that it all came out really clean and matched so well,” said Lisiecki.

The collisions have the added effect of shutting down volcanic arc activity, which cuts off that source of CO2. “But if it was a volcanic effect, it wouldn’t matter where the volcano was,” Lisiecki said. It’s only the weathering effect where latitude makes a difference. And the team found a much stronger relationship between the climate and collisions that happened in the tropics, rather than those that were outside the tropics.

“These hypotheses are not necessarily entirely independent,” said Macdonald, “but our analysis suggests that the strongest relationship is with the weathering piece.”

Macdonald embarked on this large compilation project after several of his colleagues had pushed back on results from studies with smaller scopes. “I thought, ‘You’re absolutely right. We need to look at this more broadly,'” he recalled. Now the team hopes this paper challenges their colleagues to make a more rigorous case for their own hypotheses.

Macdonald and Lisiecki also know that this paper is not the last word. “The database is open,” Macdonald said, “so I’m hoping that this is an iterative project. And as more constraints come online, they can be entered and the model can be refined.” To that end, he is currently investigating how strong an effect rock type has on this hypothesis.

Humans have lived for hundreds of thousands of years with little concept of the dramatic changes the planet has witnessed over the eons. Although the subjects it studies are ancient, modern geology developed relatively recently. The theory of plate tectonics, for example, was not widely accepted until the 1960s. “We often think of Earth as always being like we’re seeing now,” said Macdonald. “But it’s been a totally different planet throughout its history.”

###


From Eurekalert

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99 thoughts on “New insights emerge on what drives long-term climatic trends

  1. On any scale, though, the primary agent of climate change is carbon dioxide (CO2).

    I’m pretty sure that’s not true. On millennial timescales, ice core samples clearly show CO2 is a lagging indicator. See, for instance, An Inconvenient Truth, despite the movie’s attempt to obscure that fact, it is there in the charts they use. On longer timescales, ocean currents dominate. See, for instance, the Antartic ice cap, which formed after Antartica seperated from Australia and currents shifted so that warm water from the equator no longer reached the island or Europe, which is kept freakishly warm by the gulf stream.

    • Yeah, my jaw dropped when I saw that claim. They are trying to rewrite geological history!

      It seems they got their degrees citing Al Gore’s sci-fi epic movie, rather than conventional study.

      The results appear in the journal Science.

      So that shows what the “peer review” process is really worth these days, when you can get blatantly false, smack you in the face, claims like that published in a top journal.

      … or is this just some BS added by a media studies undergrad “activist” in the PR dept.? There is no indication this claim was in the paper nor was it given as a direct quote from one of the team of researchers. Eureka !

    • We are witnessing the development of doctrine in the Church of Climastrology.

      MacDonald and Lisiecki went up to the mountaintop. They fasted and meditated, relying only on the comfort of their cannabis for forty days and forty nights. “CO2, master control knob”, was their koan. And lo, the angel of the Lord Carbon did appear before them, and they were sore afraid.

      Ignore ye the ice core data, for it leadeth astray. Ignore ye also the vile thermohaline circulation and its collusion with plate tectonics.

      And they did exclaim “EurekAlert!” (from the ancient Greek for I have not found it).

      • I stopped reading when they made the claim that continental collisions, which impacted volcanism and the weathering of rocks. I could tell that they were building up to make a claim about CO2 being the master molecule.
        Too bad for them we already have good proxies for CO2 levels, and these proxies do not match up with their theories.

    • The lack of a bow to correlation and lag vs tperature kind of blows up his whole arguement and made it a hurtle to finish reading the article. Few people would argue that tectonics have no roll in climate change from distribution of land masses to volcanics.

    • I agree. This reads as if written by a convert to the “greenhouse gas rules the universe” cult. Lots of evidence in the geologic and historical records that this is not true.

    • Tim, I am positive that extracted sentence is false. One only need look at the recent periods of 1940-1975 and 2001-2015 to see that CO2 cannot be the primary driver of global atmospheric temperature as is claimed.

      And as you pointed out, over longer time scales, increases (and decreases) in CO2 are found to lag increase (and decreases) in global temperatures, respectively, as expected just from the temperature dependence of CO2 solubility in Earth’s surface ocean waters.

      If “greenhouse gases” have any meaningful “forcing” on the variability of Earth’s temperature, one should look first and foremost at water vapor, which is: (a) a far greater absorber of near-IR and mid-IR incoming radiation from the sun, and (b) a far greater absorber of LWIR from Earth’s surface. In comparison to water vapor, CO2 is a bit player.

      Moreover, water vapor–because it a condensible over the range of normal tropospheric pressures and temperatures–additionally controls Earth’s radiation balance and surface temperature balance to extraordinarily large degrees via evaporation (surface energy transport), cloud formation (albedo variation and additional radiation absorption across UV to LWIR wavelengths), and condensation (surface-air energy transport, areal energy transport/distribution, surface albedo variation with snowfall, etc.)

      • Ooops . . . meant to say “precipitation” instead of “condensation” in my last sentence. Condensation is, of course, what forms clouds.

      • Gordon wrote: “I am positive that extracted sentence is false. One only need look at the recent periods of 1940-1975 and 2001-2015 to see that CO2 cannot be the primary driver of global atmospheric temperature as is claimed.”

        Gordon, you need to learn something about chaos and climate. The warm surface of our ocean is floating on top of a 10-fold bigger pool of much colder water. If these two pools of water were suddenly fully mixed, temperature would plunge at least 10 degC. There are regions of upwelling and subsidence that slowly mix these pools. As with all flow in fluids, such currents fluctuate chaotically – without apparent cause. El Nino can be partially described as an example of such a fluctuation wherein warming is driven by a reduction in the upwelling of cold water off Equatorial South America and downwelling of warm water in the Western Pacific. This can produce “global warming” of about 0.3 K in six months! The existence of El Nino certainly doesn’t prove that CO2 is not the primary driver of temperature on longer time scales.

        There are other changes in ocean currents (such as AMO and PDO) that change on longer time scales than ENSO. These slower processes are poorly understood. They occur so slowly that they can be confused with the forced climate change. Variability in climate can be attributed to three causes: naturally-forced variability (driven by the sun, volcanos, cosmic rays?), anthropogenically-forced variability (driven by GHGs, aerosols, land use changes), and UNFORCED VARIABILITY (driven by chaos, like ENSO).

        The IPCC likes to downplay the possibility of unforced variability when claiming that warming in the last half-century has been driven by rising GHGs. Skeptics like you ignore the FACT that minor fluctuations in warming could be driven by chaos – that climate DOES change without apparent cause, just like the weather does.

        The pause in the 2000’s, the lack of warming from 1950 to 1970 (with a small dip in the middle), and the 1920-1945 warming (too big to be driven by CO2) presumably are all examples UNFORCED variability and involve changes of a few tenths of a degC – just like El Nino. It is absurd to draw conclusions about CAUSATION when chaos can be responsible for these phenomena. It is just as stupid as saying that Force is not the product of mass times acceleration because one data point in an experiment doesn’t lie exactly on a straight line. There is a wonderful 1991 paper from Lorenz (one of the discoverers of Chaos) entitled “Chaos, Spontaneous Climatic Variability, and Detection of the [Enhanced] Greenhouse Effect [from Rising GHGs]” that clearly describes the problem in the last two pages. Please read.

        http://eaps4.mit.edu/research/Lorenz/Chaos_spontaneous_greenhouse_1991.pdf

        “Imagine for the moment a scenario in which we have traveled to a new location, with whose weather we are unfamiliar. For the first ten days or so the maximum temperature varies between 5 and 15 degC. Suddenly, on two successive days, it exceeds 25 degC. Do we on the second warm day, or perhaps the first, conclude that somebody or something is tampering with the weather? Almost surely we do not …”

        “Now consider a second scenario where a succession of ten or more decades without extreme global average temperature is followed by two decades with decidedly higher averages; possibly we shall face such a situation before the 20th century ends.”

        “Does this situation really differ from the previous one? … Certainly no observations have told us that decadal-mean temperatures are nearly constant under constant external influences. If we discard all theoretical considerations [such as forcing], we can not distinguish between the two scenarios.” [10 days and 10 decades of little change followed by 2 days or decades of change.]

        Lorenz was warning his colleagues in 1991, that the warming that prompted the founding of the IPCC and its first report was meaningless. Before the pause in the 2000’s, which is equally meaningless. The same conclusion applies to the other short periods you point out.

        The crucial question is whether the 0.9 degC of warming in the past half-century was forced by rising CO2 or could also be due to chaos/unforced variability. (We know that natural forcing contributed little during this period.) Lorenz was writing in 1991, when rapid warming had persisted for less than two decades. Past climate fluctuations like the LIA and MWP are perhaps comparable to warming over the last half-century, but natural-forced variability (less active sun and more volcanos) appears to have contributed to the LIA. We have about 70 centuries of temperature proxy data since the last ice sheets stopped melting to tell us how much climate has varies from a combination of naturally-forced and unforced variability. Unfortunately, ice cores reflect local, not global, climate change. The variability observed in the LIA, MWP, RWP and Minoan WP is obvious and large in Greenland ice cores, but not found in Antarctic ice cores. The “global” nature and magnitude of such warm periods is a subject of controversy.

        • Frank, you long post has done nothing other than to reinforce my point that CO2 cannot be the primary driver of global atmospheric temperatures over 15-30 year (and undoubtedly longer) timescales. You argue that “chaotic” variations (ENSO, AMO, PDO, etc.) override whatever effect CO2 “forcing” has on global temperatures . . . egro, it follows that CO2 cannot be “the primary diver” of climate change since atmospheric CO2 concentration has been on an ever-increasing slope over the last 200 years and HAS NOT exhibited chaotic behavior during this period.

          And I strongly disagree with your characterizations of climate-related oscillations as being chaotic. Poorly understood causation in not the same as being chaotic.

          • Gordon: Thanks of for the intelligent, though slightly inaccurate reply. Sorry my comment was so long; chaos is a challenging subject.

            You wrote: “CO2 cannot be the primary driver of global atmospheric temperatures over 15-30 year (and undoubtedly longer) timescales.”

            Question: What CAN be the primary driver of global atmospheric temperature over 15 years, 30 years, or longer? Answer: Anything that effects the amount of incoming absorbed or outgoing radiation. The law of conservation of energy demands that any imbalance cause the Earth to warm or cool until restored balance results in a new steady state temperature. At any time, chaotic internal transfers of heat within the ocean can change temperature in the absence or presence of an imbalance.

            CO2 will only be the primary driver of climate change when it dominates other factors. Natural climate variability from the 11-year solar cycle is negligible. Willis’s “Spot the Volcano” posts show that natural month to month variability and ENSO can obscure the cooling from large eruptions. (If you average over 2-4 years, monthly variability and ENSO averages out and volcanic cooling is easy to spot (:)) To clearly see the effect of rising CO2, the change needs to large enough to dominate other changes.

            Over 15 years: The Pause in the 2000’s shows that unforced variability can suppress warming that averaged 0.2 K/decade for nearly a half-century. Empirically, 10-15-years is too short a period to be confident that that rising CO2 would dominate – and it is too short a period define climate (30 years).

            Over 30 years: The “Pause” from 1945-1975 and the mostly unforced warming from 1920-1945 are also periods when forcing changed too slow to dominate unforced variability. In fact, the forcing change over these periods was comparable to the forcing over these earlier periods.

            Over longer periods: Over the last half-century forcing has increased at a rate of about 0.4 W/m2/decade and temperature at nearly 0.2 K/decade. The appropriate question is whether there are any example of unforced, global climate change similar to this large change, or is CO2 dominant on this time scale.

            https://www.ipcc.ch/site/assets/uploads/2018/02/Fig8-18-1-1024×643.jpg

            Hopefully AR5’s Figure showing the total change in forcing with time has been pasted immediately above. The entire picture is consistent with 0.3 K of warming from El Nino or slower forms of unforced variability being able to temporarily dominate the warming from about 0.5 W/m2 of forcing, while warming from larger amounts of persistent (non-volcanic) forcing dominates over decades.

          • Gordon wrote: “And I strongly disagree with your characterizations of climate-related oscillations as being chaotic. Poorly understood causation in not the same as being chaotic.”

            I will refer you again to Lorenz’s very short paper on chaos in climate and weather. Lorenz shows how numerical solutions to the earliest differential equations describing weather produced periods of seemingly well-defined oscillations that deteriorate in chaos and then return to apparent regular oscillations. There is clear evidence for two oscillations of the AMO with roughly a 65-year period. One might expect to find similar oscillations in the Central England temperature record going back into the 1600’s, but the pattern isn’t clear.

            The clearest example of chaos is ENSO. Despite all the information we collect about the Equatorial Pacific, no one today is able to predict with any skill weather there will be El Nino conditions next January. The trade winds are weakest in spring – that is when an El Nino starts – winds blowing from the warmer Western Equatorial Pacific towards the East, suppressing upwelling. In a few months, predictions for El Nino next winter will show significant skill. Before spring, no measurements of the ocean or atmosphere can skillful predict the future. Lorenz defined deterministic chaos as being:

            “When the present determines the future, but the approximate present does not approximately determine the future.”

            There is a huge difference between poorly understood causation and the deterministic chaos associated with the solutions to the equations of fluid flow and related systems of differential equation. As seen in Wikipedia, the physics of coupled pendulums is well understood, but they behave chaotically. If the starting location is moved even slightly, the pattern will be entirely different.

            https://en.wikipedia.org/wiki/Chaos_theory#/media/File:Double-compound-pendulum.gif

            AOGCMs are initialized with temperatures randomly tweaked by 0.000001 degC, and they chaotically divergent within a few months or years.

            Before drawing conclusions from the behavior of our chaotic climate system, you need to understand how chaotic systems really behave. If the Pause in the 2000’s can be due to chaos, then the conclusions that you drew from that Pause are meaningless. Just like the change in weather for a day or two that Lorenz described.

    • Tim M. wrote: ” … or Europe, which is kept freakishly warm by the gulf stream.

      Your statement (made by many, wrongly) is much like St. Patrick chasing snakes from Éire – a myth.
      The warmth of the Gulf Stream dissipates in the Atlantic waters just south of eastern Canada, that is, the Island of Newfoundland.
      Here is a view:
      https://www.coastalreview.org/wp-content/uploads/2015/11/gulf-stream.jpg

      This article makes the “myth” claim and provides a plausible explanation for Europe’s mild climate.
      Source of Europe’s Mild Climate, Richard Seager

      • The Gulf stream continues to warm much further NE than just SE Canada as can been seen on SST’s below.

        https://www.thegeographeronline.net/uploads/2/6/6/2/26629356/2695842_orig.jpg

        If the waviness in the westerly flow was the only reason, then why has the same latitude over the Pacific side of the USA much cooler?

        The westerly flow is around the same either side of North America despite the Rockies.

        Other reasons why a westerly flow would not cause the vertical placed region to be much warmer than Pacific side when it is much further North than the waviness in the westerly flow.

        Sea ice always much closer to the North pole on the Atlantic side than the Pacific side because sinking cold water brings warmer SST’s towards the Arctic ocean on the Atlantic side.

        This is without even mentioning how much colder the North Atlantic ocean become in the Younger Dryas and other severe cooling periods. The waviness in the westerly flow would prevent this from happening if it was the main cause for it being relative warm now.

        • Matt G.,
          That’s a nice image. Note the small yellow-ending in blue part over against the eastern coast of North America. That yellow bit is the Gulf Stream. Blues and purple means cold.
          This gets even more complicated when one considers the warm saline rich water from the Mediterranean Sea, called the Mediterranean Outflow Water (MOW). Where does it go? What does it do?
          The northern branch of MOW follows the coasts of Portugal and Spain, enters the Bay of Biscay, and continues northward toward the Rockall Trough.
          The Rockall Trough (Google Earth labels this the Ireland Trough) is just to the northwest of County Mayo.
          More reading: https://www.aoml.noaa.gov/phod/docs/Bozec_etal_2011.pdf

    • Yes, pointing the finger at CO2 was moronic. However, the issue of Plate Tectonics is not – the two biggest impacts one can point are first, when Antarctica separated from Australia and migrated south, seeing up the southern circumpolar current and creating a frozen South Pole, something Earth had not had since the “Snowball Earth” stagea about 500 million years ago or so.

      The next was when the North American plate crashed into the South American plate, shutting down worldwide equatorial flow. Those two events together had far more of an impact on climate than any atmospheric conditions ever did.

      • Ignoring the obligatory bow to CO2, I find this paper very interesting because it comes to the table with a new analysis of existing data. They related much work that has gone into figuring out how the plate tectonics as shown up in the fossil record and how various plates moved and formed and linked it to weathering rock in specific locations. The rock weathering does absorb a lot of CO2, and every glaciation appears to associated with decreasing CO2. Presently CO2 is at a very level because CO2 in the atmosphere has been trending down for millenia as it has been absorbed into rocks.

        This paper is far better evidence for CO2 as a climate variable, but not in the way of the current fad. Absorption of CO2 into rocks causes global cooling on a vaster scale than anything humanity can even approach in producing more. Human emissions are a pittance on a global scale to mass sequestration of CO2.

    • Tim: Most likely, we don’t know whether CO2 lead or lagged climate change in Antarctica. In ice cores, O18 or deuterium in snow records differences in temperature and air bubbles record the CO2 concentration. The question is: How long does it take for the snow to be converted to ice which traps air bubbles. The rate at which snow accumulates at a dry place like Vostok is so low, that it can literally take a millennium or more for ice to be permanently encased in ice and no longer equilibrate with the rest of the atmosphere. There is a great deal of scientific uncertainty about this lag today and no consensus that the lag at Vostok was 700 years. Ice cores have been drilled at other sites in Greenland and Antarctica where the accumulation rate is higher and the lag shorter, but a consistent picture hasn’t developed.

      What we CAN say is that the change in CO2 is far too small and slow to have driven the bulk of the warming as the last ice age ended. CO2 increased about 50% as the last ice age ended (about 6? degC of warming) and since pre-industrial (about 1 degC of warming; or 1.5 degC if you add some “committed warming”).

      Furthermore, the end of the last ice age is nothing like global warming in the last century. In Antarctica, warming began about 17 millennia ago (IIRC). However, there was no warming in Greenland ice cores until about 12 millennia ago. Today’s warming (allegedly from rising GHGs) is greatest in the Arctic and hasn’t begun in the Antarctica. When the temperature of the atmosphere doesn’t decrease with altitude – as is the case on the Antarctic plateau, there is no GHE.

      https://en.wikipedia.org/wiki/Schwarzschild%27s_equation_for_radiative_transfer#Origin_of_the_greenhouse_effect

      There is a correlation between CO2 and local temperature in ANTARCTIC ice cores, but that correlation tells us nothing us useful about CO2 causing GLOBAL warming. That correlation is propaganda, not science.

    • “On any scale, though, the primary agent of climate change is carbon dioxide (CO2)” in the beginning of paragraph 5. I stopped reading there and then.

      I earned my BS Geology at UC Santa Barbara in 1969 when it was a great school with amazing faculty (John Crowell, Art Sylvester, Bob Webb, Cliff Hopson, Bob Norris, Preston Cloud, Gordon MacDonald, and others). Sea-floor spreading, subduction zones, and plate tectonics were hypotheses just then being tested and refined. Definitely not “settled science”. Everything was open to question – and it was great fun and hard work.

      Geologists should be the most skeptical of such a simplistic concept as “CO2 drives the temperature” because we have studied radical changes in earth environments over vast time scales. With so many gaps in evidence of earth history, we operated under the guidance of “Multiple Working Hypotheses”

      What has become of skeptical inquiry and curiosity? [sigh]

  2. [On any scale, though, the primary agent of climate change is carbon dioxide (CO2). The question is what factors influence the amount of CO2 in atmosphere. Some processes produce CO2, while others absorb it. Scientists call these sources and sinks.]

    when i read that..i pretty much gave it up as crap

    • Me too. In fact I quit reading at that point.

      You would have thought they would have been a little creative …. like maybe ….. tech tonic activity influences ocean currents, possibly starving the poles of heat resulting in ice caps. But no ….. they had to go to CO2.

      • When I read the CO2 comment, …..I stopped reading the article and scrolled to the reader comments.

      • I agree that CO2 cannot be the controlling factor, but there is a problem with your theory that tectonic activity possibly starved poles of warming ocean currents. The reigning current theory on ocean currents is that the raising of the Panama isthmus blocked equatorial currents between Atlantic and Pacific oceans, ending a period of an ice-free arctic, starting a period of cyclical glaciation of northern hemisphere. One thought is that resulting Gulf Stream provided increased WV over northern Europe that fell as snow.
        It is difficult to have Gulf Stream causing both an ice age, and ice-free poles.

        SR

  3. Sorry but I don’t believe it. Once again it is the old CO2 demon which just gets so boring and unbelievable.
    While I am prepared to believe that massive shifts in the plates could have some affect I don’t believe it could cause massive shifts from a glacial to non glacial period.
    I am tempted to take up playing darts again as I feel that is what these so called scientist are doing.

    • Just remembered a song from when I was a lot younger, “Here comes the sun little darlin’, her comes the sun”. I do think it has something to do with our climate.

  4. Ozone in the stratosphere prevents ultra violet with 48 times the energy absorbed most strongly by carbon dioxide from reaching the surface. Tectonic stresses induce volcanic episodes which can last for thousands of years. Explosive volcanoes tend to cool the world but extrusive flood basalts release bromine and chlorine that deplete ozone which allows powerful ultra violet to warm the surface more than otherwise. Global warming and extinction events always follow major flood basalt events. Milankovic cycles and tectonic movements are linked.

    see: https://fallmeeting.agu.org/2015/files/2015/12/PeterwardAGU121315finalpdf.pdf

      • Lower stratosphere – where most ozone lives – cooled by 0.5 K after both El Chichon and Mt Pinatubo, …. when was most of the “man made global warming” : in exactly those decades.

        Less ozone means more energy making it to lower climate system.

      • Have a look at:
        ‘What Really Causes Global Warming?: Greenhouse Gases or Ozone Depletion?’
        by Peter Langdon Ward

  5. “On any scale , though,the primary agent of climate change is carbon dioxide (CO2).”

    When I read that I knew these scientists were NOT scientists. No honest scientist would make a statement like that which preempts any conclusion that may be reached.

    The fact that the statement is a load of rubbish is neither here nor there. These people seem intent on destroying the reputation of honest scientific endeavour.

    An interesting read nonetheless.

  6. The more conventional explanation for the relatively recent ice covered arctic is that the continents moved around and changed the ocean circulation patterns. link

    • It’s also an explanation that lines up with the known facts.
      Unlike the theory that CO2 controls the climate.

  7. 97% of the world’s water is in the oceans, it’s the most important ‘greenhouse’ gas, and up there’s the sun.
    CO2? Yeah, right, as the saying goes!

  8. Pure, Grade A pseudoscientific drivel. These “scientists” should be ashamed. Maybe someday they will be.

    • “These “scientists” should be ashamed. .Maybe someday they will be.”

      Let’s hope.

      They should be ashamed to call themselves scientists when they base their study on unsubstantiated claims about the effects of CO2 on Earth’s atmosphere.

  9. When the oceans contain almost (and I mean almost) all the heat, I would look there. How the oceans absorb and give up the heat control the global temps.

        • I don’t recall being proven wrong, and particularly by you, but I can assure you I am not upset in the least.

          • So you’ve never read the replies to your posts then.
            BTW, did I ever say I was the only one who has been proving you wrong?

          • Everybody thinks they are right. Obviously that doesn’t mean that they are right.

            Surely I am not right on everything I say, particularly since climate is such a complicated matter. However I’ve seen a confirmation of most of the things I see about climate since 2015 when I became seriously involved with it.

            -The Pause in Arctic sea ice extent melting. I started talking about that in 2015 so it is already 4 years and going strong.
            -The temporary warming of the 2015 El Niño with a continuation of the pause afterwards. It has already cooled most of it and will soon return the rest in 2020-21.
            – The cold snowy winter of 2017-18 given solar activity and QBO conditions.
            – The final arrival of El Niño for this season.

            Other things are on their way to be confirmed, some looking good:
            – The solar minimum for early 2019.
            – A La Niña for 2020-2021.
            – A warmer 2019 than 2018.
            – A resuming of cooling after 2020.
            – A reduction in the rate of sea level rise.
            – Solar activity for SC25 that should be higher than SC24 but lower than SC23.

            So overall I would say that I am more right about climate change than most. Your idea that I am proven wrong looks funny to me. Having different opinion on the evidence about hypotheses isn’t proof of anything regardless of your beliefs.

    • Note that the statement “On any scale, though, the primary agent of climate change is carbon dioxide (CO2).” doesn’t appear in the earlier EurekAlert sourced posting on WUWT and that the current posting seems to come from UC Santa Barbara. This lends credence to the comment made by Greg earlier that since the statement did not appear in the paper, it was likely inserted by some activist-type at UCSB.

  10. This is big IQ research? Really. You open or close an ocean basin, all the ocean circulation changes, and hence the climate. Most recent would be Central America volcanic connecting North and South America. A prevailing easterly flow through the Gulf of Mexico got cut off. Previously North America was attached to Europe and there was no Atlantic.

    • Ocean circulation changes are much more a Bingo concept than these alleged researchers ever could achieve.

  11. Total crock. Reorganization of ocean circulations changes the climate. CO2 is irrelevant, and above a certain level, oolitic limestone is spontaneously precipitated in the ocean shelves.

  12. The early Earth’s atmosphere contained no free Oxygen and 10000ppm+ CO2 and the Earth did not become like Venus even when all the carbon was to be found in the atmosphere.
    Early life on Earth was blue green algae which thrived in this CO2 rich atmosphere – liberating vast quantities of Oxygen.

    Note: Free Oxygen does not exist on planets as it is highly reactive and forms metal oxides which sequestrate it into solid carbonates and oxides – so much so that cosmologists searching for exoplanets [planets outside of our solar system] look specifically for the tell-tale spectrographic signature of Oxygen as an indication of life existing on those planets – thus far nothing has shown up.

    This oxygen made the air toxic to the algae – remnants of such species can be found in the class of “anerobic” organisms.

    New species evolved to use the oxygen which also allowed more energy intensive biology – eventually leading us to where we are today.

    So the first successful species were the megaflora – so successful they “polluted” their atmosphere with Oxygen and were extinguished at the end of the Carboniferous period – which laid down the Carbon that is the basis of all today’s fossil fuels.

    The Oxygen rich (±30%) atmosphere gave rise to the mega fauna – Dinosaurs and such – have you ever noticed that dinosaurs have relatively small chests ? If we brought a T-Rex into being (A’La Jurassic Park) it would stand there wheezing – gasping for breath in our Oxygen depleted atmosphere.

    You should also note there is a symbiotic relationship between volcanic action and the Earth’s carbon based life forms (that’s you, me and most every living thing). Without volcanic CO2, all the Carbon would eventually become sequestered into limestone and life as we know it would slowly come to an end. Life on Earth requires volcanic and tectonic action to “reprocess” the sequestered CO2 In the rocks and release it back into the atmosphere.

    CO2 is essential to life on our planet – it does not “control” the climate in any significant way.

    Prior to the industrial revolution, CO2 was spiralling dangerously downwards. Our production of CO2 is saving the planet not destroying it !

    Man is responsible for all manner of hideous crimes against the environment – CO2 just simply isn’t one of them.

    The unscientific distraction of the Global Warming / CO2 phantasm is diverting attention, funds, resources and scientific examination of these very real problems. This willful neglect will be viewed by future generations as one of the most damaging of acts or omissions ever inflicted by humankind on the environment.

    • I happen to agree with you and believe your progression of events on the planet may be mostly accurate.
      I would like to see some corroboration of the 30% oxygen levels after the carboniferous. Can you provide links?
      What you are describing is runaway processions albeit over millions of years that end with total
      changes in life on Earth. Plenty of evidence of these changes in geology. It does not explain why the Earth became the cold ice house it still is today or what might bring it back to a warmer future.
      I think Earth is indeed a dying planet as the interior cools and tectonic activity slows. The likelihood of future large flood basalt events seems very remote. Our little bit of interference in natural processes is only a reprieve of of an eye blink in geologic timescales. Not worth fretting about.

        • Think of of wildfires with 35% oxygen. I can’t imagine a scenario where they would not cause extreme devastation. Could the atmosphere over land have been moist enough to dampen them somewhat? Coal beds today suggest the plant life did not burn up.

    • Good comments, Ken.

      Earth’s history is fascinating.

      How large would humans grow in a 30-percent oxygen atmosphere? 🙂

    • The only thing I feel missing is the emergence of oxygen coincided with the first mass extinction event. Once I saw that information at more than Museum of Nature and Science, it was the nail in the coffin for my belief in Al Gore’s Warming.

  13. So much crap in one little article. Less than 1% probability due to chance? With only three glacial epochs over 550 million years, there’s not a lot of data points to hang your hat on. And it seems to me at least the last two were as much characterized by large continental land masses in high latitudes as tropical continental collisions.

  14. On any scale, though, the primary agent of climate change is carbon dioxide

    So why – apart from the money – do they bother? They are just parroting that the science remains settled – as far as they are concerned

  15. That CO2 drives the earth’s climate is not a Law. It is not a Theory, it is not even an Hypothesis. At best, it is a conjecture. To began any experiment with such bias is not science. Calling it propaganda would be too kind.

    • What’s more, they are (or at least the named lead author is) allegedly (a) geologist(s), a field which their so-called “science” does a great disservice.

      Where the hell is the CO2 “effect” on climate in the geocarb temperature and CO2 reconstruction?! There is NO effect shown whatsoever, AND significant episodes of REVERSE correlation that show that the notion that the “primary agent of climate change is CO2” is a joke.

      https://www.geocraft.com/WVFossils/CO2_Temp_O2.html

  16. From the article: “On any scale, though, the primary agent of climate change is carbon dioxide (CO2).”

    Pure speculation. They start right off the bat assuming things not in evidence. THIS is modern-day alarmist climate science.

    You can’t get to the truth by starting out with a false or unsubstantiated assmption.

  17. The big sinks for CO2 are the ice free polar oceans and CO2 is not controlling temperature. The water cycle is. CO2 changes in the atmosphere are also being controlled by the water cycles. Water has to be in soil, rocks or trees for land areas to be sinks.

  18. Now I”m waiting for some ecohippies and pseudo-science types to propose stopping plate tectonics to reduce CO2 in the atomosphere. It will involve the usual ‘gimme yer cash’, grants funded ad infinitum, proposals for construction of tectonic movement barriers, etc., etc., etc.

    Anyone want to buy the bridge I have up for sale in Brooklyn?

  19. How in the name of science can scientists publish articles with so many unproven assumptions stated as unalterable fact? Answer: Not science.

  20. Yet another ode to ….’King CO2, main driver of climate.
    Long live the …’King.

    For a little light relief & a glimpse at some minor climate influences, may I recommend geology Prof. Ian Plimer’s great book:
    Heaven and Earth, Global Warming: The Missing Science.
    500 + pages, 2000 ref’s & well indexed.

    JD.

  21. How about multi-million year solar variation as a cause? We know the sun energy output pulses up and down today over short periods of years or hundreds of years. We know the sun was less vigorous than now a billion or more years ago. Do we know the nature of its energy increase? Was it precisely linear or did it pulsing up then down a bit over cycles lasting many millions of years? I suspect CO2 is a short scale variant on such long time scales and it seems implausible that it could account for ice ages lasting so long. Perhaps there are ways of measuring isotopes in rocks to help determine whether there were such cycles but if the only way for researchers to get money is to try and pin the problem on CO2, we will never know.

  22. “On any scale, though, the primary agent of climate change is carbon dioxide (CO2).”
    As with other commentators here, I can find no basis for this statement. I suggest that it was included to ensure funding and the approval of their UN masters whose ambition is to achieve “One World Government”, with them in charge, of course.

    In my analysis of CO2 time series from stations across the globe, I have yet to find a correlation between CO2 and satellite lower troposphere temperature. However there is a significant positive correlation between the temperature and the annual rate of change of CO2 concentration. As the Tropics has the greatest average temperature, it is the zone that generates most of the atmospheric CO2 which moves out towards the Poles, which are the sink for the CO2 due to the increase in solubility of CO2 with decreasing temperature.

    The time series for the CO2 rate of change for the South Pole station matched the Tropics temperature but not the South Pole temperature.

    Hence the study has mistaken cause and effect in defining their four periods of low temperature. The larger areas of ice provided a greater sink for the CO2 not the lower CO2 concentration being the cause of the lower temperature.

    For detail see: https://www.climateauditor.com

    My guess is that it is the land based life forms which proliferate in the warmer, wetter climate of the Tropics and are the major source of atmospheric CO2. Thus it is reasonable for the study to find that tectonic activity in the Tropics has an effect on the atmospheric CO2 concentration.

    As for the proposition:
    “…. glacial climates occurred during periods of extensive collision between continents and volcanic arcs in the tropics. “….. could it be that the tectonic activity was driven by the loading of continents by the increased area and thickness of ice sheets ?

  23. “On any scale, though, the primary agent of climate change is carbon dioxide (CO2).”
    I always have to wonder why these kinds of articles happen to show up on this website without any comments ridiculing them in the main body. Seriously? You want some people to take this seriously?

  24. Just remember, there is absolutely NOTHING that CO2 cannot do! Except anything good, of course. Someone had a webpage for all that CO2 going from 3 molecules per 10,000 to 4 molecules per 10,000 in the atmosphere, is supposed to be able to do, even before breakfast and coffee. He had to stop updating it because there were just too many wild and contradictory claims, he could not keep up – it read like poor satiric comedy. King Canute was a piker compared to CO2 (yes I know he didn’t really think he could stop the tide, unlike our current crop of “scientists” and politicians)!

  25. “Scientists have a relatively good understanding of what factors influence the climate on a thousand-year timescale”

    They do? Since when?

    • Yep, I saw that and just shook my head. We are doing well if we know 1% of the factors that influence the climate on a thousand-year timescale.

    • Scientists have a relatively good understanding of what factors influence their ability to attract grant funds.

  26. The one problem with proclaiming that CO2 is the master control knob of climate is the fact that on geological scales, there is no correlation between CO2 and temperature. None, Zip, Nada.

  27. Again with this “CO2 is the primary actor” bullshit.

    CO2 has ZERO control over Climate changes because of it’s near uniformity above 6000m and climate changes are caused by ground level thermal and moisture interactions. Climate is driven by water, sunlight and cosmic bombardment resulting in localized prevailing wind and weather systems.

    If you go find the CO2 concentration at altitude over time you’ll find the actual global signal is the opposite of the yearly Mauna Kea hysteresis and NEVER as strong as the concentrations measured at ground level.

  28. How about continental drift changing ocean currents? That affects whether or not parts of the world can get snow and ice cover. That affects the planet’s overall albedo. Then, the ratio of atmospheric to oceanic CO2 is a positive feedback. Then, if a lot of ice accumulates somewhere, sea level drops, and that reduces ocean currents that bring warmth to cold places. Conversely, the reverse if the world warms.

    Of course that’s not the whole story, because there was CO2 removal when vegetable matter was changed to fossil fuels after being built from CO2.

    • DLK
      And global air currents are disrupted by mountain ranges. Mountain ranges cause orographic precipitation, which will be predominantly snow for very high mountains, meaning little or no chemical weathering. Often there are deserts on the leeward side of mountains, again meaning little chemical weathering compared to mechanical erosion.

  29. Over simplification of earths processes without any factors of grand scale geological change over millions of years and their effect. Never mind lack on real understanding that dosen’t look like dry lab experiments.

  30. It’s Sun ! !
    On decadadal scale TSI varies about 0.1, on Megaannum scale the variability could be much greater, + or – 1% with associated feedbacks might easily do it.

  31. “These rocks are readily eroded, particularly in warm, wet, tropical latitudes, and the sediment is sent out to oceans where it consumes CO2.”

    The situation is not as simple as the authors portray. The removal of a mountain range proceeds by a mixture of chemical weathering and mechanical erosion. The chemical weathering predominates at high temperatures, with abundant water (low elevations). However, it doesn’t take long (geologically speaking) for a growing mountain range in the tropics to get to an elevation where the chemical weathering is dominated by stream erosion, frost wedging, and even glacial erosion. Therefore, the mafic and ultramafic rocks are no longer more highly susceptible to removal than sialic rocks. More importantly, with high mountains being reduced primarily by mechanical weathering, the ferromagnesian minerals are not acting as sinks for CO2 because they are not releasing magnesium and calcium ions, just grains of sand. Additionally, ophiolite blocks tend to be unusual situations, not the normal surface-exposed rocks produced by subduction. Once the mountain range ceases growing, it will be reduced to a peneplain in about 50 million years. At that point, it is developing a deep lateritic soil profile that (as the authors) acknowledge protects the bedrock from chemical weathering. There is a lot that has been overlooked in this paper!

    Geologists are renowned for hand waving when promoting new hypotheses. However, these two seem to have added a propeller beanie to their distractions for a not very well thought out scenario.

  32. Plate tectonics is what drives this geologic carbon cycle. When one tectonic plate slides under another — usually a dense ocean plate under a continent — the melting rock fuels a row of volcanoes on the top plate called a volcanic arc. The Cascade Range of the Pacific Northwest is one example of this.

    1) This geologic carbon cycle is only 0.1% for volcanism. Hence, it is way too small for it to have any affect. 2) Why not ice free now with no ice caps when volcanic activity has been active for thousands of years recently. Only recent decades volcanic activity had declined that effected the stratosphere.
    3) Plate tectonics change the ocean currents and ultimately decide where most of the planets energy is going.
    4) Plate tectonics hugely alter the planets albedo based on our 3) affects the glaciers and ice caps.
    5) CO2 lags temperature at all time scales, especially thousands and millions of years ago referring to this article.
    6) Points 3) + 4) largely determine where vegetation can exist on the planets surface and affect about 28% of the carbon cycle on this vegetation alone.

    This article only confirms that some scientists are still learning how the behaviour of a complexed system behaves and still stick by claims that are in fact incorrect.

  33. This came out of the university of california, if they hadn’t pushed the CO2 Barrow then they probably would have been fired. there would certainly have been no follow up grants to do any research.

  34. This obsession with CO2, is it the requirement for yet another government
    grant.
    Its all very simple, the continents float on the molten core. So as they move
    around so the seas also move in different directions, transporting the heat
    from the Equater to both North and South.

    For example when the North and South of America were two seperate land
    masses, the transportation of this hat energy would have been very different
    from today.

    Throw in the factors affecting us from Space, and any combination of climate
    is possible,

    But never fear, it all happens so slowly that we adaptable human beings can
    manage, and just as long as we can access energy in all of its forms, we will
    prosper.

    MJ E VK5ELL

  35. Interesting that no one has mentioned galactic cosmic rays (GCR) and the effects they can have on cloud formation. Very basically the more GCR’s that enter the atmosphere the more clouds form which leads to cooling and vice versa. When talking about climate change on a time scale of 1000’s of years it can be assumed that the number of GCR’s reaching the solar system is constant, but the number reaching the Earth varies due to changes in the strength of the sun’s magnetic field. This leads to cooling during periods of low solar activity, e.g during the little ice age and warming during periods of high solar activity, e.g the late 20th century. However on time scales of millions or 10’s or 100’s of millions of years the number of GCR’s reaching the solar system changes as the Earth’s position in the galaxy changes and we move from areas with a lot of stars to areas with fewer stars, as well as being affected by nearby super nova explosions. This is likely to be the main factor in determining the onset of ice ages or warm periods, although the location of land masses and their effect on ocean currents may well have some role.
    For a book length discussion of the above I recommend The Chilling Stars by Henrik Svensmark and Nigel Calder. For what it’s worth, in my opinion it is the best book on climate change yet. Not sure if it’s been published in the U.S. but well worth tracking down, ISBN-13: 978-1840468-15-1.

  36. CTM: DId this one get lost in moderation? Or ? Posted at around 4PM Calif daylight time
    2nd try:

    I’m sorry to see that the response to this interesting proposal is (as far as I read) carping about the mention of CO2 warming. Folks, there isn’t any debate over WHETHER CO2 is a GH gas, the $64 Trillion question is, by how much? Much weaker than water vapor, for sure!

    UCSB has a long history of innovative thinking about plate tectonics and climate, led by my colleague Tanya Atwater. And the idea that ice ages may be driven by the rise of the Himalayas was originated by B. Clark Burchfiel, my old structural geology prof at Rice.

    Anyway, the point is, this is (sfaict) a serious scientific proposal, and treating it as Yet Another Michael Mann-style folly makes us, the skeptics, look silly So stop it .
    My comments (of course) don’t apply to the more serious responses later in the thread.

    Peter D. Tillman, certified skeptic
    B.Sc., Geology & Chemistry, Rice Univ.
    M.Sc., Geochemistry, UNC -CH

    “Perhaps the earliest widely-held theory for the Tunguska
    explosion was that the world was about to end. As the minutes
    passed, this theory was dropped in favour of other, less final
    theories, until today one is hard-pressed to find anyone who
    truly believes the world ended on the morning of 30 June 1908..”
    –K. Zahnle, Nature_383_, 674-75 (1996)

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