Researchers have always been curious as to past climates where the earth was sometimes much colder and mostly ice covered, or much warmer with forests up to the poles. Or somewhere in between. In more rational times, it was recognised that tectonic shifts and rearrangement of continents, causing changed ocean circulation patterns, was the main reason for these very long term climate changes over tens and hundreds of millions of years. The oceans contain more than half a billion cubic kilometers of water, a substance with an unusually high heat capacity. This gigantic heat capacitor dominates climate. It is fair to say that climate is a study of ocean behaviour while weather is the study of atmospheric processes.
Figure 1. The global system of ocean circulation at multiple depths is called the “Thermo-Haline Circulation”or THC. It is the main way that heat is carried from the equator to the poles and redistributed among continents.
However we no longer live in rational scientific times. The coercive control of the politics of climate change means that scientists, if they wish to continue their careers and have correct and approved reputations, must bow the knee to a new doctrine that everything in climate is, and always has been controlled by nothing but CO2. Tectonic movements and ocean circulation can no longer be discussed as reasons for climate and climate change – it can only be CO2. If anything else is mentioned, it is only insofar as it affects CO2.
The recent paper, Soreghan et al 2019, “Explosive volcanism as a key driver of the late Paleozoic ice age”
shows the morass of self-defeating confusion into which palaeo climate research has fallen on account of its subservience to the dogma of CO2 control of climate.
The abstract begins with the half-sentence “Atmospheric CO2 exerts a robust and well-documented control on Earth’s climate”, which is the equivalent of starting with “in the name of the Father, the Son and the Holy Ghost” or “there is one Allah and Mohammed is his prophet”. However the second half of that same opening sentence is self-contradictory, “but the timing of glaciation during the late Paleozoic Ice Age (LPIA; ca. 360–260 Ma) is inconsistent with pCO2 reconstructions, hinting at another factor.” So the first sentence could be paraphrased as “CO2 controls the climate. Except when it doesn’t.”
Climate change over deep time is primarily driven by tectonic rearrangement of continents and of the system of 3 dimensional ocean circulation. And by factors such as mountain uplift at colliding plates and coverage of the poles by land. But this dominant palaeo climate driver is completely absent from this paper. That alone invalidates it completely, without having even to look at its CO2 obeisant narrative. The word “tectonic” is absent from the paper. The word “ocean” appears three times; in each case only to ascribe to the ocean the role of capacitor, storing and remembering atmospheric driven changes in climate.
“Diminishing pCO2 along with lower solar luminosity (Crowley and Baum, 1992) is the preferred explanation for the LPIA.” “Preferred” is code for doctrinally mandatory. Tectonic shift, continental configuration and ocean circulation have ceased to exist as agents of long term climate change. PhD students in this research field are quite likely no longer even aware of the existence of these phenomena. It’s “atmosphere only” for agents of climate change. The oceans just lag obediently behind atmospheric driving of temperature. The tail wags the dog.
“Atmosphere only” of course means mainly CO2, with correcting tweaks as necessary from volcanoes. Volcanism can both cool climate as needed in the LPIA, and also warm it in the cases of the Deccan Trap (end Cretaceous) and Siberian (end Permian) flood basalt extinction events. You just alternate the focus between particulate shading for cooling and CO2 (salla Allahu alayhi wa-ala Ali-hi wa-sallam) backradiation for warming.
Never was the volcanic control knob of the CO2 control knob more needed than in the LPIA (late palaeozoic ice age). The authors truthfully reveal one of the most glaring mismatches in palaeo climate history between changing temperatures and changing CO2 levels. The discrepancies are explained thus by the authors:
For example, pCO2 (Foster et al., 2017) exhibits an ambiguous relationship to the timing of onset, demise, and peak of the LPIA: whereas pCO2 reached a nadir at ca. 338–334 Ma, peak glaciation occurred ca. 298–295 Ma (Fig. 1). The highest-resolution reconstructions (Montañez et al., 2016) cover a brief interval of the LPIA (ca. 311–298 Ma) and show pCO2 lows ca. 305 Ma and 298 Ma, closer to peak ice conditions, but depict pCO2 rising at the apex of the LPIA (ca. 298–295 Ma; Fig. 1). Moreover, climate and climate–ice sheet models indicate a CO2 glaciation threshold at ∼560 ppmv (Lowry et al., 2014), but high-resolution pCO2 reconstructions for the interval near peak icehouse (Montañez et al., 2016) show a high-frequency oscillation both above and below this threshold. Finally, climate models cannot account for hypothesized equatorial glaciation (Soreghan et al., 2014) in moderate-elevation uplands without invoking pCO2 levels (<200 ppmv) that would stress modern vegetation (Pagani et al., 2009), calling into question either the data or the modeling.
So CO2 was rising, not falling, at the coldest glacial maximum of the LPIA. Furthermore, equatorial glaciation, as occurred during the LPIA (late Palaeozoic ice age) can only be induced in computer simulations (built on the assumption of CO2 control of climate) where CO2 drops to levels (below 200 ppm) where plants are stressed – inconsistent with data showing no such stress and aridity (or evolution of C4 photosynthesis that happen only 200 million years later in the modern CO2 starved era). Again, CO2 centrism drives the argument into an impossible dead end.
The apostle Paul said “I take all human arguments and make them subservient to Jesus Christ.” The modern equivalent of this is making all scientific discourse on climate subservient to Carbon Dioxide. So continental tectonic shifts don’t change climate by changing transport of the half billion cubic kilometres of the molecule water with its anomalously high heat capacity, from equator to poles, or by cooling the atmosphere directly by uplifting permanently frozen mountain ranges. Or the latitudinal level of continents. No – the effect of tectonic movement can only be via silicate weathering draw-down of CO2, or volcanic release of CO2, or volcanic release of CO2-cancelling sulphate particulates. And the ocean is dismissed as a mere memory-puddle, carrying a trace of atmospheric forcings of the prior 2000 years or so.
Insisting on carbon centric control of climate leads to tortuously complicated non parsimonious explanations of the LPIA in which one mechanism initiates glaciation, and another (sulphate particulates from volcanism) sustains it while overwhelming a recalcitrantly rebounding higher CO2 level.
Although CO2 forcing likely drove the cold of the Late Mississippian, we posit that volcanic forcing was particularly critical for sustaining cold conditions thereafter (Fig. 3).
This is similar to the extraordinary contortions required to explain why in the high resolution ice core record of the glacial Quarternary, changes in CO2 lag behind matching changes in temperature by 500-1000 years. Some “other” mechanism that is mumbled then quickly forgotten, initiates the temperature change; CO2 begins to rise in response to the temperature change, but then, wonder of wonders, this reactive increases in CO2 suddenly jumps into the driving seat and becomes the chief driver of the temperature change. The roles of parent and child are miraculously swapped. The arrow of time reverses. By this stage in the narrative the gushing focus on CO2 means that the initial cause of temperature change is already conveniently forgotten.
Volcanoes dim the atmosphere with particles for only a short time after eruption. However much sound and fury accompanies their eruption, atmospheric circulation and precipitation are efficient at removing these quite fast, so that dimming and cooling effects are quite short lived. This is well documented for Pinatubo and other big recent volcanoes. So it is quite a stretch to argue that sustained deep glaciation is maintained by a string of volcanoes. This would also argue that the cooling forcing of sulphate from a volcano must be stronger than the warming forcing from the CO2 (salla Allahu …) that the same volcano also emits. This would argue for much sharper cooling post-volcano than is actually observed in recent volcanoes like Pinatubo, whose cooling imprint is scarcely detectable in the context of steady warming.
Geologists are taking a big risk by hitching their wagon so totally to the carbon story and basing all palaeo geology on a foundation of CO2 control of climate. Even rewriting theory of glaciation and forgetting – maybe even soon repudiating – tectonic continental drift. And ignoring the oceans. If and when the CO2 back radiation myth of heat creation finally collapses, much of this revisionist CO2 geology will go right down with it.