Carbon dioxide level unprecedented in 15 MY… More evidence it’s not the climate control knob!

Guest “implied face palm” by David Middleton

From The Grauniad (where else?)

Figure 1. Lions and Tigers and Beras! The Grauniad

“Beras” is not a typo… I’m a big fan of the late Yogi Bera, and I will try to fit a Yogi’ism in here somewhere.

Standard Graunad tripe (or is it trope?)…

The amount of carbon dioxide in the Earth’s atmosphere is approaching a level not seen in 15m years and perhaps never previously experienced by a hominoid, according to the authors of a study.

At pre-lockdown rates of increase, within five years atmospheric CO2 will pass 427 parts per million, which was the probable peak of the mid-Pliocene warming period 3.3m years ago, when temperatures were 3C to 4C hotter and sea levels were 20 metres higher than today.

The Grauniad

Figure 2. Implied face palm.

The Grauniad article links to a very good paper (de la Vega et al., 2020). They compiled a high resolution reconstruction of Mid-Pliocene Piacenzian stage CO2 concentrations.

Figure 3. 300-450 ppm CO2 – Run away! (de la Vega et al., 2020)

If the Earth was 3-4 °C warmer with a much higher sea level 3.3 million years ago, with about the same CO2 concentration, what does this say about the potency of it as a climate control knob?

The last time CO2 levels were this low, Earth was in the deepest ice age of the Phanerozoic Eon, the Pennsylvanian (Late Carboniferous)-Early Permian.

Figure 4. “Anthropocene” CO2 levels are a lot closer to the C3 plant starvation (Ward et al., 2005) range than they are to most of the prior 540 million years. Data from this WUWT post by Bill Illis.

You can see that the atmospheric CO2 levels of the Pennsylvanian Period were comparable to the “Anthropocene” (yes, a fake word – but I use it for sarcastic effect). We can also see that Earth was perhaps even a bit colder then than it is today.

Figure 5. Phanerozoic temperatures (pH-corrected) and carbon dioxide. The Miocene is the first epoch of the Neogene Period (Berner et al, 2001 and Royer et al., 2004) (older is toward the left).

While estimates of Pennsylvanian-Permian CO2 concentrations vary widely, the average level was likely in the 400-450 ppm range. So Earth was at least somewhat colder the a similar CO2 concentration in the Late Paleozoic.

Thanks to Bill Illis, I have this great set of paleoclimate spreadsheets.  One of the paleo temperature data sets was the pH-corrected version of Veizer’s Phanerozoic reconstruction from Royer et al., 2004.  The Royer temperature series was smoothed (spline fit?) to a 10 million year sample interval matching Berner’s GeoCarb III,  thus facilitating cross-plotting.

A cross-plot the pH-corrected Phanerozoic temperatures with CO2 yields a climate sensitivity of 1.28 °C per doubling, very much in line with recent observation-based low sensitivities. More of a treble adjustment, rather than a control knob.

Figure 6. Phanerozoic CO2 vs temperature. Unlabeled x-axis is in millions of years before present.

Royer’s pH corrections were derived from CO2, so it shouldn’t be too much of a surprise that the correlation was so good (R² = 0.6701)… But the low climate sensitivity is truly “mind blowing”… /Sarc.

The notion of Phanerozoic Eon climate change being driven by atmospheric carbon dioxide levels was generally scoffed at as recently as the 1970’s.

Suggestion that changing carbon dioxide content of the atmosphere could be a major factor in climate change dates from 1861, when it was proposed by British physicist John Tyndall.

[…]

Unfortunately we cannot estimate accurately changes of past CO2 content of either atmosphere or oceans, nor is there any firm quantitative basis forestimating the the magnitude of drop in carbon dioxide content necessary to trigger glaciation.  Moreover the entire concept of an atmospheric greenhouse effect is controversial, for the rate of ocean-atmosphere equalization is uncertain.

Dott & Batten, 1976

What about 15 million years ago?

There is a school of thought that the warmth of 15 million years ago, the Mid-Miocene Climatic Optimum (MMCO) was driven by CO2 released from the flood basalt eruptions of the Columbia River Basalt Group (CRBG).

Figure 7. I feel as if I’ve written this before… Yogi’ism #1. Midwest Capital Advisers

According to Kashbohm & Schoene (2018)…

Flood basalts, the largest volcanic events in Earth history, are thought to drive global environmental change because they can emit large volumes of CO2 and SO2 over short geologic time scales. Eruption of the Columbia River Basalt Group (CRBG) has been linked to elevated atmospheric CO2 and global warming during the mid-Miocene climate optimum (MMCO) ~16 million years (Ma) ago. However, a causative relationship between volcanism and warming remains speculative, as the timing and tempo of CRBG eruptions is not well known. We use U-Pb geochronology on zircon-bearing volcanic ash beds intercalated within the basalt stratigraphy to build a high-resolution CRBG eruption record. Our data set shows that more than 95% of the CRBG erupted between 16.7 and 15.9 Ma, twice as fast as previous estimates. By suggesting a recalibration of the geomagnetic polarity time scale, these data indicate that the onset of flood volcanism is nearly contemporaneous with that of the MMCO.

Kashbohm & Schoene (2018)

It does appear that the timing of the vast majority CRBG eruptions can be fairly well tied down to a 700,000 to 900,000 year period coincident with the Mid-Miocene Climatic Optimum. However, even with the prodigious volume of CO2 associated with flood basalt eruptions, it’s not enough to significantly move the “climate needle”:

A statistic: It is estimated that an erupting basalt lava flow with a volume of 2000 km3 would release approximately 7 billion tonnes of carbon (or 26 billion tonnes of CO2).

This is about the same as the amount currently released by burning of fossil fuels – each year.

Saunders & Reichow

Armstrong McKay et al., 2014 estimated that the main phase of the CRBG eruptions, along with “cryptic degassing” of country rock, etc., emitted 4,090 to 5,670 billion tons of carbon over a 900,000 period. This only works out to 5-6 million tonnes of carbon per year… That’s an order of magnitude less than a rounding error. Our current 10 billion tonnes per year is only equivalent to 3% of the total annual sources in the Earth’s carbon budget. Self et al., 2005 found that CO2 emissions from flood basalt eruptions were insignificant relative to the mass of CO2 in the atmosphere and unlikely to have played a signifcant role in past episodes of “global warming.” Although they did note that the sulfur gas emissions may truly have been unprecedented.

While the impact of volcanic S gas release may be profound, the mass of CO2 directly released by individual flood lava eruptive events is tiny in comparison to the normal mass in the troposphere and stratosphere. The predicted increases in atmospheric concentration are a fraction of the current anthropogenic CO2 released from hydrocarbon burning (~25 Gt per year). Moreover, while the amount of CO2 in the atmosphere is currently ~3000 Gt, it was perhaps double this value during the late Cretaceous (i.e. ~6000 Gt). It is therefore unlikely that volcanic CO2 had a direct effect on mechanisms of global warming, supporting earlier findings by Caldeira and Rampino (1990). In addition, there would have been more than sufficient time for the extra mass of CO2 added to equilibrate, given that the lava-forming eruptive events must have been spaced at least hundreds, and probably thousands, of years apart. By contrast, SO2 emissions and the atmospheric burden of sulfate aerosols generated during flood basalt events appear to be unprecedented at any other time in Earth history. Acid rain may also have been widespread. What is less certain is whether affected biota would have had time to recover from the deleterious effects of sulfate aerosol clouds and acid rain, although quiescent intervals lasting millennia appear to offer ample time for the recovery of local biological and environmental systems (Jolley 1997).

Self et al., 2005

This ultimately takes us full-circle back to my Historical Geology textbook…

Unfortunately we cannot estimate accurately changes of past CO2 content of either atmosphere or oceans, nor is there any firm quantitative basis for estimating the the magnitude of drop in carbon dioxide content necessary to trigger glaciation.  Moreover the entire concept of an atmospheric greenhouse effect is controversial, for the rate of ocean-atmosphere equalization is uncertain.

Dott & Batten, 1976

We can’t even be certain that the atmospheric concentration of CO2 during the Mid-Miocene Climatic Optimum was significantly elevated relative to the extremely low values of the Quaternary Period.

Figure 8. Neogene-Quaternary temperature and carbon dioxide (older is toward the left).

We can see that the range of estimates for MMCO range from 250 to 500 ppm, rendering any efforts to draw conclusions about the CRBG, CO2, MMCO totally pointless. According to Pagani et al, 1999:

There is no evidence for either high pCO2 during the late early Miocene climatic optimum or a sharp pCO2 decreases associated with EAIS growth.

Pagani et al., 1999

Pagani et al., suggest that changes in oceanic circulation driven by plate tectonics (opening of the Drake Passage) and the presence (or lack thereof) of a large polar ice sheet were the primary drivers of Miocene climate change. And this takes us to another of my 1970’s Earth Science textbooks:

FORECASTING THE FUTURE. We can now try to decide if we are now in an interglacial stage, with other glacials to follow, or if the world has finally emerged from the Cenozoic Ice Age. According to the Milankovitch theory, fluctuations of radiation of the type shown in Fig. 16-18 must continue and therefore future glacial stages will continue. According to the theory just described, as long as the North and South Poles retain their present thermally isolated locations, the polar latitudes will be frigid; and as the Arctic Ocean keeps oscillating between ice-free and ice-covered states, glacial-interglacial climates will continue.

Finally, regardless of which theory one subscribes to, as long as we see no fundamental change in the late Cenozoic climate trend, and the presence of ice on Greenland and Antarctica indicates that no change has occurred, we can expect that the fluctuations of the past million years will continue.

Donn, William L. Meteorology. 4th Edition. McGraw-Hill 1975. pp 463-464

Despite having less than 12 years to solve the “climate crisis,” we are still living in an Ice Age, and will be so long as Antarctica remains isolated over the southern polar region, Greenland retains its ice sheet and the northern polar region retains at least seasonal ice cover.

Figure 9. From Zachios et al., 2001 (older is toward the bottom).

The roughly 1.0 °C of warming since the coldest climatic period of the Holocene, the Little Ice Age, hasn’t budged us out of the Quaternary Period temperature “noise level.”

Figure 10. High Latitude SST (°C) From Benthic Foram δ18O (Zachos, et al., 2001) and HadSST3 ( Hadley Centre / UEA CRU via http://www.woodfortrees.org) plotted at same scale, tied at 1950 AD (older is toward the left).

Another 0.5 to 1.0 ºC between now and the end of the century doesn’t even put us into Eemian climate territory, much less the Miocene or even the Pliocene. We will still be in the Quaternary Period noise level. Bear in mind that the instrumental temperature data are of much higher resolution than the δ18O derived temperatures. As such, the δ18O data reflect the bare minimum of dynamic amplitude range. Actual paleo temperatures would have reflected a far greater range of variability (higher highs and lower lows).

When you come to a fork in the road…

Figure 11. Yogi’ism #2 AZ Quotes

When you come to a fork in the road, take it… unless that fork follows an utterly failed paradigm. While there is ample evidence that atmospheric CO2 levels have some effect on the bulk temperature of the troposphere, the notion that it was a primary driver of climate change was scoffed at as recently as the 1970’s.

This sort of nonsense is… nonsense:

At pre-lockdown rates of increase, within five years atmospheric CO2 will pass 427 parts per million, which was the probable peak of the mid-Pliocene warming period 3.3m years ago, when temperatures were 3C to 4C hotter and sea levels were 20 metres higher than today.

So what? We can take a long walk through deep time and find lots of periods when temperatures and sea levels were much higher with CO2 levels ranging from 250 to 2,500 or more ppm. We don’t find many periods when it was colder than today, with lower sea levels.

Figure 12.  L-R: Relative sea level (Miller et al., 2005), atmospheric CO(Berner & Kothavala, 2001) and temperature anomalies (Royer et al., 2004) since Late Jurassic Period (170 MYA).

If you just go with the observations, you won’t take the wrong fork.

Figure 13. Yogi’ism #3. (Goalcast)

When did CO2 become the control knob?

We can see from my college text books and the geological record that CO2 wasn’t the control knob as recently as 1976. For than matter, the March 1, 1975 cover of Science News magazine was 180 degrees out of phase with today’s narrative.

Figure 14. Science News March 1, 1975

The much-vaunted IPCC tells us that all of the warming since The Ice Age Cometh is due to human activities, primarily COemissions.

Figure 15. Figure TS.23 from IPCC AR4. The lower panel (b) has two curves. The black curve depicts IPCC’s version of observed temperature changes since 1900. The blue curve is what IPCC says how temperatures would have evolved “if humans had not contributed to greenhouses gases in any way at all”, or at least not very much.

As can be seen in TS.23 (b), according to the IPCC, the human contribution to global temperatures was insignificant before The Ice Age Cometh in 1975.

Figure 16. How the Current Fake Climate Crisis Saved Us From… That 70’s Climate Crisis Show

Back to The Grauniad

I was so busy with the geology stuff that I forgot to quote the funniest bit of The Grauniad article…

“A striking result we’ve found is that the warmest part of the Pliocene had between 380 and 420 parts per million CO2 in the atmosphere,” one of the co-authors Thomas Chalk, said. “This is similar to today’s value of around 415 parts per million, showing that we are already at levels that in the past were associated with temperature and sea-level significantly higher than today.”

“Currently, our CO2 levels are rising at about 2.5 ppm per year, meaning that by 2025 we will have exceeded anything seen in the last 3.3 million years.”

The authors said the study of the past provided a guide to what is likely to happen in the future as the Earth responds to the buildup of greenhouse gas from the past two centuries of industrial emissions.

“Ice sheets today haven’t had a chance to catch up with CO2 forcing. We are burning through the Pliocene and heading towards a Miocene-like future,” said another of the authors, Gavin Foster, a professor of isotope geochemistry at the University of Southampton. “We now have to go further back in time to find situations that are relevant.”

The Grauniad

Figure 17. Yogi might have said this… But it’s credited to Larry the Cable Guy.

The authors said the study of the past provided a guide to what is likely to happen in the future as the Earth responds to the buildup of greenhouse gas from the past two centuries of industrial emissions.

The problem with today’s academic geology is that, all too often, they get the principle of uniformitarianism bass-ackwards.

The past history of our globe must be explained by what can be seen to be happening now. No powers are to be employed that are not natural to the globe, no action to be admitted except those of which we know the principle.

James Hutton, 1785

“The past history of our globe must be explained by what can be seen to be happening now,” not by model-derived assumptions about what’s happening now. The assumption that CO2 is the primary driver of modern climate change now has polluted interpretations of the past, leading to wildly exaggerated estimates of climate sensitivity and models which have consistently overestimated the predicted warming. I think Yogi had one for this too.

Figure 18. Yogi’ism #4 (First Coast Advisers

But, of course…

Figure 19. Yogi’ism #5 (AZ Quotes)

Five Yogi’ism’s in one post! Unprecedented?

References

Armstrong McKay, David, Toby Tyrrell, Paul A. Wilson, & Gavin Foster. (2014). “Estimating the impact of the cryptic degassing of Large Igneous Provinces: A mid-Miocene case-study”. Earth and Planetary Science Letters. 403. 254–262. 10.1016/j.epsl.2014.06.040. Special thanks to David Armstrong McKay for kindly sending me a copy of his paper.

Berner, R.A. and Z. Kothavala, 2001. GEOCARB III: A Revised Model of Atmospheric CO2 over Phanerozoic Time, American Journal of Science, v.301, pp.182-204, February 2001.

de la Vega, E., Chalk, T.B., Wilson, P.A. et al. Atmospheric CO2 during the Mid-Piacenzian Warm Period and the M2 glaciation. Sci Rep 10, 11002 (2020). https://ift.tt/2W7ngzT

Donn, William L. Meteorology. 4th Edition. McGraw-Hill 1975. pp 463-464

Dott, Robert H. & Roger L. Batten.  Evolution of the Earth.  McGraw-Hill, Inc.  Second Edition 1976.  p. 441.

Illis, B. 2009. Searching the PaleoClimate Record for Estimated Correlations: Temperature, CO2 and Sea Level. Watts Up With That?

Kasbohm, Jennifer, and Blair Schoene. “Rapid Eruption of the Columbia River Flood Basalt and Correlation with the Mid-Miocene Climate Optimum.” Science Advances, American Association for the Advancement of Science, 1 Sept. 2018, advances.sciencemag.org/content/4/9/eaat8223.

Miller, Kenneth & Kominz, Michelle & V Browning, James & Wright, James & Mountain, Gregory & E Katz, Miriam & J Sugarman, Peter & Cramer, Benjamin & Christie-Blick, Nicholas & Pekar, S. (2005). “The Phanerozoic Record of Global Sea-Level Change”. Science (New York, N.Y.). 310. 1293-8. 10.1126/science.1116412.

Pagani, Mark, Michael Arthur & Katherine Freeman. (1999). “Miocene evolution of atmospheric carbon dioxide”. Paleoceanography. 14. 273-292. 10.1029/1999PA900006.

Royer, D. L., R. A. Berner, I. P. Montanez, N. J. Tabor and D. J. Beerling. CO2 as a primary driver of Phanerozoic climate.  GSA Today, Vol. 14, No. 3. (2004), pp. 4-10

Self, Stephen & Thordarson, Thorvaldur & Widdowson, Mike. (2005). “Gas Fluxes from Flood Basalt Eruptions”. Elements. 1. 10.2113/gselements.1.5.283.

Tripati, A.K., C.D. Roberts, and R.A. Eagle. 2009.  “Coupling of CO2 and Ice Sheet Stability Over Major Climate Transitions of the Last 20 Million Years”.  Science, Vol. 326, pp. 1394 1397, 4 December 2009.  DOI: 10.1126/science.1178296

Zachos, J. C., Pagani, M., Sloan, L. C., Thomas, E. & Billups, K. “Trends, rhythms, and aberrations in global climate 65 Ma to present”. Science 292, 686–-693 (2001).

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July 10, 2020 at 08:37PM

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