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Birth of oil: geology, temperature, CO2

The left-wing blogosphere tries to humiliate Rep Barton and climate change at geological timescales. I am stunned by the extremely low quality of the discussion at most blogs. They essentially try to picture Rep Barton as a Young Earth creationist - there is no justification for such a description here - and they ignore his question completely.

Dr Chu failed to give a particularly quantitative answer to Rep Barton; see Steve McIntyre's article dedicated to the same observation.

So let us ask again: Why is there oil in Alaska? Where did all the biological material come from? It turns out that continental drift was comparably important for the elevated temperatures needed to create oil as the global mean temperature. In this sense, Chu and Barton were comparably close to the truth, despite the emotional indications of many superficial blogs.

Late Jurassic, about 150 million years ago, when the world's largest oil fields were born. The continental drift has substantially changed the arrangement of continents since that time.

Here are the periods of the Phanerozoic eon, together with the fashionable life forms, temperatures, CO2 concentrations, and places where petroleum or coal was being born. Recall that the current global mean temperature is about 14 °C and the CO2 concentration, including the human contributions as of 2009, equals 385 ppm. You will see that the temperature used to be noticably higher and the CO2 concentrations used to be substantially higher. All the data are taken from Wikipedia.

The timestamps are written in between the periods:

  • 542 million years ago
    Proterozoic era ends, Paleozoic era begins
  • The Cambrian: 4500 ppm, 21 °C
    expansion of life, trilobites (anthropods)
  • 488 million years ago
  • The Ordovician: 4200 ppm, 16 °C
    marine animals, mollusca
  • 444 million years ago
  • The Silurian: 4500 ppm, 17 °C
    corals, mosses
  • 416 million years ago
  • The Devonian: 2200 ppm, 20 °C
    seeds, forests, many sharks, fish
  • 359 million years ago
  • The Carboniferous: 800 ppm, 14 °C
    sea stars, sponges, corals, fish, equisetales, insect, tetrapods, fungi
  • 299 million years ago
  • The Permian: 900 ppm, 16 °C
    invertebrates, reptiles, cockroaches, cynodonts
    Coal in Siberia, East Asia, Australia; Oil in the U.S.
  • 251 million years ago (extinction event)
    Paleozoic era ends, Mezozoic era begins
  • The Triassic: 1750 ppm, 17 °C
    no coal, new corals, ammonites, turtles
  • 199 million years ago
  • The Jurassic: 1950 ppm, 16.5 °C
    dinosaurs, crocodiles, conifers, coralline algae
    Oil in Middle East, North Sea, Siberia (part)
  • 145 million years ago
  • The Cretaceous: 1700 ppm, 18 °C
    figs, magnolias, some mammals, birds, modern sharks
    Oil around Venezuela; Earth by 4 °C warmer than today; see Climate Audit
  • 65 million years ago (extinction event)
    Mesozoic era ends, Cenozoic era begins
  • The Paleogene: 500 ppm, 18 °C
    birds and mammals explode
  • 23 million years ago
  • The Neogene and The Quaternary Period (last 2 megayears): 280 ppm, 14 °C
    mammals include early humans
  • Today
  • Our world in 2009: 385 ppm, 14 °C
You can see that there have been several periods, e.g. The Ordovician, when the CO2 concentration was more than 10 times higher than it is today. But the temperature only differed by 2 degrees Celsius. And this is true despite the fact that the bulk of the CO2-temperature relationship is actually caused by outgassing rather than the greenhouse effect.

At any rate, both global changes as well as the continental drift have been contributing to the ability of different regions to create petroleum while the CO2 has been violently changing and has been irrelevant for the climate throughout the history of the Earth.

And that's the memo.

Bonus: geological climate sensitivity

Finally, let me perform a simple exercise with Mathematica: by the way, the price is now GBP 195 plus VAT only. Click the logo below.

While I have emphasized that the CO2-temperature relationship is mostly caused by the influence of temperature on the gas concentrations (as seen through the 800-year lag in the Vostok data), let us assume that this whole relationship is caused by the greenhouse effect. And let us calculate the climate sensitivity - warming per CO2 doubling - from the 11 geological data points above.
Download the geological notebook
Let us define the CO2 concentration and temperature vectors:
ppm = {4500, 4200, 4500, 2200, 800, 900, 1750, 1950, 1700, 500, 280};
temp = {21, 16, 17, 20, 14, 16, 17, 16.5, 18, 18, 14};
Now, calculate the base-two logarithms of the CO2 concentrations:
logPPM = N[Log[ppm/280]/Log[2]] =
= {4.0064263, 3.9068906, 4.0064263, 2.9740048, 1.5145732, 1.6844982, 2.6438562, 2.7999754, 2.602036, 0.83650127, 0.}
Finally, we will find the linear fit for those data:
data = Transpose[{logPPM, temp}]
lm = LinearModelFit[data, logCONC, logCONC]; Normal[lm]
Now, get ready for a shock. The result is
14.854913 + 0.89326377 logCONC
This means that for 280 ppm, the predicted temperature should be 14.85 °C, higher than today. For 385 ppm, this function predicts 15.26 °C. The warming expected from a CO2 doubling, based on those 11 ancient historical points, is just 0.89 °C. Now, this result assumed that the whole relationship is due to the greenhouse effect. Actually, less then 10% is caused by the greenhouse effect.

This correction would imply that a sensible estimate for the climate sensitivity would be just a tenth of a degree, much less than Richard Lindzen's minimalistic estimates.

Of course, many other changes have occurred on the Earth. At any rate, geology strongly indicates that the CO2 concentration has always been irrelevant and it is sensible to expect that it will be irrelevant in the future, too. The sensitivity - warming caused by the CO2 doubling - is between 0.1 °C and 1 °C.

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snail feedback (1) :

reader Unknown said...

I don't believe that is valid to conclude the concentration of CO2 in the atmosphere is irrelevant, especially to an ecosystem.

For example, if we take today's entire ecosystem, living in the Quaternary, and put it in the Cretaceous, what will be the impact to the ecosystem? Assume that the Cretaceous ecosystem is replaced by the Quaternary.

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