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PETM – Finally an example of CO2 causing heat?

Posted by Frank Lansner (frank) on 7th May, 2010
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PETM – Finally an example of CO2 causing heat? Finally an example where CO2 and the greenhouse gasses can be the direct initiator of heat in real data?

- Now and then the Global Warming hypothesis is defended by mentioning the ”PETM”.
The “Paleocene–Eocene Thermal Maximum” lasted around 100.000 years, occurred 55 million years ago and separates the Paleocene and Eocene periods.

The PETM reached a maximum global temperature around 5-6 Kelvin above temperatures before and after the PETM, and the PETM was accompanied by raise in CO2 content in the atmosphere.

In other words, the PETM is one more large temperature/CO2 rise in addition to the large temperature peaks during the ice ages that enables analysis of the supposed strong warming effect of CO2.

In the case of the ice age temperature peaks, I reach the conclusion that data cannot show the supposed strong warming effect of CO2:

 - Can the PETM finally show the supposed strong warming effect of CO2? Can we finally have some data that actually shows the strong CO2-effect?

For the PETM, what came first, the heat or the CO2?
In many sources, this quite central issue is not mentioned, and the Dutch scientist Appy Sluijs from the University of Utrecht has compiled a fantastic useful and competent overview of all writings about the PETM where all specific issues of the PETM is considered wisely.

Sluijs has found and summarized the writings that comments on the timing: What came first, heat or CO2?

The general conclusion is, that the Carbon input to the atmosphere for the PETM appeared around 3000 thousand years AFTER the temperature rise….

In this context read chapter 7:

Sluijs: "Global warming leads the carbon isotope excursion at the Paleocene-Eocene thermal maximum"


 Examples from different studies referred to in Sluijs conclusion:

1) "Assuming above sedimentation rates, the onset of the Apectodinium acme leads the onset of the CIE by in the order of 4-5 kyr."

- the onset of the Apectodinium acme is an indicator of heat

- the onset of the CIE is the indicator of Carbon input to the atmosphere, due to changes isotopic content of Carbon.

 2) "Critically, the record implies that the onset of anomalous warming is located ~25-30 cm below the CIE, with approximately half of the PETM warming occurring before the onset of the CIE (Fig. 2). Assuming above sedimentation rates, the onset of warming preceded the onset of the CIE by approximately 2.5-3 kyrs"

3) At Wilson Lake, the onset of the CIE, representing the main negative step in δ13C, is assigned to 109.8 mbs based on both δ13CDINO and δ13CBC (Fig. 3). This implies that also here the onset of the Apectodinium acme (~110.4) leads the CIE 112 Warming precedes the CIE by ~0.6 m. Assuming the above sedimentation rates this would represent about
4-5 kyr.

4) Atthe North Sea site, the lowermost position to which the onset of the CIE can be attributed is at ~2927 meters below sea floor (mbsf) (Fig. 3), while the onset of the δ13CTOC CIE by ~0.5 m, which represents about 4 kyr at this site.

The PETM episode like the glacial temperature peaks shows CO2 increasing after temperatures. Like the Glaical temperature peaks, the PETM episode does not rule out some effect of CO2, but we still need the evidence that CO2 it self can drive temperatures strongly.

This is interesting because we have many huge volcanoes inducing CO2 over the time, so it should be possible to show many peaks of temperature rise based on CO2 (and greenhouse gasses) only? It should be possible to point out the real evidence of CO2 warming if it is there.





Why is it, that we dont really have an independent volcano induced large CO2-input to the atmosphere that actually STARTS a large temperature jump? 

Last changed: 7th May, 2010 at 13:36:13



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