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CO2 Coalition's Most Recent Political Tract from Happer and Lindzen

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A few years ago, I responded to a political " comment " from the CO2 Coalition in which Happer, Lindzen (and potentially ghost writers) made a series of self-contradictory claims about climate sensitivity. Recently I became aware of another political tract in which they simplified their argument tremendously. They've also hidden almost all their math, making it more difficult to check up on what they say. However, there is plenty we can say about this that shows that they are still actively changing their opinions, and this always in the direction of distancing themselves from the best scientific evidence. Much of this tract depends on the following graph: The graph above is supposed to agree with another chart in the tract, and it mostly does, except that ΔT14 = 0.054°C above but is wrongly rounded up to 0.06°C. In the description of these calculations, this tract asks, " How much warming did CO2 cause when CO2 increased from 280 ppm in 1750 to the 420 ppm in the ...

What Caused the Paleocene-Eocene Thermal Maximum (PETM)?

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The Paleocene–Eocene Thermal Maximum (PETM) was a period of time beginning about  56 million years ago. Temperatures increased by 5–8°C[2][4] due to a large excursion of biogenic carbon. Temperatures increased extremely rapidly, and the perturbation of the carbon cycle led to ocean acidification and a mass extinction of benthic foraminifera. The warming event occurred suddenly, geologically speaking, perhaps in as little as 10,000 years[12], making it one the most rapid warming events detected in the Phanerozoic. The extreme warmth of the PETM lasted less than 220,000 years before returning to "normal" Eocene levels. The rapid warming warming associated with the PETM makes it a good analogue to current warming, so I think it would be helpful to cover this event as well as provide a bibliography for further reading on the subject. The PETM is also one among many examples in geologic history where it is clear that GHGs were driving global warming. CO2 led (and drove) the warmin...