Wood Romances

I saw a s hort presentation  by R.B. Alley a while back that did a marvelous job of explaining why geologists have overwhelmingly concluded that greenhouse gases (and in particular CO2 ) are the primary drivers of climate changes on geologic time scales. This presentation was given prior to the publication of Judd et al 2024 ,[1] so I thought it might be fun to show how his argument would be enhanced even more with the more recent data we now have about Phanerozoic temperature and CO2. But let me set the stage. GMST is set by a balance between incoming absorb solar radiation (ASR) and outgoing longwave radiation (OLR). ASR is affected by changes in how much sunlight reaches the earth ( solar variability ), where and when sunlight reaches the earth ( orbital cycles ) and how much is reflected vs absorbed ( albedo ). Outside influences can also at least theoretically play a role in affecting process on earth ( galactic cosmic rays ) that could change how much incoming solar is a...

GMST Follows CO2 Forcings , not Solar Forcings You could be forgiven for looking at the above graph and thinking that quite obviously temperature (GMST) is following CO2 forcings and not solar forcings. But these facts are inconvenient for the "It's the Sun, stupid" crowd, so they have to figure out a way to turn this on its head. The most common way I've seen is for contrarians to say we have causation reversed. It's actually the increase in GMST that causes CO2 to increase, since warming temperatures causes the oceans to outgas CO2. The mantra I hear from this crowd is that " CO2 always lags temperature ," usually followed with "by hundreds of years." Let's examine if this claim makes any sense, looking first at the paleoclimate evidence (where this myth originated) and then the historical evidence, where this claim can be conclusively refuted. Paleoclimate Evidence The "CO2 always follows temperature" myth has its origin a mis...

Accounting for Climate Forcings Puts ECS Near 3 °C From ClimateBrink The so-called "Climate Working Group," hired by the Department of Energy to write what Roger Pielke Jr termed a "red team" response to climate science  (my initial response is here ) is predictably critical of the central scientific estimate for ECS. The first ECS estimate I know of was calculated by Arrhenius, who concluded that 2xCO2 would cause between 4-6°C warming. This value was revised downward by Gilbert Plass in the 1950s to ~3°C, and since the 1970s this has become the standard estimate. The IPCC currently says the likely range is 2.5-4.0°C, largely as a result of Sherwood et al 2020 (S22),[1] which is still to date the most comprehensive assessment of ECS (Sherwood's likely range was 2.6-3.9°C). There is a growing body of scientific literature arguing that recent observational evidence is more consistent with an ECS closer to 4°C, suggesting that the IPCC may be a bit conservative on...

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...