Wood Romances

I watched a lecture recently with Dr. Jessica Tierney, who is a professor of geosciences at the University of Arizona. Her lecture was fascinating to me because she explains how reanalyses (what she calls Data Assimilation or DA) can be used to reconstruct past climates. The lecture also gives us a preview to an upcoming paper with Tierney as a co-author that reconstructs global temperatures over most of the Phanerozoic (almost 500 million years). The method they use is notable to me for it's use in  Osman's recent reconstruction for which Tierney is a co-author. I won't go into a lot of detail here, since she explains it in the above video, but essentially DA starts with  an ensemble of model simulations of past climates as a "prior." The model ensemble is spatially complete, but it isn't real - it's a simulation of what the past may have been like. DA then corrects the model results with proxy data. The proxy data has a huge advantage over models in tha...

It's well-established physics that the Earth's surface is ~33K warmer than its effective temperature, and the relationship between increasing CO2 and radiative forcing can be approximated by the following logarithmic equation: ΔF = 5.35*ln (C/Co) where, Co is an initial concentration of CO2 (preindustrial CO2 is generally regarded as 280 ppm).  C is the concentration of CO2 at any given time (currently 420 ppm). The equation shows the change in the outgoing flux at the top of the atmosphere caused by a change in CO2 concentrations. Since CO2 concentrations have increased by 50%, we can say CO2 has caused a decrease in the outgoing flux of 5.35*ln (1.5) = 2.2 W/m^2. As a result of this decrease in outgoing flux, more energy enters the climate system than escapes into space, and so the planet's surface must warm until the outgoing flux equals incoming again. The relationship between a change in radiative forcing and temperature is linear, so ΔT = λ*ΔF So essentially the relat...

WA07 Demonstrating Verification Failure of M&M This is part 3 of a 3 part series on M&M's accusations of "tricks" on the part of MBH and the hockey stick. Part 1 is here and Part 2 is here . Stephen McIntyre is reporting another "Nature Trick" on his ClimateAudit blog. The post is from Nov 24, 2023. As I've pointed out before, the MBH98/99 hockey stick have been replicated so many times that it's really old news. In 2007, Wahl and Amman were able to emulate the MBH98/99 hockey stick reconstruction and verify that it was robust to statistical method. But there were some slight differences between the two, and it seems some people won't be happy until they emulate it exactly.  An "Audit" of MBH98/99 In 2021, Hampus Söderqvist apparently succeeded in reproducing MBH98/99 exactly, but in the process of doing so, he discovered some minor errors from the infilling of grid box temperatures in Jones & Briffa 1992 that affected MBH98/99...

Cenozoic CO2 and Temperature A new paper was published this month that I think will produce some exciting new insights for those interested in historical geology and paleoclimate studies. The paper is a product of the Cenozoic Carbon dioxide Proxy Integration Project (CenCO2PIP) Consortium, and it looks to reconstruct the proxy evidence for CO2 levels during the Cenozoic (the last 66 million years). The Cenozoic began after the asteroid impact (and/or volcanism) at the Cretaceous-Tertiary (K-T) boundary that caused the mass-extinction that included the extinction of non-avian dinosaurs. The value of this kind of work will have significant benefits for scientists as they seek to constrain estimates for long-term climate sensitivity (ESS). We can think of "sensitivity" on roughly three time scales:  TCR : On a near-immediate time scale, GMST increases with increasing CO2 in what is called transient climatic response (TCR), which generally speaking tells you how quickly temperat...

By 2007, the MBH98/99 papers had been thoroughly investigated. The MBH hockey stick was found to be robust to statistical method and it was replicated by multiple other reconstructions (above, and discussed  here , here and here ). After the CRU emails were hacked and published, a new set of conspiracy theories were popularized on blogs and YouTube - these were based on a misreading of various emails (discussed  here and here ), but contrarian rhetoric was ramping up to a frenzy. Mann was frequently labeled a criminal and fraud, the hockey stick was called a scam or a hoax.  The Mann v Ball Libel Suit In an interview with the Frontier Centre for Public Policy  (FCPP), Tim Ball was asked, "Various government and academic agencies have whitewashed the Climategate scandal so far. Do you think anyone will be prosecuted for fraud?” Tim Ball's response was, “Michael Mann at Penn State should be in the State Pen, not Penn State.” This was posted on the FCPP website and a...

Hockey Sticks Featured in the North Report In two previous posts ( here and here ), I described the challenges by McIntyre and McKitrick (M&M) to the initial two hockey stick papers published by Mann, Bradley and Hughes (MBH98 and MBH99). In these posts I summarized M&M's multiple critiques of the MBH hockey stick papers, essentially that the "hockey stick" is an artifact of flaws in the MBH statistical method and an over reliance on one set of North American tree ring proxies. However, multiple peer-reviewed papers following M&M's criticism generally found that M&M's criticisms lacked merit and vindicated the MBH hockey stick reconstruction. To summarize: 1. Biases associated with MBH's statistical method were small and contributed very little to the shape of the MBH hockey stick reconstruction. Biases associated with M&M's statistical method went in the opposite direction, and M&M exaggerated the effect of statistical bias on the...