Another Round Of Anti-Science From The IPCC

by P. Homewood, Aug 19, 2021 in NotaLotofPeopleKnowThat


McIntyre is promptly on the job again. Here is his post of August 11, basically dismantling the new Hockey Stick. If you have a taste for a lot of technical detail, I urge you to read the whole thing. But the gist is actually simple. This time these people were not going to get caught furtively “hiding the decline.” Instead, they announce boldly that they are simply going to exclude any data that do not fit the narrative that they are putting forth.

McIntyre goes through multiple of the data series that contribute to the “shaft” of the new stick. Most just appear to be random fluctuations up and down. But then there are the few key series that show the sharp 20th-century uptick needed to support the Hockey Stick narrative. One such series is the McKenzie Delta tree ring series from Porter, et al., of 2013. McIntyre goes back to that Porter article and quotes the passage that describes how the researchers chose those trees that would contribute to the series:

AR6 and The Paleocene-Eocene Thermal Maximum

by Andy May, Aug 18, 2021 in WUWT


The PETM or Paleocene-Eocene Thermal Maximum was a warm period that began between 56.3 and 55.9 Ma (million years ago). The IPCC AR6 report (actually a draft, not a final edited report), released to the public on August 9, 2021, suggests that this warm period is similar to what is happening today and they expect to happen in the future (IPCC, 2021, pp. 2-82 & 5-14). During the PETM, it was very warm and average global surface temperatures probably peaked between 25.5°C and 26°C briefly, compared to a global surface temperature average of about 14.5°C today, as shown in Figure 1.

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oday we have tens of thousands of daily temperature measurements around the world and can calculate a fairly accurate global average surface temperature. To construct a global average for the PETM we must rely on proxy temperatures, such as oxygen isotope ratios, Calcium/Magnesium ratios in fossil shells, and fossil membrane lipids that are sensitive to temperature like Tex86. Proxy temperature values are sparsely located and have a temporal resolution, 56 Ma, of thousands to hundreds of thousands of years. Thus, in terms of rate of temperature change, they are not comparable to today’s monthly global averages.

Before diving into the PETM, we will provide some geological perspective. According to Christopher Scotese, the highest global average temperature in the Phanerozoic (the age of complex shelled organisms, or the past 550 million years) was the Triassic hothouse event, following the end of the Karoo Ice Age, around 250-300 Ma. Global average surface temperatures peaked then at about 27.9°C.

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Two Dozen Top Scientists: IPCC “Premature” Blaming CO2 Emissions…Warming Mostly From Natural Cycles

by P. Gosselin, Aug 18, 2021 in NoTricksZone


Most of the energy in the Earth’s atmosphere comes from the Sun. This new study found that the UN’s Intergovernmental Panel on Climate Change (IPCC) only considered a small subset of the published TSI datasets when they assessed the role of the Sun in climate change and that this subset only included “low solar variability” datasets. As a result, the IPCC was premature in ruling out a substantial role for the Sun in recent climate change.

A diverse expert panel of global scientists finds blaming climate change mostly on greenhouse gas emissions was premature. Their findings contradict the UN IPCC’s conclusion, which the study shows, is grounded in narrow and incomplete data about the Sun’s total solar irradiance.

The paper by 23 experts in the fields of solar physics and of climate science from 14 different countries is published in the peer-reviewed journal  (RAA). The paper, which is the most comprehensive to date, carries out an analysis of the 16 most prominent published solar output datasets, including those used by the IPCC.

Scientists come to opposite conclusions recent climate change causes 

The researchers compared them to 26 different estimates of Northern Hemisphere temperature trends since the 19th century (sorted into five categories), including the datasets used by the IPCC. They focused on the Northern Hemisphere since the available data for the early 20th century and earlier is much more limited for the Southern Hemisphere, but their results can be generalized for global temperatures.

The IPCC’s attribution methodology is fundamentally flawed

by R. McKitrick, Aug 18, 2021 in ClimateEtc.


One day after the IPCC released the AR6 I published a paper in Climate Dynamics showing that their “Optimal Fingerprinting” methodology on which they have long relied for attributing climate change to greenhouse gases is seriously flawed and its results are unreliable and largely meaningless. Some of the errors would be obvious to anyone trained in regression analysis, and the fact that they went unnoticed for 20 years despite the method being so heavily used does not reflect well on climatology as an empirical discipline.

My paper is a critique of “Checking for model consistency in optimal fingerprinting” by Myles Allen and Simon Tett, which was published in Climate Dynamics in 1999 and to which I refer as AT99. Their attribution methodology was instantly embraced and promoted by the IPCC in the 2001 Third Assessment Report (coincident with their embrace and promotion of the Mann hockey stick). The IPCC promotion continues today: see AR6 Section 3.2.1. It has been used in dozens and possibly hundreds of studies over the years. Wherever you begin in the Optimal Fingerprinting literature (example), all paths lead back to AT99, often via Allen and Stott (2003). So its errors and deficiencies matter acutely.

The abstract of my paper reads as follows: