Andy May Petrophysicist

A Critique of AR6

By Andy May

Read in German here, courtesy of Christian Freuer.

After more than two years of hard work, Marcel Crok, I, and 11 other scientists have finally published our critique of the Intergovernmental Panel on Climate Change (IPCC) sixth report (AR6). The entire book has been extensively peer reviewed and a low-resolution pdf of a nearly final draft of the book has been available for weeks at clintel.org. All comments received on this draft have been carefully considered and incorporated, if approved by the team, in the final book. We are a bit hard on AR6, but our criticisms are well deserved. Only the eBook is out now, the print edition should be along in a week or two. The Kindle edition is text-to-speech enabled. Available at Amazon and Kobo.

The Holocene CO2 Dilemma

Guest Post By Renee Hannon

This post evaluates the relationship of global CO₂ with regional temperature trends during the Holocene interglacial period. Ice core records show that CO₂ is strongly coupled with local Antarctic temperature and slightly lags temperature over the past 800,000 years (Luthi, 2008). Whereas the emphasis has been on CO₂ and temperature lags/leads, this study focuses on Holocene millennium trends in different latitude-bounded regions.

Open letter to Dr Hoesung Lee, Chair of the IPCC

The following letter was sent to Dr. Lee, the Chair of the IPCC earlier today (May 25th, 2023) by Dr. A.J. (Guus) Berkhout, President of Clintel, Emeritus Professor of Geophysics, and a member of the Royal Netherlands Academy of Arts and Sciences

Read in German here, courtesy of Christian Freuer.

Professor Dr. Hoesung Lee, Chair of the IPCC,
c/o World Meteorological Organization
7bis Avenue de la Paix C.P. 2300
CH -1211 Geneva 2, Switzerland.

The Hague, May 25, 2023

Dear Dr. Hoesung Lee,

With the recently published Synthesis Report, the IPCC finished its sixth assessment cycle, consisting of seven reports in total. An international team of scientists from the 1500-strong Climate Intelligence Foundation (Clintel) has assessed several claims from the Working Group 1 (The Physical Science Basis) and Working Group 2 (Impacts, Adaptation and Vulnerability) reports. Results have been summarized in Clintel’s report The Frozen Climate Views of the IPCC:

Thorough analysis by Clintel shows serious errors in latest IPCC report – Clintel

Is AR6 the worst and most biased IPCC Report?

By Andy May

This is the text of my presentation on Tom Nelson’s podcast which can be viewed here. The question and answers start at about 18:15 into the interview.

Christian Freuer has translated this post to German here.

The first IPCC Physical Science Basis report is called “FAR” and was first published in 1990. An updated 1992 version of the report contains this statement:

“global-mean surface air temperature has increased by 0.3°C to 0.6°C over the last 100 years … The size of this warming is broadly consistent with predictions of climate models, but it is also of the same magnitude as natural climate variability. … The unequivocal detection of the enhanced greenhouse effect from observations is not likely for a decade or more.”
(IPCC, 1992, p. 6).

The Mysterious AR6 ECS, Part 4, converting observations to ECS

By Andy May

Christian Freuer has translated this post to German here.

In part one we discussed various estimates of climate sensitivity (ECS, TCR, and observation-based values) and what they mean, especially those reported in the latest IPCC report, AR6. In part 2 we discussed the uncertainty in estimating cloud feedback to surface warming, and cloud feedback’s relationship with ECS. In part 3 we compared the various estimates to one another and discussed the differences between them. In this part we will discuss how Lewis and Curry convert their observation-based estimates of climate sensitivity to AR6-equivalent ECS values. Most conversions of observations to model based ECS are done in a similar way.

The Mysterious AR6 ECS, Part 3, What is Climate Sensitivity?

By Andy May

Christian Freuer has translated this post to German here.

The Mysterious AR6 ECS, Part 2, the Impact of Clouds

By Andy May

Christian Freuer has translated this post to German here.

The yearly net impact of clouds on outgoing and incoming radiation varies over one W/m² from year-to-year, according to CERES satellite data.^[1] AR6 tells us that cloud feedbacks, to GHG surface warming, are the largest source of uncertainty in their assessment of the warming in the past century as we can see from the AR6 Figure 7.10—our Figure 1.

AR6 page 926, reports that it is very likely global net cloud feedback is positive, but the uncertainty is much higher than for other surface temperature feedbacks. The very likely range they report is -0.1 to 0.94 W/m²/°C.^[2] Thus, the total uncertainty is over one W/m² per degree of surface warming, this estimate is totally model based.

The Mysterious AR6 ECS, Part 1

Chart, waterfall chart Description automatically generated

By Andy May

Christian Freuer has translated this post to German here.

The climate sensitivity to CO₂ and other greenhouse gases (GHGs) is arguably the most important number in the climate change debate. AR6^[1] claims the sensitivity, which they call “ECS” or the equilibrium climate sensitivity, is three degrees per doubling of CO₂, or 3°C/2xCO₂ (“/2xCO₂” simply means per doubling of the atmospheric CO₂ concentration). They claim the very likely (10% to 90%) range of possible values is from 2 to 5°C/2xCO₂ and the likely (66%) range has narrowed to 2.5 to 4°C. Since 1979, with the publication of 1979 Charney Report,^[2] the range of possible ECS values has normally been about 1.5 to 4.5°C for a total range of 3°C, how has it now narrowed to 2.5 to 4°C, a full likely uncertainty range of only 1.5°C? It is generally accepted that the direct warming effect of CO₂ and other greenhouse gases is small, only about one degree per doubling of CO₂,^[3] so the debate is all about the feedbacks, especially cloud feedback to the greenhouse gas warming.^[4]

The error of the mean: a dispute between Gavin Schmidt and Nicola Scafetta

By Andy May

You can read this post in German here, courtesy of Christian Freuer.

Here we go again, writing on the proper use of statistics in climate science. Traditionally, the most serious errors in statistical analysis are made in the social sciences, with medical papers coming in a close second. Climate science is biting at their heels.

In this case we are dealing with a dispute between Nicola Scafetta, a Professor of Atmospheric Physics at the University of Naples and Gavin Schmidt, a blogger at RealClimate.org, a climate modeler, and director at NASA’s Goddard Institute for Space Studies (GISS).

Past and Present Warming – A Temporal Resolution Issue

By Renee Hannon

Christian Freuer has translated this post into German here.

This post examines how present global surface temperatures compare to the past 12,000 years during the Holocene interglacial. The AR6 IPCC climate assessment report, Climate Change 2021: The Physical Science Basis, by Working Group 1 states in their Summary for Policymakers section A.2.2:

“Global surface temperature has increased faster since 1970 than in any other 50-year period over at least the last 2000 years (high confidence). Temperatures during the most recent decade (2011–2020) exceed those of the most recent multi-century warm period, around 6500 years ago [0.2°C to 1°C relative to 1850–1900] (medium confidence). Prior to that, the next most recent warm period was about 125,000 years ago, when the multi-century temperature [0.5°C to 1.5°C relative to 1850–1900] overlaps the observations of the most recent decade (medium confidence).”
AR6

Renee Hannon on The Holocene CO2 DilemmaJune 3, 2023
The Osman study is a blended evaluation using a climate model that incorporates proxy data. Osman also presents his proxy…
Renee Hannon on The Holocene CO2 DilemmaJune 3, 2023
“ The Holocene conundrum is well on way to being resolved by the same author who identified it”. Bova’s 2021…
Jack Dale on The Holocene CO2 DilemmaMay 31, 2023
if you like books about climate and history, I also suggest Firmament by Simon Clark. https://www.amazon.ca/Firmament-Science-Weather-Climate-Surrounds/dp/1529362318
Andy May on The Holocene CO2 DilemmaMay 31, 2023
I bought it, it looks good. We are going on holiday tomorrow, so I'll read it on the plane.
Andy May on The Holocene CO2 DilemmaMay 31, 2023
I bought Fagan's book, it looks interesting and I really like books that combine history and climate, I've read several…

A Critique of AR6

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The Holocene CO2 Dilemma

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Open letter to Dr Hoesung Lee, Chair of the IPCC

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Is AR6 the worst and most biased IPCC Report?

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The Mysterious AR6 ECS, Part 4, converting observations to ECS

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The Mysterious AR6 ECS, Part 3, What is Climate Sensitivity?

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The Mysterious AR6 ECS, Part 2, the Impact of Clouds

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The Mysterious AR6 ECS, Part 1

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The error of the mean: a dispute between Gavin Schmidt and Nicola Scafetta

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Past and Present Warming – A Temporal Resolution Issue

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