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

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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).
Continue reading “Is AR6 the worst and most biased IPCC Report?”

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.

Continue reading “The Mysterious AR6 ECS, Part 4, converting observations to ECS”

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

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 this part we compare the values from various sources to one another.

Continue reading “The Mysterious AR6 ECS, Part 3, What is Climate Sensitivity?”

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.

Continue reading “The Mysterious AR6 ECS, Part 2, the Impact of Clouds”

The Mysterious AR6 ECS, Part 1

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]

Continue reading “The Mysterious AR6 ECS, Part 1”

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).

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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
Continue reading “Past and Present Warming – A Temporal Resolution Issue”

Koonin wins in Cornell Oxford Style Debate

By Andy May

Steve Koonin is still undefeated!

The Steamboat Institute hosted a Campus Liberty Tour Oxford style debate at Cornell University on Mar 15, 2023. Drs. Steven Koonin and Robert Socolow debated the resolution:

“Climate science compels us to make large and rapid reductions in greenhouse gas emissions.”

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Atmospheric water vapor (TPW) and climate change

By Andy May

Christian Freuer has translated this post into German here.

In the latest IPCC major report, AR6, they report: “a best estimate of equilibrium climate sensitivity of 3°C, with a very likely range of 2°C to 5°C”.[1] They also report that CO2 concentration might control climate change.[2] This estimate includes the laboratory estimate that CO2 alone, if doubled in the atmosphere, would increase the average global surface temperature about 1.2°C.[3] The remaining 1.8°C (60%) is supposedly achieved through feedbacks to the initial CO2-caused warming. The main proposed feedback mechanism is an increase in atmospheric water vapor caused by the CO2 warmed air.[4] Water vapor is a more powerful greenhouse gas than CO2, due to its greater abundance, and can cause more warming.[5]

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