Dear Dr . Hoesung Lee,

With the recently published Synthesis Report, the IPCC has completed its sixth assessment cycle, comprising a total of seven reports. An international team of scientists from the 1,500-strong Climate Intelligence Foundation (Clintel) has reviewed several claims from the Working Group 1 ( The Physical Science Basis ) and Working Group 2 ( Impacts, Adaptation and Vulnerability ) reports. The results are summarized in Clintel’s report The Frozen Climate Views of the IPCC . Clintel’s in-depth analysis reveals serious flaws in latest IPCC report.

As background, I would like to remind you of the InterAcademies Council (IAC) review of IPCC procedures in 2010, which was commissioned after catastrophic publicity about errors in previous IPCC reports and revelations about attempts by IPCC lead authors to suppress debate. The IAC concluded in part:

Since the IAC report was partly produced after the discovery of errors in the most recent assessment, the committee also examined the IPCC’s review process. It concluded that the process is thorough, but that stronger enforcement of existing IPCC assessment procedures could minimize errors. To this end, the IPCC should encourage review editors to fully exercise their authority to ensure that all review comments are adequately considered. Review editors must also ensure that real controversies are reflected in the report and be sure that due consideration has been given to well-documented alternative viewpoints. Lead authors must explicitly document that the full range of considered scientific views has been considered. Seehere.

We regret to conclude that the IPCC has not followed this advice and that the AR6 has the same shortcomings as before, namely a biased selection of evidence, a failure to reflect real controversies and a failure to adequately take into account well-documented alternative views.

For example, the IPCC ignored crucial peer-reviewed literature showing that normalized disaster losses have decreased since 1990 and that human deaths from extreme weather have decreased by more than 95% since 1920. The IPCC authors made the opposite conclusions based on cherry-picked evidence, claiming that damage and death rates from anthropogenic climate change had increased, and the review process failed to correct this inaccuracy.

Clintel’s 180-page report, The Frozen Climate Views of the IPCC , is the first large-scale international ‘assessment’ of the IPCC’s Sixth Assessment Report. In 13 chapters, the Clintel report shows that the IPCC makes numerous serious scientific mistakes that generally reflect a bias towards ‘bad news’ versus ‘good news’.

This was the case throughout the report and especially in the preparation of the Executive Summary for Policymakers. For example, the good news about disaster losses and climate-related deaths was omitted from the Executive Summary for Policymakers.

In addition, where the IPCC AR6 has taken into account evidence pointing to bleak, worst-case prospects, such as the recognition that the RCP8.5, SSP5-8.5 and SSP3-7.0 emissions scenarios are low probability and that models systematically predict warming overestimates in the tropical troposphere, these findings are buried deep in the chapters and are not highlighted to the media or policy makers.

Even worse, despite the fact that the discussion of emission scenarios concludes that the extremes are unlikely, they nevertheless receive maximum attention in other parts of the report to project the climate effects.

Finally, we note that the IPCC has remained silent while the UN Secretary-General and other senior officials have repeatedly misrepresented the IPCC’s findings. For example, Secretary General Guterres said of the Working Group 1 report:

“Today’s IPCC Working Group 1 report is a code red for humanity. The alarm bells are ringing and the evidence is irrefutable: greenhouse gas emissions from fossil fuel burning and deforestation are suffocating our planet and putting billions of people in immediate danger.” Source here .

The AR6 Working Group 1 report did not say these things, but the IPCC never corrected it, nor did it dispute the similarly inaccurate media coverage that distorts the content of your report.

With all due respect, dr. Lee, seriously misleading the world on such an important subject and on such a large scale is unacceptable for a UN organization that claims to be scientific. The errors and biases Clintel found in the AR6 report are worse than those that led to the 2010 IAC Review, suggesting that the IPCC is still failing to deliver on its mission.

The Clintel network therefore requests the following:

• That the IPCC commission a team of representatives from Clintel and other independent individuals not involved in the IPCC leadership to assess whether the IPCC has fully implemented and followed the 2010 reforms recommended by the IAC Review, and whether there are more reforms are needed.

• That the IPCC review prominent statements by major world leaders and media outlets that paraphrase the contents of the AR6 and correct the report where those statements are misleading or inaccurate.

• That the IPCC meet with Clintel representatives to get input on the key deficiencies identified in our report that require formal correction.

Looking forward to your response,

Sincerely,
dr. AJ (Guus) Berkhout, chair of Clintel
Emeritus Professor of Geophysics
Member of the Royal Netherlands Academy of Arts and Sciences

Gus Berkhout.

***

Gus Berkhout.

PS

The main objective of the Climate Intelligence Foundation (Clintel) is to generate knowledge and insight into the causes and consequences of climate change, as well as into the effects of climate policy. Clintel published the World Climate Declaration , which has now been signed by more than 1,500 scientists and experts around the world, rivaling the IPCC Working Group’s author lists in scope and credentials. See here .