Clintel Climate Intelligens

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

Dr. A.J. (Guus) Berkhout
President of Clintel

The Hague, September 20, 2023 

Dear Dr. Skea,

On August 25 Clintel has sent you a registered letter with the sad conclusion that the IPCC has failed to follow the advice of the 2010 InterAcademy Council (IAC) review. The IPCC Sixth Assessment Report (AR6) exhibits the same flaws as in previous reports, namely biased selection of evidence, failure to reflect genuine controversies and failure to give due consideration to properly documented alternative views.

In the same letter, Clintel’s propositions for IPCC were formulated as follows:

– That the IPCC commissions a team with representation from Clintel and other independent persons not involved in IPCC Leadership to review whether the IPCC has fully implemented and followed the reforms recommended by the 2010 IAC Review, and whether more reforms are needed.

– That the IPCC reviews prominent statements by major world leaders and media outlets paraphrasing the contents of the AR6 and corrects the record where those statements are misleading or inaccurate.

– That the IPCC meets with representatives from Clintel to receive input on the key deficiencies highlighted in Clintel’s report The Frozen Climate Views of the IPCC that require a formal correction.

A new situation has occurred that makes Clintel’s proposal for cooperation most urgent.

Recently, scientists at CERES-Science have co-authored three important peer-reviewed scientific papers, providing substantial scientific advances in the very complex scientific problem that is technically referred to as the “detection and attribution of climate change” since the mid-19th century*.

In short, the CERES scientists have come with a very important conclusion: “The IPCC’s chosen estimates of the changes in solar activity (“total solar irradiance” or TSI for short) only represented a small subset of those used by the scientific community. Several of the TSI estimates the IPCC had neglected in their analysis suggest that most of the warming since the 19th century could be natural – especially from the non-urbanized data.” The latter is very relevant, given the fact that measurements in urban areas have been increasingly influenced by the well-known ‘heat island effect’.

*For a quick summary of what they found, see the Sep 1st, 2023 press release. For a more detailed summary see their recent Sep 8th, 2023 blog post.

Given these data-driven results, we at least must conclude that the scientific community is nót in a position to say that the global temperature changes since the mid-19th century have been “mostly human-caused” as IPCC AR6 claimed. An excellent opportunity to start the dialogue as proposed in my previous letter to you.

Unfortunately, a handful of activist scientists has been carrying out an orchestrated disinformation campaign to discredit and misrepresent the findings of the CERES scientists. This campaign seems to be largely organized by the team (

As I am addressing here the essence of the climate debate – finding the principal causes of climate change – let us together organize an open discussion on “The natural and human causes of climate change”.

We are sure that scientific transparency, honesty and openness would positively impact on IPCC’s credibility. We must cooperate to eliminate the present dogma’s, harsh polarization and exclusions, which we increasingly witness in the scientific community.

Finally, Clintel will make a public statement that the campaign of is not the proper way of having a scientific debate. I hope IPCC will do the same.

Looking forward to hearing from you,

Yours sincerely,

Dr. A.J. (Guus) Berkhout, President of Clintel
Emeritus Professor of Geophysics
Member of the Royal Netherlands Academy of Arts and Sciences

P.S. The main objective of the Climate Intelligence Foundation (Clintel) is to generate knowledge and understanding of the causes and effects of climate change, as well as of the effects of climate policy. Clintel published the World Climate Declaration, which has now been signed by more than 1600 scientists and experts worldwide, thus rivalling in size and credentials the IPCC’s Working Group authorship lists. See