Clintel: The Frozen Views of the IPCC

In 2023 an organization called Clintel (a combination of Climate and Intelligence) published a document called The Frozen Climate Views of the IPCC: An Analysis of AR6. The title cracks me up because this document implies that the IPCC has views that are "frozen" in place, and their unwilling update their views with new evidence. But in point of fact, the IPCC publishes new versions of their assessment every few years, while the talking points in this document are basically the same talking points contrarians have been using for decades.

The Clintel Foundation published a statement claiming "there is no climate emergency." They've gotten perhaps 2000 people (scientists and professionals) to sign the document. A few of the signatories were climate scientists (though most are retired). This publication was not authored by any of these qualified climate scientists. The two named authors are: 

• Marcel Crok is "science writer, climate optimist, speaker, co-founder of the Climate Intelligence Foundation." 
• Andy May is a "writer and petrophysicist," by which he means he has a B.S. in Geology and career working for Exxon before becoming a climate blogger. 

Neither of the lead authors have any expertise or experience in climate science. The contributing authors fare little better:

• Dr. Javier Vinós (molecular biologist, writer, Spain) 
• Dr. Ross McKitrick (Professor of Economics, University of Guelph, Canada) 
• Dr. Nicola Scafetta (Professor of Atmospheric Physics, University of Naples Federico II, Italy) 
• Kip Hansen (science research journalist, USA) 
• Dr. Fritz Vahrenholt (Professor, University of Hamburg, Germany) 
• Dr. Ole Humlum (Professor, University of Oslo, emeritus, Norway)

Of these, only Scafetta has credentials that would qualify him to contribute to a document evaluating AR6, and while he's cited several times, he's only listed as an author of one chapter on why the IPCC supposedly downplays the Sun (they don't). Many of these writers have a history of writing very poor critiques of various climate science in the past, and (heads up) nothing is going to change here. 

The fact that virtually none of these contributing authors have any expertise or experience in climate science to evaluate AR6 does not at all mean that this document is a flawed criticism of AR6, but it might explain why so little of this document actually evaluates AR6. The document is for the most part a compilation contrarian talking points that these authors (and other contrarians) have been sharing on blogs, self-published books, and political sites for years, and they have already been refuted. In fact, I had already written rebuttals to many of these points before the Clintel document was published. Crok and May just added some superficial references to AR6 to contrarian talking points that have been debunked for decades.

So it occurs to me that this document can be debunked in about the same way it was written. I've already written rebuttals to many of these arguments, and as have many others. So below I reproduced the table of contents for this document, and underneath the headings, I link to responses I've already written, so you can click on the links to get a rebuttal. For headings where I haven't written anything, if I know of other rebuttals, I'll link to those. And when I write rebuttals of any of these talking points I'm currently missing, I'll add links to this. Note: I combined a few headings for short, related sections, and I've deleted a few headings in the outline that seem redundant or unnecessary (like summary and conclusion sections).

A. Observations

1. No confidence that the present is warmer than the Middle Holocene

Graph from Ryan Katz-Rosene

Proxy-Based Temperature Reconstructions

There is plenty of evidence that the 21st century is already warmer than the HTM and therefore warmer than the past 125K years.

1. My discussion of Marcott et al 2013, Part 1 and Part 2. Part 2 is particularly relevant to whether current warming is exceptional and conclusive that current warmth has surpassed that of the middle Holocene.
2. I also discuss the way that Vinós tampered with Marcott's data to make the HTM fully 2x warmer than the LIA by rescaling the graph.
3. Reanalysis studies tend to show a mid-Holocene that is cooler wrt the present than proxy-only reconstructions. Osman's reconstruction shows relatively flat temperature trends for most of the Holocene.
4. This paper discusses uncertainties related to the warmth of the HTM. 

The Holocene Temperature Conundrum

The Holocene Temperature Conundrum is real. Models have a hard time reconstructing the HTM in a way that matches studies like Marcott. This is an area of ongoing research, but it's not evidence against CO2 as a primary driver of GMST changes

1. Osman's reconstruction is closer to models. This is an area of ongoing study, but it's certainly not evidence that CO2 isn't the primary driver of global warming.
2. Comparing CO2 to GMST for the last 24,000 years shows a broad correlation between CO2 and GMST.

Glacier Advances & Treelines

1. This post from Ryan Katz-Rosene does a good job of explaining geologically how warming rates affect glacial advances and treelines.

Instrumental Temperature Changes Uncertainty

1. This section of the Clintel document has some of the most humorous nonsense of the entire document. I respond to their claims about instrumental uncertainties here.
2. I have a series of posts addressing challenges to the GMST temperature record, an outline of which can be found here.
3. I have a series of posts addressing challenges to the CONUS temperature record, an outline of which can be found here.

2. The Resurrection of the Hockey Stick

Are humans 100% responsible for Modern Warming?

1. The short answer is "yes." AR6 was based on a large amount of evidence that this is the case, though perhaps the most significant is Gillett et al 2021, which I discuss here.

University of Bern and the Hockey Stick

1. I have a series of responses to challenges to the hockey stick, an outline of which can be found here.
2. The hockey stick has been replicated in the scientific literature about 60 times. Jim Java has a running list of these replication papers here. It's hard to find a more well-established finding in climate science than this.

How the Medieval Warm Period disappeared from AR6

1. It's becoming increasingly clear that the MWP was warm in parts of the globe but not all of the globe. It appears warmer in graphs of Central England Temperatures from the 1960s (like Lamb's reconstruction), but it becomes less pronounced when using globally distributed proxy evidence.

How robust is the new hockey stick?

1. If the hockey stick was not robust it, it would not be found in every reconstruction of global mean surface temperature showing at least the last 1000 years. It is robust to types of proxy evidence and statistical method. This has been shown time again in the 60+ reconstructions that replicate the hockey stick.

3. Measuring Global Surface Temperatures

How significant is the global warming since the 19th century?

1. The four major GMST datasets using thermometer networks (HadCRUT5, NASA, NOAA, BEST) agree with reanalysis products (ERA5, JRA-3Q). The annual uncertainties are typically less than 0.05 C in recent decades. In the late 19th century, they are typically less than 0.2 C. The values from all these major reconstructions fit in the uncertainty envelope for HadCRUT5.
2. It's indisputably true that 1.3 C warming above the 1850-1900 mean is exceptionally large and rapid for the time frame, and quite possibly unprecedented in the Phanerozoic (with a couple candidates for more rapid warming.
3. Satellite temperatures are valuable, but they lack the accuracy of thermometer datasets. Extremely rapid warming is detected even in UAH, which shows the slowest warming rates of the major datasets.

Ocean temperatures

1. About 93% of the excess energy ends up in the ocean, and so ocean heat content is increasing significantly.
2. Patrick Frank's paper on instrumental uncertainties for surface temperatures is basically a joke. It's riddled with errors and arbitrary decisions designed to artificially inflate uncertainties. There are lots of rebuttals to read, including one from me. 

GSAT, the Global Surface Air Temperature

1. This section contains very little content. They seem confused by the fact that UAH shows different warming rates for the southern hemisphere, northern hemisphere, and the tropics. This is not confusing to those who understand that land warms more rapidly than the ocean, and the NH contains more land than the SH.

4. Controversial Snow Trends

I haven't written much on this, so I'll have to add to this later. There isn't much about snow trends that is "controversial," though. This section appears to be heavily-weighted towards some pseudoscience papers published by Ceres-science in MDPI journals. I'll bookmark this to return to later.

5. Accelerated Sea Level Rise: not so fast

Relative sea level

1. This section seems to make a big deal about the fact that NOAA publishes tide gauge data for individual tide gauges, and they draw a linear trend line through the data. Of course, the fact that you can draw a line through a curve doesn't make the curve go away. You can draw a linear trend through any curve. 
2. When  you account for vertical land movement, sea level is both rising and accelerating.

Absolute sea level rise

1. Whether you use satellite measurements, tide gauges, or a mixture of both, sea level rise is both happening and accelerating. The contrary "evidence" that Clintel cites here appears to come from blogposts on WUWT.
2. The long-term effects of sea level rise are large. We're looking at multiple meters of sea level rise on time scales from hundreds to thousands of years.

B. Causes of Climate Change

6. Why does the IPCC downplay the Sun?

Numerous case studies support solar participation in the climate equation

1. Solar activity has been ruled out as a significant contributor to current warming for decades. This argument comes mostly from pseudoscience papers published by Ceres-science in MDPI journals. There is no longer an ongoing debate on the subject.
2. Published papers assigning blame to the Sun end up being very bad papers, and some end up being retracted.

The Past as a Plausibility Check

1. Reconstructions of TSI show that solar variability since 850 CE has a negligible effect on global temperature.
2. So-called Bray and Eddy cycles are real, but they do not have a substantial impact on global temperature trends.

The Cosmic Ray Amplifier

1. The hypothesis that cosmic rays may explain some fraction of current warming has been thoroughly investigated, and there's broad agreement in the literature that it simply isn't happening. There's no trend in cosmic rays that explains the 1.1 C increase in global temperature since 1970. I have a list of studies that demonstrate this here.

IPCC has progressively downgraded the sun

1. No, the IPCC has not downgraded the Sun. But about 25 years ago, scientists learned that the Sun is much more stable a star than they thought in the late 20th century, and the IPCC's evaluation of the Sun's impact on climate is consistent with the overwhelming scientific evidence. I discuss this here.

7. Misty Climate Sensitivity

A Sensitive Matter & Ringberg Castle

1. There is a broad agreement in the scientific literature that ECS is near 3 C, including the most comprehensive study on the subject to date. This holds up in studies evaluating paleoclimates, instrumental observations, and yes, even models. I have a list of studies evaluating this here.
2. The darling paper among contrarian appears to be Lewis & Curry 2018, which I updated with more recent evidence to show even their approach agrees with an ECS near 3 C.
3. Lewis' critique of Sherwood's sensitivity paper has some significant problems.

Models versus observations

1. Models with an ECS near 3 C agree with observations.
2. Even Hansen's 1988 model agrees with observations.
3. Contrarians frequently claim models don't agree with observations with some really poor graphing.
4. One recent paper intended to show that AR6 models predict too much warming failed to do so. 

The pattern effect

1. This section is confused. ECS evaluates the temperature response after the effect of rapid feedbacks. Long-term feedbacks are included in ESS, and ESS estimates tend to be 2xECS.
2. The literature evaluating ESS generally concludes that it's in the neighborhood of 6 C or higher.

8. AR6: More confidence that models are unreliable

Is Warming Amplified Higher in the Atmosphere?

1. I discuss the so-called "hot spot" problem here. The hotspot is detected in radiosonde data, though limitations of satellites make it difficult to detect.
2. A list of studies pertaining to the hotspot is here.

Is the Stratosphere still Cooling?

1. The short answer is "yes."

AR6/CMIP6 Models are too Warm Globally

1. CMIP6 models with an ECS near 3 C do not predict too much surface warming. 
2. There is a model-observation mismatch when looking at the bulk troposphere, which RSS discusses here.

In the future, I'll come back to this to post links to rebuttals of their C and D sections. In the meantime, here's an image that has been floating around social media written by the "Clintel Group" in which they claim "1,100 eminent scientists" believe there is no climate emergency. The entire article misspells CO2 as CO² instead of CO₂. This is not the cream of the crop of science communicators.