Are we in the midst of a climate crisis? Broadly speaking, there are three answers to this question.

Yes and we must decarbonize immediately. King Charles III delivered the keynote speech at the COP28 international climate conference organized by the United Nations last December. A confident and persuasive public speaker, Charles called for a “zero-carbon future” and said that a global climate catastrophe is imminent.

How imminent is “imminent”? UN Climate Change Executive Secretary Simon Stiell told a conference recently that “we have two years to save the world”. That was on April 10, so there are only 718 days left. The clock is ticking.

Yes but sensibly so that we don’t return to the Stone Age. To the consternation of participants, UAE Sultan Al Jaber, the president of COP28, stated: “There’s no science out there that says that the phase out of fossil fuels is what is going to achieve 1.5 [℃]. 1.5 is my North Star.”

No and we shouldn’t decarbonize. Many scientists believe that there is no climate crisis and that an increase in CO₂ would actually be beneficial. The CO₂ Coalition website is loaded with scientific facts at odds with the IPCC view. These are not guys wearing tinfoil hats.

Since the IPCC is widely regarded as authoritative, it’s worth having a closer look at the claims in its latest publication. This is called the Sixth Assessment Report (AR6). Three working groups have produced three reports – one on the physical science behind climate change, one on impact and adaptation, and one on mitigation. I will be examining Climate Change 2021 The Physical Science Basis (CC 2021).

The UN General Assembly created the IPCC in 1988. The IPCC doesn’t conduct its own scientific research on climate; it compiles research done by scientists from around the world. So far, it has published six rounds of assessment reports, each one taking 5 to 8 years to complete. (The latest reports can be viewed here.)

Let’s look at a few key points in the IPCC’s narrative.

Is climate science really science?

CC 2021 states: “United Nations Secretary-General António Guterres has stated that ‘the evidence is irrefutable’ and ‘we see the warning signs in every continent and region’.”

Rhetoric like this is seriously misleading. The great philosopher of science, Karl Popper, said: “It is easy to obtain confirmations, or verifications, for nearly every theory — if we look for confirmations.” But science is not about confirming theories: it is about falsifying theories.

For instance, Popper was very sceptical of Marx, Freud, and Adler, the authors of some of the grand narratives of the early 20th century. His criticism might apply to some of the IPCC’s conclusions:

I felt that these other three theories, though posing as science, had in fact more in common with primitive myths than with science; that they resembled astrology rather than astronomy …  These theories appear to be able to explain practically everything that happened within the fields to which they referred. … Once your eyes were thus opened you saw confirmed instances everywhere: the world was full of verifications of the theory. Whatever happened always confirmed it.

Mr Guterres’s statement is a clear example of science as confirmation, not science as falsification. You can see this fallacy at work every day in the media. If there is a hurricane in Florida, global warming is at work. If there is a drought in California, global warming is at work. If there are Arctic temperatures in Texas, global warming is at work.

Feedback loops

At the core of King Charles’s concern about climate catastrophe is the notion of “dangerous feedback loops.” “Feedback” has a prominent role in CC 2021 The 2,391-page document uses the word 2,440 times.

At the risk of oversimplifying things, positive feedback makes Earth warmer and negative feedback makes it cooler.

A good example of a feedback loop is clouds. About two-thirds of Earth is covered by clouds at any time. CC 2021 states that clouds have positive feedback. So increases in temperature cause changes to clouds that in turn warm the Earth, the IPCC believes.

But not all climate scientists agree. In 2001 Dr Richard Lindzen and colleagues published an article “Does the Earth Have an Adaptive Infrared Iris?” Their research showed that as air temperature increased, high wispy cirrus clouds dissipated, allowing more thermal energy to escape to space, and thereby cooling the planet. That is negative feedback.

It’s not unusual to have contradictory views among scientists, but I was taken aback by what I learned next.

On page 94, under “Earth System Feedbacks”, CC 2021 says that the net feedback is positive: “The combined effect of all climate feedback processes is to amplify the climate response to forcing (virtually certain).” (Forcing is net thermal energy directed downwards to Earth). Well, there’s not much doubt in that statement is there?

And yet, just two pages later, Figure TS.17 shows that the sum of all climate feedback is negative. That is completely the opposite.

I initially thought that I had misunderstood something. Is this kind of contradiction even possible given the document’s hundreds of authors and reviewers, and its editorial team of 19 highly qualified individuals? I asked Dr Richard Lindzen about this. In his opinion, the working group which produced CC 2021 “has never been totally coherent”. However, there is a political need for positive feedback. “This leads, he said sardonically, “to increasing disagreement with observations.”

Anthropogenic climate change is not a done deal

CC 2021 declares that recent climate change is “overwhelmingly due to human influence”. But not all climate scientists agree. An international team of 37 scientists published a paper in 2023 that stated, “the scientific community is not yet in a position to confidently establish whether the warming since 1850 is mostly human-caused, mostly natural, or some combination.” They re-iterated this in a follow-up paper.

Temperature Targets of 1.5℃ and 2℃

The goal of limiting a temperature increase to 2℃, 1.5℃ ideally, relative to 1850-1900 was introduced at COP16 in 2010. AR5 Climate Change 2013: The Physical Science Basis was the latest climate science available to the delegates at COP21 in 2015 that produced The Paris Agreement.  AR5 referred to only one scientific paperpublished in 2011 dealing with 1.5℃ warming. AR6 referred to 20 scientific papers on warming of 1.5℃, mostly published in 2018. Oddly, the paper published in 2011 found in AR5 doesn’t even appear in AR6.

None of this proves anything conclusively, but it does fuel the suspicion that some scientists are producing reports to fit the political narrative to obtain funding. That in turn raises questions about the reliability of their research.

Hockey stick graphs

Al Gore made famous Michael Mann’s hockey stick graph in his Oscar-winning documentary, An Inconvenient Truth (2006). CC 2021 has its own versions, (p.6 and p.46). These are impressive diagrams.

There’s a problem, though, according to Steve McIntyre, a citizen scientist. He demonstrates via analysis of temperature proxy data from tree rings, ice cores, etc. that we don’t have accurate temperature data for the past 2000 years. This undermines the credibility of these hockey stick graphs. (For detailed references, please contact the author at https://climateaudit.org/)

It may be tempting to dismiss a citizen scientist, but his work on temperature proxy data is thorough, rigorous, published in peer-reviewed literature, uncontested in US federal court and was confirmed by the National Academy of Sciences.

CO₂ saturation

In my opinion, the most troubling discovery I made consists of two sentences on pp. 1006-1007: “These started as early as Angstrom (1900) criticizing the results of Arrhenius (1896) arguing that the atmosphere was already saturated in infrared absorption such that adding more CO2 would not lead to warming. The assertion of Angstrom was understood half a century later to be incorrect.”

What does this mean? The IPCC is claiming that (1) CO₂ doesn’t get saturated and therefore there would be no upper limit to heating caused by additional CO₂ in the atmosphere, and (2) we have known about this since about 1950.

However, we’ve known since 1971 that CO₂ does get saturated and its effects as a greenhouse gas diminish as it increases. In other words, CO₂ is subject to the law of diminishing returns.

If this is true, efforts to reach Net Zero are useless and incredibly wasteful after a certain point.

* * * * *

All IPCC documents rely upon the science in Climate Change 2021 The Physical Science Basis. The vast majority of those who attended COP28 probably have accepted them as reliable and are now using them to shape climate policies in their home countries. This is a big problem.

If the IPCC is correct, and we don’t decarbonize, much of the world will be destroyed. If they are incorrect, decarbonization (i.e. Net Zero), will needlessly inflict much hardship upon the world. There will be widespread starvation.

Few world leaders have dared to express scepticism about the substantial conflicting science around climate, e.g. climate feedback, the impact of CO₂ vs natural climate variability, etc. Sultan Jaber came close, but not close enough.

We need a new kind of leader to emerge, someone with courage and integrity who can organize and execute an honest and fully transparent review of the basic science of Earth’s climate. Nothing else will do, because the stakes are so high. We must get this right.

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This article was originally published on Mercator under a Creative Commons license (CC BY-NC-ND 3.0).

Image credit: Pexels