Reducing atmospheric CO₂ to a single number makes as much sense as a mean global temperature, and it is a pity they are both remodelled by the political scientists masquerading as climate scientists.
To the extent that understanding the natural world and how the climate works is an antidote to propaganda, Will Happer and Richard Lindzen and their most recent contribution takes us backwards. (Not quite to the Stone Age, but somewhere approaching.)
It is being promoted by those who should know better, this one-pager that shows a dramatic bar graph: enormous warming from the first 20 ppm of CO₂, then rapidly shrinking contributions as concentrations rise. By the time we reach modern levels, the added warming looks trivial. The implication is clear — most of the greenhouse effect from CO₂ happened long ago, and today’s rise is barely worth worrying about.
It’s a simple narrative and appealing to those who like cheering on one side.
The CO₂ Coalition crowd lead by Greg Wrighstone also do this with temperature, because it is convenient. As though a global mean temperature has much meaning beyond politics, which is how they use it: for political point scoring.
Indeed, Richard Lindzen told me a couple of years ago that all my temperature homogenisation work was a waste of time, because it wasn’t needed to disprove catastrophic human-caused global warming. According to Lindzen, we don’t need an accurate understanding of the last 150 years of temperature change for anywhere on the planet but rather should concern ourselves with politics, and rebuttals. It is such a shame that when it comes to climate science, it is these political types who rise to such positions of influence in the West. (For sure, in places like China and Russia, even Iran, they still do proper science when it comes to climate. The West is good at gathering data, but useless when it comes to analysis and interpretation.)
It is actually critically important that the average punter in Australia at least, begin to understand that carbon dioxide is not a well-mixed gas in our atmosphere. Furthermore, the big emissions to the atmosphere each year are not from China, but from the Arctic!
Consider this recent NOAA visualization of CO₂ concentrations in the marine boundary layer from 2016 to 2024:
There is a long-term rise, yes — but superimposed on that are strong seasonal waves that are massive in the Northern Hemisphere, especially at high latitudes.
In winter and spring, CO₂ builds up noticeably more in the far north before the summer drawdown. The Southern Hemisphere shows the same overall climb but with far weaker seasonal swings.
To be clear, CO₂ emissions are geographically and seasonally concentrated at high latitude northern hemisphere locations during spring.
Then there is the question of how atmospheric concentrations have changed through time?
Early ice core work showed much higher concentrations during the early Holocene; that it is much more complicated than a simple low baseline as suggested by Lindzen and Happer.
In 1980, Berner, Oeschger, and Stauffer published measurements from the Camp Century (Greenland) and Byrd Station (Antarctica) cores covering the last 40,000 years. Their Figure 1 from the Camp Century core is particularly striking. During the transition into the Holocene — the beginning of our current warm period — the first extraction fraction showed CO₂ values climbing well above 300 ppm, with several points exceeding 500 ppm before settling somewhat lower in parts of the record.

The samples came from ice formed thousands of years ago.
While later cores have produced smoother/homogenised curves around 260–280 ppm for the Holocene, the 1980 data from Camp Century recorded significantly higher concentrations at the start of the warm period, with apparent drops afterward.
Werner Berner, the lead author on that 1980 paper, did a lot of the hands-on CO₂ measurement work and extraction technique development for the study.
Hans Oeschger, the the senior scientist/group leader at the University of Bern, is generally regarded as one of the key pioneers who developed the overall methodology for extracting and measuring gases (including CO₂) from ice cores in the 1970s and early 1980s.
Bernhard Stauffer, the third co-author, also worked extensively on ice core gas techniques.
These three men were not political types, very unlike Lindzen and Happer, Michael Mann and on the list goes of American talking heads.
So, when there is mention of the original early ice core CO₂ work coming out of Bern, they’re usually referring to the Oeschger group, with Werner Berner doing the specific CO₂ analysis published in that 1980 paper (especially the Camp Century data in Figure 1). It is impossible with more recent reconstructions to know who actually did the measuring and then who directed the smoothing. (That is the American way, just put your name on someone else’s data even confiscate their natural resources as they have done in Venezuela.)
But for sure Lindzen and Happer accept the homogenised reconstructions, by which I mean the remodelled carbon dioxide data along with the homogenised reconstructions of temperature. And Greg Wrightstone defends all of this and then calls it science. It is scandalous really.
Anyway, if we take the original measurements seriously (from experts before it became politically incorrect to show anything but a steady rise in C02), the ‘pre-industrial’ or early Holocene baseline was not a single low, stable number.
It already contained higher excursions. That makes any chart that assumes a clean, low starting concentration as Lindzen and Happer do, and then diminishing returns from there even more arbitrary. Nonsense for sure, that is a best description of the most recent Lindzen and Happer contribution as published by the CO₂ Coalition.


Jennifer Marohasy BSc PhD is a critical thinker with expertise in the scientific method.

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