Daily Sceptic 'Fact Checked' Over Claim That CO2 Increase Lags Behind Global Warming So Cannot Cause It – But That is What the Data Show

Another week, another climate ‘fact check’ for the Daily Sceptic. Four in the last month – not a single fact proved wrong, but plenty of gripes from green activists about scientific interpretations. Maybe it is time for an appearance by the Monty Python Colonel, who frequently interrupted sketches by claiming they were “too silly”.

Virginia-based academic public relations company Newswise has claimed our June 10th article titled “Net Zero Shock: Carbon Dioxide Rises AFTER Temperature Increases, Scientists Find”, was “mostly false”. The Newswise story was written by Editor-in Chief Craig Jones and Texas-based professor of atmospheric sciences Andrew Dessler. Professor Dessler is a man of considerable scientific certitude, and has been described as the “alarmist’s alarmist”.

In our article, we reported that two climate science professors, Demetris Koutsoyiannis and Zbigniew Kundzewicz, sequenced the changes in temperatures and carbon dioxide growth rates from 1980 to 2019 from widely available sources, and discovered that CO₂ values lagged temperature by about six months. The scientists made the obvious point that in attempting to prove causality by stating that increases in temperature are the result of human-caused CO₂, cause cannot lag effect. I went on to note that other scientists had struggled to find evidence that CO₂was the global climate thermostat knob. In 2015, Professor Ole Humlum from the University of Oslo found similar lags in the recent record. In addition, the Vostock Ice Core, providing 422,766 years of Antarctic snow accumulation, showed that CO₂ lagged the onset of glaciations by several thousands of years. Finally, a wider reconstruction of CO₂ and temperature going back 600 million years to the start of life on Earth showed few correlations between the two.

Of course, nobody denies that CO₂ has warming properties in the atmosphere. The debate within science over the human contribution to warming, now largely ignored, if not actually demonised by mainstream media, is over the extent. Some scientists say it is a lot, many others say it is negligible. The notion that the matter is ‘settled’ is little more than a political corruption of the scientific process.

Professor Dessler kicks off with the statement that the argument is “nonsense”. He says the scientific community is “100% sure that the increase in CO₂ we see in the atmosphere is from the combustion of fossil fuels (with a contribution from land-use changes)”. Of course it depends how Dessler defines “land-use”. If he is only talking about peat bogs and building skyscrapers, he is plain wrong. If he includes the 96% of C0₂ that arises naturally from the planet as oceans outgas, volcanoes emit and animal and plant life evolves, he is stating the obvious.

This conclusion (whatever it is) is said to be supported by several lines of evidence. “First, for the past half century, each year’s increase in carbon dioxide in the atmosphere has been on average 44% of what humans released into the atmosphere in that same year. Thus, when humans were emitting smaller amounts of carbon dioxide in the 1960s, atmospheric carbon dioxide was increasing at a slower rate than when humans were dumping large amounts of carbon dioxide in the atmosphere, as we are today.”

As with Dessler’s opening remarks, it is a little difficult to know what he is writing about. The sentence producing the 44% figure presumably relates to the 3-4% of CO₂that humans release into the atmosphere. If, as many distinguished scientists suggest, the gentle 1°C increase in global temperatures that has occurred over 200 years is largely a natural response after the lifting of the so-called mini ice age, most of the extra CO₂ in the atmosphere would have arisen from natural causes, as rising temperatures trigger natural CO₂ release. So far as references to the 1960s are concerned, it is always interesting to point out that CO₂ was rising during this period, as temperatures were briefly falling.

Dessler is a keen supporter of every command-and-control green deal and Net Zero project going. If we don’t take action, warming up to 9°F (5°C) is as “certain as death and taxes”, he claims. Scientists are said to be “certain” that humans are the cause of climate change. Such absolute certitude is of course rare in scientists, although not, it might be noted, in green activists. Recently he informs us that his work had shifted towards the “intersection of climate change and human society”. If he gets his way and removes fossil fuel from the world economy (about 80% of current energy supply) within less than 30 years, he must be hoping that he can stop nature in its tracks, and the 96% of CO₂still being emitted will co-operate with his grand designs.

Activist scientists often claim that carbon isotope ‘finger printing’ proves the recent increases in atmospheric CO₂ arises from fossil fuel. Dessler notes: “Scientists measuring the composition of the increasing CO₂ in the atmosphere find it matches the isotopic composition of fossil fuels.”

Again, one might wish for a little more precision in Dessler’s prose. Presumably he is not referring to all the CO₂ entering the atmosphere, just the 4% produced by humans. The isotope evidence – of carbon, again one must presume, not fossil fuels – is interesting, and needless to say the science on the matter is not settled. The carbon in living matter has a slightly higher proportion of ¹²C isotope, and when burnt it is said to slightly alter the balance of other atmospheric carbon isotopes. But a recent study by a team of scientists at the University of Massachusetts led by Professor Kenneth Skrable found that the claims of the dominance of anthropogenic fossil fuel in the isotope record had involved the “misuse” of statistics to validate the suggestions. The scientists concluded that the amount of CO₂released by fossil fuel burning between 1750 and 2018 was “much too low to be the cause of global warming”.

The Daily Sceptic welcomes debate all on scientific matters, including climate change. But the recent flurry of ‘fact checking’ the subject is composed of little more than asserting ‘your facts are false or misleading’ and ‘my opinion is right’.

Chris Morrison is the Daily Sceptic’s Environment Editor.