I have recently become aware of some ‘climate change’ arguments being propagated, based around the percentage of CO2, carbon dioxide, in the atmosphere. From the top of my head I couldn’t remember the figure. I had a look and found it’s low, about 0.04% of the atmosphere. Does that matter? No.
However, many climate change denial conspiracists use this fact, and the fact that nitrogen (78%) and oxygen (21%) make up a far higher percentage of the atmosphere – and use people’s ignorance of this data – as a ‘gotcha’. They say the claim that carbon dioxide caused climate change and the risks thereof is a “lie”, given such ‘obvious’ data. But there is no substance to this ‘gotcha’. I explored why that is the case; here’s what I learned.
Greenhouse gases
Nitrogen and oxygen are not ‘greenhouse’ gases. Simply put, their molecular structures are pretty simple. So they are not very capable of absorbing energy at the wavelength of the energy radiated from the surface of the Earth after being heated by the Sun (typically infrared, so about 700-1,000 nanometres). Carbon dioxide, however is more complex – as is methane – and so is much better at absorbing radiation at these wavelengths.
“As CO2 soaks up this infrared energy, it vibrates and re-emits the infrared energy back in all directions. About half of that energy goes out into space, and about half of it returns to Earth as heat, contributing to the ‘greenhouse effect’.”
Columbia Climate School
There are plenty of on-line articles, papers, and so on on this subject. Clicking on each of these words will take you to one. As is often the case in science, simple explanations almost always have a more complex foundation. This video by Sabine Hossenfelder really unpacks the phenomenon of greenhouse gases. I learnt even more by watching it, though am still scratching my head over some of it.
I took the trouble to satisfy myself that the percentage of CO2 in the atmosphere is irrelevant. It is the actual quantity of CO2 in the atmosphere that is the key data set. And that figure has nearly doubled in the last 300 years, most especially in the last 60 years.

In fact, the amount of CO2 in the atmosphere now is still increasing – fast – and is higher than at any time in human history. Yes, it was higher in the distant past, such as when the dinosaurs were around. But hey, people … we are not dinosaurs. Modern humans and our ecosystems have evolved around our present climate. We are holocene creatures. Any dramatic changes to our climate and ecosystems will cause evolutionary change and extinctions. Sure, life will go on. But not as we know it. We really ought to avoid that.
Most who saw and shared the ‘gotcha’ tweets, Facebook messages, and so on, often in the millions, probably didn’t take the time to ‘find out’. Some probably just sourced further social media commentary that reinforced the misinformation. I have since seen others asserting these data sets as if their conspiracy theory had been vindicated. Someone on Twitter also tried to use, “But there is a higher percentage of CO2 in the Martian atmosphere than on Earth, but Mars is cold”!
Ignorance and influence
Oh, dear. A quick look and, again, a clear explanation was found. Two things to note here:
- Do people really think that thousands of climate scientists completely missed the impact of such a low percentage of CO2 in our atmosphere for decades? Or conspired to hide such an obvious insight from the general public? Or, worse, are working together on some ‘great global reset’ experiment?
- It is clear that social media can quickly propagate ‘a little knowledge’ in a most dangerous way, misinforming and often evangelising millions of people, making them less amenable to real data, analysis, and insight. The irresponsible sources of such social media messages ought to be held to account. They clearly don’t know how science works, or want to. And they rely on people being easily influenced by erroneous but plausible claims based on misrepresented data and ignorance of the underlying science.
The latter is a deeply worrying phenomena. Especially at a time when average global temperatures are expected to exceed the 1.5C limit for the first time.
I trust the scientific community to collectively inform me, to be objective, to always try and uncover truths about our how our world works. It’s the least-bad system we have developed; imperfect, but the best we have. It is based on theory, experiment, refinement, peer review, challenge, and scrutiny. When theories are in error or incomplete, it is generally other scientists – following the scientific method, publishing papers that are peer-reviewed – who uncover earlier misunderstandings. And so they collectively improve our knowledge.
It is never ‘shock jocks’, social media personalities, ‘Twitter warriors’, or that bloke down the pub who read something about atmospheric carbon dioxide in the Daily Mail doing this.
I’d also add, it’s rare that a scientific theory is completely deposed. It’s often refined or otherwise improved through the availability of more accurate and granular data, and experimentation and analysis thereof, often based on more sophisticated experiments and equipment. It’s what quantum physics and relativity did to Newtonian physics at the beginning of the last century. The latter still works well in 99% of circumstances, including going to the Moon in chemical rockets. But we know that at the scale of the atom it does not (hence quantum theory) nor at speeds closer to the speed of light (hence relativity).
The reality is that premature scientific claims (cold fusion) and sometimes fraudulent science (Piltdown Man) get found out, yes, by other scientists reviewing, repeating, re-analysing and applying their knowledge with intellectual honesty and objectivity. It’s never Dave From the Pub, or That Bloke on Facebook.
Climate change and gotcha claims
Sadly, our mass media is full of such ignorant and dangerous claims, often propagated by ignorant-opinion-formers. Would the same people who are offering such insight get on an aeroplane – having never flown – and barge into the cockpit to try and tell the pilots how to fly? When those pilots have trained for years to secure the appropriate qualifications? Would they trust their teeth to a ‘dentist’ who knows no dentistry?
We trust and rely on experts to inform us. And we depend on other experts, the scientific process, systems, regulations, and so on to challenge them. The truth is, the more one studies a complex subject, the more one realises how much one does not know. That is true expertise.
Too many people with little or no knowledge of a subject, and lacking an obvious appreciation of the details, don’t appear aware of how little they know. Yet they often seem the most vocal in sharing their opinions.
Bertrand Russell is reputed to have said:
“The whole problem with the world is that fools and fanatics are always so certain of themselves, and wiser people so full of doubts.”
This is what we are witnessing now as regards climate change science. I would add that this phenomenon, and a degree of straw-manning and whataboutery, also impact understandings of epidemiology and evolution. And even, bizarrely, urban design, and 20mph speed limits.
I am not sure how patient we can remain with the phenomenon of the often-amplified Dunning-Kruger effect brand of ignorance. It’s a real risk and impediment to progress on addressing our climate change obligations. If people want to counter this, and really know what’s going on, the most recent Intergovernmental Panel on Climate Change update for policymakers is a good place to start. And this video from climate scientist Professor Kevin Anderson and the United Nations University is an essential watch.
This article is an edited version of a blog entry by Professor Mark Barry, which you can find here.

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