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But if CO2 drives temperature...

10 Mar 2021 | News Roundup

A lot of people say it’s too late to debate this claim, especially in the policy arena. The fossil fuel industry, they insist, should rally round the white flag, admit their product destroys the planet then ask for permission to send it through pipelines anyway. (And then look stunned when the answer is invariably “No, you mad fools.”) But here’s the weird thing. Well, one of them anyway. There’s very little evidence that CO2 drives temperature when you look closely. You may be tempted to say good grief, that ship has sailed, we know rising CO2 correlated with rising temperatures in the 20th century. But have you checked? Someone or something on YouTube called “Philosophical Investigator” just did, and rather than assuming what he set out to prove, programmed a computer to test the hypothesis, asking it to list times when they moved together and times when they did not. And guess what? The nays have it. Even after 1750 they move together 15% of the time, and apart the rest of the time.

This result is remarkable. And the analysis didn’t begin with Henry Ford, or even James Watt. It went back thousands of years. Almost as if the spirit of scientific inquiry were alive and well. And here’s what it found.

From 7500 BC on, and especially about 4800 BC until 1500 AD, CO2 and temperature, or the proxies we hope represent them, moved in opposite directions for thousands of years. How can it be, if CO2 is the “Principal Control Knob Governing Earth’s Temperature“?

OK, one possibility is that it’s wired backwards. Because the simple fact is that if you came to the warming debate cold, and looked at that data, you’d conclude that CO2 reduced temperature. Weird, huh? But of course that was then, as in, back when we didn’t even know why CO2 was rising except we knew it wasn’t human beings. But NB that the claim that CO2 drives temperature does not depend on there being two kinds, one natural that does not and one man-made that does. The theory stands or falls by whether CO2 of any sort drives temperature. And historically it does not. (Nor does it prehistorically.)

Once we get to 1750 the picture becomes less speculative. For instance we know, or think we know, why atmospheric CO2 started rising: Humans were releasing enough to drive the increase. Or to be exact we think we know why the rate of increase began to increase, since it had been rising anyway. But what of temperature? Well, from 1750 to 1850, using IPCC WG1AR5, PI says temperature kept falling. And even Michael Mann agrees.

Wait. There’s another 100 years of rising CO2 and falling temperature? Yes. Again there are minor fluctuations and it would be unreasonable to rely on the proxies to capture them all. But basically from the invention of agriculture until the invention of the telegraph, the planet saw rising CO2 and falling temperature. So where did this idea that CO2 even correlates with temperature increase, let alone causes it, come from?

Perhaps the more recent past? After 1850 we have even better data, in the form of direct if very patchy and incomplete thermometer temperature records, and some direct CO2 data too. And from 1850 to 2019, from a distance, you seem to see something like a hockey stick. Aha? Not really. Because again, PI had the computer search that period for stretches when temperature does not rise (negative or neutral) and one such period is… 1850 to 1929. What? The first 80 years of the confirmatory era don’t confirm it? Then what does?

Good question. Because the first 180 years of post-Industrial Revolution CO2 and temperature data do not, even though according to the widely accepted notion of ECS, namely that every doubling of atmospheric CO2 produces the same absolute increase in temperature, we should see the climate more sensitive to rising CO2 when it’s at lower absolute levels. And we don’t.

Yeah yeah yeah. Ancient history. Pre-television. What about the hot and bothered 20th century? Well, from 1930 to 1944 CO2 rises and so does temperature. Gotcha! Except from 1945 to 1980 CO2 keeps rising but temperature does not. It is basically flat (the data say slightly negative but we dispute the precision).

All this evidence is pretty bad. For the theory we mean, though also in its precision. But to the extent that we believe it, from 8000 BC to 1980 AD there’s no reason, outside one anomalous 15-year interval, to think rising CO2 means rising temperature. So where did the idea come from?

Well, of course from 1981 to 2000 both rose, and the AGW movement was born and grew into a giant in that brief period. At the hands of people with severely restricted and self-centred time horizons, what Oliver Wendell Holmes Sr. called “one-storey intellects” who cannot see past their own limited historical period. But even inside that cramped world-view there’s a problem: the hiatus.

From 2001 to 2012, CO2 surged onward and… temperature stalled again. Even though CO2 was now rising faster than between 1981 and 2000. Strange.

Mind you from 2013 to 2019 CO2 kept rising, naturally. Or rather unnaturally. And even faster. And temperature rose. Gotcha 2.0!

No. From 10,000 years of data, much of it speculative, we have 42 years with CO2 and temperature rising together and over 9900 years without. There are lots of very clever explanations of how CO2 increases temperature. But if it doesn’t they’re not worth the storage media they’re written on.

As PI notes, that CO2 causes warming is a theory that can be subjected to the key scientific test, an effort to falsify it by looking at the data. And by his count it was falsified four times and corroborated three times. And it gets worse because those tests are not evenly weighted chronologically. Even looking just at 1750-2019, it was falsified for 228 years and corroborated for 42. Which comes out to 84.45% vs 15.55%. Not a bet you’d take with $100, let alone your whole economy, is it?

PI notes that if we just use 1850 to 2019, discarding data we don’t like or possibly just don’t trust, overall both rise. But even in that stretch, there’s only 42 years of positive relation and 127 without. And in case you think well, none of that matters, we’re now facing runaway temperatures, Christopher Monckton reminds us that if instead of measuring from 2013 to 2019, you look at 2016-2021, you find… another hiatus. Five years and seven months with rising CO2 and no warming.

Almost as if the evidence were telling us what it seems to be, that… nah, can’t be. Mustn’t be.

18 comments on “But if CO2 drives temperature...”

  1. Great article, and thank you for bringing it to the Wednesday Wake-up. I've been following the insightful work of Philosophical Investigations for almost 2-years now and find his analysis and approach very robust. His work should be used in later high-school and university education.

  2. Ah yes, Philosophical Investigations; the slow-talking, methodical guy with the very Welsh accent! Maybe he would like to have a discussion with Jim Bowen, the credentialed (I'm a published geochemist you know) rude-boy, who states opinion as fact, and posts stuff by his mates that they say proves what their models forecast (well, Gavin would say that, wouldn't he?)...nasty little man...and a liar of sorts...(but a credentialed one, so that's alright then...)

  3. This is another excellently written explanation. I'm grateful.
    I know people who would never read this because they're locked into a mental state and this information would cause a shattering.

  4. Everyone --especially politicians--should read Patrick Moore's new book Fake Invisible Catastrophes and Threats of Doom. It puts the climate alarmists and their dogma to rest!!

  5. How is it our governments haven’t looked at the data that proves CO2 it is not the earths thermostat? Instead Politicians are committing to wasting billions and billions of dollars on what can only be a futile attempt to reduce atmospheric CO2 that is not correlated toTemperature historically? That is unforgivable; I expect a lot more from those who wish to govern us.

  6. I have a slight problem here I'm afraid. Before I get started I'm not trying to say that this wole article is completely wrong or anything like that. The Earths atmosphere is quite masive and very complicated. What I'm getting at is that if the temperatures were in the process of dropping due to some other influence, when the atmospheric CO2 levels began to spike it could probably last several decades, to actually make the curve of the temperature as the funkcion of time to first flaten and then turn the other way. Better way of looking for possible periods of time, when CO2 appears to not be in direct correlation with temperatures would be to search for turning points in the graphs of temperatures and atmospheric levels of CO2.

  7. One take-away from PI's excellent analysis is that current CO2 concentrations may have little or nothing to do with human activities, but are caused by an independent factor which is not causally linked to current global temperatures. So here is a possible theory.
    1. We know that about 98% of all CO2 is in solution in the oceans.
    2. We know that oceanic CO2 concentration increases by about 20% for the first kilometre in depth, and then is more or less constant down to the ocean floor (see GEOSECS data for details).
    3. We know that the solubility of CO2 in water varies inversely with temperature; as sea water cools down it will absorb CO2, and expel it ('outgassing') as it warms up.
    4. The volume of Earth's oceans is about 1.37 million cubic kilometres. The thermal time constant for a mass of this size, i.e. the time it will take to respond to an ambient temperature change, will probably be measured in centuries.
    5. The last time the Earth was significantly warmer than today for a prolonged period was the Medieval Warm Period about 800 to 1000 years ago. This length of time may well be the same as the ocean thermal time constant, i.e. the time it takes for all that heat of that period to be dispersed into the depths of the ocean and then start outgassing from the ocean floor upwards.
    6. Is it not therefore possible that some or all of the CO2 increase we are seeing today simply consists of oceanic outgassing resulting from the Medieval Warm Period?
    As corroboration for this theory, ice core data indicates that over the long term (hundreds of millenia), temperature and atmospheric CO2 concentration tend to track each other, but CO2 lags temperature by about 800 years, i.e. atmospheric CO2 starts to increase about 800 years after a sudden temperature rise occurs.

    I don't say that this explanation of the current rise in CO2 is necessarily correct, but has anyone ever looked seriously at it as a possibility?

  8. 1. CO2 is not the only driver of global temperature. There are many other drivers, with varying periodicities. The location of the planet relative to the rest of the solar system has a big impact (Milankovitch cycles). The location of the land masses relative to the tilt of the earth has a big impact (plate tectonics). Etc. So there will be a great deal of natural variability over geological time. Trying to tease out the influence of CO2 from all of this noise is much more complicated than looking for direct correlations. PI's analysis is only compelling against the most simplistic versions of the theory. Which, to be fair, is about 97% of the versions that ever get talked about: i.e. the IPCC, Mann, the mainstream media, etc. So it is good enough for most purposes.
    2. Out-gassing from the oceans, suggested by Roger, might be a possible explanation for the time-lag problem. I understand that there is some literature suggesting that the ratio of carbon isotopes is different when the CO2 comes from the burning of fossil fuels vs. other sources. Scientists have tried to determine the source of the "extra" CO2 by measuring these ratios, but I don't know what their results have been. I know the propagandists and alarmists claim that the "extra" CO2 can be traced back to the burning of fossil fuels through the measurement of changes in the isotope ratio, but I haven't seen a discussion of this issue that I can assess, yet. There may be good evidence and argument on this point out there; I'm just not aware of anything that helps me come to a conclusion. (This isn't my field.)

  9. It's my understanding that the "CO2 drives global warming" theory was first proposed by the Swedish chemist Aarhenius in the late 19th century. It sounded like an attractive theory at the time, and many people went along with it, but Aarhenius didn't offer any proof. A few years later Angstrom, another Swedish chemist, decided to test the theory, and set up experiments at different heights above sea level. The result: totally negative. And Aarhenius theory was abandoned for many years. Then years later (50 years?) it was resurrected, apparently by a British scientist called Callendar. He also offered no proof......... yet the theory was widely believed, as it still is today. Why is this? have I got this wrong?

  10. None of which negates the need to restrict the production of CO2 in urban areas for health.reasons.

  11. actually Co2 and temperature have about an 800 year gap. As Temperature rises CO2 rises 800 years later and vice versa. So, CO2 is not a cause of temperature rise but instead it is a result of it. This has something to do with the temperature of the oceans and how much time it takes for them to warm and cool and how much CO2 they emit or absorb.

  12. Gregory Brown: "None of which negates the need to restrict the production of CO2 in urban areas for health.reasons." CO2 in itself is neither toxic nor harmful in any other way, and certainly not in the miniscule quantities in which it is found in urban and any other areas. If it was toxic we would all be dead, because the air you exhale from your lungs has about one hundred times the CO2 level of the air you breathe in. However, the by-products of incomplete combustion, such as carbon monoxide (CO) and various nitrogen oxides (NOx) and sulphur oxides (SOx) plus particulate matter can be harmful. Considerable strides have been made in recent years in improving combustion systems to remove such pollutants. Interestingly enough, the gases going up the chimney stacks of modern garbage incinerators are typically cleaner than the urban air which surrounds them.

  13. Well said, and should be widely circulated.
    Maybe sent to Justin and his hordes, to stop the massive waste of tax $ on futile climate control schemes.

  14. Gregory, what makes you think that 415ppm is bad for human health? Did you know that the allowance for submariners is thousands/ppm?

  15. Playing devil’s advocate, perhaps Mr. Brown is referring to an article at air quality news, and the report in Nature Sustainability it links to.

    The focus is on enclosed spaces, but it does venture to suggest that by 2100 some cities could exceed 1000ppm for parts of the year. Looking at the paper, though, I note that this speculation is based on our old friend RCP8.5.


  16. Scientists can prove that CO2 has heat absorption capability. But at 4 parts CO2 to 10,000 parts nitrog/oxy, CO2 is simply not a heat retention "blanket" in the atmosphere. There is simply way too small a quantity of atmospheric CO2 to have any temp impact one way or the other.

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