A Few Things Ill Considered

The CO2 Rise Is Natural

This is just one of dozens of responses to common climate change denial arguments, which can all be found at How to Talk to a Climate Sceptic.


It’s clear from the ice cores and other geological history that CO2 fluctuates naturally. It is a bogus assumption that the rise happening today has to be from humans.


Surely it is not so hard to believe that since we emit billions of tons of CO2 into the air and, lo and behold, there is more CO2 in the air, therefore the CO2 rise is our fault. But if this simple common sense is not enough there is more to the case than that and that case has been well made. (It is worth noting that the investigation of this very issue by the climate science community is a pretty good indication that they are not taking things for granted or just making assumptions, not even the reasonable ones!)

It is true that CO2 has gone up on its own in the past, most notably during the glacial interglacial cycles. During this time CO2 rose and fell by over 100 ppm, ranging between around 180 to 300ppm. But these rises, though they look steep over a 400Kyr timeframe, took 5 to 20Kyrs depending on which glacial cycle you are looking at. By contrast, we have seen an equivalent rise of 100ppm in just 150 years! Check this plot for a very dramatic juxtaposition of the slow glacial termination versus the industrial revolution.

But there is still more to the case than the initial common sense argument and the circumstantial evidence above. By analysing the isotopes of the carbon and oxygen atoms making up the atmospheric CO2, in a process similar to carbon dating, scientists can, and have, detected a human "fingerprint" of what is now accumulating in the atmosphere. What they have found, via the isotope signatures can be thought of as "old" carbon, which could only come from fossil fuel deposits, combined with "young" oxygen, as is found in the air all around us. So, present day combustion of fossilized hydrocarbon deposits (natural gas, coal and oil) are most definitely the source of the CO2 that we see accumulating, just as common sense tells us.

For more of the nitty gritty technicalities straight from the climate scientists, including links to the actual research that has established this, please visit RealClimate’s article on how we know the CO2 is ours.

Of all the pillars holding up the theory of Anthropogenic Global Warming, this really is one of the most unassailable.

This is just one of dozens of responses to common climate change denial arguments, which can all be found at How to Talk to a Climate Sceptic.

“The CO2 Rise Is Natural” was first published here, where you can still find the original comment thread. This updated version is also posted on the Grist website, where additional comments can be found, though the author, Coby Beck, does not monitor or respond there.


  1. #1 Crakar14
    March 25, 2009

    Found this article and thought it worth posting here is a selected quote;

    “This does not favour the continuous increase of CO2 from the use of fossil fuels as the source of isotope ratio changes. The constancy of seasonal variations in CO2 and the lack of time delays between the hemispheres suggest that fossil fuel derived CO2 is almost totally absorbed locally in the year it is emitted. This implies that natural variability of the climate is the prime cause of increasing CO2, not the emissions of CO2 from the use of fossil fuels”

    Reference; http://wattsupwiththat.com/2009/03/24/study-hemispheric-co2-timing-suggests-that-annual-increases-may-be-coming-from-a-global-or-equatorial-source/#more-6524

    Ooops sorry Coby i think i just knocked over one of your pillars.



  2. #2 coby
    March 25, 2009

    yes, sure, Crakar. And the earth is flat.

  3. #3 Crakar14
    March 26, 2009

    As usual any scientific study which casts doubt on the theory is dismissed via name calling and insults.

    We can nip this whole debate in the bud with just one simple question.

    Can you or any other “believer” out there show scientific evidence that an increase in CO2 will cause an increase in the Earths temp ie Global Warming, how CO2 “re emits” the IR energy and in which direct, and how CO2 behaves/reacts when CO2 and water vapour bands overlap etc etc.

    By way of scientific evidence i mean real world experimentation, when and where the experiment was conducted, how the experiment was conducted, under what conditions was this experiment conducted (altitude, environmental conditions etc), and what where the results of said experiment.

    Examples of things not considered as evidence;

    * Global temps, somehow accurate to the first decimal place
    * Evidence that sea levels are rising or falling
    * Ice extent
    * Evidence of ocean temps are falling or rising
    * Theories scribbled on pieces of paper
    * Any and all computer model predictions

    These will not be considered as evidence because none show CO2 is the cause.

    Failure to reproduce such evidence of CO2 causing global warming will be viewed logically as though such evidence does not exist. If so then AGW is indeed just a theory………..No make that an hypothesis.

    Which of course renders AGW into the realms of religion.

    Good luck


  4. #4 Adam
    March 27, 2009

    Crakar –

    The IPCC report has all the information you could want, including references to the studies themselves.

    If you’re honestly interested in the science, take a look.

    If so then AGW is indeed just a theory………..No make that an hypothesis. Which of course renders AGW into the realms of religion.

    This is just a completely illogical line of thinking. Attempt at slander noted, but really, you just make yourself look silly.

  5. #5 Crakar14
    March 29, 2009

    Once again you simply throw the IPCC report around to avoid debating any issue that threatens the AGW theory.

    Did you read this? I know Coby did not.


    In regards to my question, you can read all the IPCC reports you like but it will not give the information i asked for. It will not provide the real world experimental results that i asked for. Because they never did it, or if they did they are not saying so.

    You defend a theory that as yet has never been tested, but simply rely on anecdotal data to try and prove it correct. When challenged as always you simply go into a defensive mode and start name calling.

    So you can shove your petty comments where the sun dont shine for all i care Adam.

  6. #6 Matt Bennett
    March 29, 2009


    I was reading James Lovelock’s latest last night and I think he was referring to you when he said that deniers are for the most part unsophisticated and boring.

  7. #7 Crakar14
    March 31, 2009

    To Adam,

    Thanks for the link, (i have read it before) but as this is the only document you have put forward as evidence then i will respond to it. Here is the only reference to experimental testing i could find

    “Numerous experiments have been conducted using climate models to determine the likely causes of the 20th-century climate change.”

    Now i dont mean to be rude but experiments using climate models just dont cut the mustard. So as i have eluded to in the past no one has actually conducted an experiment to falsify or prove the theory correct.

    Have you read Chap 9? I lost count of how many times the words “likely”, “very likely” were used.

    Everytime they make a statement of fact it is qualified by these types of words, nothing is black and white and they always leave the door open in case they are wrong. Eg we are 90% sure CO2 has caused the warming. Why 90%? because they have no idea thats why.

    To Matt, yes me and James go way back so it is no surprise he references me in his book, i am surprised he did not mention me by name. I did not think you of all people would be stupid enough to buy his book.

    I dont supposed James talks about real world testing (non computer models) to prove just how CO2 interacts with other gases etc to cause global warming? Or is this just an OT cheap shot which you have become reknowed for?

  8. #8 Adam
    April 1, 2009

    Crakar –

    Since you seem genuinely interested in the science of the greenhouse effect, I recommend starting with the work of John Tyndall. He performed some of the experiments you’re curious about in the 19th century.
    Section 1.4.1 of the WG1 actually does a pretty thorough job of explaining the history of the science of the greenhouse effect.

    The phrases “likely” and “very likely” only indicate something other than 100% certainty, which in science is responsible writing. We cannot be 100% sure of anything in science (or most aspects of life for that matter).

    Everytime they make a statement of fact it is qualified by these types of words, nothing is black and white and they always leave the door open in case they are wrong.

    Um, right. They’re presenting what the bulk of the evidence suggests/indicates. Considering we only have one run (so to speak), we can’t be 100% sure of anything. There’s so little in life that is 100% certain (black and white as you say), why would you demand it in this case?

    Eg we are 90% sure CO2 has caused the warming. Why 90%? because they have no idea thats why.

    The percentages show degree of confidence. A higher percentage indicates a higher degree of confidence. And, yes, the numbers are fuzzy. They’re not intended as anything other than showing the rough confidence in any given statement. This is so basic it shouldn’t need to be brought up.

  9. #9 Matt Bennett
    April 1, 2009

    Crackar, try reading his book, I don’t take everything anyone says as given, but you should at least read widely varying opinions – that’s actually how intelligent people reach consensus on difficult topics.

    You’d be surprised to find James actually agrees with you on a lot of things, esp that some of the main GCMs are hopelessly wrong and mistakenly linear and that there has been a recent levelling off of temps. His interpretation of what this all means is where you two would differ. Have you played Daisyworld, as a simple flat-earth example of the self-regulating systems he’s talking about?

    Read the book, it’ll take you only a few hours, I recommend it for another view. Only time will tell who’s right.

    When you gonna take up my bet?

  10. #10 Crakar14
    April 1, 2009

    Hello Adam,

    Yes Tyndall was a very clever man for his time, Unfortunately i would not consider lab experiments from 150+ years ago qualifies as testing the AGW theory. Even if you did this quote sums it up “He concluded that water vapour is the strongest absorber of radiant heat in the atmosphere and is the principal gas controlling air temperature. Absorption by the bulk of the other gases is negligible.”

    So it is clearly obvious that the IPCC does not fully understand how the climate works or how the GHG interact with each other under the many various environmental conditions which is why the numbers are fuzzy and they chose thier words very carefully.

    As we have no scienticfic experimental data etc to call on lets examine your theory a bit closer and see where we end up.

    Is this how it works? we have X amount of CO2 in the Atmosphere and the climate is in a stable? condition. I then build a machine that produces CO2 which increases the amount of CO2 in the A/sphere which causes it to warm, in turn warming the planet, in turn releasing CO2 and water vapour, in turn warming the A/sphere in turn warming the planet, in turn releasing CO2 and water vapour and so on.

    The effects of this is melting ice, higher temps etc and as there is no negative feedback to stop the warming we will reach a tipping point were catastrophic climate change will destroy the planet.

    Of course there are other factors that control climate/weather in the short term which gives us our ups and downs in temp but overall the basic idea is as CO2 goes up so will the temp.

    Is this basically how your theory works? If not please feel free to correct any errors.


  11. #11 Crakar14
    April 1, 2009


    I will keep an eye out for his book and if i find it i will read it OK, what was your bet again? Something to do with temps i believe. Re post it and i will take it into consideration.


  12. #12 coby
    June 16, 2009

    Comments on this article are closed, please post any further thoughts on this dedicated open thread, thanks.

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