What Causes Rising Atmospheric CO2?


This post is prompted by a recent exchange with those reasserting the “consensus” view attributing all additional atmospheric CO2 to humans burning fossil fuels.

The IPCC doctrine which has long been promoted goes as follows. We have a number over here for monthly fossil fuel CO2 emissions, and a number over there for monthly atmospheric CO2. We don’t have good numbers for the rest of it-oceans, soils, biosphere–though rough estimates are orders of magnitude higher, dwarfing human CO2.  So we ignore nature and assume it is always a sink, explaining the difference between the two numbers we do have. Easy peasy, science settled.

What about the fact that nature continues to absorb about half of human emissions, even while FF CO2 increased by 60% over the last 2 decades? What about the fact that so far in 2020 FF CO2 has declined significantly with no discernable impact on rising atmospheric CO2?

These and other issues are raised by Murray Salby and others who conclude that it is not that simple, and the science is not settled. And so these dissenters must be cancelled lest the narrative be weakened.

The non-IPCC paradigm is that atmospheric CO2 levels are a function of two very different fluxes. FF CO2 changes rapidly and increases steadily, while Natural CO2 changes slowly over time, and fluctuates up and down from temperature changes. The implications are that human CO2 is a simple addition, while natural CO2 comes from the integral of previous fluctuations.  Jeremy Shiers has a series of posts at his blog clarifying this paradigm. See Increasing CO2 Raises Global Temperature Or Does Increasing Temperature Raise CO2 Excerpts in italics with my bolds.

The following graph which shows the change in CO2 levels (rather than the levels directly) makes this much clearer.

Note the vertical scale refers to the first differential of the CO2 level not the level itself. The graph depicts that change rate in ppm per year.

There are big swings in the amount of CO2 emitted. Taking the mean as 1.6 ppmv/year (at a guess) there are +/- swings of around 1.2 nearly +/- 100%.

And, surprise surprise, the change in net emissions of CO2 is very strongly correlated with changes in global temperature.

This clearly indicates the net amount of CO2 emitted in any one year is directly linked to global mean temperature in that year.

For any given year the amount of CO2 in the atmosphere will be the sum of

  • all the net annual emissions of CO2
  • in all previous years.

For each year the net annual emission of CO2 is proportional to the annual global mean temperature.

This means the amount of CO2 in the atmosphere will be related to the sum of temperatures in previous years.

So CO2 levels are not directly related to the current temperature but the integral of temperature over previous years.

The following graph again shows observed levels of CO2 and global temperatures but also has calculated levels of CO2 based on sum of previous years temperatures (dotted blue line).


The massive fluxes from natural sources dominate the flow of CO2 through the atmosphere.  Human CO2 from burning fossil fuels is around 4% of the annual addition from all sources. Even if rising CO2 could cause rising temperatures (no evidence, only claims), reducing our emissions would have little impact.


CO2 Fluxes, Sources and Sinks

Who to Blame for Rising CO2?

Fearless Physics from Dr. Salby

In this video presentation, Dr. Salby provides the evidence, math and charts supporting the non-IPCC paradigm.

About 18 minutes from the start Dr. Salby demonstrates that all the warming since 1945 came from two short term events.

If these two events 1977-1981 and 1994-1998 are removed, the entire 0.6C increase disappears.  Global Warming theory asserts that adding CO2 causes a systemic change resulting in a higher temperature baseline.  Two temperature spikes, each lasting four years, are clearly episodic, not systemic.  A further proof that warming over the last 70 years arose from natural variations, not CO2 forcing.


  1. Hifast · August 3, 2020

    Reblogged this on Climate Collections.


  2. Michael Lewis · August 3, 2020

    Excellent analysis, confirming what I have suspected for decades.


    • Ron Clutz · August 3, 2020

      Thanks Michael. I had been struggling to get a plain language explanation of this important climate factor.


      • oiltranslator · August 4, 2020

        Serendipity. I had just started a review of (lest we forget) math, and this comes onscreen. Thanks


  3. Raymond · August 3, 2020

    Hi Ron
    After having done so many charts on the topic I’d come to the same conclusion. I’m sure we’re adding to the CO2 to the atmosphere as FF CO2, but even then it would take so much more then we could durn to make a difference that would cause a globale collapse. But it’s so much easier to push the narcissistic view only man can influence the plants climate because of his behavior. This isn’t new since in the past it was the gods who punished us with bad weather if we did something wrong. It always revolves around us, no other influences could be responsible which for me is very narcissistic. So I guess we’re still dealing with the same problems of not being able to accept that we’re only a part of the eco system!


    • Ron Clutz · August 3, 2020

      Does this mean you’re not signing up for the guilt trip? Everyone else is going, so don’t be left out!


      • Raymond · August 4, 2020

        I do best when I’m left out of things. Group think isn’t my kind of thing! Sorry no chance there!


  4. Jamie Spry · August 4, 2020

    Reblogged this on Climatism and commented:
    “This means the amount of CO2 in the atmosphere will be related to the sum of temperatures in previous years.” An inconvenient fact completely ignored by ‘CO2-consensus’ zealots.


  5. ozonebust · August 4, 2020

    Hi Ron
    In the last section you stated 6C, should it be 0.6C.
    This is a very nice easy to read summary. The two temperature steps are effectively increases in Ocean heat release from low latitudes. Note the decreased Arctic sea ice extent reduction over the same period. Most of the increase in the two meter temperature is the high NH latitudes (Ceres 2000 to 2004), and the source of the temperature rise is from the convection displacement from low latitudes.
    The two meter temperature record measures heat transport, nothing more. It records heat loss.


    • Ron Clutz · August 4, 2020

      Thanks Martin for the comment, and the heads up. Fixed
      Your mention of the mechanism of warming is very helpful. Few realize that any warming in the surface records (for any reason) comes at higher latitudes by way of meridional heat transfer. And the “Global” temperature average is driven by the highly volatile records at higher latitudes. I learned that from Clive Best, but much appreciate your reminder.



  6. ozonebust · August 4, 2020

    Ceres 2000 to 2017………


  7. Geir Kjosavik · August 23, 2020

    So explain what caused the rise in CO2 from 275ppm to 415ppm over the past 150 years.


    • Ron Clutz · August 23, 2020

      Read the article. Rising temperatures since the LIA along with oceanic fluctuations cause the release of CO2 from natural sinks.


  8. Pingback: Why CO2 Can’t Warm the Planet | Science Matters

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s