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CO2 Through the Ages

July 5, 2016

In my book, Nothing to Fear, I use the 2,000 year period between today and the time of Christ to demonstrate that there is no clear evidence that atmospheric CO2 levels have had an effect on temperatures. For example, the medieval warm period had temperatures as high as today’s, while CO2 levels were unchanged.

In the book, I use an IPCC chart showing that, prior to around 1850, atmospheric CO2 levels were constant at around 280 ppm going back for 2,000 years. I used the IPCC chart since few people would likely criticize the data.

GHG Graph from IPCC AR4

GHG Graph from IPCC AR4

In my talks, I go back 4,000 years to make the same point.

4,000 year history of temperatures and CO2

4,000 year history of temperatures and CO2

During this 4,000 year period, there have been four warm periods, including today’s. In the previous warm periods, Medieval, Roman and Minoan, temperatures have been as high, or higher, than they are today, while atmospheric CO2 has remained essentially constant at around 280 ppm.

This again supports the contention that CO2 is having little effect on temperatures rise.

It’s possible to go back hundreds of thousands of years and still see that CO2 hasn’t seemed to affect temperatures. I didn’t propose going back that far in my book since there were so many other forces at work about which much is still unknown.

During the Carboniferous period, for example, the formation of skeletal life drew CO2 from the atmosphere and locked it permanently in the Lithosphere as Limestone.

However, as the following chart shows, atmospheric CO2 has been very much higher than today, while CO2 levels over the past three million years have been among the lowest levels during the Earth’s history. Meanwhile temperatures have varied widely, with little correlation to atmospheric levels of CO2.

While these records comparing atmospheric CO2 levels with variations in temperatures provide substantial proof that CO2 has not been the primary cause of temperature change, they do not infer that CO2 hasn’t had some effect on temperatures.

They also don’t infer that mankind hasn’t affected the environment.

They do, however, demonstrate that the CO2 hypothesis, claiming that atmospheric CO2 is causing global warming and climate change, is unsubstantiated, and that history has shown there is little correlation between CO2 and temperatures.

Geologic Time Scale CO2 and Temperatures

Geologic Time Scale CO2 and Temperatures

There are other hypotheses for the cause of global warming with greater scientific support than the CO2 hypothesis.

For example, there is Dr. Svensmark’s hypothesis, where cosmic rays create low-level clouds that shade the Earth and reflect sunlight back into space. This is explained more fully in Nothing to Fear.

The recent CERN CLOUD experiments have provided support for Dr. Svensmark’s hypothesis. See, Global Warming Science isn’t Settled.

Not only does it appear that the CO2 hypothesis is weak, but that it has been transformed into a political weapon with political, rather than scientific, purposes.

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Nothing to Fear explains why CO2 isn’t to be feared. Chapter 15, An Alternative Hypothesis, describes Dr. Svensmark’s hypothesis on cosmic rays.

Nothing to Fear is available from Amazon and some independent book sellers.

Link to Amazon:

Book Cover, Nothing to Fear

Book Cover, Nothing to Fear

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3 Comments leave one →
  1. Elissa Feit permalink
    October 30, 2019 10:49 am

    Your conclusion is incorrect -:you’ve made an error in your logic.

    increased CO2 causes warming
    (Compare to “poisoning causes death”)

    Here are 4 periods of warming in which CO2 was not increased.
    (Paul died from a heart attack, Suzy died from cancer, Bobby died from a gunshot wound.)

    Ergo, CO2 does not cause warning.
    (Ergo, poisoning does not cause death. )

    No one is claiming CO2 is the only factor that results in warming. We are in an otherwise cool period, with respect to solar activity. And yet, hottest 15 years in history in the last 18…

    • October 30, 2019 11:28 am

      First, the last several years are not the hottest in history. Temperatures have been higher than today over most of the last 10,000 years since the last Ice Age.
      Second, CO2 does play a small role in temperature change. Please go to and download, We Have Nothing to Fear From CO2.

    • Truthocracy permalink
      May 30, 2022 6:25 am

      @Elissa Feir:
      “No one is claiming CO2 is the only factor that results in warming. We are in an otherwise cool period, with respect to solar activity. And yet, hottest 15 years in history in the last 18…”

      >> At 400ppm/v CO2 is a trace gas and, besides that, the forcing beyond the 400ppm/v level is essentially zero. Climate sensitivity to CO2 is only hypothesised within the climate models (hence the plethora of modelling applications) and it’s not something we solidly understand or quantify.
      The past 7 years (2015 to 2022) the Earth is in a cooling trend of -0.10C per decade (NOAA’s own data and tool).

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