An examination of the relationship between temperature and carbon dioxide

Natural variation trumps CO2

Many climate scientists claim that our carbon dioxide emissions are the principal driver of global warming. I have asked several University of Arizona professors, who make such a claim, to provide supporting physical evidence. So far, none have been able to justify the claim with physical evidence.

In this article, we will examine the Earth’s temperature and the carbon dioxide (CO2) content of the atmosphere at several timescales to see if there is any relationship. I stipulate that the greenhouse effect does exist. I maintain, however, that the ability of CO2 emissions to cause global warming is tiny and overwhelmed by natural forces. The main effect of our “greenhouse” is to slow cooling.

There is an axiom in science which says: “correlation does not prove causation.” Correlation, however, is very suggestive of a relationship. Conversely, lack of correlation proves that there is no cause-and-effect relationship.

Estimates of global temperature and atmospheric CO2 content based on geological and isotope evidence show little correlation between the two. Earth experienced a major ice age in the Ordovician Period when atmospheric CO2 was 4,000ppm, 10 times higher than now. Temperatures during the Cretaceous Period were rising and steamy, but atmospheric CO2 was declining.

Notice also, that for most of the time, Earth’s temperature was much warmer than now and life flourished. There were some major extinction periods, all associated with ice ages.


During the latter part of our current ice age, glacial-interglacial cycles occurred with a periodicity of about 100,000 years which correlates with the changes in Earth’s orbit around the sun as it changes from nearly circular to elliptical with an eccentricity of about 9%. Here we see an apparent correlation between temperature and CO2. The data are from ice cores collected at the Vostok station in Antarctica. The scientists working on the Vostok core noticed that temperature changes PRECEDED changes in CO2 concentration by about 800 years. Again, we see that CO2 doesn’t have much influence on temperature, but the temperature has great influence on CO2concentration because temperature controls CO2 solubility in the ocean.


  • Petit, J.R., et al., 1999. Climate and atmospheric history of the past 420,000 years from the Vostok ice core, Antarctica. Nature 399: 429-436.
  • Mudelsee, M, 2001. The phase relations among atmospheric CO2 content, temperature and global ice volume over the past 420 ka, Quaternary Science Reviews 20:583-589.
  • Siegenthaler, U. Et al., 2005. Stable carbon cycle-climate relationship during the late Pleistocene. Science 310: 1313-1317.

The Holocene represents the current interglacial period. For most of the past 10,000 years, the temperature was higher than now. CO2 was fairly steady below 300ppm (vs over 400ppm now). There were cycles of warm and cool periods at a periodicity of 1200 to 1500 years. This periodicity correlates with the interplay of the several solar cycles. The sun itself goes through cycles of solar intensity and magnetic flux. When the cycles are in a strong phase, the strength of the cosmic rays entering our atmosphere is reduced, and there are fewer clouds to block the sun, making it warmer.

When solar cycles wane, as is beginning to happen now, more cosmic rays enter the atmosphere and produce more clouds which block the sun, so it becomes cooler. The number of sunspots (hence magnetic flux) varies on an average cycle of 11 years. There are also 87-year (Gliessberg) and 210-year (DeVriess-Suess) cycles in the amplitude of the 11-year sunspot cycle which combines to form an approximately 1,500-year cycle of warming and cooling.

Read rest…

Comments (3)

  • Avatar

    Spurwing Plover


    All those who want CO2 banned or regulated have either been lied to listen too much or Gores or DiCaprios mindless babbling or are just plain stupid becuase plants need CO2

  • Avatar

    Dan Pangburn


    The observation that CO2 is a ghg (greenhouse gas) is a shallow penetration of the science. Delve deeper into the science and discover that CO2 does not now, has never had and will never have a significant effect on climate.

    Here is why.

    1) Essentially all absorbed outgoing longwave radiation (OLR) energy is thermalized (i.e. shared with surrounding molecules).
    2) Thermalized energy carries no identity of the molecule that absorbed it.
    3) Emission from a gas is quantized and depends on the energy of individual molecules.
    4) This energy is determined probabilistically according to the Maxwell-Boltzmann distribution.
    5) The Maxwell-Boltzmann distribution favors lower energy (longer wavelength) photons.
    6) Water vapor exhibits many (170+) of these longer wavelength bands.
    7) The Maxwell-Boltzmann energy distribution in atmospheric gas molecules effectively shifts the OLR energy absorbed by CO2 molecules to the lower energy absorb/emit bands of water vapor. The ‘notches’ in top-of-atmosphere measurements over temperate zones demonstrate the validity of this assessment.
    8) As altitude increases (to about 10 km) the temperature declines, magnifying the effect.

    The only thing countering the temperature decline that would otherwise be occurring is the increasing trend in water vapor. (‘Otherwise’ results from declining net effect of ocean cycles since 2005 and declining solar activity which has been declining since 2014 and dropped below ‘breakeven’ in early 2016). Average global atmospheric water vapor has been measured and reported by NASA/RSS since 1988 and shows an uptrend of 1.5% per decade. WV has increased about 8% since the more rapid increase began in about 1960. This is more than 2.5 times the expected rate from temperature increase alone (i.e. feedback).

    Further discussion of this with graphs and links to source data are at which also identifies the factors which do cause climate change (98% match 1895-2016).

    The warmer temperature is welcome but the added WV increases the risk of flooding. IMO all rainwater retaining systems (dams, dikes, etc.) should be upgraded from 100 yr floods to 10,000 yr floods.

  • Avatar



    If someone gave these scientists multiple billions of dollars in return for mere “scientific” claims, I’m sure they would be willing to tell us the moon is made of green cheese.

Comments are closed