International Journal of Atmospheric and Oceanic Sciences


Submit a Manuscript

Publishing with us to make your research visible to the widest possible audience.

Propose a Special Issue

Building a community of authors and readers to discuss the latest research and develop new ideas.

The Impact of CO2, H2O and Other “Greenhouse Gases” on Equilibrium Earth Temperatures

It has long been accepted that the “greenhouse effect”, where the atmosphere readily transmits short wavelength incoming solar radiation but selectively absorbs long wavelength outgoing radiation emitted by the earth, is responsible for warming the earth from the 255K effective earth temperature, without atmospheric warming, to the current average temperature of 288K. It is also widely accepted that the two main atmospheric greenhouse gases are H2O and CO2. What is surprising is the wide variation in the estimated warming potential of CO2, the gas held responsible for the modern concept of climate change. Estimates published by the IPCC for climate sensitivity to a doubling of CO2 concentration vary from 1.5 to 4.5°C based upon a plethora of scientific papers attempting to analyse the complexities of atmospheric thermodynamics to determine their results. The aim of this paper is to simplify the method of achieving a figure for climate sensitivity not only for CO2, but also CH4 and N2O, which are also considered to be strong greenhouse gases, by determining just how atmospheric absorption has resulted in the current 33K warming and then extrapolating that result to calculate the expected warming due to future increases of greenhouse gas concentrations. The HITRAN database of gaseous absorption spectra enables the absorption of earth radiation at its current temperature of 288K to be accurately determined for each individual atmospheric constituent and also for the combined absorption of the atmosphere as a whole. From this data it is concluded that H2O is responsible for 29.4K of the 33K warming, with CO2 contributing 3.3K and CH4 and N2O combined just 0.3K. Climate sensitivity to future increases in CO2 concentration is calculated to be 0.50K, including the positive feedback effects of H2O, while climate sensitivities to CH4 and N2O are almost undetectable at 0.06K and 0.08K respectively. This result strongly suggests that increasing levels of CO2 will not lead to significant changes in earth temperature and that increases in CH4 and N2O will have very little discernable impact.

Carbon Dioxide, Climate Sensitivity, Greenhouse Effect, Climate Change

David Coe, Walter Fabinski, Gerhard Wiegleb. (2021). The Impact of CO2, H2O and Other “Greenhouse Gases” on Equilibrium Earth Temperatures. International Journal of Atmospheric and Oceanic Sciences, 5(2), 29-40.

Copyright © 2021 Authors retain the copyright of this article.
This article is an open access article distributed under the Creative Commons Attribution License ( which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

1. Zhong, W. Y., and J. D. Haigh (2013), The greenhouse effect and carbon dioxide, Weather, 68 (4), 100–105, doi: 10.1002/wea.2072.
2. G. Myhre et al, Anthropogenic and Natural Radiative Forcing, Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, United Kingdom (2013).
3. H. Harde, Radiation Transfer Calculations and Assessment of Global Warming by CO2, International Journal of Atmospheric Sciences, Vol. 2017, Article ID 9251034.
4. W. A. van Wijngaarden & W. Happer, Dependence of Earth’s Thermal Radiation on Five Most Abundant Greenhouse Gases. Atmospheric and Oceanic Physics arXiv: 2006.03098 (2020).
5. S. E. Schwartz, Resource Letter GECC-1: The Greenhouse Effect and Climate Change: Earth’s Natural Greenhouse Effect, Am. J. Phys. 86, (8), 565-576, (2018).
6. S. E. Schwartz, Resource Letter GECC-2: The Greenhouse Effect and Climate Change: The Intensified Greenhouse Effect, Am. J. Phys. 86, (9), 645-656, (2018).
7. K. E. Trenberth, J. T. Fasullo and J. Kiehl, “Earth’s Global Energy Budget”, Bulletin of the American Meteorological Society, vol. 90, no. 3, pp 311-323, 2009.
8. Stevens, B., S. C. Sherwood, S. Bony, and M. J. Webb (2016), Prospects for narrowing bounds on Earth’s equilibrium climate sensitivity, Earth’s Future, 4, 512-522. Future, 4, 512–522 doi: 10.1002/2016EF000376.
9. D. J. Wilson and J. Gea-Banacloche, Simple Model to Estimate the Contribution of Atmospheric CO2 to the Earth’s Greenhouse Effect, Am. J. Phys. 80 306 (2012).
10. I. E. Gordon, L. S. Rothman et al., The HITRAN2016 Molecular Spectroscopic Database, JQSRT 203, 3-69 (2017).
11. U.S. Standard Atmosphere 1976, National Oceanic and Atmospheric Administration, National Aeronautics and Space Administration, Washington, DC, USA, 1976.
12. A. L. Buck (1981), New equations for computing vapour pressure and enhancement factor, J. Appl. Meteorol., 20: 1527-1532.
13. Hermann Harde, "Radiation and Heat Transfer in the Atmosphere: A Comprehensive approach on a Molecular Basis", International Journal of Atmospheric Sciences, vol. 2013, Article ID 503727, 26 pages, 2013.
14. H. Harde, Radiative and Heat Transfer in the Atmosphere: A Comprehensive Approach on a Molecular Basis, Int. J. Atm. Sci. 503727, (2013).
15. M. Etminan, G. Myhre, E. J. Highwood and K. P. Shine, Radiative Forcing of Carbon Dioxide, Methane and Nitrous Oxide: A Significant Revision of the Methane Radiative Forcing, Geophys. Res. Lett. 43, 12614 (2016).
16. I. M. Held and B. J. Soden (2000) Water Vapour Feedback and Global Warming, Annual Review of Energy and the Environment, Vol. 25:441-475 (Nov 2000).
17. K. W. Thoning, A. M. Crotwell, and J. W. Mund (2021), Atmospheric Carbon Dioxide Dry Air Mole Fractions from continuous measurements at Mauna Loa, Hawaii, Barrow, Alaska, American Samoa and South Pole. 1973-2019, Version 2021-02 National Oceanic and Atmospheric Administration (NOAA), Global Monitoring Laboratory (GML), Boulder, Colorado, USA.