File:IPCC Radiative Forcings.gif

From Global Warming Art


A climate modeling study's interpretation of how the evolution of the various forcing factors have affected climate during the last 100 years.

Changes in radiative forcings between 1750 and 2000 based on estimates by the Intergovernmental Panel on Climate Change (IPCC 2001a, [1]). The words across the bottom indicate the IPCC's assessment of how well each factor is understood.

Understanding global warming requires understanding the changes in climate forcings that have occurred since the industrial revolution. These include positive forcing from increased man-made greenhouse gases, negative forcing from man-made sulphate aerosols, poorly constrained forcings from indirect aerosol feedbacks, and a variety of other minor contributions from natural and artificial sources such as solar variability. The poorly constrained aerosol effects result both from limited physical understanding of how aerosols interact with the atmosphere and limited knowledge of aerosol concentrations during the pre-industrial period. This is a significant source of uncertainty in comparing modern climate forcings to past states.

Contrary to the impression given by this figure, it is not possible to simply sum the radiative forcing contributions from all sources and obtain a total forcing. This is because different forcing terms can interact to either amplify or interfere with each other. For example, in the case of greenhouse gases, two different gases may share the same absorption bands thus partially limiting their effectiveness when taken in combination.


This figure is one of the more well-known IPCC images from the Third Assessment Report and is used here to efficiently summarize the scientific understanding of radiative forcings. It is believed that the educational use of this small portion of the non-profit IPCC reports is consistent with the United States fair use doctrines.


Copyright undetermined This work is copyrighted and unlicensed. However, the individual who uploaded this work asserts that this use qualifies as fair use of the material under United States copyright law. Anyone wishing to make further use of this image should carefully consider fair use law and make an individual determination of whether their use is likely qualify for this protection.


  • [full text] IPCC (2001a). Houghton, J.T.,Y. Ding, D.J. Griggs, M. Noguer, P.J. van der Linden, X. Dai, K. Maskell, and C.A. Johnson (eds.): Climate Change 2001: The Scientific Basis. Contribution of Working Group I to the Third Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge, UK: Cambridge University Press. ISBN 0521807670. 

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