Solar, volcanic, and CO2 forcing of recent climatic changes


The climate, as represented by the mean Northern Hemisphere temperature, has shown substantial changes within the past century. The temperature record is utilized as a means of elucidating the relative importance of anthropogenic CO2 increase, volcanic aerosols, and possible solar insolation variations in externally forcing climate changes. Solar luminosity variations, suggested by observed solar radius variations on an ≈ 80 yr time scale, allow a self-consistent explanation of the hemispheric temperature trends. Evidence for solar influences on the climate is also found on the shorter 11 and 22 yr time scales present in solar activity cycles.

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The author is a staff scientist at the High Altitude Observatory, P.O. Box 3000, Boulder, CO 80307, of the National Center for Atmospheric Research.

This work was completed while the author was a postdoctoral fellow in the Advanced Study Program of NCAR.

Any opinions, findings and conclusions or recommendations expressed in this paper are those of the author and do not necessarily reflect the views of the National Science Foundation.

The National Center for Atmospheric Research is sponsored by the National Science Foundation.

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Gilliland, R.L. Solar, volcanic, and CO2 forcing of recent climatic changes. Climatic Change 4, 111–131 (1982).

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  • Solar Radius
  • Solar Activity Cycle
  • Recent Climatic Change
  • Solar Insolation
  • Radius Variation