Departmental Colloquium

Dependence of Global Temperatures on Atmospheric CO2 and Solar Irradiance

D. J. Thomson
Department of Mathematics and Statistics
Queen's University, Kingston, Ontario

Time
Wed. March 5, 2003     1:30 PM     Stirling A

Abstract

Changes in global average temperatures and of the seasonal cycle are strongly coupled to the concentration of atmospheric CO2. I estimate transfer functions from changes in atmospheric CO2 and from changes in solar irradiance to hemispheric temperatures that have been corrected for the effects of the precession of the Earth. They show that changes from CO2 over the last century are about three times larger than those from changes in solar irradiance. The estimated sensitivity of global average temperature to changes in solar irradiance is close to that expected from the Stefan-Boltzmann law. The increase in global average temperature during the last century is at least 20 times the standard deviation of the residual temperature series left when the effects of CO2 and changes in solar irradiance are subtracted. In addition to the warming, the timing of the annual cycle is being seriously disrupted by CO2. This may have even more serious consequences than the simple change in temperature.

Refreshments will be available in the lounge after the talk.

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