October 21, 2008
by Roy W. Spencer, PhD
Principal Research Scientist
The University of Alabama in Huntsville
Here follows a simplified version of Dr. Spencer's paper he ispreparing for submission to Geophysical Research Letters) Abstract
A simple climate model forced by satellite-observed changes in the Earth's radiative budget associated with the Pacific Decadal Oscillation is shown to mimic the major features of global average temperature change during the 20th Century - including two-thirds of the warming trend. A mostly-natural source of global warming is also consistent with mounting observational evidence that the climate system is much less sensitive to carbon dioxide emissions than the IPCC's climate models simulate.
For those who have followed my writings and publications in the last 18 months (e.g. Spencer et al., 2007), you know that we are finding satellite evidence that the climate system could be much less sensitive to greenhouse gas emissions than the U.N.'s Intergovernmental Panel on Climate Change (IPCC, 2007) climate models suggest.
To show that we are not the only researchers who have documented evidence contradicting the IPCC models, I made the following figure to contrast the IPCC-projected warming from a doubling of atmospheric carbon dioxide with the warming that would result if the climate sensitivity is as low as implied by various kinds of observational evidence. FULL REPORT PDF, with Graphics and subject matter covering