Monday, October 20, 2008

PDO Update

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.
It is significant that the observed scale factor (1.9) that converts the PDO index into units of heating
or cooling is just what the model required (1.7 to 2.0) to best explain the temperature behavior
during the 20th Century.
Thus, these recent satellite measurements - even though they span less
than 6 years -- support the Pacific Decadal Oscillation as a potential major player in global
warming and climate change.