[sanchmo]

Solar Irradiance:

Scafetta & West, Jun-Sep 2006: The sun might have contributed approximately 50% of the observed global warming since 1900

The much lower 10-40% came from an article published a year earlier, where Scafetta admits "I think it is important to correct the climate models so that they include reliable sensitivity to solar activity.Once that is done, then it will be possible to better understand what has happened during the past hundred years."

[megatherium]

A detailed response to the Scafetta and West paper: http://www.realclimate.org/index.php/archives/2006/10/how-not-to-attribute-climate-change/ (I haven't read this in detail however. But the web site realclimate.org is probably the best place for detailed information written by climate scientists who support the doctrine of anthropogenic global warming.)