Simple observation of the climate effects caused by the Mount Pinatubo eruption falsifies the above statement, irregardless of any examination of anthropogenic forcing factors.
The only outside source of energy is the sun.
The only other source of energy is orbital/rotational friction, which has to be very small, by comparison.
The effects of volcanic erruptions are short; rarely last longer than 8 months, while sunspot cycles are 11-17 years.
The current lag in sunspots has measurably reduced IR, while allowing an increase in UV due to the reduction of water vapor from the reduced IR. This isn’t new.
Irregardless is not a word in our language.
Cogitator, the sun is the sine qua non for earth's climate (and for all life on earth to exist). To claim, therefore, that the sun is only responsible for 10 to 30% of earth's climate variability (as you and Hathaway do) brings me to...
Definition Two — Folly: a lack of understanding; foolish belief.