The CO2 reconstruction through the early Holocene bears a striking similarity to reconstructed solar activity changes. This may suggest a rapid response of climate to minor changes in solar activity during this dynamic period, which in turn impacted the global carbon cycle. This can, to some extent, also be seen in the climatic responses associated with the Maunder Minimum in the mid-17th to early 18th centuries.
--CA Jessen et al, Global and Planetary Change, June 2007
Via Benny Peiser.