I don't think there was much prior uncertainty in the literature over the general notion that orbital forcing changes were an initiating factor and that consequent rises in CO2 contributed a major subsequent warming influence, but the timing (regional vs global) and the interaction between the hemispheres has not been well illuminated. (realclimate.org)
We know there have been previous ice ages and subsequent warming cycles; we know when they were, and how much time elapsed between them. (dotearth.blogs.nytimes.com)
Those eruptions meant there was more subsequent warming in the following years, making the rate of warming appear to be rising as a result of man - made emissions or other factors, Christy said. (cfact.org)