"orbital forcings"???   You mean the 'theory' that the earth shifted it's axis 5000 years ago?    Berger and Loutre in 2002 predicted a possible 50,000 years of warm, with or without man.

Since the fastest orbital period is about 20,000 years,  orbital forcing seems a worthy candidate for any continuous climate change.  Since orbital mechanics require that the length of the seasons be proportional, and currently the northern hemisphere summer is 4.66 days longer than winter, one would expect changes to what has been recorded as 'the weather averages' over the 250 year recordkeeping of man.  
Remember a 1% error in anyone's calculations can result in a very large number when impacted over 5000 years or the 12000 years since the last NA Ice Age.