It is not hard for a scientist (i.e. not you) to figure out when orbital variations have affected our planet because they are periodic.  But because there are several layers to it the periodicity is not a simple recurrence of every X years.  In other words, some aspects have periods of, say, 75,000 years while others are longer.  When you layer them together it is complicated.  
The medieval warm period was not a global phenomenon, rather different portions of the planet warmed at different times, contrary to what you probably think.  In other words, there was no planet-wide forcing mechanism.  Same with the little ice age.  
I am not a hypocrite for pushing the idea that our actions our detrimental to our planet, as I take all kinds of efforts to reduce my impact which is probably a fraction of yours.