rising, more forest lands were being converted to fields, and the rise of towns began to quicken in pace. At or about the turn of the 14 century (1325 or so), colder and longer winters, larger amounts of rain, and ultimately bubonic plague began to decimate population and fields were abandend. The weather, then climate, began to be less hospitable than the previous century.
All of this was without industrialization or direct human intervention. It is also very evident to me that most of these climate scientists do not know social history for if they did it is very hard to disprove actual occurrence versus supposed theory.