I'm of the belief that humans impact the planet less than we think. I'd blame our egos (ie: sun circle around the earth kind of thinking).
I think all of this can be explained with geomagnetic pole reversal. Basically, the north pole goes south for the winter, (which is a cyclical event) and causes mass climate disturbances. According to the cycles, we are due for one in the near future. (The first one for recorded humanity!!)
Exciting times ahead.