Global warming sure wasnt helped with the Industrial Revolution and so on, but this always happens. Throughout history one can see rises in temp..and the watch it drop. The earth warms up, has an ice age, kills off what cant survive, what does survive evolves to adapt and the process repeats itself. Man has had a factor in the current trend but I am sure it will only be a matter of time before mother earth says "fuck this" and freezes everything.
The last major weather change was around the time of the plague in Europe. It warmed up fast, people hadnt had time to develop good immune systems, new disease rolled in, whacked alot of folks.