Apart from the Ice Age was there any other Climate Changes?

The climate of the planet has been changing over time since it cooled from molten rock. It was generaly warmer with higher oxygen when dinosaurs roamed the earth, cooled and warmed again over several ice ages. Realize though that the temperate at any one place goes up or down depending on season and weather, so they are talking annual averages. While this graph of temperature goes up and down alot (a lot of variability) the trend overall is upwards. The concern now is that the planet seems to be warming faster then in any othe time, faster then animals or plants can adapt. Also, many fear the weather will become not just warmer, but erratic. If weather is totally unpredictable, farmers won't know when to plant crops, and world wide famine could happen.