I made a follow up to this video explaining more:    • The Milankovitch Cycle Timeline: Wher...  
Many people are confused in thinking this has something to do with the global warming debate. This explains how the climate changes naturally over hundreds of thousands of years and is unrelated to any changes over the past century. Please see my follow up video.

The Milankovitch Cycles are changes in the Earth's orbit and rotation that cause the Earth's climate to change over hundreds of thousands of years.

For more information, I recommend Dan Britt's lecture on the history of climate:
   • Dan Britt - Orbits and Ice Ages: The ...