Milankovitch Cycles

http://www.ncdc.noaa.gov/paleo/milankovitch.html

http://en.wikipedia.org/wiki/Milankovitch_cycles

http://sploid.gizmodo.com/climate-change-is-moving-the-poles-and-changing-earths-1482864396

http://www.dailymail.co.uk/sciencetech/article-2095571/Natural-tilts-earths-axis-alter-temperature-cause-ice-ages-says-Harvard-scientist.html

interesting stuff