The distribution of world biomes, (Raven and Johnson, 1992)
Presently the earth's biomes are located in the areas depicted above. Within earth's history, the distribution of these zones have been extremely variable due to climatic changes.
This WEB page will talk about the effects of climatic changes on the earth's biome distribution. Due to the scope of such a topic, the focus will be on climate induced glacier expansion and retreat, and the resulting movements of terrestrial vegetation.