The current ice caps of Greenland and Antarctica and Alpine glaciers are remnants of the last ice age. Conversely, if more carbon dioxide is given off than absorbed, then the carbon dioxide concentration in the atmosphere will rise and there is clear evidence over geological time that this has resulted in periods of global warming.
Erinevate geoloogiliste aegkondade põhjal on selgelt tõendatav, et see on omakorda toonud kaasa globaalse soojenemise perioode.