http://www.uwgb.edu/dutchs/EarthSC102Notes/102PTEarthHist.htm80 million years ago:
150 years ago:
From the above two maps, it is clear that most of Antarctica was already within what we call the Antarctic Circle, but part of it was attached to Australia till about 50 mya.
Present theory says Antarctica had no permanent ice till about 20 million years ago (mya). The Antarctic probably had snow and ice during the winter, but none in the summer.
http://en.wikipedia.org/wiki/Ice_age Present theory also holds that the CO2 has a cycle. CO2 in the air is slowly absorbed into the ocean via river currents. The River deposit the CO2 nuggets onto the ocean floor where they law till a tectonic plate forces them into the mantel. Once in the Mantel the C02 flows till it comes to a Volcano and is released into the air. Once in the air, Plants absorb the CO2 to make "sugar" which is then deposited into the ground when the plant dies (or into the ground when an animal who ate that plant dies). These deposits are then driven into rivers by rain fall and the whole system starts all over again.
This system is not perfect. During the time that the Indian Subcontinent was into the Indian Ocean heading to Asia, it flows over a huge amount of Carbon deposited into the Indian Ocean. This lead to a slow increase in world wide temperatures till the Indian Plate hit the Asiatic Plate. When that collusion occurred you had a slow drop in Carbon going into the mantel and with that slow drop, you also had a slow drop in world wide temperatures starting about 50 mya, leading to the world getting cold enough to permit permanent ice in Antarctica by 20 mya.
More on Plate tectonics and CO2:
http://woodstown.org/ACS/resources/ec/ch12/act4.pdfhttp://www.geo.umass.edu/climate/papers2/deconto_tectonics&climate.pdf