Antarctica Climate Number: 300,000 Years
For the first half of the Cenozoic (the era spanning 65 million years ago to today), Earth was too warm to support ice sheets and sea levels were much higher than today. Then, about 34 million years ago, the Earth crossed a threshold. Over a period of about 300,000 years, the temperature dropped and ice sheets began to form on Antarctica. While most of the ice formed in the highlands of East Antarctica, some ice probably formed in West Antarctica, which is much closer to sea-level. The amount of ice on Antarctica has both grown and shrunk significantly over the past 34 million years, but the ice sheet covering East Antarctica has been relatively stable for about the past three million. The water in both ice sheets came from the ocean; as the ice sheets formed during this 300,000 year period, sea level fell by 220 feet, creating much more land area.
Seasons: Winter, Spring, Summer, Fall
Wilson, DS and Luyendyk, BP. “West Antarctic paleotopography estimated at the Eocene-Oligocene climate transition.” Geophysical Research Letters 36 (2009): L16302 and Katz, ME et al. “Stepwise transition from the Eocene greenhouse to the Oligocene icehouse.” Nature Geoscience 1 (2008): 329-334.
