Drop in Carbon Dioxide Levels Led to Polar Ice Sheet, Study Finds

Scientist at Yale and Purdue, state that a climate change can be caused by the change in carbon dioxide. For example, the drop in carbon dioxide made an ice sheet form over the Antarctic. Before the ice sheet can melt the greenhouse gases have to increase, how much is still unknown. Due to the ice sheet and change in climate many species became extinct over about 100,000 years. Before the drop in carbon dioxide all kinds of species inhabited the North and South Poles and Earth has subtropical climates and it was warm and wet. Since the ice sheet formed over the Antarctic the sea levels fell. Carbon dioxide had an importance from the past to the present. They do not know what caused the rise and fall in the carbon dioxide level, but they study ancient algae in the deep ocean sediments and crust.