Climate - Extinctions

Cenozoic life was severely affected by a major extinction event that occurred between 10,000 and 8,000 years ago. The sudden disappearance of many mammals since the Ice Age is attributed to one of two factors: Climate change associated with the melting of Pleistocene glaciers and killing by Paleolithic hunters. The latter is thought to be due to rapidly developing technology that allowed Paleolithic humans to hunt more efficiently.

At the beginning of the Cenozoic era, the Earth was much warmer than it is today, and the temperature gradient from the equator to the poles was less than half of what it is today. The cooling of the Earth began about 50 million years ago and continued unabated, with many changes leading up to the current interglacial climate. The Cenozoic Era was characterized by the development of glaciers in Antarctica about 35 million years ago and in the Northern Hemisphere between 3 and 2.5 million years ago. The Ice Age left a widespread geologic record on the continent in the form of ice floes and glacial moraines, which fell from icebergs to the seafloor along a line stretching from North America to Kansas, Illinois, Ohio and Long Island, New York.