In the beginning of the Cenozoic, the Earth was much warmer than it is today. Most of the past 65 million years has been warmer than today. The current Era started off roughly 8-10 °C (18 °F) (16) warmer than it is now. The major difference in temperature was at the poles. Antarctica had no permanent ice and was probably comparable to Canada as we know it today. The Arctic was probably even warmer than Antarctica.
