Cenozoic Era

THE CENOZOIC ERA is the most recent of the nine eras in geological time, and extends from 65 million years ago to the present. The Cenozoic Era catalogues extensive climate changes, ranging from hothouse climates with warm-temperate to sub-tropical forests near both the north and south poles, to icehouse climates with ice sheets kilometers thick covering much of the high latitudes in both hemispheres. The first 30 million years of the Cenozoic were the warmest of the era and were characterized by several extreme warmth events.

The first of these climate maxima is the Initial Eocene Thermal Maximum, which occurred approximately 55 million years ago. Geological evidence suggests that at this time, atmospheric CO2 concentrations soared to nearly 20 times current levels, and temperatures in the ...