Australia: The Land Where Time Began

A biography of the Australian continent 

Palaeocene Climate

At the beginning of the Cenozoic, the Palaeocene, there was a hothouse climate with both poles ice free and trees grew on the Kamchatka Peninsula of Russia, and new animal groups were arising to fill the niches that had been vacated at the K-T boundary. At that time the global average temperatures were as high as 15° C or more higher than at the present. Evidence from fossils indicates that in Greenland in the Northern Hemisphere and Patagonia in the Southern Hemisphere, that are cold places at the present, the vegetation in the Palaeocene was of a subtropical type. The poles were cool, not cold, and were forested instead of the tundra extending across most high latitudes of the present. There were tropical and subtropical forests in the humid equatorial regions that are believed to have appeared similar to the tropical rainforests of the present, though it was to become much hotter as the climate underwent great changes to a degree that has occurred only a few times in the entire history of the Earth.

The global temperatures remained high following the waning of the PETM, much higher than at the present for about 5-6 My, the Early Eocene Climate Optimum (EECO), during which the climate remained humid and balmy. The character of the Cenozoic climate began changing following the end of the EECO, as the global temperatures continued to drop throughout the remainder of the Eocene, the climate becoming broadly cooler and drier. As the atmospheric CO₂ levels dropped the temperatures followed them down, from a hothouse at the start of the Eocene Epoch to a icehouse world, and by the Middle of the next epoch, the Oligocene, the atmospheric concentration of CO₂ reached as low as 500 ppm.

Sources & Further reading

1. McGuire, Prof. Bill, 2012, Waking the Giant: How a changing climate triggers earthquakes, tsunamis, and volcanoes, Oxford University Press.