Antarctica – Once Warm and Full of Greenery

Surprising new evidence shows that the Antarctica was once green, warm and resembled some of the greenery and tundra found in parts of modern day Chile and New Zealand. The coasts of the Antarctica were once lined with beeches and a type of conifer. According to Sarah Feakins, a biogeochemist from the University of Southern California, the evidence comes from abundant remains of leaf waxes in sediment cores taken from deep within the Antarctica’s Ross Ice Shelf.

15 million years ago the area had a warm period which temporarily thawed the Antarctica and caused it to burst into greenery. Not only were the leaf wax remnants numerous when found an analysis of their chemistry revealed the continent was warmer than originally thought. The Antarctic coast would have been about 15 degrees Fahrenheit on a summer day. This period of time was known as the Miocene period, which is known for being warm but warmer then originally thought.

When plants die, most of it decomposes, except for pollen grains and waxes on its leaves. When the leaf wax gets trapped and preserved in sediment it creates a kind of molecular fossil. Leaf waxes are able to keep climate records by capturing the ratios of water isotopes that a plant drank while it was alive.

Pollen grains found in the sediments showed two types of tree species: the beech Nothogagus and a shrubbery conifer in the genus Podocarpidites. Species of trees vary in how far their pollen grains can be transformed from the plaant. Neither of these plants grains can travel far, and if the trees had grown far inland on Antarctica, the pollen would not have been found in coastal sediments.

While the Miocene was generally a warmer period than it is today, the new research may have some bearing to the current trend of global warming. Earth’s average global temperature has increased about 1.4 degrees Fahrenheit since 1880. Two-thirds of that warming has happened since 1975. Understanding the Miocene period and rainfall patterns may help scientists figure out how much wetter it will get as the world gets hotter.

Warming related changes to the global warming cycle can be troubling as it’s not easy or inexpensive for societies to adjust to big changes in water supply. This new research also suggests that there will be substantial shifts in water cycles making areas either rainier or drier, due to current temperature changes. In terms of Earth and climate, this Antarctic warming was not very long ago and the distribution of continents and chemistry of the atmosphere was not very different than today.