How The Antarctic Ice Melted 23 Million Years Ago? Fossil Leaves Provide Evidence

How the climate changed and influenced the Antarctic ice-sheet 23 million years ago has been explained by the discovery of fossilized leaves from a crater lake in New Zealand. A scientist stated on Thursday, the fossil leaves found in Foulden Maar, in the Ontago region of South Island, has evidences of a sharp increase in the atmospheric levels of carbon dioxide. This sudden hike might be associated with a major collapse of the ice-sheet.

The study conducted by a group of US scientists found that certain changes in the stomatal cells and carbon isotope rations in the discovered leaves indicated a remarkable increase in the levels of CO2. The carbon dioxide levels have been raised from 500 ppm (parts per million) to somewhere between 750 and 1,550 ppm over a span of 10,000 years, approximately, according to The Indian Express.

Historic Shrinking of Antarctic Ice Sheet Linked to CO2 Spike https://t.co/lrLtRpWm0i pic.twitter.com/IiJ3WcLI16

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"What surprised us was how such large CO2 fluctuations occured over geologically, relatively short time scales," said Beth Fox, a Waikato University paleoclimatologist and member of the research team. She added further that the team found a link between the increase in CO2 levels and decline of the ice-sheet.

 As soon as the carbon dioxide levels started to hike rapidly, the ice-sheet began to melt. More importantly, once the process of melting was initiated, it kept going on by itself because the ice did not stop melting even when the carbon dioxide levels dropped back to normal. Some recent models have suggested that at the present rate, the Antarctic ice-sheet might arrive at a critical tipping point and begin destabilizing itself rapidly which had happened previously.

As per the report by Time India, the scientists are not yet sure at which point between 500 and 1,550 ppm did the destabilization take place. Now, they want to experiment and study different plant species in order to confirm their findings and draw appropriate conclusions.