Last time CO2 levels were this high, there were trees at the South Pole
Trees growing near the South Pole, sea levels 20 metres higher than now, and global temperatures 3C-4C warmer. That is the world scientists are uncovering as they look back in time to when the planet last had as much carbon dioxide in the atmosphere as it does today. Using sedimentary records and plant fossils, researchers have found that temperatures near the South Pole were about 20C higher than now in the Pliocene epoch, from 5.3m to 2.6m years ago.
Many scientists use sophisticated computer models to predict the impacts of human-caused climate change, but looking back in time for real-world examples can give new insights.
The Pliocene was a “proper analogy” and offered important lessons about the road ahead, said Martin Siegert, a geophysicist and climate-change scientist at Imperial College London. “The headline news is the temperatures are 3-4C higher and sea levels are 15-20 metres higher than they are today. The indication is that there is no Greenland ice sheet any more, no West Antarctic ice sheet and big chunks of East Antarctic [ice sheet] taken,” he said.
Fossil fuel burning was pumping CO2into the atmosphere extremely rapidly, he said, though it took time for the atmosphere and oceans to respond fully. “If you put your oven on at home and set it to 200C the temperature does not get to that immediately, it takes a bit of time, and it is the same with climate,” Siegert said, at a Royal Meteorological Society meeting on the climate of the Pliocene.
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on Apr 6 2019. Filed under Climate change.
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