Study finds the Earth’s climate is highly sensitive to “relatively small variations in atmospheric CO2.”
The last time carbon dioxide levels in the atmosphere were as high as they are today, sea levels were 60 feet higher and it was so warm that trees grew in Antarctica.
Current CO2 levels of 410 parts per million (ppm) were last seen on Earth three million years ago, according to the most detailed reconstruction of the Earth’s climate by researchers at the Potsdam Institute for Climate Impact Research (PIK) and published in Science Advances.
Their in-depth analysis of plant fossils and sediments reveal that such CO2 levels were last seen in the late Pliocene Epoch, a time when there were no ice sheets covering either Greenland or West Antarctica, and much of the East Antarctic ice sheet was gone. Temperatures were up to 7 degrees Fahrenheit warmer globally, at least double that at the poles, and sea levels were some 20 meters (65 feet) higher.
“This is an amazing discovery,” Jane Francis, director of the British Antarctic Survey, told The UK Guardian. “They found fossil leaves of southern beech. I call them the last forests of Antarctica.”
While the discovery is remarkable, it’s implications are dire. “Twenty metres of sea level rise would have a major impact on our all our coastal cities,” Francis warned.
The good news is that the Earth does not warm instantly, and mile-thick ice sheets melt even more slowly. So the temperature rise will take several decades, and tens of feet of sea level rise will take hundreds and hundreds of years. That means the choices we make now can affect the rate of rise and determine whether we blow past 65 feet of sea level rise to beyond 200 feet.
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