Earth's carbon dioxide levels highest in 3 million years, study says

Carbon dioxide – the gas scientists say is most responsible for global warming – has reached levels in our atmosphere not seen in 3 million years, scientists announced this week in a new study.  At that time, sea levels were as much as 65 feet higher than they are now, Greenland was mostly green and Antarctica had trees.“It seems we’re now pushing our home planet beyond any climatic conditions experienced during the entire current geological period, the Quaternary,” said study lead author Matteo Willeit of the Potsdam Institute for Climate Impact Research in Germany. “A period that started almost 3 million years ago and saw human civilization beginning only 11,000 years ago. So, the modern climate change we see is big, really big; even by standards of Earth history.”