Carbon dioxide levels cross 400 ppm threshold, highest in millions of years. As the US House Committee on Science disagrees with climate science consensus, NASA’s chief climate scientist, Gavin Schmidt, is not optimistic: “In my opinion, we won’t ever see a month below 400 ppm”
Earth’s atmosphere now has carbon dioxide levels unseen for 15 million years
We might be past the point of no return
Data Point: the last time atmospheric carbon held above 400 ppm was 15 million years ago. The world was three to six degrees warmer, and sea levels were between 75 and 120 feet higher, according to research published in the journal Science.
News of the 400 ppm threshold comes as world leaders are making progress towards ratification of the Paris Agreement on climate change, which aims to systematically reduce carbon emissions worldwide starting in 2020.