the concentration of carbon dioxide in earth’s atmosphere has climbed to a level last seen more than 3 million years ago — before humans even appeared on the rocky ball we call home.
the concentration of carbon dioxide in earth’s atmosphere has climbed to a level last seen more than 3 million years ago — before humans even appeared on the rocky ball we call home.
carbon dioxide in earth's atmosphere:15
the daily average concentration of atmospheric co 2 at mauna loa observatory first exceeded 400 ppm on 10 may 2013 although this concentration had already been reached in the arctic in june 2012.