Measurements — first taken on top of the Mauna Loa volcano on the Big Island of Hawaii — eventually lead to the Keeling Curve, which some scientists have called “an icon of modern science.” The curve shows the rapid increase in atmospheric carbon dioxide since Keeling began taking measurements almost half a century ago.When Keeling first began taking measurements, atmospheric carbon dioxide measured at about 310 parts per million, meaning that carbon dioxide made up about .03 percent of the Earth’s atmosphere. That was already a marked increase from preindustrial levels, when atmospheric carbon dioxide measured about 280 parts per million.
Note – CO2 score is incomplete. CO2e, which includes other GHG’s(greenhouse gases), scored as high as 485ppm as long ago as 2012. The longer the delay, the more drastic and expensive the response needed