Carbon dioxide was measured at 400 parts per million at the oldest monitoring station in Hawaii on last Thursday. The burning of fossil fuels has caused the overwhelming bulk of the man-made increase in carbon in the air. The amount should be even higher than 400 parts per million, but the world’s oceans are absorbing some of it, keeping it out of the air.

When measurements of carbon dioxide were first taken in 1958 at Mauna Loa station in Hawaii, it measured 315 parts per million. By drilling for ice cores and analyzing the air bubbles, scientists have found that, at no point during at least the past 800,000 years have atmospheric CO2 levels been as high as they are now. In fact, the last time the worldwide carbon level was that high was about 2 million years ago during the Pleistocene Era when there were forests in Greenland and modern humans didn’t exist. Sea level was higher, between 10 and 20 meters.

What does this information mean for you and me and our children?