Atmospheric CO2 reaches 415 ppm, highest in modern human history

“Atmospheric CO2 is rising at accelerating rates—currently climbing at close to 3 ppm each year, and getting faster. Every year, the world sees new levels that were previously unrecorded in modern human history. The last time CO2 concentrations hit 415 ppm was likely close to 3 million years ago... Samples taken from ancient sediments at the bottom of the ocean, fossilized corals, or ancient ice from Greenland or Antarctica can provide researchers with chemical information about the Earth’s climate millions of years in the past... During the last geological era that saw CO2 concentrations over 400 ppm, global temperatures were about 3 C higher... There was very little ice on Greenland, there was no ice on West Antarctica, and the East Antarctic ice sheet was a little bit reduced... sea levels as a result were a lot higher.”