There hasn’t been this much CO2 in the air in 3 million years. We have to stop, UN warns byAlexandru Micu October 31, 2017 Uh-oh.
Carbon dioxide hits 400 ppm for the first time in human history byMihai Andrei May 27, 2014 Carbon dioxide levels throughout the northern hemisphere hit 400 parts per million (ppm) for the first time in human history ...