400 ppm of CO2 was just another line in the sand, and we’re not stopping there

We have spent the entirety of calendar year 2016 above 400 ppm atmospheric carbon dioxide. If you aren't concerned, you aren't paying attention.

from ExtremeTechExtremeTech http://www.extremetech.com/extreme/236558-400-ppm-of-co2-was-just-another-line-in-the-sand-and-were-not-stopping-there