We Just Passed the Climate's "Grim Milestone"

Mother Jones

Over the last couple weeks, scientists and environmentalists have been keeping a particularly close eye on the Hawaii-based monitoring station that tracks how much carbon dioxide is in the atmosphere, as the count tiptoed closer to a record-smashing 400 parts per million. Yesterday, we finally got there: The daily mean concentration was higher than at any time in human history, NOAA reported today. Details here. 

Poster designed by PLT.

PLT: Authorities did a "double-check" of the number and announced it was a fraction of a ppm below 400. But I think we all get the idea!