Carbon Dioxide Levels in Atmosphere Reach Terrifying New Milestone

By Eric Holthaus

It’s official: Earth’s atmosphere is now in uncharted territory, at least since human beings evolved hundreds of thousands of years ago.

The Scripps Institute at the University of California-San Diego confirmed the news on Thursday:

And another first: April 2014 average CO2 value was 401.33, the first monthly average over #400ppm in human history. #globalwarming-- Keeling_Curve (@Keeling_curve) May 1, 2014