WATCH: What Does 400 ppm Mean? Talking with Climate Scientist Michael Mann

Last week in Washington, DC, leading climate scientist Michael Mann of the University of Pennsylvania sat down with Climate Desk Live to talk about the significance of an planetary milestone—we’ve reached 400 parts per million of carbon dioxide in the atmosphere. As Mann explained, humans are altering the content of the atmosphere at an alarming rate—one perhaps never seen before in the history of Earth itself.

More MotherJones reporting on Climate Desk

FACT:

Mother Jones was founded as a nonprofit in 1976 because we knew corporations and the wealthy wouldn't fund the type of hard-hitting journalism we set out to do.

Today, reader support makes up about two-thirds of our budget, allows us to dig deep on stories that matter, and lets us keep our reporting free for everyone. If you value what you get from Mother Jones, please join us with a tax-deductible donation today so we can keep on doing the type of journalism 2019 demands.

We Recommend

Latest

Sign up for our newsletters

Subscribe and we'll send Mother Jones straight to your inbox.

Get our award-winning magazine

Save big on a full year of investigations, ideas, and insights.

Subscribe

Support our journalism

Help Mother Jones' reporters dig deep with a tax-deductible donation.

Donate