Letters From the West

CO2 levels hit 400 ppm for first time in human history

A view of the melting arctic from a jetliner last Fall. (Rocky Barker photo)

A view of the melting arctic from a jetliner last Fall. (Rocky Barker photo)

Planet Earth has reached a new record thanks to two centuries of burning coal and other fossil fuels.

For the first time in history, well human history anyway, the daily mean concentrations of carbon dioxide in the atmosphere reached 400 parts per million. The reading came at the National Oceanic and Atmospheric Administration’s Observatory, near the top of Mauna Loa on the big island of Hawaii.

Scientists there have been measuring carbon dioxide since 1958 and the 400 reading is the highest yet. You should care because carbon dioxide is the major greenhouse gas that has been warming the planet for more than a century, leading to all kinds of climate changes.

I said it was the first time in human history CO2 levels have been so high but Plant Earth has seen it before, two to three million years ago. It was a lot warmer then.

Scientists have been warning us for more than a decade that we face the potential of dramatic climatic changes after we passed 350 ppm. No one really knows since we’ve never been here before. But the fear is that eventually temperatures warm to the point they change the carbon cycle so the Earth releases more carbon than it captures.

We already have warmer rivers, earlier runoff, lower flows in late summer and fall, more and larger wildfires, warmer winters and in Idaho at least, good red wines.


Rocky Barker is the energy and environment reporter for the Idaho Statesman and has been writing about the West since 1985. He is the author of Scorched Earth How the Fires of Yellowstone Changed America and co-producer of the movie Firestorm: Last Stand at Yellowstone, which was inspired by the book and broadcast on A&E Network. He also co-authored the Flyfisher's Guide to Idaho and the Wingshooter's Guide to Idaho with Ken Retallic. He also was on the Statesman’s team that covered the Sen. Larry Craig sex scandal, which was one of three Pulitzer Prize finalists in breaking news in 2007. The National Wildlife Federation awarded him its Conservation Achievement Award.

Posted in Letters from the West