Climate Change Odometer Hits Sobering Threshold

May 16, 2013
by Tom Prigg

The world’s climate odometer just crossed one of those big, round numbers. For the first time in human history, the atmospheric concentrations CO2 have reached 400 parts per million. The measurements were observed at Hawaii’s Mauna Loa observatory, the oldest monitoring station in the world. In the 1950s, when scientists started measuring atmospheric carbon dioxide—the main driver for climate change—that number was about 315.

“400 ppm CO2 is a milestone—it’s a sobering milestone. We have now reached a concentration of CO2 in the atmosphere that the earth has not seen most likely in at least 4 million years," says Michael Mann, a Distinguished Professor of Meteorology at Penn State University.

The last time the Earth experienced these high levels of CO2, sea levels were a hundred feet higher.

“We are likely committing ourselves to dangerous and irreversible changes in the climate. We’ve crossed—we’re in a process where we’re crossing a whole array  of points of no return,” explains Mann.

The climate picture that Michael Mann paints appears bleak. If this is what a climatologist thinks, what does the average person on the street think about the new CO2 theshold?

Relaxing in Market Square in Downtown Pittsburgh during lunch, Terayln Iscrupe of Pittsburgh said, “I consider myself to be more than average when it comes to being up on environmental news and I haven’t heard anything about it so it really surprises me,” says Iscrupe. “In general, I have been following this sort of information and of course it’s a concern for us all,” she added.