An alarming milestone
By Steve Benen
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Fri May 10, 2013 3:20 PM EDT
We talked a week ago about the climate crisis, and the fact that the ratio of carbon emissions in the atmosphere " flirting with" 400 parts per million -- an alarming threshold climate scientists have long hoped to avoid.
It appears that flirtatious period is over.
The proportion of carbon dioxide in the atmosphere broke 400 parts per million Thursday, according to one of the best climate records available.
The Keeling Curve, a daily record of atmospheric carbon dioxide, has been running continuously since March 1958, when a carbon dioxide monitor was installed at Mauna Loa in Hawaii. On the first day, the observatory measured a carbon dioxide concentration of 313 parts per million (ppm). The number means there were 313 molecules of carbon dioxide in the air per every million air molecules.
Now, the Keeling Curve has reached 400 ppm for the first time in human history, with a new measure of 400.03 ppm. The data are preliminary, pending quality control checks, according to the National Oceanic and Atmospheric Administration (NOAA).
The last time the planet topped 400 ppm, there were no humans. What's more, there has never been an increase comparable to the accelerated increases we're seeing now.
The crisis, which many of today's U.S. conservatives perceive as a "hoax" cooked up by liberals to undermine capitalism, is only going to get worse without concerted efforts from policymakers here and around the globe. |
