Heat-Trapping Gas Passes Milestone, Raising Fears
The average carbon dioxide reading surpassed 400 parts per million at the research facility atop the Mauna Loa volcano on the island of Hawaii for the 24 hours that ended at 8 p.m. on Thursday.
By JUSTIN GILLIS
Published: May 10, 2013 700 Comments
The level of the most important heat-trapping gas in the atmosphere, carbon dioxide, has passed a long-feared milestone, scientists reported Friday, reaching a concentration not seen on the earth for millions of years.
The best available evidence suggests the amount of the gas in the air has not been this high for at least three million years, before humans evolved, and scientists believe the rise portends large changes in the climate and the level of the sea.
“It symbolizes that so far we have failed miserably in tackling this problem,” said Pieter P. Tans, who runs the monitoring program at the National Oceanic and Atmospheric Administration that reported the new reading.
Ralph Keeling, who runs another monitoring program at the Scripps Institution of Oceanography in San Diego, said a continuing rise could be catastrophic. “It means we are quickly losing the possibility of keeping the climate below what people thought were possibly tolerable thresholds,” he said.