Levels of the greenhouse gas are approaching 400 parts per
million; Scripps offering daily Twitter feed, news and analysis of climate
indicators
For the first time in human history, concentrations of the
greenhouse gas carbon dioxide (CO2) could rise above 400 parts per million
(ppm) for sustained lengths of time throughout much of the Northern Hemisphere
as soon as May 2013.
To provide a resource for understanding the implications of
rising CO2 levels, Scripps Institution of Oceanography at UC San Diego is
providing daily updates of the “Keeling Curve,” the record of atmospheric CO2
measured at Hawaii’s Mauna Loa. These iconic measurements, begun by Charles
David (Dave) Keeling, a world-leading authority on atmospheric greenhouse gas
accumulation and Scripps climate science pioneer, comprise the longest
continuous record of CO2 in the world, starting from 316 ppm in March 1958 and
approaching 400 ppm today with a familiar saw-tooth pattern. For the past
800,000 years, CO2 levels never exceeded 300 parts per million.