Geoscience Reference
In-Depth Information
In 1956, when two of his papers on CO
2
appeared, Gilbert Plass worked at
the Lockheed Aircraft Corporation in southern California. Not far away at the
California Institute of Technology, a young postdoctoral fellow named Charles
David Keeling (1928-2005) had read Plass's papers and become curious about the
amount of CO
2
in the atmosphere. The astute Revelle soon recruited Keeling to
Scripps. It took only two years of measurement for Keeling to find that the amount
of CO
2
in the atmosphere was indeed increasing. At that time, the atmosphere con-
tained about 315 ppm of CO
2
. Keeling and his successors, one of them his son,
have continued their measurements to the present day, but never once has the an-
nual level of CO
2
in the atmosphere fallen. On May 9, 2013, at the height of the
spring upswing in CO
2
emitted by plants, atmospheric CO
2
exceeded 400 ppm for
the first time in human history. Following the seasonal cycle, it then began to de-
cline. But as surely as the Sun will rise tomorrow, for the indefinite future each
successive monthly peak and trough in the Keeling Curve will be higher than the
ones before. Within a year or two of the publication of this topic, the
yearly
aver-
age will exceed 400 ppm, and by the early 2030s it will reach 450 ppm. How long
and how far CO
2
levels will rise after that, no one can say. At the moment, no end
is in sight.
