Rise in Earth’s atmospheric carbon dioxide

Rise in Earth’s atmospheric carbon dioxide

Fig. 4.21 . The average monthly concentration of atmospheric carbon dioxide, or CO2 for short, in parts per million (106), abbreviated ppm, of dry air plotted against time in years observed since 1958 at the Mauna Loa Observatory, Hawaii. It shows that atmospheric amounts of the principal waste gas of industrial societies, carbon dioxide, have risen steadily for more than forty years. The up and down fluctuations, that are superimposed on the systematic increase, reflect a seasonal rise and fall in the absorption of carbon dioxide by trees and other vegetation. Summertime lows are caused by the uptake of carbon dioxide by plants, and the winter highs occur when the plants’ leaves fall and some of the gas is returned to the air. (Courtesy of Dave Keeling and Tim Whorf, Scripps Institution of Oceanography.)

Copyright 2010, Professor Kenneth R. Lang, Tufts University