Mauna Loa and global trends in air quality

Abstract

The geophysical observatory at Mauna Loa was established as part of the U.S. contribution to the International Geophysical Year in 1957 largely at the instigation of the late Dr. Harry Wexler. Its record of carbon dioxide concentration in clean air is unique. There is much concern in recent years lest the growing pace of man's activities affect the weather or climate on a large scale. Among the prime constituents of the air which may cause such changes are carbon dioxide and dust. Both of these elements are monitored at Mauna Loa. The upward trend of carbon dioxide superimposed on a seasonal variation confirms the contribution from man's combustion of fossil fuels but the normal incidence solar radiation measurements exhibit no long term trend other than that due to volcanic activity beginning with the eruption at Mt. Agung in 1963. The records of atmospheric carbon dioxide and normal incidence solar radiation of several other stations confirm the carbon dioxide trends but temperate latitude stations show no decrease in normal incidence solar radiation. The ultimate objective of monitoring is the prediction of future concentrations so that their impact on the environment can alert society for a need to control its activity if necessary. The future prediction of atmospheric carbon dioxide based on a simple atmosphere-ocean-biosphere model calibrated by bomb carbon-14 leads to predictions of about 380 ppm in the year 2000 but with many reservations.