In 1958, observations of carbon dioxide concentration in the atmosphere were begun at an Observatory on Mauna Loa, Hawaii. This site was selected to be representative of the global average conditions near the surface of the earth. Figure 1 shows the change of carbon dioxide concentration since 1958, from Ahrens,1 and the estimated values before observations began and into the next century. The general trend shows an overall accelerating increase in concentration. If no other global variable changes, the concentration is expected to double from the current 350 parts per million within a century.