The observations come, at a time when a warming trend could have been expected from the increase of carbon dioxide in the atmosphere due to extensive fuel burning. The gas inhibits the escape of solar heat from the earth. Dr. Kukla, in a telephone interview this week, said that the cause of the apparent cooling remained unknown and that no scientific attempt to predict whether the trend would continue was possible. Monitoring of the various indexes is continuing, he added.
It was the soot level filtering the sun. Once we started scrubbing coal plant emissions the world started ‘warming’.
You did see that this article was from 1978.