Global cooling was a conjecture, especially during the 1970s, of imminent cooling of the Earth culminating in a period of extensive glaciation, due to the cooling effects of aerosols or orbital forcing. Some press reports in the 1970s speculated about continued cooling; these did not accurately reflect the scientific literature of the time, which was generally more concerned with warming from an enhanced greenhouse effect.[1]
In the mid 1970s, the limited temperature series available suggested that the temperature had decreased for several decades up to then. As longer time series of higher quality became available, it became clear that global temperature showed significant increases overall.