Scientists were unclear as to what was the cause of this cooling but a prime suspect was the level of pollution that was blocking out sunlight as outlined in the following comment from January 1970. 'Since the advent of the Industrial Revolution debris from manufacturing processes has been accumulating in the atmosphere to such an extent that the earth is now enveloped in a layer of dust which has the effect of reflecting back into space a portion of the energy radiated by the sun. The result has been a measurable lowering of average temperatures, not merely in industrial areas but worldwide.' Some pundits were predicting that if the trend continued drastic action would need to be taken to combat the problem even suggesting 'outlawing the internal combustion engine for vehicles and outlawing or strict controls over all forms of combustion.'
As the decade wore on concern about the global cooling started to mount as this comment from November 1973 makes clear - 'with regard to the present cooling trend a number of leading climatologists have concluded that it is very bad news indeed. They say that it is the root cause of unpleasant weather around the world and they warn that it carries the potential for human disasters of unprecedented magnitude.' Others however were less pessimistic 'we observe these trends in the northern hemisphere, and we've seen they're real.... but it is thought that the present cooling trend will reverse itself for natural reasons, aided perhaps by the greenhouse effect.'
At this time scientists were still sufficiently open minded to admit that they were uncertain about both the cause of the cooling trend and likely future direction of the global climate as this comment from March 1975 reveals - 'The cooling trend observed since 1940 is real enough, but not enough is known about the underlying causes to justify any sort of extrapolation. Particularly dangerous would be any attempt to generalize from even shorter-term experience, like the bad weather in 1972 and following years, to prognosticate any future weather patterns. On the other hand, the cooling since 1940 has been large enough and consistent enough that it will not soon be reversed.'
Nevertheless scientists were concerned about the impact of global cooling as these next two observations from March 1975 illustrate. 'In the last decade the Arctic ice and snow cap has expanded 12 percent, and for the first time this century, ships making for Iceland ports, have been impeded by drifting ice' and 'Many climatologists see signs of evidence that a significant change in climate is taking place- a shift that could be the forerunner of an ice age.' With regard to the last point many scientists had begun to fear that the cooling trend might not be caused by human pollution but instead was the early stages of the next ice age as demonstrated in this observation from October 1979 'climatic disruptions, such as the changing influences of polar cold fronts, which resulted in the winter of 1977, one of the most severe on record, seem to add credence to an advancing ice age hypothesis.'
One of the features of the present global warming alarmism is the doom laden scare stories not only for the future but also the present. Needless to say the 1970s ice age theory also stoked up alarmist fears from environmental pundits such as the following choice example from 1976 - 'This global cooling has already killed hundreds of thousands of people. If it continues and no strong action is taken, it will cause world famine, world chaos and world war, and this could all come about before the year 2000.' Does this kind of hysterical exaggeration sound familiar? Sadly it is the case that greenhouse or ice age, flood or drought, vocal leftist political activists will all call for the same remedy. We must have bigger government, more political regulation and control, higher taxes, and permit less individual and private sector liberty if we are to survive whatever current modish environmental horror story that is being promoted.