Transcript
SPEAKER 1:
The weather satellite depicts a planet that grieves for its lost harvests, while the price of food keeps going up.
HELEN CZERSKI:
Climate was becoming an issue but the central message was rather different to today.
SPEAKER 2:
Will a new Ice Age claim our lands and bury our northern cities? It's buried Manhattan Island before when great glaciers half a mile thick filled the valley of New York's Hudson River.
SPEAKER 1:
Unless we learn otherwise, it will be prudent to suppose that the next Ice Age could begin to bite at any time.
HELEN CZERSKI:
Global warming, as the theory was called then, was also being studied by scientists and it was mentioned in the same program, but almost as an interesting aside.
BERT BOLIN:
And there is a lot of oil and there are vast amounts of coal that they seem to be burning it with an ever increasing rate. If we go on doing this, in about 50 years time, the climate may be a few degrees warmer than today. We just don't know. Let's therefore keep an eye on the amount of carbon dioxide in the air.
HELEN CZERSKI:
It would be global warming, not the threat of an Ice Age, that would go on to become the dominant scientific issue. It's fascinating to look back to a time when global warming wasn't the main story. Scientists are only just beginning to get to grips with the complexities of the climate system and how and when it might be changing. And that just wasn't enough information around for them to be confident about what was happening. But that was beginning to change.
In the late 1970s, the arguments for a new Ice Age began to melt away. The theory was based on emissions of the gas sulfur dioxide, then a major atmospheric pollutant. This gas was known to have a cooling effect and some scientists calculated that this could push the planet into an Ice Age. But it soon became clear that both the amount of sulfur dioxide pollution and the size of its cooling effect had been overestimated. There would be no big freeze after all.