Whatever Happened to the Coming Ice Age?

“Climate Change” is now synonymous with “global warming”. However, in the 1970’s, global cooling was the major topic. Wikipedia now claims that there was no consensus among climatologists about global cooling in the 70’s and that such a consensus is just an urban myth. Is this just an example of Soviet-style re-writing of history to fit current political needs?

Having lived through the 70’s, I decided to check through my sources to see if mainstream climatologists did fret about a coming ice age in the 70’s …

I found two sources:

• “The Weather Machine and the Threat of Ice” by Nigel Calder, 1974, published by the BBC (there was an associated TV series); 143 pages.
• “The Cooling World” by Peter Gwynne, Newsweek, April 28, 1975.

Wikipedia Entry

Currently, the Wikipedia entry on global cooling states: “Global cooling was a conjecture during the 1970s of imminent cooling of the Earth’s surface and atmosphere culminating in a period of extensive glaciation. This hypothesis had little support in the scientific community, but gained temporary popular attention due to a combination of a slight downward trend of temperatures from the 1940s to the early 1970s and press reports that did not accurately reflect the full scope of the scientific climate literature, which showed a larger and faster-growing body of literature projecting future warming due to greenhouse gas emissions.

“The Weather Machine and the Threat of Ice”

The first of these is by the most prominent populariser of science in Britain at the time, so represents the thinking at that time. Key points from the book are:

• Ice ages are more frequent than previously thought and are separated by warm periods of roughly 10,000 years duration. The current warm period is about 10,000 years long.
• The next ice age will develop within the next 1000 years.
• Ice ages can develop quite fast, say in about 100 years.
• These changes are associated with variations in the earth’s orbit around the sun. Using tables of these variations from A. D. Vernekar, the author was able to get a reasonable match to the historical amount of ice in the world (from N. Shackleton and N. Opdyke).
• CO2 and the greenhouse effect are discussed – “As scientists have recognised for a long time, carbon dioxide probably warms the earth, by the ‘greenhouse effect’ ”.
• The rising levels of CO2 in the atmosphere are illustrated by measurements from the Mauna Loa Observatory, starting from 1958.
• Dust and soot created by human activity have a cooling effect on the earth.

“The Cooling World”

The Newsweek article (reproduced in full here) states the following:

• Earth’s weather patterns have begun to change dramatically, leading to decline in food production
• After three quarters of a century of extraordinarily mild conditions, the earth’s climate seems to be cooling down.
• Drop of half a degree in average ground temperatures in the Northern hemisphere between 1945 and 1968
• Satellites show large increase in Northern hemisphere snow cover in the winter of 1971-72.
• Slight drop in overall temperatures …. causes an increase in extremes of local weather such as droughts, floods, extended dry spells, long freezes, delayed monsoons and even local temperature increases.
• “The longer the planners delay, the more difficult will they find it to cope with climatic change once the results become grim reality”.

Conclusions

Both these sources represent the prevalent views at the time. The Newsweek authorities cited are from NOAA, NAS and others. These are now some of the major proponents of the perils of global warming.

It is hard to reconcile these with the author of Wikipedia’s entry that “This hypothesis had little support in the scientific community”.

• Global warming was difficult to promote when the temperatures were actually falling.
• The number of papers on a topic is not a good measure of scientific consensus (see future blog)

As with most investigations, this one leads to some other questions:

• One of the perils of Global warming is the increase in “extreme weather events”. However, in the 1970’s it was claimed that global cooling would lead to “extreme weather events”. These cannot both be right. Which is correct?
• How much real science went into these predictions?

A final point – the idea of global cooling is not dead yet. A recent paper claims we are entering a new “mini ice-age” .  The paper, “The New Little Ice Age Has Started.”, comes from the Pulkovo Observatory of the Russian Academy of Science and was reported in the National Post by Lawrence Solomon (22 December, 2016). The National Post is a Canadian paper of distinctly right-wing views and strongly in the “denier” camp, so is not objective, though the study is undoubtedly real. We must also consider that anything coming out of Russia today may be yet another attempt to undermine the West.