The global cooling scare of the 1970s

An article by Bernie Lewin in Watts Up That is worth reading. I cite the particular paragraph below because it lays out the fact that the recent (last 700,000 years ) of earth’s history has been a continuous ice age interrupted by brief interglacials, such as the last 10,000 years. This is called the Quaternary ice age, and we are still in it. My inference from this fact is that humans have much less control over the planet’s climate than the global warming catastrophists would have us believe. And as others have demonstrated, there has been a continuous leaching of CO2 out of the atmosphere for the last 33 million years.

Atmosphere CO2 levels from 600 million years ago to present


Combine these two facts. The earth has experienced increasingly severe ice ages in the last 700,000 years. CO2 has been depleted from the atmosphere for a long time. Some have reasoned that this has accelerated from the time the Indian plate collided with the Asian tectonic plate between 50 and 25 million years ago and pushed up the Himalayas. The action of monsoon rains falling on exposed limestone has had the effect of leaching CO2 from atmosphere, and dissolving it in the oceans. [It is important to note that regardless of the cause of the CO2 depletion, it has been occurring over a vast stretch of time.]  Quaternary CO2 levels reached a low of 180 parts per million (PPM). Partly because of human activities, CO2 is back up to over 400 ppm, the highest in the last 800,000 years. This is not the catastrophe that some would have us believe, but a recovery from a low point associated with ice ages.

Accordingly, if this association of depleted CO2 and ice ages is correct, then the threat to the planet is cold not heat. So far we are dealing with inferences from observed facts in the geological records.

And now to the conjectures.

Since humans are adding to the planet’s atmospheric CO2, then perhaps humanity’s function is to keep a recurrence of the next ice age from happening. Rubbish? Teleology? Maybe James Lovelock is right, and that our job as a species is to keep Gaia happy. In either case, we are heading into another ice age, unless the heat that humans are adding to the environment prevent one. And I rather doubt our power to prevent the next big advance of ice, but that is mere conjecture on my part.

So back to the global cooling scare of the 1970s (the one I think is better founded, because it rests on the demonstrable facts of glaciology). As Mr. Lewin writes:

The one great scientific advance that contributed to the 1970s cooling scare was a revolution in Quaternary geology. Until the late 1960s, it was generally agreed that there had been four recent glaciations, however their timing was largely unknown due to inadequate dating techniques. As the new dating technology was brought into play, it revealed that since the last geometric reversal, around 700,000 years ago, there had been no less than 8 cool/warm cycles. It also showed that cool was the norm. Indeed, the whole Quaternary period (i.e., the last 2.5 million years) is best described as an ice age punctuated by brief ‘interglacial’ warm ‘epochs’. These interglacials appeared like clockwork on a 100,000 cycle, and the record clearly showed that this cycle was about to switch phases. That is to say, the current epoch—the ‘Holocene’, the 10,000 years of warm stable climatic upon which agriculture-based civilization had been built—was about to end.

Quaternary Geologists promote a cooling scare

The realization that we are at the end of a warm period was not itself alarming, as rapid climate change on a geological scale might be 1o C per millennia. Such a gradual trend would hardly be recognizable with all the local and global fluctuations known to occur across centuries and decades. If the decline out of past warm periods were associated with wider fluctuations on these time scales then this would remain unknown because the proxies indicators for temperature did not have the necessary resolution to pick them up. However, soon some geologists were claiming resolution down to a century or two which revealed evidence of climatic instability as previous interglacial epochs ‘broke down’. According to the Danish geologist, Willi Dansgaard, if the deep past is anything to go by, then ‘the conditions for a catastrophic event are present today’. This quote comes from the conclusion of a paperpresented to a conference at Brown University early in 1972 that was called in light of the new evidence to answer a question of singular pertinence:

The present interglacial, how and when will it end?

The article continues with a discussion of the politics and organization of world conferences on climate change, and concludes:

Thus it can be seen that the cooling scare—linked as it was with the food and energy crisis—provided the impetus behind the launch of the warming scare, and it also provided the institutional platforms upon which the launch of that scare would take place.