There was a great interview in Mother Earth News back in 1976 describing what was then known about global cooling and global warming. The person being interviewed is Reid Bryson, who died back in 2008, and he describes the whole mess very well.
If you read it you will understand why they though they were seeing global cooling in the 70s and now the trend is global warming.
https://www.motherearthnews.com/natu...n-zmaz76mazraw
Quote:
Darn right. Which brings us to Step Three of the points you outlined a few minutes ago: Do you know of any logical reason for such a change to take place?
Oh yes. And so do you, because I've already given you that reason. Just think of the whole Northern Hemisphere as a gigantic heat engine that absorbs an excess of solar radiation in the tropics and a deficit of the same radiation in the Arctic. This difference sets up a circulation of the atmosphere which transports heat from the tropics to the polar region. Right? And as those masses of warmed air from the tropics move north, they radiate their heat energy out into space until—by the time they've reached the Arctic — they've cooled and begun to flow back to the tropics.
This is what the circulation of the atmosphere is all about. Transporting heat from the tropics to the polar regions and getting rid of it there. And if you pump enough particulate matter into the air to reduce the amount of sunlight that strikes the earth's surface in the first place or if you reduce the amount of carbon dioxide in the atmosphere so that the heat energy which does get in can immediately radiate right back out into space, then you have less warmth to haul from the tropics to the polar regions. And, as we've already documented in the Northern Hemisphere, those polar regions — in this case, the Arctic — get colder.
Is this what's happening?
Yes and no. Actually the amounts of both particulate matter and carbon dioxide in the atmosphere are increasing. It's just that the cooling effect caused by the first is increasing faster than the warming effect caused by the second. And, as a result, the Arctic has gotten colder.
Where does the particulate matter and the carbon dioxide come from?
Volcanoes used to be the primary source of particulate matter found in the atmosphere. When you go back over the last century and chart out the hemisphere's temperature, you find that periods of heavy volcanic eruption show up on the graph as cold times and stretches of quiet volcano activity are warmer. We've tabulated some 5,000 volcanic events and there's a very definite correlation. Massive eruptions during the 1880's, for instance, made the Northern Hemisphere colder. Then there was a quiet period and then, from about 1904 until 1920, a fair amount of activity. After that, volcanoes really died down until around 1955, then they tapered off again until — from 1963 on — we see a lot of eruptions. The important point is that, when you chart this activity out, you immediately notice that the hemisphere warms up during periods of few volcano eruptions and cools following heavy eruptions.
And that's all there is to it?
Oh no. A completely wild card got shuffled into the deck back about 1930 or so, when the Industrial Revolution became a worldwide phenomenon and we began spewing both man-created particulate matter and man-created carbon dioxide into the air at an increased rate. This new source of atmospheric pollutants really started to influence the earth's climate significantly around 1945.
Why then?
Because by 1945, as a by-product of the Industrial Revolution, we had learned to use antibiotics and pesticides. By 1945 we were beginning to control malaria on a massive scale and we were beginning to save tens of millions of other lives that ordinarily would have been lost to diseases and accidents. Thanks to antibiotics and pesticides, the planet's human population suddenly had a much higher survival rate without a corresponding reduction in its birth rate.
The Industrial Revolution, in effect, fed upon itself. It made it possible for many more of us to live and reproduce at the same time it allowed each of us to farm more marginal land, build and operate bigger machines, construct larger foundries and factories, and so on. All of this increased activity by a burgeoning population, for the first time, pumped tons upon tons of man-created particulate matter into the air. And that's a major reason why our climate began to cool around 1945, and has been cooling more or less ever since.
Well it's certainly obvious that, thanks to the Industrial Revolution, our consumption of fossil fuels has increased an incredible amount. And it's just as obvious that, as we burn that oil and coal and gas in our factories, we're spewing a great amount of both carbon dioxide and black glop into the air.
Yes. Thanks to today's environmental awareness, most of us now recognize at least part of what you've just pointed out. Dozens of scientific papers, in fact, have been published about industry's consumption of fossil fuels, its creation of carbon dioxide, and how the resultant "greenhouse effect" will cause a rise in the temperature of the atmosphere.
I find it interesting, however, that the same people who write those papers generally seem to overlook the even greater amounts of particulate matter which those same factories and foundries pump into the air. Not to mention the tremendous quantities of particulates now kicked into the atmosphere by poor farmers in primitive agricultural and marginal semi-arid regions all over the world.
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Now, during the 70's there was also a tremendous effort to clean up the air. The smog around our major cities has pretty much disappeared in most places. This is less particulate matter going into the atmosphere so the cooling effect is nullified somewhat.
But we are still spewing all sorts of CO2 so now the warming effect takes precedent.
We know a lot more about climate science now then we did 40 years ago so while it was still being debated back then as to whether man had enough influence it has now been more or less determined to be fact.
The interview covers lots of ground and if you read it you will discover that he blames the situation more on over population rather than industry and he makes a good argument in that direction.
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