As is well known by now, a passel of climatologists in the 1970s, including such personalities as Stephen “It’s OK to Exaggerate To Get People To Believe” Schneider, tried to get the world excited about the possibility, and the dire consequences, of global cooling.
From the 1940s to near the end of the 1970s, the global mean temperature did indeed trend downwards. Using this data as a start, and from the argument that any change in climate is bad, and anything that is bad must be somebody’s fault, Schneider and others began to warn that an ice age was imminent, and that it was mainly our fault.
The causes of this global cooling were said to be due to two main things: orbital forcing and an increase in particulate matter—aerosols—in the atmosphere. The orbital forcing—a fancy term meaning changes in the earth’s distance and orientation to the sun, and the consequent alterations in the amount of solar energy we get as a result of these changes—was, as I hope is plain, nobody’s fault, and because of that, it excited very little interest.
But the second cause had some meat behind it; because, do you see, aerosols can be made by people. Drive your car, manufacture oil, smelt some iron, even breath and you are adding aerosols to the atmosphere. Some of these particles, if they diffuse to the right part of the atmosphere, will reflect direct sunshine back into space, depriving us of its beneficial warming effects. Other aerosols will gather water around them and form clouds, which both reflect direct radiation and capture outgoing radiation—clouds both cool and warm, and the overall effect was largely unknown. Aerosols don’t hang around in the air forever. Since they are heavy, over time they will fall or wash out. It’s also hard to do too much to reduce the man-made aerosol burden of the atmosphere; except the obvious and easy things, like install cleaner smoke stacks.
Pause during the 1980s when nothing much happened to the climate.
Then, since the 1990s, the Earth’s temperature noticeably began to increase. So back to the old argument: any change is bad, and it’s somebody’s fault. One of the main culprits everybody knows: increasing carbon dioxide, a gas which (fairly inefficiently, actually) captures outgoing radiation, leading to warming. Both CO2 and warming also tend to increase plant production (making a greener world), but never mind that. Aerosols are still in the game, but now are seen as mitigators: the sunlight they reflect helps to cool things off (the overall effects of clouds is still unknown).
Changes in orbital forcing still need reckoning, but these were and are largely ignored. These orbital changes, and their inevitability, form one of the two main differences in perception between cooling and warming.
For both global cooling and global warming, we were able to find a way to perceive it as being our fault: by ascribing the changes either to man-made increases in aerosols or CO2. But back in the cooling days, we also had unchangeable circumstance in the form of the Milankovitch cycle (or the earth’s orbit) and other obscure physics, which there was nothing anybody could do to change. Because of that, more people were resigned to their fate, so to speak, thus more ignored the scientists.
Overall, then, in the late 1970s it was hard to get people too excited about mankind’s effect on climate, though there was a consensus (a now favorite word) that some kind of global cooling was coming our way. But there just wasn’t enough substance to hold the media’s and the public’s attention.
So how did global warming become so well known?
http://wmbriggs.com/blog/2007/12/24/two-differences-in-perception-between-global-cooling-and-global-warming/
