It's an article about the Milanankovitch Theory http://en.wikipedia.org/wiki/Milankovitch which theorizes that ice ages are caused by cycles in the eccentricity, axial tilt, and precession of the earth's orbit. The Wikipedia article cites some problems with the theory.
There are other theories. One I like is that ice ages are caused by global warming. The arctic ocean becomes ice free leading to increased evaporation and water from the melting Greenland ice cap shuts off the gulf stream, resulting in lots more snow and big glaciers. [citation needed] And maybe it's variations in the the sunspot cycle, the Maunder Minimum, but bigger.
Some measurements of air temperatures show failing temperatures but the sea has been steadily warming. The amount of heat stored by water is much greater than air and so the total heat in the system has increased.
No, it is a little diversionary tactic used by anti-global warming crusaders.
What happened was a few scientists mused about it in a few papers and a few publications wrote articles about it, but it was never investigated deeply nor was it ever endorsed by scientific organizations like the NAS.
So what did the NAS say in the mid-70s about "global cooling"?
>>"we do not have a good quantitative understanding of our climate machine and what determines its course. Without the fundamental understanding, it does not seem possible to predict climate."
Fast forward to today, and what is the NAS stance on global warming?
>> "In the judgment of most climate scientists, Earth’s warming in recent decades has been caused primarily by human activities that have increased the amount of greenhouse gases in the atmosphere. ... On climate change, [the National Academies’ reports] have assessed consensus findings on the science..."
How people believe the two to be one and the same is quite beyond me.
It amuses me the great lengths people go to trying to downplay 70s global cooling. You're doing it yourself -- a few scientists, a few publications. If it really was only a few publications, and as trivial as you insist, then why does everyone remember it so well? And if it really was a crackpot minority getting undeserved media attention, where was the backlash from the alleged majority of scientists who didn't believe it? The majority these days are pretty quick to discredit anyone who questions global warming. It doesn't seem to me that there were many scientists back then labeling it a crusader's diversionary tactic.
I mean we must have 10,000 cures for cancer by now ;-)
PS: There is a fair amount of global cooling due to particulate matter in the air. However, while CO2 sticks around particulate matter tends to end up as dust.
Fun fact: the whole "global cooling" thing in the 60s and 70s was primarily the result of sulfur dioxide.
Sulfur dioxide has a much more immediate effect than most greenhouse gases, and reflects a great deal of sunlight--enough to significantly decrease global temperature. But it has a more important consequence than that--acid rain. This led to a huge push to eliminate it and other toxins from emissions.
Because it's in acid rain, of course, this means it has a relatively short half-life in the atmosphere. Give it a few years, and it begins to all drop out.
Thus, with the campaign against acid rain, sulfur dioxide in the atmosphere drastically decreased...
... and suddenly everyone started having to worry about global warming because they had just eliminated one of the main chemicals offsetting the warming.
There are other theories. One I like is that ice ages are caused by global warming. The arctic ocean becomes ice free leading to increased evaporation and water from the melting Greenland ice cap shuts off the gulf stream, resulting in lots more snow and big glaciers. [citation needed] And maybe it's variations in the the sunspot cycle, the Maunder Minimum, but bigger.