When I read about the global warming, my perverse nature immediately turned to the idea of global cooling. The first thing that came to mind was the ice ages, and an Internet search lead me to the Illinois State Museum as a popular source. (www.museum.state.us.il) The information was interesting.
It seems that there are three reasons for what they call global cooling. Ice age referring only to periods of glaciation which is what most of us usually think about.
There is a 100,000-year cycle caused by eccentricities associated with earth's orbit about the sun. There is a 41,000-year cycle associated with wobble in the tilt of the earth's axis in relation to the sun. And finally, there is a 22,000-year cycle (ice ages) related to the speed in which the earth spins.
The web page contains graphs of each cycle and a graph of the combined cycles. Perhaps global warming and cooling are out of our hands.
A thought that struck me was that we get fixated on causes/ solutions. Here we have evidence that there have been numerous cooling periods in the earth's history and yet no one has come up with that light-bulb-over-their-head realization that there had to be an equal number of global warming periods to melt all that ice.
So, if global cooling is an established cyclical event, isn't global warming also? Being extremely logical and referring only to the last ice age (about 10,000 years ago), what caused the warming? It surely wasn't the campfires of the cave men or the exhausts from autos. Something else warmed the earth.
This isn't to say we shouldn't continue to minimize our production of greenhouse gasses, but if we're going to take these things seriously, we should continue to research the subject. As it is, once we find an acceptable villain or cause, we drop everything else and focus all our attention on that.
This reminds me of a story. When I first became a highway engineer I was reading the congressional hearings related to the Interstate Highway System. The highway engineers had just finished testifying about how much safer new highways were becoming. A representative from the medical industry testified next.
The gist of his testimony was that, while he didn't want to take anything away from the highway engineers, there had been a few lifesaving advances in medicine over the years, more hospitals were being built, more people were moving into and near cities and so, more accidents were happening near hospitals that offered advanced medical procedures. Perhaps the health care sector should get some credit for the reduction in highway fatalities.
This points out that we shouldn't automatically give all the credit or blame for something to one factor just because it represents part of the problem or part of the solution. Simple solutions/ relationships are readily accepted when they prove our opponent is wrong. But when applied against us, we can always show that the problem isn't that simple and so no simple solution is possible.
Man-made processes are no doubt affecting global warming. But until we can quantify that, we need to keep searching for all the contributors to global warming so we might better understand what lies ahead.
My belief is that natural changes in the earth's orbit around the sun, its tilt in relation to the sun and its change in rotational speed are what change the basic warmness or coolness of the earth. We may be contributing to that warming with our burning of fossil fuels.
On the other hand, the Illinois data also indicates that an increase in CO/2 preceded each cooling period. Other references indicate that something (maybe warming?) triggers a change in the Gulf Stream, which brings about a cold period in Europe.
With our greenhouse gasses, we may only be speeding ourselves into the next scheduled ice age.