by Alycia Keating

Created on: May 26, 2007   Last Updated: April 19, 2012

Global warming is a very difficult subject to explain to someone who is not trained in geology or meteorology. It is a complex subject and as such, we tend to rely heavily on the interpretation of those we trust in the media, government, and in scientific organizations.

Wait a minute: did I just mention trusting the media and government? I didn't say that, did I?

Let's back up a little bit. I decided to learn a little Science 101 on my own, because face it: we can't really just trust such a huge subject to the politicians.

Global warming and cooling runs in several cycles. These are tied to sunspots; the pitch and wobble of the earth's axis as it revolves around the sun; and the variations in the three-dimensional orbit - all over a period of approximately 100,000 years.

As a result, Earth experiences what is called an "Ice Age" every 100,000 years. We're in one now - but have been in a slightly warmer pocket in time called an "Interglacial". That's just a big word that means "between the Ice Ages."

This interglacial we've enjoyed has been remarkably stable for the past 5,000 years. That in itself is unusual as there are normally wild temperature fluctuations within an interglacial period. Note also that human beings turned to agriculture and settled into communities starting at about the same time.

When scientists talk about Global Warming, they are thinking in Ages and Eons, huge chunks of time, huge distances, and impossibly large numbers. A decade is not important to a climatologist. A millenium is just a little dollop of time.

There is no doubt in any of the scientific literature, published *before* the Big Media Buzz (and its corporate owners) got hold of it, that humans have over-warmed the planet for the last 150 years, since the beginning of the Industrial Revolution. In fact, from 1970 to 2004, greenhouse gas emissions (that's mostly carbon dioxide and a couple of other gases) have risen 70% (according to the Intergovernmental Panel on Climate Change's May 2007 report).

And that warming is going to continue on its own momentum for at least a century. There is no doubt that glaciers are melting and the polar ice caps are melting as well. The last time this happened, there was a mass extinction of species.

The last global warming event took place starting 180 million years ago during a "methane burp" (possibly caused by volcanic activity under the sea). This increased the Earth's reflectivity but also trapped the light and heat that did get in. This

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