Global Warming, Part 1

The media, the greens, the Democrats, the presidential candidates, and everyone else is taking it seriously. The Senate is debating a "close down every smokestack" bill right now.
There are a number of questions voters ought to ask them selves. For instance, is the world really warming up?
To answer this question, you want to look at real measurable data, like historical temperature records or ice cores. Computer models don't mean much. All the computers do is solve mathematical equations and the answers are no better than the equations and data fed into them. The computer adds nothing to the process, scientists could solve the equations by hand with a slide rule. Using a computer makes the results seem more true, but with or without computer all we have is a theory. Science demands that theories be backed up with real observations or experiments. Theory unsupported by observations is mere speculation. It might be true, it might not be true, but until supported by real data, it's just a theory.
The most obvious data is records of temperature, made with thermometers, going back as far as the records go. That's less than three hundred years. Fahrenheit didn't invent his thermometer until 1724. A Scientific American article some years ago dug up every temperature reading in existence and tried to find a warming trend in that mountain of data. The article proceeded to explain the corrections they had to apply to the data. For instance, as vast cities grew up around historical weather stations, the temperature readings will rise, because cities covered with black asphalt roads, black asphalt roofs, lacking green trees, are significantly hotter than the surrounding country side. In sailing ship days, sea temperature was measured by heaving a canvas bucket overside, hauling the bucket of seawater up on deck, and dropping a thermometer into it. Steamers take in seawater to cool the engines, and the thermometer is permanently mounted in the cold water intake. The canvas bucket sitting on deck would warm up slightly before the thermometer reading could be taken. The sailing ship temperature readings were corrected downward a fraction of a degree to compensate. After much more correcting and data crunching the article concluded that yes, the earth had warmed up slightly. The amount of warming was smaller than the various corrections applied to the raw data.
Translation. The amount of global warming over the past three hundred years is too small to reliably observe with a thermometer.
Going back further, we have historical records of things like the start of the grape harvest, extent of Alpine glaciers, date of freezing of seaports, first day of spring planting, first snow of winter, and so on. Looking at this historical data suggests the existence of a medieval warm period centered in the 11th and 12th centuries and a little ice age from mid 15th century until the late 18th century. The medieval warm period coincides with the high middle ages, harvests were good, life was pleasant. In the depths of the little ice age it was so cold that the River Thames froze hard enough to conduct ice fairs and markets on the river ice. That doesn't happen today. The Viking colonies in Greenland failed at the onset of the little ice age.
Translation: Historical data suggests that the world has been both warmer and cooler than today, within historical times. The little ice age only ended two hundred years ago, so some warming is expected as we come out of it.
Then we have longer term evidence from ice cores. Quite a few have been taken and analyzed. The results are equivocal, some experts see global warming in the ice cores, others don't. Not being an experienced reader of ice cores myself, all I can go on is what the experts say, and right now the experts are arguing with each other.
Finally I have seen some very dramatic satellite photos of polar ice caps. One pair of photos shows a dramatic shrinkage of the Arctic ice cap over the last dozen years. I'd like to see a few more photos just to make sure we aren't seeing summer vs winter or just a short warm spell, but the two selected photos are impressive.