TESTING GLOBAL WARMING
Science works by means of prediction on the basis of testing a hypothesis.
Once data is collected and evaluated, and a hypothesis formed, scientific method requires that certain predictions be made to act as tests of the overall theory. If the predictions work out, we can regard the hypothesis as proven. If not, we vow to do better next time.
How, then, can the hypothesis of man-made ("anthropogenic") global warming be tested? Wouldn't one way be to have access to some natural example comparable to what's occurring now, so that we could analyze it and get some idea of what we're facing?
It so happens that we have exactly that. This isn't the first time warming has occurred on earth - it's a commonplace and recurring phenomenon. One such episode took place in relatively recent historic time - the Medieval Warm Period.
During the MWP, worldwide temperatures rose by 1 to 3 degrees centigrade for a roughly three-hundred-year period beginning in the 10th century and ending late in the 13th century.
Warming advocates have made a series of predictions concerning climatic effects over the coming century. Do they pass the MWP test?