Fausta on Global Warming

Over at the Bad Hair Blog Fausta writes:

Snow on the ground, due to all that global warming
Excuse my scepticism, but I'm not all that sold on global warming, if only because weather trends encompass centuries, and back in the 1960s and 1970s some people were seriously worrying about the upcoming ice age. The Middle Ages were warmer than today, which brought about "a wonderful period of plenty for everyone," according to researchers and historians, so global warming per se might not turn out to be the disaster some are predicting.

Actually, the time period she is talking about is usually called the Medieval climate optimum. It is believed to have lasted from the 10th to 14th centuries. During this period wine grapes were grown in England and the Vikings colonized Greenland. The myth that the Vikings deliberately misnamed Iceland and Greenland is likely false as during this period of warm temperatures Greenland was most likely green. It is also believed that this was a northern hemisphere issue not a global issue.

It gets interesting after that. Although no one can really say when it started, somewhere in the 14th century the weather took a severe turn. Many scientist's believe that the average temperature of the hemisphere dropped up to 1-2 degrees centigrade. The effect was devastating. Most of Northern Europe's population was unable to farm as they had previously and many starved. Some historians posit that the plague was directly attributable to this cooling because people stayed inside longer and their homes were infested.

What Fausta is pointing out,however, remains true. Although the Eco's blame man for changing weather patterns, it is more probable that it is a natural cycle of the Earth and Sun than man.