Dear Tom,
How does the current global warming trend compare to the Medieval Warm Period between the 10th & 14th centuries? What is the possibility of the weather cooling as it did at the start of the Little Ice Age which followed?
Sara C. Mickel, Chicago
Dear Sara,
Our planet’s mean temperature appears to have been 2 (degrees) (F) warmer than today during the Medieval Warm Period from 750 to 1280 A.D. If the current rate of global warming were to continue another 50-100 years, says climatologist Dr. Wayne Wendland, earth’s temperature would reach comparable levels . It’s often called the Little Climatic Optimum because many effects proved beneficial. Europe reached the warmest temperatures in 4,000 years; grapes were grown in England, settlement of Iceland and Greenland became possible as ice retreated and snow-clogged alpine passes cleared, allowing trade between Italy and Germany. The arrival of the Little Ice Age lowered global temperatures about 2 (degrees) below current levels between the 16th and 19th centuries. Such climate shifts appear to take place fairly quickly. Yet, says Wendland, the exact moment of change often can’t be identified until after the fact. The full impact may take a century or two to take place.
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Tom Skilling is chief meteorologist at WGN-TV. His weather forecasts can be seen Monday through Friday on WGN News at noon and 9 p.m.
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