Should temperatures pulled out of a hat be the basis for energy and economic policies?

Do you believe in magic … climate numbers?

By Paul Driessen
Saturday, December 11, 2010

Average annual global temperatures have risen a degree or two since the Little Ice Age ended some 150 years ago. Thank goodness. The LIA was not a particularly pleasant time.

Prolonged winters, advancing glaciers, colder summers, more frequent storms and extended cloudiness reduced arable land, shortened growing seasons, rotted grain in wet fields, and brought famine, disease and death. Coming after the prosperous Medieval Warm Period – when farmers grew wine grapes in England and Vikings raised crops and cattle in Greenland – it must have been quite a shock.

The LIA underscored how much better a warmer planet is than a colder one. Moderate warming above today’s norm would likely bring expanded cultivation during longer growing seasons in northern latitudes, fewer people dying from hypothermia during frigid winters, and many other benefits.

What caused the Medieval Warm Period to end, and the Little Ice Age to come and go, is still debated. Even the best scientists don’t fully understand what alignments of solar, cosmic, oceanic, atmospheric and planetary forces control this millennial warm-cool rhythm.

In any event, the initial warming of 1850-1900 was followed by perhaps an additional overall 1.3 degrees Fahrenheit (0.8 degrees Celsius) of warming during the twentieth century. However, it was not a steady rise in temperatures, proportionate to increasing atmospheric carbon dioxide levels, as “manmade climate disasterâ€