The earth’s temperature may have fluctuated more wildly during the past 1,000 years than previously thought.  This, according to the Science and Environmental Policy Project which reports on a new study out of Germany that challenges how researchers have come up with their numbers for gauging past temperature.  The study found that using indirect proxy measurements like tree rings, coral, and ice cores may have badly underestimated past temperature fluctuations, and that changes dating back to medieval times may be underestimated by a factor of two or more.  If true, this means that recent warming might not be as unique as previously thought, and may simply be due to natural temperature cycles, not man-made emissions of carbon dioxide.