The following was provided by Dr. William F. Downs, a Geochemist and friend. I’ve done a tiny bit of editing, and added a comment at the end. The timing is perfect as a contrast to the review posted today.
There is little controversy over the fact that the temperature of Earth is currently rising and has been since the end of the “Little Ice Age” which lasted from about 1380 AD until circa 1780 AD. Previously the climate experienced a warm period which was called the “Millennium Optimum” (c. 850 AD – 1300 AD) when I studied it during the 1960s. It was considered “optimum” because the Vikings were able to expand into and develop farms in Greenland and grapes that had been planted in Britain by the Romans produced wine. By the early 1300s, Greenland was no longer able to sustain agriculture and the Viking society in Greenland had collapsed. There was another warming period termed the “Roman Warm Period” that existed in the first few centuries after the time of Christ. The “Little Ice Age” was documented by Monks in Monasteries along the roads to Rome as Alpine Pilgrims on their way to Rome told their stories of glacial destruction of their Villages.
The temperatures and CO2 contents of the atmosphere in the past are estimated by measuring the oxygen isotope ratios and concentrations of CO2 released from ice cores collected from Vostok Glacier in Antarctica. These data have been collected from ice that had formed during the last 100,000 years or so. These data indicate that the current temperature level is lower than those experienced during the Millennial Warming Period. Continue reading