What was done
The authors derived individual ground surface temperature histories from the temperature-depth logs of 98 separate boreholes drilled on the territory of the Czech Republic.

What was learned
In the words of the authors, "the existence of a medieval warm epoch lasting from 1100-1300 A.D. is clear," which epoch they describe as "one of the warmest postglacial times."  They also note that during the main phase of the Little Ice Age, from 1600-1700 A.D., "all investigated territory was already subjected to massive cooling," and that "the observed recent warming may thus be easily a natural return of climate from the previous colder conditions back to a 'normal'."

What it means
Both the Medieval Warm Period and Little Ice Age were major climatic events, notwithstanding the attempt of a number of climate alarmists to reduce them to such insignificance that they do not even appear on the temperature history of the world over the past thousand years (see our Editorials of 15 June, 1 July, 15 July and 2 August 2000).  Why do the climate alarmists do this?  Because they want to promote the idea that the world is currently experiencing unprecedented warming due to increases in the atmospheric concentrations of greenhouse gases, particularly CO2.  As the results of this study clearly show, however, whatever warming may have occurred over the past century or so may be easily nothing more than a return to more normal conditions from the global chill of the Little Ice Age.