[Illustrations, footnotes and references available in PDF version]
It has been claimed that the last decade of the 20th century was the warmest of the past hundred years and possibly the warmest of the entire past millennium (Mann et al., 1998, 1999). It has also been claimed that this observation is a cause for much concern, because the temperatures in question are supposedly so unprecedented. In fact, those who would have us believe that these supposedly high air temperatures are the result of anthropogenic CO2 emissions resulting from the burning of fossil fuels contend that the near-surface air temperature of the planet is currently so high that we must radically reformulate the energetic basis of the entire industrialized world in order to avoid a host of unwanted climatic consequences. But is this climatic characterization correct? … and is its adherents’ call to action truly prudent?