December 12, 2009
Clearly, the term "pre-industrial temperature" is meant to make this temperature reading "canonical" or "holy" so that we should keep ourselves in the vicinity of their temperature. What the "pre-industrial temperature" actually means is an arbitrarily chosen and mostly unknown temperature at a random year during the feudal era.
Because they believe that the temperature has increased by 0.8 °C since the pre-industrial times, they must mean a year between 1700 and 1800 as their pre-industrial day of creation. But which one?