Originally Posted by
Warb
Playing Devil's advocate for a moment, I'm always a touch sceptical of these temperature numbers. When I was trained as a scientist (industrial chemist) many years ago, we were taught that for measurements to be meaningfully compared they must be like for like. 65 years ago, most temperature readings were taken by the local postmaster, probably using a max-min mercury thermometer, or something equally "old fashioned". These days they are taken by far more advanced systems, sometimes even satellites. 65 years ago, most local post offices were in small towns, and even the ones in cities had far more green space than they do now. A study by one of the Sydney universities suggested that the ambient temperature of Sydney would be lowered by (from memory) around 3C if all the buildings had light coloured roofs. Do we allow for these changes when we compare the readings?.