Here’s an update to the digging through our historic records we discussed a month ago, we can now include nearly twice the stations and the difference between temperatures originally recorded 100 years ago and temperatures today are even smaller.
Chris Gillham has been working with CSIR documents and official Commonwealth Year Books. Last month he used the 1953 Year Book which contained 44 weather station averages for 1911-40 to compare with 2000-14 temperatures, but has since discovered that the 1954 Year Book provides an additional 40 stations with 1911-40 data. The average rise in mean temperatures across all 84 weather stations around Australia over the last 70 years of global warming is about 0.3C. This larger dataset suggests as much as two thirds of the current official trend in Australian warming was due to post hoc adjustments, not heat recorded by thermometers.