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.
These historic temperatures were calculated by the best scientists of the day, using the best equipment of the era (the same Stevenson Screen we use now). Yet again, global warming appears to have a “man-made” contribution. Far more important than CO2 is man-made “pollution” called homogenisation.
When doubling the recorded trend makes “No difference”
Bear in mind – some adjustments are necessary because raw is not automatically right. Stations have moved. But the Australian Met bureau can’t explain why all these adjustments are necessary, and indeed still claims the adjustments make no difference to the trend when clearly they do. Ken Stewart heard Dr Vertussy, the Director of the Bureau of Met (BoM), claim on radio last week that the adjustments make “no difference at all”. We look forward to Dr Vertussy’s reply.
And then there is the bizarreness of the half a degree adjusted cooling that occurs in these historic records when modern screens are much more likely to be near tarmac, bitumen, jumbo jets and 15 storey apartment blocks. The Urban Heat Island effect means that modern temperatures are artificially elevated in city CBDs by as much as 5- 7 C, with tests also showing several degrees of UHI at regional weather stations