The iconic Sydney Observatory is Australia’s longest running weather station. But everything around the site has changed. Bill Johnston has spent months researching, photographing, and hunting through historic files to document those changes. He wasn’t paid for this work, but what he found was that the BOM has missed that the area around the thermometers has changed dramatically over the last century, so much so, that he claims it’s scientifically meaningless to try to construct climate trends from this data. Aerial photographs show exposure of the instruments changed in 1950, when Stevenson screens were moved, and after a brick wall was built metres from the screen in about 1972. It is suspicious that the changes are undocumented in Bureau reports, especially given they are responsible for much of the “unprecedented warming” in Sydney’s temperature data. The BOM may counter that this site is not used to calculate warming trends across Australia, but as Bill points out, Sydney Observatory is used to homogenize other sites that are. So site changes and the urban heat island effect infects many country sites, and the traffic in Sydney “warms the nation”. — Jo

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Its fake news week! Guest post by Dr. Bill Johnston[1]. […]