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Adjusted! Another degree shaved off Darwins history — (it’s cooling so fast, in 50 years Darwin won’t even be tropical)

Graham Lloyd and Jen Marohasy scorch through the BoMs latest revision of Darwin.

On the 1st of January 1910 the maximum temperature recorded at the Darwin post office was 34.2 degrees C, then it became 33.8 C, and now it was, is, 32.8 C. (What’s the past tense of something that is now, but wasn’t then? We don’t even have grammar for this.)

Extrapolate that adjustment trend: One degree of cooling in 6 years (since the last adjustment) becomes 16 degrees cooler in a century. Darwin won’t know what hot days were!

Look what they’ve done to history Mum

The Bureau of Meteorology has no interest in the hot pre-1910 era which just gets chopped.  And even if they did include it, after they’ve adjusted it — it wouldn’t be hot anymore anyway. Remember the Federation Drought? No one else does either.

Temperature is whatever you want to make it.

Darwin, temperatures history, graph, Bureau of Meteorology

Mean maximum annual temperatures as measured at the Darwin Post Office and airport shown with the new remodeled ACORN-SAT Version 2, which is the new official record for Australia.

“What the Bureau has done to the historical temperature record for Darwin is indefensible. ” –Marohasy


As Marohasy explains, the record at Darwin matters because the site had some of the best and earliest data for the vast northern reaches of Australia:

Graham Lloyd, The Weekend Australian –

“Scientist Jennifer Marohasy said Darwin’s temperature record was important because the city was the only location in central northern Australia where temp­era­tures had been measured since 1895 from within an instrument shelter. The Darwin record include­s temperatures taken at Darwin post office from 1882 until 1941 and from Darwin airport from 1942 to the present.”

The Bureau of Meteorology have plenty of vague excuses:

“For the case of Darwin, a downward adjustment to older records is applied to account for differences between the older sites and the current site, and differences between older thermometers and the current automated sensor.

“In other words, the adjustments estimate what historical temperatures would look like if they were recorded with today’s equipment at the current site.”

But the World War I site that was hasn’t changed in the last six years. Why were the 2012 corrections in need of re-correcting again? According to Marohasy the Bureau says the site was shaded by trees after 1937 and “other factors” changed too.

No dissent allowed

Jen Marohasy almost got a paper published on Darwin’s adjustments but after being accepted it was pulled at the last minute. Marohasy argues that the cooling wasn’t caused by shading but by a cyclone that wiped out the plants that were stopping the sea breeze getting in to the post office.

Dr Marohasy said many would claim the raw record for Darwin must be wrong because it showed a general trend of cooling to about 1950, and then warming.

As readers here know scientists in 1952 were discussing how Australia had cooled since the turn of the century. It was well known at the time — the cooling stretched all the way from Alice Springs to Narrabi and Hay, across the Eastern States. Marohasy provides a graph comparing Darwin to Richmond:

Darwin, Richmond, historical temperatures, Australia, Graph.

Darwin, Richmond, historical temperatures, Australia, Graph.

I often satirize the changes by mocking how old thermometers were always measuring “too high”. The Bureau protests:

 The bureau said the adjustment of historical temperatures in its ACORN-SAT dataset did not suggest records at any point in time were too high or too low. “Both upwards and downwards adjustments have been made at many ACORN-SAT sites to ensur­e past observations are consistent with modern conditions,” the bureau spokesman said.

Lo and verily, we all know the aim is supposedly to compare the past with today — but all the extra concrete, airports, and air conditioners means thermometers in bare paddocks in the horse and carriage era need to be adjusted up, not down.  And what about the all new one-second-records from electronic equipment? The old glass thermometers couldn’t measure a one second blast of hot air from a 747 that wasn’t there in 1898 either. (Even if it was there, they couldn’t measure it.) The slow acting mercury thermometers need to be adjusted up, not down, to compete with super sensitive electronic gizmos.

We know the Bureau have made adjustments “up and down”, but go on, tell the obvious bleeding truth — historic adjustments go down far more often than they go up and none of it makes sense unless the BoM is under the spell of a religion or is an advertising agency for the Big Gov that funds them.

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