COOLING the past relative to the present has the general effect of making the present appear hotter – it is a way of generating more global warming for the same weather.
The Bureau of Meteorology has rewritten Australia’s temperature in this way for the second time in just six years – increasing the rate of warming by 23 percent between Version 1 and the new Version 2 of the official ACORN-SAT temperature record.
Temperatures from the Rutherglen research station in rural Victoria are one of the 112 weather stations that make-up ACORN-SAT. Temperature have been changed here by Blair Trewin, under the supervision of David Jones at the Bureau.
Dr Jones’s enthusiasm for the concept of human-caused global warming is documented in the notorious Climategate emails, during which he wrote in an email to Phil Jones at the University of East Anglia Climatic Research Unit on 7 September 2007 that:
“Truth be known, climate change here is now running so rampant that we don’t need meteorological data to see it.”
We should not jump to any conclusion that support for human-caused global warming theory is the unstated reason for the Bureau’s most recent remodelling of Rutherglen. Dr Jones is an expert meteorologist and an honourable man. We must simply keep asking,
“What are the scientifically valid reasons for the changes that the Bureau has made to the temperature records?”
In 2014, Graham Lloyd, Environmental Reporter at The Australian, quoting me, explained how a cooling trend in the minimum temperature record at Rutherglen had been changed into a warming trend by progressively reducing temperatures from 1973 back to 1913. For the year 1913, there was a large difference of 1.7 degrees Celsius between the mean annual minimum temperature, as measured at Rutherglen using standard equipment at this official weather station, and the remodelled ACORN-SAT Version 1 temperature. The Bureau responded to Lloyd, claiming that the changes were necessary because the weather recording equipment had been moved between paddocks. This is not a logical explanation in the flat local terrain, and furthermore the official ACORN-SAT catalogue clearly states that there has never been a site move.
Australians might nevertheless want to give the Bureau the benefit of the doubt and let them make a single set of apparently necessary changes. But now, just six years later, the Bureau has again changed the temperature record for Rutherglen.
In Version 2 of ACORN-SAT for Rutherglen, the minimum temperatures as recorded in the early 1900s, have been further reduced, making the present appear even warmer relative to the past. The warming trend is now 1.9 degrees Celsius per century.
The Bureau has also variously claimed that they need to cool that past at Rutherglen to make the temperature trend more consistent with trends at neighbouring locations. But this claim is not supported by the evidence. For example, the raw data at the nearby towns of Deniliquin, Echuca and Benalla also show cooling. The consistent cooling in the minimum temperatures is associated with land-use change in this region: specifically, the staged introduction of irrigation.
Australians trust the Bureau of Meteorology as our official source of weather information, wisdom and advice. So, we are entitled to ask the Bureau to explain: If the statements provided to date do not justify changing historic temperature records, what are the scientifically valid reasons for doing so?
The changes made to ACORN-SAT Version 2 begin with changes to the daily temperatures. For example, on the first day of temperature recordings at Rutherglen, 8 November 1912, the measured minimum temperature is 10.6 degrees Celsius. This measurement is changed to 7.6 degrees Celsius in ACORN-SAT Version 1. In Version 2, the already remodeled value is changed again, to 7.4 degrees Celsius – applying a further cooling of 0.2 degrees Celsius.
Considering historically significant events, for example temperatures at Rutherglen during the January 1939 bushfires that devastated large areas of Victoria, the changes made to the historical record are even more significant. The minimum temperature on the hottest day was measured as 28.3 degrees Celsius at the Rutherglen Research Station. This value was changed to 27.8 degrees Celsius in ACORN Version 1, a reduction of 0.5 degrees Celsius. In Version 2, the temperature is reduced by a further 2.6 degrees Celsius, producing a temperature of 25.7 degrees Celsius.
This type of remodelling will potentially have implications for understanding the relationship between past temperatures and bushfire behavior. Of course, changing the data in this way will also affect analysis of climate variability and change into the future. By reducing past temperature, there is potential for new record hottest days for the same weather.
Jennifer Marohasy BSc PhD is a critical thinker with expertise in the scientific method.
It is becoming harder to understand how the BOM can say the adjustments don’t affect the warming trend? A full blown audit of this mess needs to be undertaken, with Mackay showing a lower max than min temp in some cases. This organisation can no longer be taken seriously, and is a massive misses of taxpayers dollars. Just like the new round of emails, they have a predetermined goal, and then go about achieving that goal by making massive adjustments.
A couple of questions. First, what makes the average so significant? Given that very occasional events, such as rain in 1916-17, distorted the average over the course of a century and more. I should have thought the median value were the more significant.
Secondly, does the bureau maintain the original temperature records, such as Rutherglen or are they dispatched to oblivion? Or has the “narrative” outstripped any requirement to maintain the original sources?
Thirdly, I find the Bureau’s forecasts for the morrow and a few subsequent days more or less effective. To expect the Bureau or any other government (or, increasingly today, private) institution to be a source of “wisdom and advice” is, frankly, absurd. In very abbreviated form, unless and until the humanities revive science will continue to die.
The implications from these ‘adjustments’ to the historical temperature record are so dramatic, (turning a mild decline in temperature over the last 107 years into a significant warming trend of 1.9oC per decade or 2 degrees actual over the period) simply defies reason and commonsense.
All of those records from the same site, with the (significant and unexplained) exception of the last few years, simply could not be so neatly and progressively incorrect if it was a result of human or instrument error.
Using a homogenisation formula to arrive at this sort of conclusion clearly results in a distortion of the facts and actual historical reality, making this an unacceptable and inappropriate strategy.
It results in a major distortion of reality making it both meaningless as a historical record and much worse, a degradation of respect for the Bureau as a source of reliable data for one of the most important elements in the historical record, temperature.
And raises the question, why have they done this?
Jennifer, congratulations on this article and posting it on WUWT. There appears to be little scientific basis for the magnitude of these adjustments at rural stations away from the UHI effect, such as Rutherglen.
It seems to me that BOM have had to come out with Acorn-SAT 2 adjustment to prevent embarrassment caused by the earlier Acorn-SAT 1 reconstruction.
When the BOM produced the Acorn-SAT 1 profile in 2012, it joined the measured temperatures at the current day, and ran with the current measured temperatures as they came in. Problem is, the slope of the current temperature trend is much less than the trend of the Acorn-SAT 1 reconstruction – and produces a kink in the Acorn-SAT graph. The effect of that is to lower the “global warming” signal over the trend length as time goes on.
So the BOM had to lower the past temperatures a second time to intersect with current measured temperatures, and to maintain the slope of the original Acorn-SAT 1 construction.
Of course, this show the whole Acorn-SAT reconstruction is faulty, and has seriously over estimated any warming trend.
And the way the BOM hid the process of having to put out a “remedial” Acorn-SAT 2 correction shows there is a major problem.
I predict an Acorn-SAT 3 adjustment in a few years time – the BOM will have to keep moving past temperatures down to maintain the rate of 20th C warming, as current temperatures refuse to play ball.
I have raised this before, but a temperature series, based on long-lived rural stations only should be produced – but not by the biased BOM.
If this man Jones is as good as you believe, is he asleep on his watch ?
I suspect that politics has actually invaded the BOM, or rather a culture of PC, where it has become too hard to break the narrative.
Thanks for alerting us to these repeated challenges to history, which otherwise would remain in the dark recesses of BOM’s fancy computer.
Thanks once again, Jen, for bringing this to the world’s attention.
I wonder how the BoM can keep doing this and getting away with it.
Especially when the mainstream media is so quick to point their manipulations out to all and sundry.
Oh, er, hang on…
The Elite know that AGW is bogus. They have an Agenda.
The Elite use Left Wingers, Greenies and idiot conservatives to do their work.
We should be looking more closely at the Agenda.
Christiana Figueres of the UN climate committee said “It has nothing to do with climate, it is about destroying capitalism.” or words to that effect.
I despise the Lefties and the Greens with a passion for being either so stupid or so duplicitous. More than likely, both.
The Agenda is to introduce a carbon tax and to blame carbon as a control on society. It has nothing to do with the environment. The controls are totalitarian.
“Version 1 (red) to give even more dramatic warming, which is now 1.9 degrees Celsius.”
Typo in the text under the Graph, I think you meant Version 2.
Keep up the great work.
Man-made climate change, in the sense that a forgery is a creative piece of art, or that a monster that exists as a delusional hallucination is man-made as well.
Certainly not a human caused climate crisis.
If that was the case, there would be no need to rewrite the past.
O/T but of interest, I think:
https://www.comcourts.gov.au/file/Federal/P/BRG1148/2017/actions
Peter Ridd’s case is listed for March 28 before Judge Vasta
No court room yet assigned, it seems
More on how man made climate change is a creative work:
https://rclutz.wordpress.com/2019/03/06/what-warming-1978-to-1997/
Happy to spend a month or two in Rutherglen to help sort this out, as long as the supply of durif and chardonnay holds up.
Good post
I’m certain that many years ago I was able to download the Australian historical raw data sets. Unfortunately I can’t find my copies of them, nor where they can be downloaded from again. Could someone point me to a download URL, please? I have a child who would like to do a presentation at school on the homogenising of the BOM data, and the primary sources would be necessary. Thanks.