Jennifer Marohasy The Australian September 29, 2015
For the true believer, it is too awful to even consider that the Australian Bureau of Meteorology could be exaggerating global warming by adjusting figures. This doesn’t mean, though, that it’s not true.
In fact, under prime minister Tony Abbott, a panel of eminent statisticians was formed to investigate these claims detailed in The Australian newspaper in August and September last year.
The panel did acknowledge in its first report that the bureau homogenised the temperature data: that it adjusted figures. The same report also concluded it was unclear whether these adjustments resulted in an overall increase or decrease in the warming trend.
No conclusions could be drawn because the panel did not work through a single example of homogenisation, not even for Rutherglen. Rutherglen, in northeastern Victoria, is an agricultural research station with a continuous minimum temperature record unaffected by equipment changes or documented site moves but where the bureau nevertheless adjusted the temperatures.
This had the effect of turning a temperature time series without a statistically significant trend into global warming of almost 2C a century.
According to media reports last week, a thorough investigation of the bureau’s methodology was prevented because of intervention by Environment Minister Greg Hunt. He apparently argued in cabinet that the credibility of the institution was paramount — that it was important the public had trust in the bureau’s data and forecasts, so the public knew to heed warnings of bushfires and cyclones.
Hunt defends the bureau because it has a critical role to play in providing the community with reliable weather forecasts.
This is indeed one of its core responsibilities. It would be better able to perform this function, however, if it used proper techniques for quality control of temperature data and the best available techniques for forecasting rainfall.
There has been no improvement in its seasonal rainfall forecasts for two decades because it uses general circulation models. These are primarily tools for demonstrating global warming, with dubious, if any, skill at actually forecasting weather or climate.
Consider, for example, the millennium drought and the flooding rains that followed in 2010.
Back in 2007 and 2008, David Jones, then and still the manager of climate monitoring and prediction at the Bureau of Meteorology, wrote that climate change was so rampant in Australia, “We don’t need meteorological data to see it”, and that the drought, caused by climate change, was a sign of the “hot and dry future” that we all collectively faced.
Then the drought broke, as usual in Australia, with flooding rains.
But the bureau was incapable of forecasting an exceptionally wet summer because such an event was contrary to how senior management at the bureau perceived our climate future.
So, despite warning signs evident in sea surface temperature patterns across the Pacific through 2010, Brisbane’s Wivenhoe dam, originally built for flood mitigation, was allowed to fill through the spring of 2010, and kept full in advance of the torrential rains in January 2011.
The resulting catastrophic flooding of Brisbane is now recognised as a “dam release flood”, and the subject of a class-action lawsuit by Brisbane residents against the Queensland government.
Indeed, despite an increasing investment in supercomputers, there is ample evidence ideology is trumping rational decision-making at the bureau on key issues that really matter, such as the prediction of drought and flood cycles. Because most journalists and politicians desperately want to believe the bureau knows best, they turn away from the truth and ignore the facts.
News Corp Australia journalist Anthony Sharwood got it completely wrong in his weekend article defending the bureau’s homogenisation of the temperature record. I tried to explain to him on the phone last Thursday how the bureau didn’t actually do what it said when it homogenised temperature time series for places such as Rutherglen.
Sharwood kept coming back to the issue of “motivations”. He kept asking me why on earth the bureau would want to mislead the Australian public.
I should have kept with the methodology, but I suggested he read what Jones had to say in the Climategate emails. Instead of considering the content of the emails that I mentioned, however, Sharwood wrote in his article that, “Climategate was blown out of proportion” and “independent investigations cleared the researchers of any form of wrongdoing”.
Nevertheless, the content of the Climategate emails includes quite a lot about homogenisation, and the scientists’ motivations. For example, there is an email thread in which Phil Jones (University of East Anglia) and Tom Wigley (University of Adelaide) discuss the need to get rid of a blip in global temperatures around 1940-44. Specifically, Wigley suggested they reduce ocean temperatures by an arbitrary 0.15C. These are exactly the types of arbitrary adjustments made throughout the historical temperature record for Australia: adjustments made independently of any of the purported acceptable reasons for making adjustments, including site moves and equipment changes.
Sharwood incorrectly wrote in his article: “Most weather stations have moved to cooler areas (ie, areas away from the urban heat island effect). So if scientists are trying to make the data reflect warmer temperatures, they’re even dumber than the sceptics think.”
In fact, many (not most) weather stations have moved from post offices to airports, which have hotter, not cooler, daytime temperatures. Furthermore, the urban heat island creeps into the official temperature record for Australia not because of site moves but because the record at places such as Cape Otway lighthouse is adjusted to make it similar to the record in built-up areas such as Melbourne, which clearly are affected by the urban heat island.
I know this sounds absurd. It is absurd, and it is also true. Indeed, a core problem with the methodology the bureau uses is its reliance on “comparative sites” to make adjustments to data at other places. I detail the Cape Otway lighthouse example in a recent paper published in the journal Atmospheric Research, volume 166.
It is so obvious that there is an urgent need for a proper, thorough and independent review of operations at the bureau. But it would appear our politicians and many mainstream media are set against the idea.
Evidently they are too conventional in their thinking to consider such an important Australian institution could now be ruled by ideology.
Jennifer Marohasy is a senior fellow at the Institute of Public Affairs.
‘The Forum considers that its own recommendations will deliver improvements to the management and communication of the ACORN-SAT dataset. There is a clear trend increase in both the raw and homogenised temperature data, and the temperature patterns exhibited in a variety of other datasets have a similar character. It is not currently possible to determine whether these improvements will be reflected in an increased or decreased warming trend that has been broadly observed across a range of different datasets.