Controversy about homogenisation of climate records has exploded into a global concern after similar trend changes to those raised in Australia were identified in other parts of the world. Accusations of “fraud” and “criminality” have been made against some of the world’s leading weather agencies.
CRICKET legend Donald Bradman is a useful metaphor for the escalating global row over claims the world’s leading climate agencies have been messing with the weather.
Imagine, for instance, if some bureau of sport were to revise the Don’s batting average in Test cricket down from 99.94 to 75 after adjusting for anomalies and deleting innings of 200 runs or more.
What if the bureau then claimed another batsman had exceeded the Don’s revamped record to become the greatest ever?
Critics could be told the adjustments “don’t matter” because they had not affected overall global batting averages. Just as many batsmen had been adjusted up as down. And complaints could easily be dismissed as the “cherrypicking” of a few, isolated batsmen.
David Stockwell, Australian Research Council grant recipient and adjunct researcher at Central Queensland University, raised the Bradman analogy in his submission to a newly formed independent panel that will oversee the operation of the Bureau of Meteorology’s national temperature dataset.
Stockwell was highlighting public concerns at the BoM’s use of homogenisation techniques to adjust historical temperature records to remove anomalies and produce a national dataset called ACORN-SAT (Australian Climate Observations Reference Network — Surface Air Temperature). The panel, or technical advisory forum, which will hold its first discussions with BoM staff on Monday, was formed in December after a series of questions were raised publicly about the treatment of historic temperature records that has resulted in temperature trends at some Australian sites being changed from long-term cooling to warming.
Liberal senator Simon Birmingham, former parliamentary secretary to Environment Minister Greg Hunt, instructed BoM to fast-track the appointment of the panel, which was recommended in 2011 in a peer review of ACORN-SAT’s establishment. The make-up of the panel was announced by Birmingham’s replacement as parliamentary secretary, Bob Baldwin, in January.
In the meantime, controversy about homogenisation of climate records has exploded into a global concern after similar trend changes to those raised in Australia were identified in Paraguay and in the Arctic. Accusations of “fraud” and “criminality” have been made against some of the world’s leading weather agencies. There is now the prospect of a US Senate inquiry.
Respected US climate scientist Judith Curry has facilitated a wideranging debate on the issue, saying more research was needed, but that it is probably not the “smoking gun” for climate science, as some had claimed.
There is a long history regarding complaints about how climate data has been handled by authorities and how poorly those making complaints have been treated.
The general trend is made clear in a 2007 email exchange, now known as Climategate, between a senior BoM official and scientists at East Anglia University in Britain. BoM’s David Jones said Australian sceptics could be easily dissuaded if deluged with data.
“Fortunately in Australia our sceptics are rather scientifically incompetent,” Jones wrote. “It is also easier for us in that we have a policy of providing any complainer with every single station observation when they question our data (this usually snows them)”, he said.
Even better, noted East Anglia University’s Phil Jones, was to give troublemakers a big package of data with key information missing, making it impossible to decipher.
But more than seven years on, as the world’s weather bureaus report more and more broken temperature records and further examples emerge of incongruous adjustments, the pressure is building for a transparent process to finally untangle the numbers.
In Australia, ACORN-SAT was created in 2009 to replace BoM’s so-called high-quality dataset after questions were raised about the quality and accuracy of that network.
ACORN-SAT, which the Senate was told this week is managed by a two-person team in BoM, uses information from a select range of weather stations and computer modelling to compile its national temperature record. The data is also used to help create the global temperature record.
The panel to oversee ACORN-SAT will be headed by CSIRO scientist Ron Sandland and includes a wide range of experts in statistics and mathematics.
Sandland tells Inquirer he will hold a teleconference with BoM on Monday to decide how the process would be run.
The panel was first recommended by a peer review in September 2011 headed by Ken Matthews. The peer review gave ACORN-SAT a glowing report, describing it as conforming to world’s best practice. But it also called for greater transparency, better communication and independent oversight.
Despite criticisms about transparency and the results of homogenisation at some sites by members of the public, BoM was slow to act on the peer review recommendation to establish a technical advisory forum.
BoM is one of Australia’s most widely trusted organisations. Millions of people use its online weather services and a Senate estimates hearing was told this week that more than 30,000 people followed BoM’s Twitter feed in the wake of cyclones Marcia and Lam, which landed simultaneously in Queensland and the Northern Territory this week.
However, as one of the government’s lead agencies on climate change, BoM has come under greater scrutiny. A vocal chorus has been claiming that there is a pattern of historic temperatures being reduced to make the warming trend of the late 21st century look more acute.
The questioners were quickly labelled “amateurs” by atmospheric scientist David Karoly, from the University of Melbourne, as he and other climate science academics rushed to support BoM’s work.
But the issue has exploded internationally following a declaration by US agencies NASA and the National Oceanic and Atmospheric Administration that 2014 was the hottest year on record. As in Australia, regions were found where warming temperature trends had been created or increased through a process of homogenising records with neighbouring areas, some in other countries hundreds of kilometres away.
Published examples include Paraguay in South America and the Arctic, where a warm period in the 1930s and a well-documented period of intense cold around 1970 were erased from the record by homogenisation to give a steady rising temperature trend.
“How can we believe in ‘global warming’ when the temperature records providing the ‘evidence’ for that warming cannot be trusted?” asked British contrarian and climate change sceptic James Dellingpole.
“I’m not saying there has been no 20th-century global warming, I think there probably has been,” he said. “But I don’t honestly know. The worrying part … is that neither — it would appear — do the scientists.”
The website of Britain’s The Sunday Telegraph registered more than 30,000 comments under an article by columnist Christopher Booker saying the fiddling of temperature data has been “the biggest science scandal ever”. “What is now needed is a meticulous analysis of all the data, to establish just how far these adjustments have distorted the picture the world has been given,” Booker wrote.
The integrity of global temperature records after homogenisation is fiercely defended by global climate agencies, despite the fact that satellite measurements available from 1979 show a slightly different warming trend to surface-based records.
Australia’s BoM has issued two statements ahead of the Sandland review panel. In one it says temperature records are influenced by a range of factors such as changes to site surrounds, measurement methods and the relocation of stations.
“Such changes introduce biases into the climate record that need to be adjusted for, prior to analysis,’’ BoM says.
“Adjusting for these biases, a process known as homogenisation is carried out by meteorological authorities around the world as best practice, to ensure that climate data is consistent through time.”
BoM’s American counterpart, NOAA’s National Climatic Data Centre, says for global temperatures it is important to keep in mind that the largest adjustment in the global surface temperature record occurs over the oceans.
“All NOAA methodologies go through the peer-review process standard in scientific inquiry,” it says. Despite this, there remains enormous and heated debate about the issue.
Climate scientist Curry has opened an online debate that includes key scientists from the independent organisation Berkeley Earth, which compiles its own global temperature record, the results of which accord with those of other international agencies.
The Berkeley scientists conclude that Dellingpole and Booker’s claims of the “biggest fraud” of all time and a “criminal action” by climate scientists amount to nothing.
“Globally, the effect of adjustments is minor because on average the biases that require adjustments mostly cancel each other out,” they say.
But their web post generated heated discussion covering both the science of homogenisation and the standing of science.
European climate change economist Richard Tol, responding to Curry’s post, says the more important question raised by the debate over temperatures is perhaps why the public has lost so much trust in climate science that it prefers to believe columnists such as Booker over climate scientists at Berkeley. A Telegraph poll suggested that 90 per cent of 110,000 readers had sided with Booker.
“I would hypothesise that the constant stream of climate nonsense — we’re all gonna die, last chance to save the planet, climate change is coming to blow over your house and eat your dog — has made people rather suspicious of anything climate ‘scientists’ say,” according to Tol.
“If my hypothesis is correct, instead of arguing with Booker about the details of homogenisation, you should call out the alarmists.”
Curry tells Inquirer her main conclusions from the heated exchange in response to the Berkeley post are that “the stated uncertainties in global average temperatures are too small”.
“More research needs to be done to understand the impacts of the adjustments and to make individual locations more consistent with the historical record,” she says.
She says much more data work is needed to clarify the temperatures in the Arctic, which is a big source of difference among the different datasets in the northern hemisphere.
“I suspect that all this won’t change the qualitative result from the dataset, that is that the Earth is warming,” Curry says.
The way in which the Australian review of the BoM ACORN-SAT data is conducted could go a long way towards answering some of the questions being asked worldwide.
A common criticism of climate authorities such as BoM is that justifications for temperature smoothing may sound reasonable in the broad, but are often poorly explained in the detail of individual adjustments.
It is the task of the high-powered review panel to satisfy itself that the integrity given to BoM’s dataset by the initial peer review has been maintained.
Sitting on the panel with Sandland will be:
• Bob Vincent, emeritus professor in the school of chemistry and physics at the University of Adelaide.
• Phillip Gould, from the Australian Bureau of Statistics.
• John Henstridge, who founded Data Analysis Australia, now the largest private statistical organisation in Australia,
• Susan Linacre, a former president of the International Association of Survey Statisticians.
• Michael Martin, professor of statistics in the research school of finance, actuarial studies and applied statistics at Australian National University.
• Patty Solomon, professor of statistical bioinformatics at the University of Adelaide.
• Terry Speed, a former president of the Institute of Mathematical Statistics.