Former Prime Minister Tony Abbott’s own department discussed setting up an investigation into the Bureau of Meteorology (BoM) amid media claims it was exaggerating estimates of global warming, Freedom of Information documents have revealed.

In August and September 2014, The Australian newspaper published reports questioning the BoM’s methodology for analysing temperatures, reporting claims it was “wilfully ignoring evidence that contradicts its own propaganda”.

With seven of our 10 warmest years on record being in the last 13 years, and warnings climate change will bring disastrous impacts for Australia, the accuracy and integrity of temperature information was crucial.

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The BoM strongly rejected assertions it was altering climate records to exaggerate estimates of global warming.

Nevertheless, documents obtained by the ABC under Freedom of Information show just weeks after the articles were published, Mr Abbott’s own department canvassed using a taskforce to carry out “due diligence” on the BoM’s climate records.

Late last year, the government set up a taskforce to provide advice on post-2020 emissions reduction targets ahead of the United Nations Paris climate change conference in December 2015.

The Department of Prime Minister and Cabinet originally wanted the taskforce to also conduct “due diligence to ensure Australia’s climate and emissions data are the best possible, including the Bureau of Meteorology’s Australian temperature dataset”.

An accompanying brief seen by Mr Abbott noted that “in recent articles in The Australian, the BoM was accused of altering its temperature data records to exaggerate estimates of global warming”.

“The way the bureau manages its climate records is recognised internationally as among the best in the world,” the brief said.

“Nevertheless, the public need confidence information on Australia and the world’s climate is reliable and based on the best available science.”

Public trust in BoM paramount: Hunt

The pressure intensified when Mr Abbott’s business advisory council chair Maurice Newman wrote an opinion piece in the paper, demanding a government-funded audit and review of the bureau.

Environment Minister Greg Hunt argued against having the taskforce investigate the bureau. Photo: AAP

The concerns centred on the bureau’s temperature homogenisation process — the method in which it adjusts temperatures for weather sites based on factors like trees casting shade or influencing wind or if the station is moved.

Both the Department of Environment and Environment Minister Greg Hunt argued against having the taskforce investigate the bureau.

One Department of Prime Minister and Cabinet bureaucrat described a Department of Environment official as being “on a campaign” to get the references to BoM removed from the taskforce’s responsibilities.

Further documents appear to show Mr Hunt convinced senior cabinet members to remove any references of “due diligence” or “quality assurance”.

In a letter to Mr Abbott written on November 18 last year, Mr Hunt highlighted the fact the “draft terms of reference refers to the taskforce doing due diligence on the Bureau of Meteorology’s Australian temperature data set”.

“In doing this, it is important to note that public trust in the Bureau’s data and forecasts, particularly as they relate to bushfires and cyclones, is paramount,” it said.

“Given the recent publicity about the Bureau’s temperature data sets, Senator Birmingham and I established a strengthened governance oversight of the Bureau’s ongoing work in this area.”

Review group set up in response to articles

The strengthened governance of the bureau that Mr Hunt referred to is the setting up a Technical Advisory Forum to review and provide advice on the bureau’s temperature data — a recommendation from an earlier review of the bureau’s processes.

“It is important to emphasise that this is primarily a matter of meteorology, statistics and data assurance,” Mr Hunt wrote in his letter to Mr Abbott.

A 2011 review found the bureau’s data and analysis methods met world’s best practice but recommended a group be set up to review progress on the development and operation of the temperature data.

The 2015 panel included eminent statisticians and members have told the ABC they were in no doubt that it was set up in response to the newspaper articles.

The review confirmed the credibility of the BoM in its report released in June 2015, which did not find any evidence that the BoM had been adjusting its figures to fit a pattern of global warming.