THE Bureau of Meteorology (BoM) has defended the accuracy of its climate records after documents released under freedom-of-information laws showed the Abbott government considered investigating its estimates on global warming.
The agency said that while it welcomed scrutiny of its scientific work "the bureau has always confidently maintained that it has not altered climate records to exaggerate estimates of global warming".
The comments come after documents released to the ABC showed former prime minister Tony Abbott's department discussed investigating the bureau's climate data following claims in The Australian newspaper last year that the bureau was "wilfully ignoring evidence that contradicts its own propaganda".
The inquiry, had it proceeded, would have been carried out by a taskforce in the Department of Prime Minister and Cabinet established to consider Australia's post-2020 emissions reduction targets.
One bureau source told Fairfax Media that forecasters were instructed to be "more careful" when discussing climate change after Mr Abbott was elected in 2013.
The source said the instructions were unofficial but passed down through government channels.
"It was common knowledge that the Liberal Party were not as convinced about climate change, and they just asked us not to be too keen about all these records being broken all the time," the source said.
Seven of Australia's 10 warmest years on record occurred in the past 13 years.
The bureau has repeatedly rejected claims it has altered or exaggerated climate data.
A review published in July by a technical advisory forum set up to examine the bureau's data backed the accuracy of its records, but recommended some improvements in the clarity and presentation of its information.
The FOI documents show Environment Minister Greg Hunt argued against the government's targets taskforce investigating the bureau, noting that the technical forum was already conducting its review.
Mr Abbott in correspondence to Mr Hunt asked Senator Simon Birmingham, who had responsibility for the agency at the time, to "write to me on the outcome of the review of the temperature dataset".
A briefing that was sent to Mr Abbott noted the articles in The Australian but said the way the bureau managed its records was "transparent" and "recognised internationally as among the best in the world".
"It is a scientific approach that has been peer reviewed," the note says.
"Nevertheless, the public need confidence information on Australia's, and the world's, climate is reliable and based on the best available science."
The bureau's spokeswoman said "the bureau always welcomes scrutiny of its scientific work".
"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," she said.
"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."