Academics discrediting Australia’s carbon credit system ‘serious people’, says former chief scientist

The former Australian chief scientist charged with investigating the country's divisive carbon credit system says academics who have described it as a fraud and a sham are "serious people".

In an interview with Guardian Australia, Prof Ian Chubb said there were also credible voices defending the scheme and he would need to carefully weigh the evidence.

Chubb, a neuroscientist who was an inaugural board member of the Climate Change Authority and vice-chancellor of the Australian National University, has been given six months to unpick a growing controversy over the integrity of the scheme, which is central to government and business plans to cut emissions and reach net zero by 2050.

The climate change and energy minister, Chris Bowen, will announce on Monday three panellists who will work with Chubb on the review. They are Ariadne Gorring, the co-chief executive of the climate investment and advisory firm Pollination Foundation, retired federal court judge Dr Annabelle Bennett and economist Dr Steve Hatfield-Dodds.

Carbon credits are bought by governments and businesses as an alternative to making emissions cuts. Each carbon credit represents one tonne of carbon dioxide that has either been stopped from going in the atmosphere, or sucked out of it.

Concern about the validity of the scheme has been heightened since March, when Australian National University's Prof Andrew Macintosh - who, as chair of the Emissions Reduction Assurance Committee, used to be responsible for the integrity of the scheme - released several academic papers with colleagues arguing that most credits do not actually represent real or new emissions cuts.

Macintosh, an environmental law and policy scholar, said the system run by the government and Clean Energy Regulator was "largely a sham" and a fraud on taxpayers and the environment.

The Clean Energy Regulator and Emissions Reduction Assurance Committee have rejected this, saying they had asked independent experts to test Macintosh's assertions and found no evidence to support them. They have been supported by industry body the Carbon Market Institute and some companies that run carbon credit projects.

On Friday, Macintosh and colleagues released two new papers that argue the "vast majority" of carbon credits awarded for what are known as "human-induced regeneration" projects - which involve regenerating native forests by preventing grazing by livestock and feral animals (and not be tree-planting) - had not drawn more carbon dioxide from the atmosphere than would have happened anyway.

Human-induced regeneration is the most popular method to create carbon credits. The academics said the method had "numerous flaws", including that landholders were issued carbon credits for growing trees in arid and semi-arid rangeland country though the vegetation was already there before the work started.

In a statement last month, the Clean Energy Regulator and the Emissions Reduction Assurance Committee said Macintosh and his colleagues had failed to present robust evidence of a lack of integrity in the system and - as the precise areas of land where carbon credit projects took place could not be released due to legal restrictions - had based their analysis on an incomplete dataset. They officials said it meant Macintosh had relied on "indicative project areas only".

Macintosh and his colleagues said graphs released by the regulator and committee to make this case showed forest cover in carbon credit project areas started to increase in about 2010 - about the time the "millennium drought" broke - and before work on the carbon projects began. The academics said it showed rainfall was the primary driver of forest growth and therefore the carbon storage would have happened anyway - it was not "additional", as required - and should not have been rewarded with public money from the Coalition's $4.5bn emissions reduction fund.

Chubb said having a functioning carbon credit system was important, as cutting emissions in some parts of the economy would be difficult and they would need to be offset. He said he had been a "passive observer" of the debate over the integrity of the system and described himself as a "well-informed amateur".

"My view of it is that the commentary - the commentary on both sides, really - I think they're all serious people. Our role will be coming in from the outside and looking at the weight of evidence," he said.

"I'm not surprised the language is robust from people [such as Macintosh] who are fully committed. Some of the language on the other side is pretty firm, too."

Chubb said the review would look at the integrity of methods used to generate carbon credits, whether the governance structure that oversaw it was fit for purpose and whether the social, economic and environmental impacts were appropriately managed.

He said it was valid to consider the extent to which governments and businesses should be relying on carbon credits to meet emissions targets. "What proportion [is right] I'm not sure, but we might get a better sense of that when we look at the circumstances," he said.

The new panellists have varying degrees of experience of carbon markets.

Gorring has worked on nature-based climate solutions, including with the Kimberley Land Council and in the development of the savanna carbon industry in northern Australia.

Hatfield-Dodds was the executive director of the Australian Bureau of Agricultural and Resource Economics and Sciences, worked at CSIRO and recently joined consultants EY Port Jackson Partners.

Bennett, a former federal court judge, is chancellor of Bond University, the chair of the Australian Nuclear Science and Technology Organisation and worked on the royal commission into national disasters that followed the Black Summer bushfires.

The review is due to report back by the end of the year.