Australian political figures have ignited fresh controversy over climate policy by repeatedly citing a disputed $9 trillion figure as the cost of achieving net zero emissions by 2050, despite warnings from researchers that their findings are being misrepresented.
The Origins of the Disputed Figure
In April 2023, Net Zero Australia (NZA) - a partnership between academics at the Universities of Melbourne, Queensland and Princeton University in the US - released a project report stating that achieving net zero would require Australia to "attract and invest $7-9tn of capital to 2060 from international and domestic sources."
However, the researchers emphasised this wasn't the cost to Australian taxpayers. Professor Michael Brear, NZA director, clarified in a May 2023 presentation that this figure "is not a direct indicator of our energy bills" and stressed that "most of this money should come from our international customers via export contracts."
The academics actually found the additional cost of building a low-carbon energy system to reach net zero emissions by 2050 would be approximately $300 billion - dramatically lower than the figures being circulated in political discourse.
Political Adoption of the $9tn Claim
Despite these clarifications, prominent conservative politicians began regularly citing the higher figure. Nationals MP Barnaby Joyce referenced the $7-9tn amount in July 2023 during a Channel Seven Sunrise interview, calling it "the alternative cost of renewables."
The campaign intensified in 2024 when Nationals leader David Littleproud made his first public mention of the number in June, alleging on Sky News that Australians would receive a "bill" for that amount. He later claimed net zero would have "a $7tn to $9tn cost to the Australian taxpayer."
By November 2025, the figure had become central to the Nationals' justification for abandoning their net zero commitment. Littleproud repeated the claim extensively throughout early November, including stating in a press release that the transition would cost "$250,000 per Australian."
Researchers Push Back Against Misrepresentation
As political use of the figure peaked, NZA issued a formal statement on 5 November 2025 warning that "different individuals and groups have been misrepresenting key cost estimates" from their report.
The researchers clarified that the $9tn figure referred to cumulative capital investment needed to transform the energy sector, but emphasised that "the large majority of this capital investment should be underwritten by overseas customers and not by Australians."
They specifically noted these projections "are not indicative of 'the cost of Australia reaching net zero emissions'."
Despite this intervention, Coalition members continued citing the figure. Pauline Hanson claimed on Radio National that net zero "is gonna cost us $8tn" and when confronted with NZA's clarification, responded: "I totally disagree with you."
Energy Minister Chris Bowen accused Littleproud of making a "dishonest, fraudulent statement" and claimed the Nationals leader "just shrugged his shoulders" at the researchers' clarification.
Continuing Political Divide
Nationals sources defended their position, with one claiming the cost could be even higher due to increased transmission expenses and challenges with green hydrogen development.
Meanwhile, Liberal leader Sussan Ley declined to explicitly endorse the $9tn figure when questioned, instead shifting responsibility to the government by stating: "the cost of net zero is for Labor to answer, not for us."
The dispute highlights the ongoing political tensions surrounding climate policy in Australia, with contested figures becoming central to debates about the economic implications of emissions reduction targets.
