Australia’s top court puts fossil fuel developers on notice

Australia's top court has issued its first climate-related decision, potentially impacting the economic prospects for new coal and gas projects in New South Wales. The High Court's judgment, which came about in a case brought by a community group against MACH Energy over a coalmine expansion, does not outright condemn fossil fuels.

However, it establishes a new standard for such projects, requiring planning authorities to take into account the full carbon footprint of these projects, including emissions produced when customers burn the fossil fuels overseas.

Although the ruling pertains to a specific coal mine, the Mount Pleasant in NSW, it directly impacts 17 other coal proposals currently in the state's planning pipeline. This decision could also serve as a precedent for how courts across Australia handle similar cases in the future. The case has effectively warned fossil fuel companies, including those involved in coal mining, that they are now under legal scrutiny.

The climate litigation landscape in Australia is rapidly expanding, with the country having the most such cases worldwide following the United States and Brazil. This growth is largely due to the prevalence of fossil fuel projects in the country and lax regulations, coupled with strong community engagement. Climate litigation is often the only legal recourse when government regulation is inadequate or ineffective.

The specific case in question involves the Mount Pleasant open-cut coal mine, located near Muswellbrook in NSW's Hunter Valley. Originally approved for a 22-year lifespan, the mine was seeking an extension to 2048, doubling its output. The vast majority of the mine's carbon footprint comes from the burning of the coal, classified as "scope 3" emissions, which occur when the coal is burned overseas.

In 2022, the Independent Planning Commission approved the mine's expansion. However, a local community group challenged this decision in the NSW Land and Environment Court, arguing that the commission had failed to consider the scope 3 emissions and had breached a planning rule that required it to minimize greenhouse gas emissions, including scope 3 emissions, to the "greatest extent practicable."

The community group's arguments were upheld by the NSW Court of Appeal in July 2025. MACH Energy appealed this decision, leading to the current case before the High Court.