Great news! Major high court climate ruling puts fossil fuel developers on notice

Australia’s highest court has delivered its first climate case decision, a potentially far-reaching ruling that could change how new coal and gas projects are assessed in New South Wales and beyond. The High Court decision, arising from a challenge by two local retired teachers in the Hunter Valley to MACH Energy’s proposed expansion of the Mount Pleasant coal mine near Muswellbrook, has put fossil fuel developers on notice that the climate damage caused by their products cannot be treated as someone else’s problem once those products leave Australia.

At issue was whether planning authorities had to consider the emissions produced when exported coal is burned overseas — known as Scope 3 Emissions — before approving a major coal mine expansion. In a 3-2 decision, the court found the New South Wales Independent Planning Commission failed to consider conditions to minimise all greenhouse gas emissions, including those generated after the coal was sold and shipped offshore.

The outcome is extraordinary not because it shuts down every fossil fuel project, but because it narrows one of the industry’s most convenient escape routes. For years, coal and gas exporters have argued that emissions from their products, once burned overseas, sit outside the responsibility of Australian decisionmakers. The High Court has now made clear that, at least under the New South Wales planning framework, those emissions cannot simply be waved away.

The case was brought by the Denman Aberdeen Muswellbrook Scone Healthy Environment Group Inc (DAMS HEG), a small community group from the Hunter Valley region in NSW, that argued the mine expansion’s downstream emissions would intensify climate harms felt locally. The proposed expansion would have allowed MACH Energy to extract up to 444 million tonnes of coal from the site and keep the mine operating until 2048, with more than 870 million tonnes of carbon dioxide-equivalent emissions released when the coal was burned.

The ruling directly affects the Mount Pleasant project and could influence 17 other coal proposals in the New South Wales planning pipeline. More broadly, legal experts say it may provide a blueprint for future climate litigation across Australia, giving communities, regulators and courts a stronger basis to scrutinise the full carbon footprint of new fossil fuel developments.

That makes the decision one of the most important climate law moments in Australian history: a technical judgment with consequences that could reach far beyond one Hunter Valley mine. At a time when Australia is under growing pressure to reconcile its climate commitments with its role as a major fossil fuel exporter, the High Court has sent a simple, consequential message — the emissions from Australian coal and gas do not disappear at the port.

You can find out more and support legal organisations taking climate change legal action via Environmental Justice Australia and the Environmental Defenders Office (EDO).