A legal challenge against a coal mine expansion in New South Wales has reached Australia's High Court, with a local environment group arguing that planning authorities must consider the climate impact of scope three emissions. The case, brought by the Denman Aberdeen Muswellbrook Scone Healthy Environment Group, targets MACH Energy Australia's plan to double output at the Mount Pleasant open-cut coal mine near Muswellbrook and extend its operations until 2048.
In July 2025, the NSW Court of Appeal ruled that the mine's approval was unlawful, stating that planning authorities are legally required to consider the climate impact of scope three emissions—those caused when coal is eventually burnt, including overseas exports—on local communities. MACH Energy is now seeking to overturn that ruling in the High Court, arguing the validity of the extension's approval.
Wendy Wales, who heads the environment group, said a decision in their favour could set a precedent and encourage politicians to move away from export coal. The hearing follows a landmark advisory opinion by the International Court of Justice, which specified that fossil fuel production could count towards the host country and constitute an internationally wrongful act.
Bond University professor of climate law Nicole Rogers noted that while the ICJ opinion is not binding, it remains influential, especially since Australia supported the request for the opinion. She also highlighted the growing acceptance of climate attribution science in legal proceedings, which links emissions from specific sources to particular climate impacts.
The case underscores a global trend of courts being asked whether legal systems can keep pace with the climate crisis and whether decision-makers who approve fossil fuel projects are accountable for climate impacts.
