The High Court's ruling centres on the interpretation of NSW planning law. Previously, miners were required to account only for 'scope one' emissions, the pollution created during the mining process itself.
Now, the court has decided that 'scope three' emissions, the pollution generated when the coal is burned by overseas customers, must also be considered by decision-makers, who must weigh whether measures are needed to mitigate this damage.
Professor Jacqueline Peel, an international climate law expert at the University of Melbourne, said the decision was "a game changer" for coal production across the entire country.
On its face, the ruling is narrow, applying only under NSW planning law. However, Sue Higginson, a NSW Greens MP and veteran environment lawyer, noted that climate activists will be closely examining the planning rules in other states to see if similar legal challenges can be brought against polluting mines around the nation.
Governments retain the power to legislate and amend planning laws to protect the industry, but doing so will come with increasing political cost as public and legal pressure mounts.