Australia's highest court has ruled that the approval of MACH Energy's Mount Pleasant coalmine expansion in New South Wales' Hunter Valley was invalid. This was reported by Qazaqyia.kz citing The Guardian.

On Wednesday morning, the nation's highest court ruled in a 3-2 split decision that the state's Independent Planning Commission (IPC) failed to consider imposing conditions to minimise greenhouse gas emissions that would be generated by the mine when the coal is sold and burnt overseas. Known as scope 3 emissions, these are not counted in Australia's domestic tally.

The decision sets a precedent for fossil fuel projects in the state. The coal company brought the high court case after a local community group, the Denman Aberdeen Muswellbrook Scone Healthy Environment Group (Dams Heg), halted the coalmine expansion on climate grounds in the NSW court of appeal.

Commenting on the judgment, the deputy Greens leader, Steph Hodgins-May, said: "For too long, big coal and gas companies have tried to pretend that the emissions from their products are someone else's problem once they leave Australian shores. They're not."

"When Australian coal is burned overseas, the climate damage doesn't magically disappear at the port. It comes back to communities here through worsening heat, drought, bushfires and floods," she added.

"This judgment sends a clear message to governments and fossil fuel companies that the climate impacts of their projects cannot simply be ignored or pushed down the line," Hodgins-May said.

NSW Greens MP Sue Higginson, formerly a public interest environmental lawyer, also said the high court judgment could lead to "significant legal difficulty" for the Hunter Valley Operations (HVO) coalmine extension, which was approved by the IPC a week ago.

In greenlighting the HVO extension – the biggest in the state's history – the IPC ruled that emissions from the mine would "contribute to climate change impacts on the people, economy and environment of the Hunter region, NSW and globally", but that their impacts had been outweighed by economic benefits to the region.

For both the HVO and Mount Pleasant coal developments, 98% of the emissions were scope 3 emissions, Higginson said. "HVO's environmental impact statement didn't even account for scope 3 emissions at all, and the high court has been crystal clear that consent authorities must ensure emissions are minimised to the greatest extent practicable. It seems clear that the approval of HVO fails this test."

"Lawyers should be running to the courts right now with this judgment in hand, ready to stop coal approvals in their tracks," she said.

In a joint statement, the Liberal leader, Angus Taylor, and the Nationals leader, Matt Canavan, described the decision as a threat to "Australia's standing as a reliable energy exporter" and said the federal and NSW governments "must act immediately to fix the law".

"A project extension the Independent Planning Commission approved in 2022, after years of assessment, has been sent back to square one," they said, arguing that the Minns government should amend NSW's Environmental Planning and Assessment Act to "make clear that overseas emissions from Australia's exported resources are not a consideration in project approvals".

The climate change minister, Chris Bowen, who is in Fiji chairing climate negotiations, said: "The law of the land is law of the land, as interpreted by the high court, and we respect that."

"If others don't, if others are so biased in their approach that they don't respect the law of the land, that's a matter for them. It says a bit about their approach, but that's about as all I'm going to say because it's a court case and I'm not in Australia at the moment."

Murray Watt, the federal environment minister, said on Wednesday afternoon that while he had not had an opportunity to review the judgment in full, "the decision from the high court is in relation to a New South Wales government decision based on New South Wales legislation".

"It doesn't automatically transfer to commonwealth decisions or commonwealth legislation," he told News24.

The NSW government was contacted for comment.