Australia’s High Court has delivered a landmark ruling that invalidated the approval of MACH Energy’s Mount Pleasant coal mine expansion in New South Wales, marking the nation’s first high court case to address climate change considerations in fossil fuel project approvals. The court found the state’s Independent Planning Commission (IPC) failed to properly consider the downstream greenhouse gas emissions generated when the mine’s coal is exported and burned overseas, known as Scope 3 emissions.
In a closely split 3-2 decision on Wednesday, the High Court upheld an earlier ruling by the NSW Court of Appeal that had overturned the mine expansion approval on the basis that the IPC did not consider whether conditions could be imposed to minimise these overseas emissions to the greatest extent practicable, as required under New South Wales law.
The Mount Pleasant expansion would have doubled coal output to 21 million tonnes annually until 2048, with Scope 3 emissions accounting for approximately 98 percent of the project’s total greenhouse gas emissions. The court’s decision found that while the IPC recognized the project’s emissions contributed to climate change, it did not explicitly evaluate mitigation measures for Scope 3 emissions as mandated.
The ruling sets a significant precedent in NSW and potentially across Australia, requiring planning authorities to explicitly address how fossil fuel projects may minimise the broader climactic impacts of emissions associated with exported resources. Legal and environmental experts suggest this could influence future approvals of coal and gas developments, including the recently approved Hunter Valley Operations expansion, which similarly omitted Scope 3 emissions from its environmental impact assessment.
The community group Denman Aberdeen Muswellbrook Scone Healthy Environment Group (Dams Heg), which initiated the legal challenge, described the ruling as an acknowledgment that Australia must take responsibility for the climate consequences of its exported fossil fuels. Wendy Wales, president of the group, emphasized the direct link between greenhouse gas emissions and the extreme weather events affecting Australian communities.
Environmental advocates hailed the decision as a turning point. NSW Greens MP Sue Higginson noted the judgment could create “significant legal difficulty” for other coal projects in the Hunter Valley. Greens deputy leader Steph Hodgins-May said the ruling underscored that emissions from Australian coal burned overseas are not beyond domestic regulatory consideration.
Conversely, industry representatives expressed disappointment. MACH Energy stated it would carefully review the judgment to understand its implications and continue pursuing options to maintain Mount Pleasant’s operations. The company highlighted the economic importance of the mine for local employment. The Minerals Council of Australia warned that the decision could hamper Australia’s competitiveness as a reliable coal exporter, noting the challenge of addressing emissions linked to overseas combustion.
Political responses varied. NSW Liberal and Nationals leaders described the ruling as a threat to Australia’s energy export standing and called for legislative amendments to exclude overseas emissions from project approval considerations. Federal climate ministers emphasized respect for the court’s authority while noting the ruling’s applicability to NSW state legislation rather than federal policy.
The High Court clarified that its decision did not constitute a merits review of climate change impacts broadly or settle how emissions reductions should be achieved, leaving detailed assessment and conditions to planning authorities. Nonetheless, the case establishes a legal requirement to consider Scope 3 emissions in fossil fuel project approvals, marking a significant development in Australian environmental and climate law.