Environment groups have appealed to the Federal Court to prevent Environment Minister Tanya Plibersek from approving two coal mines, including Mt Pleasant near Muswellbrook, without first considering their climate impacts.
The appeals, filed by the Environment Council of Central Queensland (ECoCeQ), represented by Environmental Justice Australia, challenge the Environment Minister's refusal to properly assess the climate impact of Whitehaven's Narrabri underground coal mine expansion and MACH Energy's Mt Pleasant expansion.
Mt Pleasant would become the largest producing coal mine in Australia, three times larger than Queensland's Adani coal mine.
Plans by MACH Energy to extend the project until almost 2050 are also subject to another legal action in the NSW Land and Environment Court.
When the minister assessed the harm of the coal mines, and subsequently defended the decision, she relied on the "market substitution" argument or "drug-dealers' defence", as well as "drop in the ocean" logic.
This argument is based on a simple, but Environment Council of Central Queensland argues, deeply flawed premise that allows companies to knowingly contribute to harm: if we didn't supply the coal, another company would, so the harm of our product doesn't matter.
The market substitution or drug dealers' defence has been categorically rejected in several jurisdictions around the world and recently in the Queensland Land Court.
"We are asking the courts to require Australia's Environment Minister comply with the law - and with climate science - and look before she leaps into approving mines that will fuel climate harm for decades to come," Environment Council of Central Queensland president Christine Carlisle said.
"We're a tiny volunteer group and we wish we didn't have to take our federal government to court to protect our environment from climate harm.
"If Australia's environment minister truly believed in science-based decision making, she would take her blinkers off and urgently act on the climate harm from new coal and gas."
Environmental Justice Australia lawyer and co-chief executive Elizabeth McKinnon said Ms Plibersek's interpretation of the law had stopped her from scrutinising the climate harm of new coal and gas projects on her desk.
"Our client believes this approach is irrational, illogical and unlawful," she said.
"Our client has filed these Federal Court appeals because, with the greatest respect, they believe the Federal Court Judge made the wrong decision.
"We are also waiting on the Minister to confirm she will not rush to approve these coal mines before these Court cases are determined."