A group of Australian teenagers has had a breakthrough in their climate change class action case against the Commonwealth. 

A case brought by a group of eight young people on behalf of ‘all young Australians’ was filed in September last year, asking the court to stop federal environment minister Sussan Ley from approving Whitehaven’s extension to its Vickery coal mine in NSW.

Justice Mordecai Bromberg this week dismissed the application for an injunction on technical grounds.

However, he ruled that the Environment Minister has a legal duty not to cause harm to young people by exacerbating climate change when approving coal mining projects.

The judge agreed that the minister had the duty of care to protect young people from climate change. He said climate change would cause catastrophic and “startling” harm to young people, and that new coal mines would increase the chance of that harm.

He ordered the two parties to make further submissions that might show how this newly determined duty of care may impact the minister's assessment of the mine.

Justice Bromberg found that approving the mine would have a small but foreseeable impact on climate change; increasing the risk of “catastrophic” harm experienced by young people in the future.

The lawyers involved say it is a global first, and may still see the Vickery coal mine expansion blocked. 

“The decision is going to reverberate for a long time,” Chris McGrath, an expert in climate litigation, has told the ABC.

“I think this has blown open a duty of care for climate change in Australia. 

“There's now a big crack in the wall… the implications for litigations against companies in negligence law are there, too.

“[Justice Bromberg has] gone through the facts of climate change, made some serious findings of facts.

“Findings on facts are not normally open to appeal, and in this case most of the facts were not contested by the minister.”

Whitehaven Coal says the application for the injunction had “no merit”.

“The company sees a continuing role for high-quality coal in contributing to global CO2 emissions reduction efforts while simultaneously supporting economic development in our near region,” it said. 

“There is strong market demand for the high-quality product of the type [the Vickery mine] will produce.”

The environment minister’s department says it is “considering the judgment”.