The nascent field of climate litigation in Australia came of age on Friday. The Chief Judge of the NSW Land and Environment Court, Brian Preston, delivered a landmark judgment refusing to approve a new coal mine because of its impacts on climate change. In the Chief Judge’s words, the mine proposal was in the wrong place at the wrong time.

When we first argued that our client, the Groundswell Gloucester, should be a party to this case and put a climate-change ground before the court, the mining companies thought it a laughable proposition, and said it would be “a sideshow”. As it happens, climate change became the main event in this court, as it is elsewhere.

A protest sign in Forbesdale, near Gloucester, opposing the proposed Rocky Hill coal mine. Credit:Liam Driver

The ramifications are likely to ripple out across Australia and possibly the world. This is climate litigation writ large.

The Chief Judge refused the Rocky Hill Coal Project, near the mid-north coast town of Gloucester, on a range of grounds, all of which are important, but what his judgment says about climate change is of greatest significance. The court accepted the evidence put by Professor Will Steffen about the global carbon budget – that is, there is a limit on the amount of fossil fuels that can be burnt if we are to meet the Paris Agreement targets and avoid dangerous climate change.