The government will have to review it's 30 year climate change plan after the Supreme Court rejected it as invalid.
It's after environmental campaigners appealed a High Court ruling which found that government policy is a matter for elected officials only.
This case dubbed 'Climate Case Ireland' and lodged by Friends of the Irish Environment argued that the government's National Mitigation Plan doesn't do enough to tackle climate change.
Last year the High Court ruled that it cannot 'second guess the government' over its climate policy and Friends of the Irish Enviroment decided to appeal.
This morning, in a landmark ruling, the Supreme court overturned the High Court's decision and quashed the goverment's climate plan.
The Supreme Court said that the plan is in breach of the Climate Action and Low Carbon Development Act 2015 and rejected it as invalid.
Today's ruling is described as a huge victory for climate justice in Ireland and the world.