The Government has been left reeling from the Supreme Court judgement which has struck down its 2017 “excessively vague and aspirational” climate strategy.
The seven-judge court ruled the National Mitigation Plan (2017-2022) lacks specificity.
It also found the plan does not comply with Ireland’s obligations under the Climate Action and Low Carbon Development Act 2015 to give sufficient detail about achieving the national transition objective of a low-carbon economy by the end of 2050.
The Government is obliged to give “some realistic level of detail” about how it intends to meet the objective and the plan “falls a long way short” of the sort of specificity the 2015 act requires, said the Chief Justice, Mr Justice Frank Clarke.
“I will examine the Supreme Court judgement," said Taoiseach Micheál Martin.
Green leader and Transport Minister Eamon Ryan said he welcomes the judgement.
“It is significant that this was a unanimous judgement of seven members of the Supreme Court, reflecting the importance of climate change as an existential challenge to humanity," said Mr Ryan.
“The scientific consensus is clear. We must cut CO2 emissions in half by 2030 and reach net zero by 2050 to ensure we protect our planet and our country from the most severe impacts of global warming.
He said his department will need to carefully examine the decision and consider its implications.
Dr Áine Ryall, co-director, Centre for Law and the Environment at University College Cork, said the ruling is a massive boost for climate action.
"The judgement is a phenomenal victory for Friends of the Irish Environment and everyone involved in Climate Case Ireland," she said.
"It has been a long road. The judgement will be welcomed around the world and will be a beacon for further climate litigation.
"The Supreme Court has set out clear markers here as to what is required in terms of the level of detail that must be included in any new plan if it is to pass muster."