Ireland’s actions are contributing to global warming to an “unacceptable” degree and the State has not disputed its performance in reducing greenhouse gas emissions is “lamentable”, the High Court has heard.

Ireland’s emissions are rising rather than falling and the State’s Climate Change Council has said the State is “completely off course” in meeting national, EU and international obligations on reducing emissions, the court was told.

The court should quash the Government’s National Mitigation Plan and direct it to produce a plan that will properly tackle the risks posed by global warming, including flooding, fires and ecological destruction and loss of life, Eoin Mccullough SC said.

He was opening a case by Friends of the Irish Environment (FIE) over the adequacy of the Government’s plans to tackle climate breakdown.

The hearing is before Mr Justice Michael McGrath and the courtroom was packed today with supporters of the action.

FIE wants orders quashing the Government’s July 2017 approval of the National Mitigation Plan (NMP) made under section 4 of the Climate Change and Low Carbon Development Act 2015.

The purpose of the plan is stated to be to ensure compliance with the State’s obligations regarding climate change.

FIE maintains the plan fails to comply with the requirements of the 2015 Act and the State has failed to comply with national law, EU law, and the provisions of the Charter of Fundamental Rights and Freedoms, particularly article 3.

The NMP sets out measures described as the first steps on a path designed to transition Ireland to a low carbon, climate resilient and environmentally sustainable economy by 2050. It concerns all sectors of government, with a particular focus on key areas including electricity generation, transport, and agriculture.

In its proceedings against the Government, Ireland and the Attorney General, FIE says the plan fails to specify any measures to urgently reduce greenhouse emissions as it is required to do.

It says the plan does not contain any mitigation measures by which the State can satisfy its international or EU law obligations under agreement including the 2015 Paris Accord on climate change.

Mr McCullough said there was no dispute between the sides concerning the causes and consequences of greenhouse gas emissions and about the steps science has prescribed should be taken to reduce those.

There was also no dispute Ireland’s performance in reducing greenhouse gas emissions is “lamentable”.

Due to emissions, the world is now one degree warmer than it was at the start of the industrial age. When the world gets 1-2 degrees warmer, there are risks to unique and threatened systems and risks associated with weather events such as droughts, cyclones, floods and wildlife affecting food production, water supply and increased morbidity and mortality across the world. If there is no mitigation of greenhouse gases, average temperatures will also rise by four degrees by the end of the century with “devastating consequences”.

The Paris agreement of 2015 and other international agreements addressed this situation and Ireland had recognised the need to hold the increase in global temperatures to well below 2 degrees and to pursue efforts to withhold the temperature rise to 1.5 degrees.

Science now shows it is not safe to allow the world to heat to 2 degrees above pre-industrial level and emissions must be cut by 2020 by 25 to 40 per cent.

Ireland has the third highest emissions per capita in the EU and contributes disproportionately to global warming, he said.

The purpose of the NMP was said to be the achievement of transition to low carbon environmentally sustainable activity by 2020 but it seemed the State thinks it is enough to reach an 80 per cent target by 2050 and, if it can show it might achieve that, the NMP is adequate.

FIE argued reductions must be achieved over the lifetime of any plan but, under the NMP, the State will not reach 25-40 per cent reductions from 1990 levels by 2020 and will not even meet EU mandated requirements by 2020 despite having a legal requirement to do so.

Evidence shows that emissions will “barely fall” by 2030, he said.

FIE’s case was not that there is a legal requirement for Ireland to achieve 25-40 per cent reductions or that it must implement particular proposals.

Rather, FIE will show the NMP is not calculated to achieve substantial emission reductions in the short- or medium-term by 2020 and 2030 and that means unacceptable risk of contributing to global warming of 2 to 3 degrees and breach of the Constitution and European Court of Human Rights.

It is not lawful to retain in place a system that contributes to the strong risk of global warming, he said.

FIE rejected the State’s claim that the NMP is not justiciable and that the group is impermissibly advancing a “prescribed policy” and seeking to impose a positive obligation on the State to deliver that, counsel added. The group was not arguing public funds should be spent in a particular way, he said.

The case continues.