Last September, the High Court dismissed judicial review proceedings brought by Friends of the Irish Environment (FIE) against the plan.
The group argues that pursuing the plan involves actions that breach fundamental rights under the Irish Constitution and the European Convention of Human Rights.
The Supreme Court says the case raises a number of issues of general public importance, as well as a number of legal points of general public importance.
These include whether such a plan is a matter for the courts to decide on, as well as the broader environmental rights asserted by Friends of the Environment.
The higher court says there is no dispute between the parties over the facts or the science of the issue, and all agree that Irish emissions are set to increase significantly over the plan’s lifetime – 2017 to 2022.
The case centres on whether the government is entitled to adopt a plan that will lead to increased greenhouse gas emissions in a situation where it has been warned that this will lead to serious environmental impacts and fundamental rights breaches.
Friends of the Environment argues that the agreed science makes it clear that any delay in achieving substantial reductions in emissions “increases the risks of severe climate-related harms”.
But the government says the plan is not a matter for the courts and that it is entitled to postpone cutting emissions to some point in the future.
Granting leave to appeal, the Supreme Court said that, as both parties broadly agreed on the science underpinning the plan, it was unlikely that a hearing before the Court of Appeal would further refine any questions of law or factual issues.
FIE is a non-profit company set up to provide a formal structure for a network of environmental activists. Its main source of funding is the Department of Communications, Climate Action and the Environment's Environment Fund.