A5: Court decision shows reach of the climate change act 2022

The High Court judgement blocking the upgrade of the A5 road shows the reach and impact of Stormont's climate change legislation.

It has implications not just for the A5 but for other road projects and possibly wider areas of Stormont policy, such as agriculture.

It means that when ministers are proposing big construction projects they will need to clearly show how they comply with climate laws.

It does not mean the A5 upgrade is dead. The judgement is clear that shortcomings in the project can be remedied.

However, it may mean the scope of the upgrade has to be revised or that trade-offs will have to be made with other schemes being cancelled or curtailed.

The roads expert Wesley Johnston has suggested that it is "likely to take years rather than months" to assemble the technical evidence to support the scheme in anything like its current form.

The Assembly passed the Climate Change Act in 2022, legally committing Northern Ireland to achieving net-zero greenhouse gas emissions by 2050, with other binding targets along the way.

It is an ambitious policy which has major implications stretching into all areas of the economy and society.

The Act puts legal duties on Stormont departments to publish targets for cutting greenhouse gas emissions in their area of responsibility and plans for how they will get there.

Implementation got off to a slow start as devolved government was effectively suspended between 2022 and 2024 when the DUP walked out in protest at NI's Brexit deal.

Central to the implementation of the Act is Section 52 which requires Stormont departments to hit their own targets and cooperate to reach the overall net-zero goal.

In his judgement Mr Justice McAlinden ruled that the Department for Infrastructure was in breach of Section 52 as it had failed to produce the evidence to show that upgrading the A5 would be consistent with overall climate targets.

He found the department had instead made "aspirational assumptions".

He said: "Section 52 does not prevent a major infrastructure project which is a source of significant greenhouse gas emissions being devised, promoted, constructed and put into operation.

"But what it does clearly rule out is the construction and operation of such a major project in the absence of robust planning, synchronisation and co-ordination between all NI government departments to ensure that the project fits into the plans, strategies and policies which map out a realistic and achievable pathway to achieving net zero by 2050."

In those words the judge throws down two challenges to how the Executive conducts its business.

It means that implementing the climate change law is going to require greater coordination between departments.

It also suggests that ministers will have to be more explicit about the trade-offs which will be necessary to reach the net-zero goal.