UK Government's Failure to Consider Its 2015 Paris Agreement Commitment Delays Heathrow Airport Expansion

On February 27, 2020, the English Court of Appeal unanimously declared that the UK Government's Airports National Policy Statement ("ANPS") is unlawful due to a failure to take into account the Government's own separate policy commitment to the provisions of the 2015 Paris Agreement on climate change ("Paris Agreement"), reversing the decision of the lower court. R. (on the application of Plan B Earth and others) v. Secretary of State for Transport, [2020] EWCA Civ 214. As a result, the expansion of Heathrow Airport—estimated to cost £14 billion—has been delayed.

The Government's policy of expansion at Heathrow Airport, announced in 2016, sought to increase airport capacity by designating a new third runway. The ANPS, adopted in 2018, set out the planning policy framework with which an applicant for the runway would have to comply for the Secretary of State to grant formal development consent.

The claimants—including five local authorities near the airport—sought relief on a number of grounds due to concerns that an additional runway would encourage more air travel and in turn increase carbon emissions. What ultimately proved fatal to the Government's case on appeal was that it had failed to fully comply with the statutory regime for the formulation of the ANPS. In particular, the Government failed to comply with the provision in section 5(8) of the Planning Act 2008, which states that a National Policy Statement "must … include an explanation of how the policy set out in the statement takes account of Government policy relating to the mitigation of, and adaptation to, climate change." The ANPS was unlawful because it failed to consider the Government's commitment to the provisions of the Paris Agreement, which was ratified by the United Kingdom in November 2016 and had been subject to firm statements by relevant Ministers, reiterating Government policy of adherence to that agreement.

The Paris Agreement ought to have been considered by the Secretary of State in the preparation of the ANPS, and an explanation given as to how it was considered, but this did not happen. In fact, the Secretary of State had received legal advice that, not only did he not have to take the Paris Agreement into account, but that he was legally obliged not to take it into account at all. This failure meant the ANPS in its present form was unlawful and so must be subject to a statutory review under the Planning Act 2008 to consider the climate change policy. The initiation, scope, and timescale of any review will be a matter for the Secretary of State to decide. The court also explained that the duty in section 5(8) does not require the Government to conform to its own policy commitments, "simply to take them into account and explain how it has done so."

Accordingly, the court's decision does not itself prohibit the additional runway on climate change grounds. The court did not have to decide whether the ANPS was inconsistent with the Paris Agreement, so the decision is not directly about how to resolve any potential policy conflict. The court confirmed this, stating:

We have not decided, and could not decide, that there will be no third runway at Heathrow. We have not found that a national policy statement supporting this project is necessarily incompatible with the United Kingdom's commitment to reducing carbon emissions and mitigating climate change under the Paris Agreement, or with any other policy the Government may adopt or international obligation it may undertake. The consequence of our decision is that the Government will now have the opportunity to reconsider the ANPS in accordance with the clear statutory requirements that Parliament has imposed.

Heathrow Airport has said it will challenge the court's decision at the Supreme Court, but the UK Government has said it will not.

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