Climate Briefing
Sep 6, 2025
The Aarhus Convention
A. High Level Summary
A1 The Aarhus Convention (“Aarhus”) is not EU law. The United Nations Economic Commission for Europe (UNECE) was set up in 1947 and is one of five regional commissions of the United Nations. Aarhus is the UNECE Convention on Access to Information, Public Participation in Decision-Making and Access to Justice in Environmental Matters.
A2 The UK signed the Aarhus Convention on 25 June 1998 at Aarhus, Denmark, when the treaty was first opened for signature. After adjustments to the UK and relevant EU laws, the Convention entered into force for the UK on 25 June 2005.
A3 Kofi Annan is quoted as saying Aarhus is “the most ambitious venture in the area of environmental democracy so far undertaken under the auspices of the United Nations”. Michael Meacher, then UK Environment secretary said Aarhus “is an important instrument which does as much for human rights as it does for creating a framework for achieving sustainable development. It deserves our strong support”.
A4 Aarhus is very wide ranging and based upon building strong environmental democracy by embedding procedural rights: public access to environmental information, public participation in planning and decision-making, and access to judicial review. The vision is that by giving citizens these procedural rights, decisions about the environment (which often involve public goods, competing interests, long time-scales) gain legitimacy, public trust, and awareness.
A5 Aarhus guarantees the public three basic rights: to know, to participate, and to challenge in the making of policy and planning decisions which impact the environment. The previous Government confirmed the UK’s commitment to respect, protect and fulfil the rights in Aarhus was not changed by Brexit.
B. Is the UK now considering exiting from Aarhus?
B1 There has been recent press speculation that the Government is discussing leaving the Aarhus convention as a means to remove the ability for environmental groups to take legal action on planning decisions for large infrastructure projects eg Heathrow’s third runway.
B2 The reason given for such a step would be to remove the ability for environmental groups access to Judicial Review on large infrastructure projects. Under Aarhus the legal costs for environmental claimants is capped to provide access to justice, as enshrined under Aarhus. Adverse costs (for example the legal fees of the Government) are capped at £5,000 for in individual or £10,000 for a group like an NGO.
B3 Any approach which weakens the public’s access to environmental Judicial Review removes important rights and risks silencing people and undermining public trust in decision making. However, leaving Aarhus - a major environmental agreement - in an attempt to resolve perceived issues in the UK Planning system, would be disproportionate and take-away many other vital environmental rights.
C. Disproportionate Impacts if the UK exited Aarhus
C1 Aarhus protects environmental defenders and requires that people exercising these rights are not penalised, persecuted, or harassed. In other words: it safeguards the right to protest. Leaving Aarhus would further strip away those protections — at a time when the government is already tightening restrictions on peaceful protest.
C2 Freedom of information and transparency would also be gutted. If the UK walks away from Aarhus, the UK’s Environmental Information Regulations — which are stronger than our domestic Freedom of Information will fall. That would severely reduce the public’s ability to access vital environmental information affecting their lives.
C3 Public scrutiny of policy decisions affecting the environment would be lost. Leaving Aarhus would not just affect planning disputes but every environmental public law case. Landmark wins against the government’s unlawful Climate plans — the Net Zero Strategy and the Carbon Budget Delivery Plan — only happened because ClientEarth, Friends of the Earth and the Good Law Project could rely on Aarhus cost capping. Those cases exposed how ministers had set target carbon budgets with no idea if the numbers added up, and with no risk assessment of whether policies would deliver - ie the plan amounted to being no plan at all. They forced the government to produce a more coherent climate policy and plan which Labour inherited. Without Aarhus, those challenges would never have reached court.
More recently a legal challenge by Scrap Carbon Capture forced ministers to review their Industrial Strategy because their environmental assessment was so poor it was unlikely to have survived judicial review. This was the first time the Environment Act was used to make the government retake a policy decision against the duty to give due regard to environmental principles under the Act — a vital precedent.
D. Summary
Withdrawing from Aarhus would
amount to the UK regressing on a very significant tranche of environmental rights for the UK public. Public engagement, and transparency and accountability of ministerial decision making, would be lost across policy and planning decisions. Numerous examples show how Aarhus has worked to help better decisions being made since the UK signed the Aarhus Convention.
further reduce hard-won rights to protest.
potentially lead to UK exit on other international rights law, such as the ECHR.
E. CALLS FOR ACTION
E1 Please sign the EDM for the UK to stay in the Aarhus convention.