‘Not Prohibitively Expensive’ Under the Aarhus Convention Article 9(4)

This article explores the obligation of State Parties to the Aarhus Convention, under Article 9(4), to ensure that costs for accessing justice are ‘not prohibitively expensive’. The analysis reveals that this criterion has two sides. Firstly, the level of costs must not be excessive, both in relation to the dispute and object at hand and in relation to the financial resources and what is at stake for a complainant. Secondly, the rules and framework for imposing legal costs must not be unforeseeable. The threshold for costs being prohibitive is when the costs are so excessive or unforeseeable that they will be dissuasive for environmental defenders seeking access to justice. In practice, problems have particularly arisen in regard to ‘loser pays’ systems, which combine high potential costs with low foreseeability. Such systems are permissible but should have limits on the level of imposable costs and on the judicial discretion that can be exercised.