NGOs and enforcement of EU environmental law: the case of ClientEarth

Poor implementation of environmental policy is a persistent global challenge. Within the European Union, we witness a trend towards increased ‘decentralized enforcement’, with the Commission initiating fewer infringement procedures, and relying more on domestic actors to bring litigation to the national courts. NGOs are thus increasingly becoming key actors in the enforcement of EU environmental law; however, we know little about how NGOs act when deciding how to push for enforcement. This paper systematically examines how one NGO – ClientEarth – acts on infringements within EU environmental policy from 2015–2025, mapping patterns in its use of complaints to the Commission and litigation across time. The findings illustrate that ClientEarth experiences an increased threshold for NGO involvement in complaints, as well as a further politicization of the infringement procedure, reducing the consistency of enforcement of EU environmental law.