AbstractThe parties to the Aarhus Convention recently established a new Rapid Response Mechanism for environmental defenders. This article analyses this mechanism and its guarantees for environmental defenders, with a specific focus on the protection of diverse forms of climate activism. The Convention's Compliance Committee has taken a broad approach towards the definition of ‘environmental defenders’ protected by Article 3(8) of the Convention. This definition includes persons who engage in demonstrations or rallies connected to environmental issues, even if there is no immediate link to the rights provided by the Aarhus Convention. In some cases, direct actions and acts of civil disobedience may fall under Article 3(8) of the Convention. Where environmental defenders suffer harmful acts such as penalization, harassment or persecution either by State authorities or private parties, the State concerned must produce evidence to show that these harmful acts were not a response to the civic engagement of the environmental defenders concerned. If environmental defenders are victims of harmful acts in the sense of Article 3(8) of the Aarhus Convention, they may address the Special Rapporteur who can swiftly issue protection measures. This could be especially relevant for detained persons, persons under police supervision or activists who undergo systematic harassment by the police or private security forces. In these cases, the Special Rapporteur may intervene and use their unique position on the international plane to ensure that environmental defenders do not suffer due to their engagement for the environment.