National laws and regulations introduced by state actors are unlikely to be sufficient to meet the emission targets set in the Paris Climate Agreement. Voluntary climate activities by non-state and individual actors can help to close this gap. While previous studies have focused on the role of state and individual actors, NostaClimate explicitly examines the role of non-state actors and their interactions with state and individual actors. Non-state actors include civil society groups (e.g. churches, non-governmental organizations), economic actors (e.g. firms, trade unions), and subnational and local actors (e.g. municipalities). For the mitigation of greenhouse gas emissions, non-state actors can in principle act through the following mechanisms: (i) Own climate protection activities, (ii) an increase of the acceptance of climate policies and climate protection activities among individual actors, or (iii) monitoring the compliance with climate protection objectives of other actors. The potential influences differ strongly between different non-state actors. As an overarching goal, NostaClimate examines the possible influences of different non-state actors through the three mechanisms, with a particular focus on the interactions between non-state and individual actors. The project consists of eight work packages (WP).