It is commonly argued that, despite the tremendous resonance Citizen Science (CS) has shown in recent years, there is still lack of understanding of important aspects defining citizens’ participation and engagement in CS initiatives. While CS initiatives could provide a vehicle to foster forms of participation contributing to the democratization of science, there is still limited attention paid to the “Citizen” component of the Citizen Science term. For the purpose of this work, we systematically reviewed the available literature for empirical studies in respect to citizens’ participation in environmental and nature-based CS initiatives established during the last two decades, using the PRISMA methodology. The participatory facet of the retrieved 119 CS initiatives was analysed on the basis of: (a) exclusion and inclusion demographic factors, (b) CS models and practices, (c) facilitators and constraints of citizen’s participation, and (d) environmental citizenship. Our findings show that the majority of the CS initiatives did not place restrictions on gender participation; however, we have identified that mostly highly educated adults participated in the reviewed initiatives. In addition, most of the CS initiatives reported in the literature were situated in the EU and USA, were mostly limited to the local scale, and primarily followed the contributory model. Academic institutions were found to coordinate the majority of the CS initiatives examined. By using digital technologies, academic scientists were able to control and increase data quality, as well as to engage a broader audience, even though they were mostly treating volunteers as “data collectors”, desiring their long-term engagement. Therefore, it will be of CS benefit to be better aligned with the mentality and needs of citizens. In this direction CS initiatives should trigger citizens’ learning gains and interpersonal/social benefits and personal, environmental, and social motivations, but also to shift their goals towards contributing to science and citizens’ connection with nature. On the other hand, there is a need to overcome any design and implementation barriers, and to enhance democratization through a more participative engagement of active and aware citizens, thus promoting environmental citizenship.

Environmental Citizen Science (CS) initiatives have been recognized over time as a promising way to engage citizens in the investigation and management of various socio-ecological issues. In this context, it has been often hypothesized that these CS initiatives may also contribute to the education and subsequent transformation of citizens into environmentally aware and active citizens. However, the potential of CS to serve as a springboard for supporting Education for Environmental Citizenship (EEC) has not been explored yet. A systematic review was conducted, seeking to examine how citizens’ participation in environmental CS initiatives contributes to the EEC, as a venue through which citizens can undertake actions in different scales (local, national, global) to achieve environmental citizenship. A content analysis procedure was implemented on thirty-one empirical studies (n = 31) retrieved from a systematic review of the literature covering the timespan of the last two decades (2000–2020), according to the PRISMA methodology. The findings indicated that the majority of the reviewed environmental CS initiatives primarily enhanced citizens’ skills and knowledge over the competences of attitudes, values, and behaviors. In addition, it was found that CS initiatives empowered primarily citizens’ personal and responsible environmental actions, which were situated in the private sphere and at the local scale. The derived environmental outcomes were mainly related to the solution and prevention of environmental problems. Finally, correlational statistical analysis indicated that there were strong correlations between the Environmental Citizenship (EC) competences, actions and EEC outcomes and unveiled a set of keystone components; namely, components of crucial significance in the field of EC. We reflect on these findings, and we discuss directions for future research.

During the last decade, many cities worldwide have implemented various green policies; in this way, they have gradually transformed into “green cities”. The emergence of green cities may provide a promising venue to address cities’ environmental degradation and citizens’ disengagement with current socio-environmental issues, thus giving rise to the notion of Environmental Citizenship (EC). Despite these assumptions, empirical research on the topic is currently emerging. In this study, we examine citizens’ engagement in green cities and its interrelatedness with EC through a systematic literature review. The selected empirical studies (n = 25) were published in peer-reviewed journals during the timespan of the last 12 years (2010–2021). In total, 31 green cities were analyzed in the 25 selected empirical studies. Thematic and frequency analysis revealed that green cities encourage citizens’ engagement with the implemented green policies, while also advancing citizens’ EC. Furthermore, correlational analysis between citizens’ engagement and the Education for Environmental Citizenship (EEC) model revealed that citizens’ engagement with the implemented green policies fosters citizens’ knowledge, skills, attitudes, values, and behaviors, fueling the undertaking of various EC actions. Importantly, green cities have also proved successful in achieving EC’s outcomes leading to sustainability.

As the global environmental crisis intensifies, there has been a significant interest in behavior change games (BCGs), as a viable venue to empower players’ pro-environmentalism. This pro-environmental empowerment is well-aligned with the notion of environmental citizenship (EC), which aims at transforming citizens into “environmental agents of change”, seeking to achieve more sustainable lifestyles. Despite these arguments, studies in this area are thinly spread and fragmented across various research domains. This article is grounded on a systematic review of empirical articles on BCGs for EC covering a time span of fifteen years and published in peer-reviewed journals and conference proceedings, in order to provide an understanding of the scope of empirical research in the field. In total, 44 articles were reviewed to shed light on their methodological underpinnings, the gaming elements and the persuasive strategies of the deployed BCGs, the EC actions facilitated by the BCGs, and the impact of BCGs on players’ EC competences. Our findings indicate that while BCGs seem to promote pro-environmental knowledge and attitudes, such an assertion is not fully warranted for pro-environmental behaviors. We reflect on our findings and provide future research directions to push forward the field of BCGs for EC.

Environmental Citizen Science (CS) initiatives are argued to provide a promising vehicle for involving citizens in the investigation of various socio-environmental issues. However, environmental CS initiatives have often been criticized for merely focusing on the achievement of their scientific goals and outcomes (science-oriented), rather than on empowering and transforming the participants into ‘environmental citizens’ (citizen-oriented). This study adopts a meta-synthesis approach to synthesize evidence from three recent systematic reviews, seeking to extract a set of design principles for the development of an integrated theoretical framework enabling Environmental Citizenship (EC) in environmental CS initiatives. The proposed framework lies on the intersection of three main research areas: (a) Participation in CS, (b) Pedagogy in CS, and (c) Education for Environmental Citizenship. Grounded on the conjunction of the aforementioned areas, the Citizen Science for Environmental Citizenship (CS4EC) framework puts forward the transformative capacity and the participatory learning aspects of environmental CS initiatives. Overall, the proposed framework lays the foundations for the design of environmental CS initiatives capable for the empowerment and transformation of citizens into ‘environmental agents of change’.