In recent decades, co-production has become a cornerstone both in science and policy-making, motivating further collaboration between different actors. To scrutinize such participatory processes within the climate and energy fields, we conducted a critical systematic review of 183 records, which includes scientific publications, but also other initiatives coming from the public administration or the non-profit sector. First, we unpack six aspects of co-production: (1) the different levels of participation; (2) the emerging topics and issues; (3) the scale and location at which initiatives are conducted; (4) the actors who take part in the processes; (5) the different methods and tools for participation and (6) the outcomes and transformational potential of the initiatives. Our results show that real co-production is still far from being mainstream, with consultation still accounting for a majority of initiatives. Themes remain focused on the mitigation sphere, a tendency related to a majority of the records happening in developed countries. However, we also observe new categories of actors challenging traditional decision-making, as well as emerging methods and tools opening the space for more social innovation and participation. Following, in our critical analysis, we argue that there is a crucial need for a better interconnection between science and policy (especially at national and international scales) and that a reflection on transformation is fundamental when planning any participatory initiative. We finally claim that, despite not being a silver bullet, meaningful citizen participation constitutes a viable alternative to tackle today's complex problems. © 2020

The PARIS REINFORCE project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 820846. We would like to acknowledge Mikel Gonz?lez, Dirk van de Ven and Jorge Moreno from the Basque Centre for Climate Change (BC3) and the PARIS REINFORCE consortium. The PARIS REINFORCE project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 820846.