The environmental history of Quebec highlights the major role of civil society actors in identifying, demanding and implementing the major changes that are needed. In particular, an examination of mobilizations over the last few decades shows the importance of the co-construction of knowledge, social dialogue and the experience of concerted action to promote the development of citizen power to contribute to the transformation of socio-ecological realities. In the context of this dynamic, this article presents the foundations and the progress of a large-scale social movement which, for several years now, has taken up the climate issue.