Resumen
This review explores the current evidence on the role and success factors of grassroots initiatives in sustainability transitions, with special attention given to social innovations and the transformation of urban food systems, a field that is still rather scantly dealt with in literature compared to technological innovations in other sectors such as energy. In addition to their contributions to get the necessary transformation towards sustainable futures off the ground, the preconditions for grassroots initiatives to thrive are presented?as well as limitations regarding their possibilities and the challenges they face. Increasingly, the importance of civil society and social movements in facilitating societal transformation is recognized by both researchers and policy makers. Within their radical niches, grassroots initiatives do not have to adhere to the logics of the wider systems in which they are embedded. This allows them to experiment with diverse solutions to sustainability challenges such as local food security and sovereignty. By means of democratic, inclusive and participatory processes, they create new pathways and pilot a change of course. Nevertheless, upscaling often comes at the loss of the transformative potential of grassroots initiatives.