Using Participatory Action Research (PAR), the research presented here sought to resolve the problematic of whether climate group-initiated legislation could stimulate effective policy action on climate change. In late 2006, Australian public concern about the impacts of climate change and the Federal Government’s weak response became more pronounced due to increased media coverage and international developments. Locally based citizens’ ‘climate groups’ began to form, including Climate Action Coogee (CAC) in Sydney. CAC wrote their own Australian Climate Protection Bill after being motivated by the UK’s grassroots success in developing and promoting the UK Climate Change Bill. This article documents 10 months of the project, from inception to widespread grassroots endorsement and political awareness of the Bill. The use of PAR processes tested and further developed the theory of double-loop learning and its applicability to such a project. These processes allowed CAC coparticipants to experience a transformation in their agency through developing their personal and collective political power. The project contributed to legislative outcomes on climate change. The findings contribute to academic literature by demonstrating the effectiveness of PAR in guiding social movement campaigns.