Amid pressure for climate action worldwide, processes of deliberative democracy are being called upon to address public policy complexities, include citizens in decisionmaking, restore faith in public institutions and enhance governance processes. The citizens’ assembly model is lauded internationally for the much-needed structure it provides to support bottom-up governance efforts as well as the potential for effective citizen engagement on complex topics. The Irish Citizens’ Assembly, which took place from 2016 to 2018, is heralded as an example of best practice in design and execution. Yet, there is a dearth in analysis of its form, structure, impact and content, particularly in the climate crisis context. This paper examines one element of the deliberative democracy process that aimed to include a wider breadth of publics beyond the 99 citizens randomly selected to take part: the public submissions invited as part of the Citizens’ Assembly process. In total, 1185 submissions were received on the topic of climate change. Our study undertakes a comprehensive content analysis of these submissions. Specifically, we explore (1) the content and concerns foregrounded within the submissions, (2) the frames and rhetorical strategies employed and (3) the stakeholders and scales called upon for climate action. The study identifies trends, preoccupations and salience within the corpus of written submissions and expands our understanding of citizen perceptions of climate science and policy. We offer both operational lessons for others aiming to enact similar deliberative forums as well as communications lessons for wider efforts to deepen public engagement on the climate crisis.