Sea level rise (SLR) is a global concern under climate change. Understanding how SLR is discussed, depicted, and framed helps urban management and public governance make more informed decisions towards climate actions and communicate more effectively. A multimodal dataset of tweets containing visuals and texts is collected, mapped, and analysed with multimodal topic modelling. It shows that SLR discussion mainly concentrates on coastal cities from the West and that complex themes are brought to the spotlight, including but not limited to risks, actions, and doubtful objections. The framework can be extended for other climate impacts, informative for climate-responsive urban management.