This study focuses on the science-policy interfaces established for knowledge producers and policymakers/planners to interact in policymaking and planning processes regarding climate change. The study claims that in order to develop effective policies/plans against the threat of climate change, it is necessary to create "co-production-based science-policy interfaces" in which knowledge producers and policymakers/planners produce knowledge, policy, and action together. The exploration is divided into two main parts. Primarily, the theoretical framework of the study in the context of the concepts of "knowledge", "scientific knowledge", and "science-policy interfaces" is presented. Afterward, to investigate the science-policy interfaces in practice, the results of the case study, which examines the Istanbul Development Agency (ISTKA) and the Izmir Development Agency (IZKA), are discussed. The findings of this study demonstrate that IZKA prioritizes climate change and creates effective science-policy interfaces regarding climate change-related issues, whereas ISTKA regards climate change only as a "co-benefit" within the other priority areas of the agency and, at least compared to IZKA, its activities on climate change focused science-policy interfaces are passive and insufficient.