The best available information on climate change projections is used here in conjunction with the observation-based conceptual site modeling framework that draws on the source-pathway-receptor-consequences approach, to conduct an impact assessment of future climatic hazards on the Panchang Bedena landfill in Selangor, Malaysia. Climate change impact assessment of landfills is currently limited by the reliability of downscaled models and inadequate information on such sites. Using the worst-case scenario where the submerged landfill is recognized as the source of contaminated water and material, surface runoff from the facility is identified as the prominent pathway for transport of pollutants, while subsurface migration is restrained by the impermeable underlying material. Receptors include the nearby settlement, agricultural land, and coastal ecosystem. The adverse consequences expected relate to the health and well-being of surrounding communities, damage of built assets, degradation of mangrove habitat, and long-term productivity loss for the agricultural sector. The findings provide a useful starting point to engage stakeholders, specifically the affected communities and government authorities, to identify adaptation options, including detailed investigations to improve the conceptual site model, monitoring, and early warning, depending on the availability of resources. The approach lays the foundation for future work to make landfills climate-resilient, specifically in developing countries with paucity of information on landfills, unreliable downscaled climate projections, and resource limitation for conducting an intensive conventional scientific investigation.