Participatory modeling aims to incorporate stakeholders into the process of developing models for the purpose of eliciting information, appropriately reflecting stakeholder interests and concerns, and improving stakeholder understanding, and acceptance of the analysis. Participatory modeling, using causal loop diagramming (CLD), was used to explore the impact of climate change on public health in Long Beach, California. CLD, commonly used in participatory modeling, provided useful information to serve as the basis for a quantitative system dynamics model to protect the citizens of Long Beach, and potentially other cities or regions affected by climate change. Diverse stakeholders constructed CLDs depicting the impacts of climate change on public health in Long Beach. This exercise aimed to (1) identify public health issues that might be caused or exacerbated by climate change; (2) examine the systemic connections between climate change and other drivers of public health/illness and mortality; and (3) identify feedback loops to gain an understanding of how climate change could impact public health over coming decades. Six groups of five stakeholders were tasked with depicting the impacts of climate change on public health. Each group designated a key health outcome of concern on a citywide scale, including critical drivers of the outcome at higher and lower scales if necessary (for example, state laws, or household-level decisions that affect health outcomes in the aggregate). Social, environmental, political, and economic variables were all considered. After the small group diagramming exercise, groups presented diagram results to other participants, and the discussion around the diagrams was recorded.