Scholars and international agencies have raised alarms about the irreversible destruction of natural habitats, emphasizing the urgent need for action to preserve healthy ecosystems. A promising approach to enhancing pro-environmental behavior and improving human well-being is fostering human-nature connectedness. However, the factors that mediate this relationship remain underexplored and mostly focused on industrialized countries. This study addresses this gap by examining three potential mediators of pro-environmental behavior in populations across various world regions: 1) adolescent exposure to nature, 2) perceived environmental landscape changes, and 3) eco-anxiety. We conducted an online survey involving 222 adults from Africa, Europe, the Americas, and Asia, focusing on nature connectedness, eco-anxiety, pro-environmental behavior dispositions, perceptions of landscape changes, and adolescent experiences with community volunteering. Our analysis revealed that adolescent exposure to nature, particularly through environmental activities and community service, is positively correlated with adult nature connectedness. Additionally, perceived landscape changes are linked to increased eco-anxiety. Multiple regression analysis verified that both nature connectedness and eco-anxiety predict pro-environmental behavior. Encouraging community and environmental volunteering from childhood can thus strengthen connections to nature and enhance resilience against eco-anxiety, ultimately fostering greater pro-environmental awareness and action.