Bridging the gap between awareness and action on environmental issues such as climate change often requires understanding the moderating roles of individual trust, institutional trust and civic engagement. This paper explores how social capital, through generalaised trust, trust in institutions and civic engagement, can either strengthen or weaken the agency on climate change on environmental behaviour. Linking climate change awareness to environmental behaviour through the mediation of perceived changes in quality of life is the chosen approach to explore the role of social capital. The results suggest that low levels of trust, whether interpersonal or institutional, reduce an individual's sense of agency by firstly reducing the impact of climate change awareness on quality of life, changing perceptions and consequently reducing environmental behaviour. Greater trust in institutions produces a stronger effect of climate change awareness on willingness to pay. On the other hand, civic engagement shows a significant effect when taxes are considered. The study suggests that the impact of social capital on environmental payments varies according to the type of payment (voluntary vs. mandatory). The mapping of the role of social capital in reducing the agency of climate change awareness in quality‐of‐life changes should be further explored, as the latter has proven to be a promising way to address climate change in developed and developing countries.