The role of environmental knowledge, subjective norms, perceived behavioral control, and institutional support in social media advocacy for geoscience-informed sustainability practices

With the rise of the digital age, social media platforms have been utilized for a wide range of purposes; however, their potential for advancing geoscience-informed sustainability initiatives remains underexplored across many contexts. While these platforms have become essential tools for engaging younger demographics, particularly university students, sustainability advocacy through social media, ranging from passive behaviors such as liking, sharing, or reposting sustainability-related content to more active engagements like creating original posts, initiating discussions, or organizing online campaigns, has not been adequately investigated. This study therefore examines the influence of environmental knowledge, subjective norms, perceived behavioral control, and institutional support on social media advocacy for sustainability among undergraduates using the Theory of Planned Behavior (TPB) as a framework. This study employed a cross-sectional survey design and collected data from 528 undergraduate students across two colleges at the Lagos State University of Education. Using structural equation modelling, the relationships between the TPB constructs and sustainability behaviors were analysed, with additional tests for the moderating effects of the predictors on the intention‒behavior relationship. The results revealed that the TPB model explains 69% of the variance in social media advocacy for sustainability behavior (R² = 0.69). Environmental knowledge (β = 0.31, p < 0.001), perceived behavioral control (β = 0.29, p < 0.001), subjective norms (β = 0.20, p < 0.001), and institutional support (β = 0.25, p < 0.001) emerged as significant predictors of advocacy behavior. However, their moderating effects on the intention‒behavior relationship were not statistically significant. These findings confirm the robustness of the TPB framework in understanding sustainability advocacy behaviors while highlighting the need for an expanded model to capture digital-specific constructs such as habitual online behaviors and emotional engagement. The findings imply that embedding sustainability education into curricula, encouraging peer-led engagement, and harnessing institutional resources are critical for strengthening sustainability advocacy through social media.