Investigating consumer behaviour and environmental sustainability for the impact of CO2 emission disclosure on German online product purchases

This research explores the determinants and implications of sustainable consumption behaviour in the e-commerce sector in Germany using a mixed-methods approach. Grounded in the Theory of Planned Behaviour (TPB) and Environmental Psychology, the study examines how attitudes, subjective norms, and perceived behavioural control influence online shoppers’ sustainable purchasing decisions. Quantitative survey data and qualitative research insights indicate that despite positive attitudes and supportive social norms predicting sustainable intentions, actual behaviour is frequently impeded by insufficient information, increased costs, and perceived inconvenience. This research contributes to theoretical frameworks by integrating TPB and Environmental Psychology in an e-commerce context and offers practical recommendations for retailers to enhance sustainability practices. The paper has applied cross sectional online survey of German online shoppers by applying Spearman correlations, Kruskal–Wallis tests and multiple linear regression. The results show that education and household income drive consumers’ readiness to absorb a carbon price premium, while willingness to pay (WTP) a green premium peak with the moderate income bracket, clarifying which consumer segments are most receptive to carbon footprint disclosures. Policy implications highlight the need for regulatory support through eco-labeling and public awareness campaigns. This study provides conclusions for academics, practitioners, and policymakers aiming to promote environmental sustainability in the rapidly growing e-commerce sector.