Toward Sustainable Supply Chains: The Spillover Effects of Customer Environmental Disclosure on Supplier Carbon Emissions

Supply chain decarbonization is essential for achieving corporate sustainability and broader climate goals, yet emission reduction across organizational boundaries remains difficult because lead firms and suppliers often operate under fragmented environmental information. Although environmental information disclosure (EID) is increasingly viewed as an important instrument for improving corporate transparency, existing research has primarily examined its consequences within firm boundaries, leaving its cross-organizational sustainability implications insufficiently understood. Drawing on signaling theory, this study examines whether customers’ environmental management disclosure is associated with upstream suppliers’ carbon emissions and conceptualizes the reduction of environmental information asymmetry as a key channel through which such disclosure may influence suppliers. Using a panel of 2213 supplier-year observations constructed from Chinese A-share listed firms from 2010 to 2022, we estimate fixed-effects panel regressions to examine the relationship between customer environmental disclosure and supplier carbon intensity. The results show that suppliers exposed to environmental information disclosure from at least one customer have approximately 10.95% lower estimated carbon emissions, while a one-point increase in the average environmental disclosure score of a supplier’s customer base is associated with approximately 2.96% lower estimated supplier carbon emissions. Further analyses show that disclosure strength does not significantly moderate this relationship, whereas the characteristics of disclosed information matter: positive environmental disclosure strengthens the negative association between customer disclosure and supplier carbon intensity, while negative disclosure weakens it. These findings extend research on environmental disclosure beyond the focal firm by documenting its association with environmental outcomes across supply chain relationships. They also suggest that customer disclosure may transmit clearer environmental signals, thereby contributing to more sustainable and resilient supply chains.