The global emphasis on sustainability has stimulated the demand for state-of-the-art solutions that drive the green and blue economy. However, the exponentially growing data analysis remains constrained, leading to a substantial disparity between data supply and demand. This discrepancy primarily arises from data being isolated, inaccessible, and infrequently shared due to concerns regarding data governance and privacy breaches. To tackle these challenges, we propose the integration of Peer-to-Peer (P2P) cross-ledgering within the Social Internet of Things (SIoT) framework as a promising approach to advance cognitive sustainability through improved information sharing and storage. The P2P network configured at the base facilitates a decentralized and secure exchange of information among diverse stakeholders involved in promoting sustainability. By leveraging the immutability and authorized accessibility of blockchain, consortia nodes evaluate and segregate data suitable for on-chain, off-chain, or one-to-one transactions. This ensures the safeguarding of sensitive data while enabling seamless collaboration and sharing. The integration of ledger systems enables interoperability across multiple platforms, fostering smooth information exchange between entities engaged in green and blue economy initiatives.