The rapid emergence of Non-Fungible Tokens (NFTs) has brought innovation and concerns to the consumer digital world. To promote green energy adoption and to combat environmental impact caused by carbon emission, it is essential to address the growing scrutiny of blockchain-based activities, particularly NFTs, for their energy consumption. Aligning technological advancements with environmental sustainability has therefore become an urgent priority. This paper proposes a blockchain-based Sustainable NFT framework that tokenizes verified carbon offsets using ERC-721 NFTs on the Ethereum blockchain. The framework enables the tokenization of carbon offset credits while linking NFT transactions to verifiable reductions in carbon emissions. This approach ensures that every NFT transaction mitigates its carbon footprint by funding renewable energy projects, reforestation initiatives, or other emission-reduction efforts. By providing a transparent mechanism for measuring environmental impact, Sustainable NFTs actively engage digital creators, collectors, and platforms in combating climate change. Smart contracts enforce carbon offset participation, establishing a consumer NFT marketplace dedicated to sustainable practices and introducing strategies to incentivize user participation in the minting, trading, and retirement of carbon offsets. The significance of this research lies in its potential to transform the NFT ecosystem from an environmental liability into a force for positive change. By encouraging sustainable practices and renewable energy investments within the consumer digital art community, Sustainable NFTs aim to reduce carbon emissions and foster a more responsible digital economy. Finally, the performance of the proposed framework is evaluated using Hyperledger Caliper under varying transaction loads to demonstrate the efficiency and effectiveness of the model.