The Ethereum network, a leading blockchain platform for decentralized applications and smart contracts, has undergone significant transformations, particularly with the transition from Proof of Work (PoW) to Proof of Stake (PoS). This paper examines the sustainability challenges of Ethereum with a focus on its historical and current power consumption, associated carbon emissions, and broader economic implications. By critically analyzing Ethereum’s environmental footprint pre- and post-Merge, we assess whether the network’s shift to Proof of Stake constitutes a sustainable solution. Furthermore, we explore the trade-offs inherent in the decentrali- 498 ”Challenges of Digitalization in the Green Economy” Belgrade, October 30th, 2025 zation-efficiency paradigm and consider Ethereum’s position within the global movement toward greener technologies.