  The distributed consensus mechanism is the backbone of the rapidly developing
blockchain network. Blockchain platforms consume vast amounts of electricity
based on the current consensus mechanism of Proof of Work. Here, we point out
an advanced consensus mechanism named Proof of Stake that can eliminate the
extensive energy consumption of the current PoW-based blockchain. We
comprehensively elucidate the current and projected energy consumption and
carbon footprint of the PoW and PoS based Bitcoin and Ethereum blockchain
platforms.
