## 6 Criticism and Debates
### Environmental Considerations  
The greatest controversy surrounding crypto collectibles is the energy consumption associated with the Ethereum blockchain, where most NFTs are being traded, which is indeed substantial. As of May 2021, Ethereum's energy consumption is estimated at 48.7 Tera-Watt Hours (TWh) per annum, which equals to the annual energy consumption of Malta [117]. As a result, NFTs have attracted severe criticism from environmentalists [118]. \"NFTs are helping to destroy our planet\" [11], argues Art Newspaper's columnist [PERSON], adding that Beeple's record auction of \"5000 Everydays\" produced 79 kg of CO\({}_{2}\) emissions, equalling those of 13 homes in a year combined [11]. NFTs, however, are merely a smart contract protocol and one that can be implemented on any blockchain; hence, they are not exclusively tied to the Ethereum blockchain; Ethereum just happens to be the blockchain where NFTs were first introduced and is currently the most developed and widely adopted blockchain at present [119] in comparison to other more energy-efficient blockchains. Secondly, a systematic effort is being made for Ethereum itself to eliminate its carbon footprint [120]. Such indications make us hopeful for the future of NFTs. Fierce critics of NFTs, however, argue that the energy consumption issues of NFTs will not be resolved anytime soon [121]. They consider Ethereum's multi-year attempt to change its transaction validation method from the energy-consuming Proof-of-Work (PoW) method with the energy-efficient Proof-of-Stake (PoS) method as a \"running joke\" [121]. Making such a fundamental change on a blockchain, whose daily transactions exceed 1 million USD [122], would require a long and monumental effort and indeed, it may prove impossible eventually. However, as explained earlier, Ethereum has repeatedly pushed the boundaries of what is possible when it comes to decentralised technologies, so they may also succeed in moving to the PoS method, which would reduce the blockchain's carbon emissions by 99% [120] and automatically reduce to the minimum the carbon footprint of all NFT-related trade. Beyond Ethereum, energy-efficient NFTs already exist and are being traded as normal. The NFT of the Whitworth Gallery mentioned above is registered and traded on the energy-efficient Tezos blockchain. There are also numerous other blockchains that also utilise the Proof-of-Stake method for transaction verification, like Cardano [123] and Algorand [44], whose \"electricity costs are comparable to using traditional servers in a centralized application\" [124]. In addition, Cardano, a project driven by academic research, will fully launch at the end of summer 2021 [125]. Cardano claims to be \"The Most Environmentally Sustainable Blockchain Protocol\" [123] due to its pioneering, peer-reviewed Proof-of-Stake implementation, whilst its capabilities for scalability, interoperability and sustainability make it a contender for challenging Ethereum's dominance [126]. Interestingly, the energy-efficient Proof-of-Stake method has also attracted criticism from environmentalists. PoS blockchains have been accused that they \"grant power to the already powerful\" (we note that according to the PoS method, the more coins a node operator holds, the more transactions they are allowed to verify with their coins being held as collateral) and \"that [this] is _also_ a climate issue\", because \"climate justice is social justice\" [121]. At that point, it is deemed necessary to explore the broader context and the alternatives available. Museums and galleries are continuously looking for ways to raise funds [9; 27]; if they were not fundraising with NFTs, they would be fundraising through current means, i.e., our financial system. The latter's carbon footprint has yet to be estimated to allow for a direct comparison.