These difficult puzzles can only be solved by computers – if they were easy to solve, the blockchain would be more vulnerable. Consequently, it requires a great deal of computing energy to solve these puzzles. To reduce the amount of heat that its data centers generate and to reduce energy costs, some of Microsoft’s data centers have been submerged underwater.
A portion of the gas fee people pay when minting or buying an NFT goes to that energy cost. For an Ethereum transaction that costs about $100 in gas, maybe about $40 goes to energy, one NFT expert speaking on background told me. Compare that cost to your monthly energy bill — $40 could cover my actual gas bill for two months.
Others calculate NFT energy consumption using different measurements. Andrew Bonneau, carbon markets advisor at Offsetra, a group focused on promoting sustainability in tech, looked at multiple NFT transactions to calculate that minting one uses between 90 and 150 kilograms of CO2. That’s about how much CO2 a Boeing aircraft emits per hour, according to CarbonIndependent.org. Memo Akten, an artist who works with emerging technologies, analyzed 18,000 NFTs back in January. He came up with an average carbon footprint of about 250 kilograms per NFT — a figure that should ring alarm bells.
What do these calculations mean?
There’s debate about how to contextualize these calculations. Joseph Pallant, founder and executive director of the Blockchain for Climate Foundation, started researching NFTs as a way for countries to start implementing Article Six of the Paris Agreement once negotiations around it are complete. “Minting an NFT doesn’t directly cause a carbon emission, because the Ethereum blockchain is running all the time,” Pallant says.
In other words, Ethereum miners would be adding new blocks to the chain whether or not your NFT transaction is part of that block, both because of constant crypto transactions and because miners are incentivized to create new blocks. They get rewards in the form of cryptocurrency for every block they create, plus a portion of the transaction fees from the transactions included in each of those blocks.
In other words, the NFT itself doesn’t expend energy; operating the blockchain does. It’s like deciding to take an international flight—if you don’t get on the plane, it’s still going to take off and burn the same amount of energy it would if you’d boarded.
Others consider this rationale a copout. “This is really like saying, whether you order a steak or not, the animal’s already dead,” says Akten. Whereas, by not eating meat, you’re opting out of an environmentally detrimental industry and eventually creating less demand for its products.
Still, Akten adds, “it would be inaccurate to say that NFTs are destroying the planet.” Compared to, say, fossil fuels or the beef industry, they’re not. And while the Ethereum network overall may account for a yearly carbon footprint comparable to Kazakhstan’s, according to Digiconomist, NFTs are just a fraction of that (the exact amount is unknown, but with the increase in NFT popularity, it’s likely getting higher).