The recent NFT boom is spurring concern that the environmental impact of minting these tokens might not be worth the benefits this emerging market is creating, with at least one artist canceling his NFT drop.
In brief, blockchain mining is very energy intensive, and by extension, so is mining NFTs.
Both the Bitcoin and Ethereum blockchains currently rely on complex Proof of Work (PoW) algorithms to validate transaction blocks and add them to the chain. The algorithms require a lot of computational energy to solve. More computational energy means more electricity usage, meaning that blockchain mining has a huge carbon footprint.
Digiconomist’s Bitcoin Energy Consumption Index estimates Bitcoin’s carbon footprint to be 37.30 metric tons of carbon dioxide (Mt CO2). They equate this with the carbon footprint of the entire country of Trinidad and Tobago. Digiconomist’s Ethereum Energy Consumption Index is currently in beta, estimating Ethereum’s carbon footprint to be 12.24 Mt CO2, roughly equated to Panama.
A carbon footprint is a measure of the amount of greenhouse gas (namely carbon dioxide and methane) that humans generate through specific activities. When we burn fossil fuels to, for instance, generate electricity (which is measured in kWh, or kilowatt hours), we release waste gases like carbon dioxide (CO2).
While safe levels of carbon dioxide exist naturally in the earth’s atmosphere, the excess carbon dioxide we generate through our actions throw the atmosphere out of balance. This causes the greenhouse effect—a natural process whereby certain gases in Earth’s atmosphere (like CO2) trap some of the sun’s heat to keep the planet warm—to dangerously amplify.
In other words, excess CO2 generated by human energy consumption leads to excess CO2 in the atmosphere which traps excess heat from the sun and makes the earth hotter than it naturally should be. This is, in essence, global warming, and identifying which human actions have the biggest carbon footprint helps us focus on what we need to change in order to better preserve our planet.
In December, computational artist and engineer Memo Akten launched a website called “CryptoArt.wtf” that calculates the energy usage and CO2 emissions of any NFT on SuperRare, NiftyGateway, or any given URL with an ETH address.
The site then compares the energy consumption of that NFT to a number of comparative metrics applicable to average people’s energy consumption in daily life. So, according to metrics on CryptoArt.wtf, the skull NFT below has consumed the same amount of energy as an EU resident’s electricity consumption for 3 weeks or a laptop’s energy consumption over the course of 1.5 years.
The Climate Cost of NFTs
Akten accompanied his site with an in-depth dive into the ecological cost of cryptoart. Based on an estimated average carbon footprint of 35 killowatthours (kWh) per Ethereum transaction (current estimates on Digiconomest have increased the average to 54kWh), Akten concluded that certain blockchain-based activities are “ludicrously energy consuming and ecologically destructive,” taking particular chagrin with NFTs due to the multi-transactional process of minting, bidding, selling, transferring, etc.
Based on his own data from CryptoArt.wtf, Akten determined that the average NFT transaction had a bloated footprint of 76kWh, and taking all of the transactions related to a single NFT into account, the average NFT had a footprint of around 340 kWh (or “an EU resident’s total electric power consumption for more than a month”).
Akten also noted that these costs are entirely reflective of the energy consumption for using a Proof-of-Work (PoW) blockchain, without taking the energy cost of creating any of the original artwork into account. He suggests Proof of Stake (PoS) blockchains like ETH2 and Polkadot as an alternative, which grants and limits mining power based on the proportion of coins held by a miner instead of based on who has the fastest computer, and is therefore far more energy efficient.
If Akten’s metrics are accurate, the sheer energy cost of NFTs are unsustainable for the environment.
To be sure, though, some readers have taken issue with Akten’s assessertions and data, prompting him to acknowledge the “one-sided” nature of his work, which he hopes will encourage conversation and action.
Canceling the Drop
Recently, the NFT climate impact debate boiled over on social media after artist Joanie Lemercier announced that he would be canceling his second cryptoart drop on Nifty Gateway (her first 53-edition drop sold out in about 10 seconds) due to the projected energy consumption.
Citing Akten’s work as a major influence on his decision, Joanie Lemercier recounted his struggle to receive accurate information from Nifty Gateway on the energy consumption of his first drop. After going through the details of her transactions with Offsetra, a carbon offset company, Lemercier determined that his first Nifty Gateway drop “consumed in 10 seconds more electricity than [his] entire studio over the past 2 years.”
He noted that Nifty Gateway eventually “confirm[ed] the magnitude of the damage,” but concluded that the lack of transparency on energy cost from the major NFT marketplaces is a major issue.
Lemercier urged any artists planning NFT drops to reconsider until more energy-efficient solutions are implemented.
Following Lemercier’s post, the SuperRare team wrote an article on Medium responding to the assertion that NFTs have a disproportionate ecological impact on Ethereum’s carbon footprint.
While SuperRare recognizes that Ethereum is energy intensive, they assert that Ethereum’s energy consumption is fixed at any given point in time, and that the network’s energy consumption isn’t affected by the quantities or types of transactions taking place. “In other words, if everyone took a break from using Ethereum apps and no transactions were sent for a whole day, the carbon emissions of the network would essentially stay the same,” they wrote.
SuperRare sourced this information from the FAQ for University of Cambridge’s Bitcoin Energy Consumption Index, which is only focused on the Bitcoin blockchain and does not touch upon the more complicated transactions taking place on Ethereum.
That said, if SuperRare is correct that Ethereum’s energy consumption is the same regardless of what transactions are occurring at any given time, then that points to a dangerously energy-inefficient system
SuperRare concluded that while NFTs don’t increase Ethereum’s energy emission, NFT-related applications still make use of the network and contribute to its adoption. In order to support long-term, sustainable solutions, they promised to donate money to ETH 2.0 research and are exploring scaling options like Polygon and Polkadot.
The Big Picture
Currently, there isn’t enough outside data available on the carbon footprint of NFT creation (or even Ethereum, for that matter) to accurately determine its long-term impact on the environment.
Still, when it comes to carbon footprints and global warming, sometimes it’s more important to look at the bigger picture than to get mired in the weeds of specific metrics or technicalities.
PoW blockchains are massive energy guzzlers, and until more energy-efficient solutions like PoS are more widespread, everyone who participates in the Ethereum space is taking part in that consumption.
That’s not to say that people shouldn’t use blockchain or enjoy NFTs, but rather that we should all be looking towards green scalability solutions as the next stop forward.