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NFTs do not have one fixed carbon footprint: their impact depends on the blockchain and the activity involved in creating, transferring, and supporting them. Ethereum’s move from proof of work to proof of stake sharply reduced its network-wide energy use and emissions, but those figures cannot be treated as the footprint of an individual NFT. A useful sustainability claim should name its method, boundary, and date.
Are NFTs bad for the environment?
Not necessarily, and not all to the same degree. An NFT is a token recorded on a blockchain; the token itself does not determine how much electricity the network uses or how carbon-intensive that electricity is. Those impacts depend on the blockchain’s consensus and transaction architecture, the network activity being counted, and the electricity sources associated with its nodes.
Ethereum is a useful example of why dates matter. Ethereum.org’s page, last updated July 28, 2026, reports an estimated annual network electricity use of 2,601 MWh and annual emissions of 870 tonnes of CO2e. These are estimates for Ethereum as a network, not a calculation for each NFT. Ethereum.org’s energy-consumption page attributes the figures to the Crypto Carbon Ratings Institute (CCRI).
What changed when Ethereum moved to proof of stake?
Ethereum’s Merge replaced proof of work with proof of stake. Ethereum.org, citing CCRI, reports that the transition reduced annualized electricity consumption by more than 99.988% and carbon footprint by approximately 99.992% compared with the previous proof-of-work network. The reported emissions comparison is from 11,016,000 to 870 tonnes of CO2e per year. These are network-level, annualized comparisons—not per-NFT savings. Ethereum.org’s explanation of the estimates provides the figures and methodology context.
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That distinction also matters when reading older commentary. In April 2022, a Hyperledger Foundation announcement described Ethereum as then transitioning to proof of stake and quoted Daniela Barbosa saying, “For all the excitement about the potential of NFTs to create new value and traceability as digital assets authenticating everything from art and collectibles to products in the supply chain, there is equal consternation about climate impact of the blockchain mining enabling them.” That was a statement about the climate debate in the pre-Merge landscape, not a description of Ethereum’s current consensus mechanism. The original announcement accompanied a 2022 report on NFT blockchain impacts.
Why electricity use is not the same as carbon emissions
Electricity consumption measures energy use; emissions estimates also depend on where the electricity is generated and the carbon intensity of local power supplies. A network with nodes in different regions can therefore have different estimated emissions even when its electricity consumption is the same.
CCRI’s Ethereum estimate uses a bottom-up approach to node electricity use across hardware and client configurations, then applies regional carbon-intensity factors to estimate emissions. The result can change as nodes join or leave. Ethereum.org says its estimates draw on publicly available data and are not an official statement or promise from the site or the Ethereum Foundation. Ethereum.org
Cambridge’s methodology likewise uses network electricity estimates, node geography, and regional generation mixes. It describes uncertainty in estimating emissions, uses scenario ranges, and limits the current index to electricity use by identified nodes rather than a full life-cycle assessment. That means associated hardware, infrastructure, and other lifecycle effects are not captured as a complete cradle-to-grave footprint. Cambridge Centre for Alternative Finance’s Ethereum GHG methodology explains the boundary; Cambridge Judge Business School’s 2023 discussion outlines the broader estimation challenges.
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Why there is no universal carbon number per NFT
A network-wide estimate cannot simply be divided by a transaction count and presented as the energy or emissions caused by one transaction or NFT. Ethereum’s block proposal and validation energy is not directly proportional to how many transactions happen to be in a block. Results also depend on how throughput is defined and whether activity on Layer 2 networks is included. Ethereum.org discusses these allocation limits.
The available current sources report network-level estimates and explain why allocating them to individual transactions is difficult; they do not establish one current, universal life-cycle carbon figure for an NFT. A 2023 peer-reviewed article’s abstract reports a model in which NFT yearly greenhouse-gas emissions reached up to 18% of the proof-of-work peak. That is a model-specific upper estimate, not a current measured total for the NFT sector and not the footprint of a single token. The article’s PubMed record identifies the study.
How to judge an NFT sustainability claim
Creators, marketplaces, and collectors can ask for a claim that specifies what was measured rather than relying on labels such as “green” or a single dramatic per-NFT number. A useful disclosure should make these points clear:
- Which network and activity? Identify the blockchain and whether the estimate covers minting, transfers, marketplace activity, or broader network operations.
- What boundary? Say whether the figure concerns electricity use, electricity-related emissions, or a fuller lifecycle assessment; state whether Layer 2 activity is included.
- What method and date? Name the source or model, its measurement period, and the date the estimate was published or updated.
- How are emissions estimated? Explain whether node geography and local electricity mixes are incorporated, and acknowledge uncertainty where the method uses scenarios or estimates.
- Is the number actually attributable to one NFT? If network use has been allocated across transactions, show the allocation method and its limitations instead of presenting the result as a directly measured token footprint.
Comparisons between chains need the same care. A fair comparison should align consensus and transaction architecture, measurement date, geographic and electricity-mix assumptions, system boundary, and treatment of Layer 2 activity. The sources cited here do not provide a current, common-boundary comparison across major NFT-capable chains, so they do not support naming one network as the environmental winner.
What creators, marketplaces, and collectors can do
Creators
Choose a network and minting route with a clearly explained operating model, and publish the basis for any sustainability statement. Avoid claiming that an NFT is carbon-neutral or low-carbon solely because a network uses proof of stake; a consensus mechanism alone does not establish a complete lifecycle footprint.
Marketplaces
Make the network used for minting and trading visible, and distinguish network-level estimates from estimates allocated to a transaction or token. When providing an emissions figure, link to the methodology and state the date and boundary behind it.
Collectors
Check which chain and transaction route an NFT uses, then look for a dated method rather than a headline number without context. If a seller cannot say what a footprint claim includes, treat it as unverified rather than as a comparable measurement.
Why older NFT footprint claims need context
A 2022 Linux Foundation Research report announcement said approximately 80% of NFTs were transacted via Ethereum. That figure is a historical claim published in 2022, not a current market-share statistic, and it belongs to a period when Ethereum was still transitioning to proof of stake. It should not be used to infer today’s distribution of NFT activity or to describe the present-day impact of Ethereum-based NFTs. The announcement provides the report’s contemporary framing.
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