Carbon footprint analysis and mitigation in minting an ERC-721
===

_Note_: I've been able to research limited topics in this time, thus haven't been able to expand on most topics (every heading needs to be discussed, including each solution!). The language isn't formal or academic either (yet).

The direction I'm aiming for is discussing important topics, quantitative analysis of the carbon footprint of present technologies, researching present innovations and their drawbacks and future ideas for developers with proposed architectures.

Guidance from environmentalists and developers on a few things that I'm not sure of would be great. I'll need a few extra weeks to consolidate this into a solid introduction for artists and researchers. I'd love to get in touch at [[e-mail]]([e-mail]).

## 1.0 Introduction

NFTs (Non-Fungible Tokens) were introduced in EIP-721 as a standard for Non-Funglble Tokens or Deeds on the Ethereum network. Uploading an image to the Ethereum network would be expensive due to GasFees, which is why EIP-721 has an optional metadata interface [1]. While all owners of NFTs buy them for different reasons, one could state NFTs are valued for authenticity and speculation. While NFTs are most known for their usage in art, they have

This paper quantitatively analyses the ecological impact of minting an NFT (ERC-721) on different platforms and discussses various mmethods of reducing the Carbon Footprint as well as weighs the pros and cons of these methods.

## 1.1 Motivation

Ethereum with the current Proof-of-Work is not an environmentally friendly by virtue of high energy consumption. There are L2 solutions, but they do not have the network effect of Ethereum. Network effect allows for the network to propagate itself forward. It is important to thus consider the network effects of Ethereum 1.0, since the transactional cost to the environement is relatively large as compared to centralized means of ownership. For example, uploading a picture on Instagram consumes 0.154 gEqCO2 (Gram Equivalent CO₂)

## 2.0 Analysis of the Carbon Footprint of a ERC-721

Please note that this research will hold valid as of the publishing date of the paper. The author requests the reader the update themselves using the research methods mentioned or refer to the sources.

It is also important to understand the tradeoffs that artists may have to consider while

### 2.1 Comparing Carbon Footprint of Different Platforms

<br>

<center>

| Name | Gas | Transactions | kgCO2 |
| ------------- | --------------- | ------------ | ---------- |
| OpenSea | 146,210,589,984 | 663,946 | 46,882,237 |
| Nifty Gateway | 22,692,781,162 | 82,920 | 8,638,915 |
| Rarible | 21,336,740,026 | 169,149 | 7,032,924 |
| Makersplace | 20,254,567,543 | 64,625 | 5,490,208 |
| SuperRare | 14,816,160,348 | 160,293 | 4,449,347 |

<i>Estimate of total CO₂ footprint for popular NFT marketplaces as of March 09, 2021</i>. Data provided by [4].

<i>kgCO₂ released per transaction</i>
</center>

### 2.2 Methodology of estimation

If $i$ is the index for all artwork, and $n$ is the total amount of artwork.

$$CarbonFootprint_\text{total} = \sum_{i=0}^{i=n} CarbonFootprint_\text{i}$$

McDonald uses Digiconomist and Etherscan to estimate Carbon Footprint of Ethereum Transactions corresponding to popular NFT marketplaces.

According to [4], it is possible that mining pool locations and thus their correponding emissions intensity may have changed. Readers are suggested to do their own due diligence.

### 2.1.2 How these platforms store NFT data

The primary method of storing the data that is comprised by the NFT is using an off-chain storage system such as Interplanetary File System. This is done using the `tokenURI` function in the ERC-721 standard.

/// @title ERC-721 Non-Fungible Token Standard, optional metadata extension
/// @dev See https://eips.ethereum.org/EIPS/eip-721
///  Note: the ERC-165 identifier for this interface is 0x5b5e139f.
interface ERC721Metadata /* is ERC721 */ {
    /// @notice A descriptive name for a collection of NFTs in this contract
    function name() external view returns (string _name);

    /// @notice An abbreviated name for NFTs in this contract
    function symbol() external view returns (string _symbol);

    /// @notice A distinct Uniform Resource Identifier (URI) for a given asset.
    /// @dev Throws if `_tokenId` is not a valid NFT. URIs are defined in RFC
    ///  3986. The URI may point to a JSON file that conforms to the "ERC721
    ///  Metadata JSON Schema".
    function tokenURI(uint256 _tokenId) external view returns (string);
}

`tokenURI` allows for metadata to be stored offchain and the code to refer to the link in the smart contract. This is one of the methods the paper discusses later.

A typical data storage solution would include using Content ID from IPFS being appended to the Smart Contract for the NFT (Nifty Gateway, for example, uses a similar method). But despite the fact that IPFS is quantifiably more permanent and reliable than similar centralized servers, IPFS is prone to erosion of data. CheckmyNFT.com conducted an audit with results where files were partially loading and not loading in some cases [].

### 3.0 Proposed Solutions: Their architecture and drawbacks.

## Carbon Offsetting on Cosmos Network

## Limiting Mining Operations to locations with clean energy:

## Labeling NFT with respective carbon footprint

### 3.1 Present Solutions

## 3.1.1 Ethereum L2 and Pseudo-L2 solutions

1. xDai based NFT marketplaces: Cargo, Unique and Beyond NFT

2. Matic (now Polygon) OpenSea platform

3. CrazyONE on Harmony Protocol

4. PalmNFT on Hyperledger + Ethereum

## 3.1.2 Non-Ethereum Ecosystem based NFTs

1. Solana's Solible Platform

2. Application Specifc NFT on Cosmos SDK

3. hicetnunc.xyz and Bazaar Market on Tezos

4. AirNFT and NFT-art.finance on Binance Smart Chain

5. KodaDot and RMRK App on Kusama Chain of Polkadot ecosystem

6. GoMint on Hedera

7. Building custom interchain network with Cosmos SDK and CosmWasm [a walkthough]

8. StellarNFT on Stellar Network

9. IOTA Digital Assets on the IOTA Platform

10. Xeno NFT Hub on Polkadot Network

## 3.1.3 Off-Chain Data Storage

1. Using IPFS: Risk. Audit and Permanence

2. Arweave + IPFS: InfiNFT

3. Arweave: Machi X DAO and Mintbase.io

## 3.1.4 Using ERC-1155

## Glossary

## References

1. [EIP-721: ERC-721 Non-Fungible Token Standard](https://eips.ethereum.org/EIPS/eip-721)
2. [Toward a New Ecology of Crypto Art: A Hybrid Manifesto](https://flash---art.com/2021/02/episode-v-towards-a-new-ecology-of-crypto-art/)
3. [A guide to ecofriendly CryptoArt (NFTs)](https://github.com/memo/eco-nft)
4. [Footprint of Cryptoart](https://github.com/kylemcdonald/cryptoart-footprint)
5. [Bitcoin and other PoW coins are an ESG nightmare](https://www.ofnumbers.com/2021/02/14/bitcoin-and-other-pow-coins-are-an-esg-nightmare/)
6. [Climate-Positive Crypto Art: The Next Big Thing Or NFT Overreach?](https://www.forbes.com/sites/lawrencewintermeyer/2021/03/19/climate-positive-crypto-art-the-next-big-thing-or-nft-overreach/?sh=3cb18142b0e6)
7. [10 Top NFT Artists Making Coin in the Latest Crypto Trend ](https://www.nasdaq.com/articles/10-top-nft-artists-making-coin-in-the-latest-crypto-trend-2021-02-26)
8. [Carbon Footprints of Ethereum Wallets](https://carbon.fyi/)
9. [It’s an NFT Boom. Do You Know Where Your Digital Art Lives?](https://www.coindesk.com/its-an-nft-boom-do-you-know-where-your-digital-art-lives)
10. [IT’S TIME TO CALCULATE THE ENVIRONMENTAL COST OF MOVING ART](https://missionmag.org/gallery-climate-coalition-art-world-sustainability/)
11. [Transactions in Ethereum](https://ethereum.org/en/developers/docs/transactions/)
12. [CheckmyNFT audit](https://web.archive.org/web/20210331212312/https://twitter.com/checkmynft/status/1371960028765245440)
13. [Clean-NFT Developer Community's collection of NFT marketplaces using Non-PoW solution](https://docs.google.com/spreadsheets/d/1A-7Ama31sYWhXDl6NoJaXnbAV9pFbjxLIgl7jb3CHOs/edit#gid=0)