We want to unlock carbon offsetting for web3. To make this a reality, we need transparent carbon credit tokenization and a robust DEcentralized Carbon Accounting ecosystem — DeCA 🦜


We want to unlock carbon offsetting for web3 and build towards an open and transparent carbon economy. To make this a reality, we first have to develop a unified, open, collaborative standard for carbon credit tokenization which is agnostic of both carbon methodology and standard body. We believe this to be the first primitive for a more transparent and composable sustainable finance ecosystem.
This is an open collaboration and we invite other actors with an interest and/or intention to tokenize their carbon credits to get on board. We aim to build consensus through participation and guarantee interoperability from day 1.


We started at the EthLondon hackathon and then joined the Blockchain for Social Impact incubator where we won the Carbon Footprint track. So obviously, this is still in early development — and only running on Ethereum Rinkeby testnet!.

Open Climate Collabathon

We see this project fitting into multiple prompts:
  1. 1.
    • New ways to monitor and verify impact data to add additional layers of trust to existing carbon offset certificates
    • Include other tokenized climate impact assets on the CO2ken platform
  2. 2.
    • Integrate offsetting functionalities into other projects like the e-commerce plug-in Ecowidgy
    • Integrate our Solidity modifier into smart contracts to offset transaction-based emissions
We would love to help build bridges between all these projects. This way we could demonstrate a full circle from carbon sequestration to consumer offsetting! ⛓

November 2020 Edition

These are the things we'll be working on:
  • Solidity smart contract developer — token contracts
  • Layer 2 blockchain developer, e.g. xDai
  • Meta-transactions, e.g. Gas Station Network
  • Wallet integrations, e.g. wallet connect, Torus, ...
  • Flight emissions calculator
  • Ethereum Emissions calculator
If you want to contribute or learn about any of them, reach out in the Discord — we're in the #CO2ken channel under the Climate Markets prompt.

What we've built so far — Version 0.1

Project architecture

The figure below shows the architecture of the project in its very first iteration. For a detailed description and an overall project overview please refer to this Medium post and this architectural overview PDF.
For the prototype we have built the following elements:
  1. 1.
    The DAO
    • We have deployed a DAO with the DAOStack framework on the Rinkeby network which you can find here
    • We have built a custom scheme (plugin) for Alchemy to be able to interact with our CO2ken.sol contract.
      • The process for setting up this scheme is described here
      • The scheme is found here
      • The custom Alchemy UI can be found here
  2. 2.
    The CO2ken Contracts
    • All contracts can be found in this folder
    • The co2ken.sol contract is the main token contract
    • The green.sol contract contains the Solidity modifier which allows third-party smart contracts to automatically offset the emissions associated with their execution
    • The co2kenData.sol contract is a data storage contract accessed by the other two contracts above
  3. 3.
    The API
    • We have deployed an API called eth-co2.js which makes it easy for all dApps to interact with our smart contracts
    • The repo containing the code can be found here
    • The published npm package can be found here
  4. 4.
    The Frontend / UI
    • We've deployed a simple web3 app at which is using our API to connect to our smart contracts
    • The backend code for this can be found here
    • We've deployed a simple web3 app called Polluter to demonstrate the functionality of the Solidity modifier. It can be found at
    • The code for the polluter page can be found here
    • It contains a leaderboard which serves as a transparent track-record of offsetting activity and adds a level of gamification


If you want to contribute directly to the project, this is obviously also possible! Check out on our GitHub.
We have experience in DAOs & open source development and have partnered with a venture builder from London called Deep Science Ventures for support on the commercialization side.
Just ping me on Discord, on Telegram or Twitter: @raphabenoi or via mail: [email protected]
Looking forward to the collaboration 💃🕺
Check out this