Background  Chinese nine regional carbon emission quota trading markets have been operated since 2011, and Chinese national market was launched at the end of 2017. The existing issues include market information transparency and regulatory difficulty, high operating cost and low management efficiency, the contradiction between confidential business information and environmental information disclosure, the market is inactive especially for forests CCER(Chinese certified emission reduction), and how to achieve financial docking from the regional national and international carbon emission quota trading platform in future. Building blockchain carbon emission quota trading patterns may be conducive to resolving these issues and ultimately in response to climate change, thus which may prevent water loss and soil erosion and achieve the goals of environmental sustainable development.

Methods  Based on the Pareto optimality and stakeholder theory, using information technology in combination with economic means, we analyzed current carbon emission quota trading business process of CCER and CEPA(carbon emission permits allocation), explored its block chain mechanism, major stakeholders, and business scenario, and considered the typical smart contracts, classification information and data interfaces.

Results  1) Six-layer core blockchain framework:data stored in shared ledger of data layer; network layer includes all blockchain nodes; distributed consistency technology and data validation mechanism are used in consensus layer; incentive layer is realized offline; contract layer could solve the automatic calculation, trading, settlement and offset following designed business rules; information application system of all market trading and major stakeholder put in application layer. 2)Five-step carbon emission quota trading through blockchain:releasing CEPA and CCER project information; recording, automatic calculating and releasing carbon emission and CCER project audit information; releasing subject matters of the transaction; trading and carbon emission quota trade information disclosure; releasing annual CEPA settlement and CCER project offset. 3) In whole process, every involver could get credible information by rules in limited low cost, all information are protected and every stakeholder is treated fairly and efficiently by rules through blockchain and smart contract. Finally the blockchain carbon emission quota trading pattern of "enterprise trade + government supervising + third-party audit + financial risk prevention" is constructed. In addition, the transaction activity of CCER projects including forestry carbon sequestration may be enhanced by analysis based on the scenario and smart contract.

Conclusions  This pattern is suitable for the technical support of national carbon emission quota trading system based on blockchain features, namely decentralization, collective maintenance data, complete transparent information, trading credible and privacy security decentralization, collective maintenance data, complete transparent information, trading credible and privacy security. It facilitates the docking of financial platforms to realize the huge economic value of carbon emission quota trading. In soil and water conservation plan and scheme, carbon sequestration forest should be planted, and carbon sequestration value should be created through timely trading, so as to achieve double benefits of ecology and economy.