> For the complete documentation index, see [llms.txt](https://aetlas.gitbook.io/aetlas/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://aetlas.gitbook.io/aetlas/for-project-developers/references-and-other-guidance/essential-principles-for-high-quality-carbon-dioxide-removal/carbon-accounting-and-monitoring-reporting-and-verification-mrv.md).

# Carbon Accounting & Monitoring, Reporting and Verification (MRV)

Project-level carbon accounting reports all greenhouse gas emissions associated with a CDR project using repeatable and verifiable GHG quantification methods. In general, this Criteria for High-Quality Carbon Dioxide Removal 10 requires the use of cradle-to-grave life cycle assessments (LCAs) and/or models that accurately estimate CDR, calibrated by periodic direct measurement. Monitoring, reporting, and verification (MRV) involves developing and adhering to a plan for long-term monitoring of the project. Carbon accounting and MRV are often closely linked. Developers should consider the interactions between these two criteria during project planning and execution. 

### Project Developers Must

* Develop a credible MRV plan prior to the start of the project. 
* Adapt the MRV plan throughout the project by incorporating the best available science and evolving industry practices. 
* Use peer-reviewed and scientifically supported carbon accounting methods to quantify the net volume of removals claimed, and disclose the specific methods used. 
* Where an LCA is provided, use a cradle-to-grave LCA and specify the use of either attributional or consequential LCA. 
* Incorporate uncertainty conservatively to avoid overstating the estimated CDR from a project. 
* Separately quantify removed, reduced, and avoided emissions, including delineating by greenhouse gas type. 
* If applicable, use models that are calibrated and validated for the specific conditions in which the project will operate. 
* If applicable, specify model assumptions that cannot be calibrated or revised due to practice constraints. Developers should periodically review MRV measurements and other scientific advancements to revise all other assumptions. 

### Project Developers Should 

* Use regionally appropriate sampling and data collection methods to quantify emissions and removals associated with a project instead of solely model-based or statistical methods. 
* Ensure that the project’s MRV plan is certified or endorsed by a third party (e.g., via a registry). 
* Obtain third-party verification of calculated net removal volumes (e.g., via a registry). 
* Directly measure carbon removed and stored throughout the duration of the project to the maximum practical extent possible. Store this data in a shared repository or facilitate data access to advance CDR MRV and accelerate market development.