Puro Standard


Download Puro Standard & Marketplace Rules

The carbon markets require the integrity of certification via carbon standards. The Puro Standard is the first carbon removal standard for engineered carbon removal methods in the voluntary carbon market. It consists of high-quality carbon removal methodologies, aligned with the IPCC definition for carbon removal, for products or processes that remove carbon from the atmosphere.

The current removal methodologies are: Biochar, Bio-based Construction Materials, Carbonated Building Elements, Geologically Stored Carbon, and Woody Biomass Burial. Besides, Puro.earth is in the process of developing a methodology for Terrestrial Enhanced Weathering and has also developed a methodology for Soil Amendments with the EU LIFE Programme, the EU’s funding instrument for the environment and climate action.

How do we measure carbon removal?

CO2 must be captured from the atmosphere, stabilized, and stored durably. Only then can it be considered removed. The Puro Standard does not credit reduced nor avoided carbon emissions, only net removals.


Puro.earth’s carbon credit is called the CORC, or CO2 Removal Certificate. Each CORC represents one metric ton of CO2 removed from the atmosphere with one of the Puro Standard methodologies. Carbon removal suppliers and projects can enter the carbon markets by getting issued CORCs and selling them to corporations who want to neutralize their carbon emissions or contribute to the growth of the carbon removal industry. This provides a revenue stream to scale up.

Carbon Removal Metholodogies

Methodologies specify the carbon removal method’s system boundaries, carbon accounting formulas to establish the net removal amount, environmental safeguards, and the documentation that independent verifiers need to issue carbon credits to a project. The distinguished panel of carbon removal experts that compose Puro.earth's external Advisory Board oversees Puro Standard methodologies and crediting rules and their mandate is to ensure high carbon credit integrity and robust principles for a science-based carbon removal standard.


Third-party independent verifiers are trained by Puro.earth to audit carbon removal project facilities or sites and issue CORCs, if the CO2 removal activity complies with methodology requirements. A rigorous verification process confirms that the products or processes are truly carbon net-negative and that environmental safeguards are being followed. CORCs are always issued ex-post, after the removal has been produced.

General Puro Standard requirements

All carbon removal suppliers need to demonstrate additionality, meaning that the removals are a result of carbon finance, by providing full project financials and counterfactual analysis based on baselines. Even with substantial non-carbon finance support, projects can be additional if investment is required, risk is present, and/or human capital must be developed. Suppliers must also show that the project is not required by existing laws, regulations, or other binding obligations.  

All suppliers must also demonstrate environmental and social safeguards, and when applicable, the activities shall be developed with informed consent from local communities and other affected stakeholders and have a policy in place to address potential grievances.

Puro Registry

For traceability, transparency and to avoid double counting, CORCs are issued in the Puro Registry where their complete lifecycle is recorded, from issuance to retirement, as emphasized by the likes of Voluntary Carbon Markets Integrity Initiative and ICROA.

To fulfill corporate climate claims, buyers assign an organization as beneficiary to the CORCs and retire them in the registry, so no other organization can claim the carbon credit. Anyone can go to registry.puro.earth to search for corporations that have made carbon removal claims based on CORCs and find project information and retirement purpose.

Puro.earth Marketplace

CORCs are available for purchase via our marketplace, other marketplaces, and channel partners who offer CORCs to their clients. Puro.earth charges an Annual Fee and a Service Fee for registering CORC changes of ownership, regardless of where the CORC was sold. There are no separate fees for CORC issuance nor verification.

Puro.earth’ position in the carbon market value chain

The voluntary carbon removal market is a flourishing market within the established carbon markets. Our vertical integration covers the independent Puro Standard overseen by an external Advisory Board, the Puro Registry, a CORC trading marketplace and an ecosystem of channel partners who sell CORCs to clients, making our platform more efficient and letting suppliers get access to buyers and capital to monetize their much needed climate service. Besides, our framework includes the training of independent verifiers.

Puro Standard Governance

To ensure governance independence, Puro.earth has two separate governance bodies consisting of a Board of Directors and an external Advisory Board. Puro Standard methodologies are co-created with a working group of scientific and industry experts and the external Advisory Board, while the Board of Directors oversees the business and trading aspects of the marketplace.

Puro Standard’s History

Today, Puro.earth is known as the go-to partner to find high-quality carbon removal projects to fulfill corporate climate pledges in a credible way but we never set out to become a carbon standard. When we started operations in 2019, the incumbent standard setters were focused on carbon reductions. While carbon reduction projects are important, they are simply not enough when we already have too much CO2 in the atmosphere.

So, we set out to identify the least disputable ways of removing carbon that also had the potential to be scaled at industrial levels. Since we were not from the offsetting world, we borrowed ideas from other industries that had robust and well-established processes, such as the renewable energy’s Guarantee of Origin certification. And because we were the first, we had no legacy to contend with. We could base everything we do on the latest scientific research. We pioneered the first methodologies for biochar, geologically stored carbon and durable construction materials.

We focused exclusively on removals that can be measured, rather than estimated through modeling, and implemented stringent third-party verification and auditing processes. We emphasized not just how carbon is captured, but also how it is stored and for how long. It was a new way of approaching offsets in the voluntary carbon market, but as outsiders it seemed natural to turn a paradigm that was not working on its head.

That is how the Puro Standard was born.

In 2021, Nasdaq acquired a majority stake in Puro.earth. In 2022, Nasdaq launched three commodity reference price indexes based on the trading of Puro Standard CORCs to bring market price transparency and help corporations understand the true cost of removing their emissions.

If you, like us, think that removals are unavoidable and the only way to restore the balance of CO2 in our atmosphere, join us. Visit our marketplace of suppliers who are already producing CORCs and visit our Pre-CORC suppliers, projects that need offtake agreements to start or expand operations.

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