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Puro Standard

The leading standard for engineered carbon removal methods in the voluntary carbon market 

The essentials of carbon removal: Why it matters

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What goes up, must come down

Since the Industrial Revolution, the reliance on fossil fuels to power our economy has resulted in atmospheric CO2 concentration levels that keep on rising. This is having an alarming impact on our planet. With rising sea levels, soaring temperatures, and changing ecosystems, climate change poses the greatest challenge we face.

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We Need to Urgently Scale a CDR Industry

Carbon Dioxide Removal (CDR) from atmosphere has to grow. We cannot afford to be complacent in the face of the climate crisis. We need to rapidly move towards a net-zero emissions economy where emissions are balanced with removals. Net-zero economy requires cutting global emissions radically by 80-90% by 2050. But some emissions will remain. Dealing with these residual emissions and the excessive 2,500 gigatons of CO2 already added since the industrial revolution requires scaling a carbon removal dioxide removal (CDR) industry that has a gigatonne capacity. That's why the Science Based Targets initiative (SBTi) and Oxford Principles for Net Zero Aligned Carbon Offsetting are calling on companies to include Carbon Dioxide Removal (CDR) in their net-zero plans.

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How the carbon removal process works

Carbon removal is the process of physically capturing CO2 from the atmosphere and locking it into durable storage. 

Carbon removal methods involve various ways of capturing and storing carbon. After capturing carbon, it can go through different stabilization steps and interim storage pools before it's finally stored for the long term. In Carbon Dioxide Removal (CDR) methods, both the capture and the final storage determine how securely and for how long the carbon is kept away from the atmosphere. The net climate impact is calculated as carbon stored minus all project emissions caused by capturing and storing it.

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What is durable carbon removal and why does it matter? 

The durability of the storage refers to the time the carbon has been locked away.

When we emit carbon into the atmosphere, it persists there for a hundred years or more. To effectively counteract the impacts of these emissions for a time that is meaningful for the climate, it is necessary to use carbon removal methods that provide long-term durability of 100 years and over. Compensating for fossil fuel emissions can only be done meaningfully with durable carbon removal.

"For credible net zero, we need to shift offsetting towards long-lived storage, which removes carbon from the atmosphere permanently or almost permanently.”

– Professor Myles Allen, the Oxford Net Zero initiative & Chairman of Puro.earth’s Advisory Board

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Puro Standard


In the world of carbon markets, trust is crucial. That's why in 2019, the Puro Standard was born as the first of its kind standard, ensuring a credible framework for certifying engineered carbon removal and issuing Puro.earth carbon credits called the CORC, or CO2 Removal Certificates. Our pioneering methods meet rigorous scientific standards and our transparent Puro Registry, tracks the lifecycle of CORCs which brings integrity to the market.

Choose the Puro Standard for:

Exclusive focus on carbon removal

We only certify durably stored carbon with net negative emissions, avoided or reduced emissions are not mixed up in the carbon accounting

Durable focus

Our methodologies focus on removing carbon to secure storages from the atmosphere for hundreds to thousands of years


High level of assurance

Removals are quantifiable with scientific rigour and independently verified  

Full transparency

All CO2 Removal Certificates (CORCs) are issued and tracked in the Puro Registry to avoid any potential for double counting

Alignment with global benchmarks 

Endorsed by the ICROA Code of Best Practice, a widely respected guideline followed by numerous corporations for procuring carbon credits, our initiative enhances buyer confidence in CORCs

Market leader

We are mobilizing the net negative economy by building the largest carbon removal ecosystem and are the pioneers behind five ground breaking carbon removal methodologies

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Carbon removal methods

Biochar

100+ years

Biomass or biowaste heated in the absence of oxygen (a thermochemical conversion named pyrolysis). A very stable, solid form of carbon that can endure in soil for hundreds or thousands of years. Multiple uses at potentially industrial volumes, for example, as greenhouse additive, in soil regeneration and in stormwater or wastewater treatment.

Terrestrial Storage of Biomass

100+ years

The storage of woody biomass in conditions that prevent decomposition and maintain carbon locked away for at least 100 years. A new innovative approach to immobilise carbon, that offers a unique opportunity for large-scale, affordable carbon removal.

 Carbonated Materials

1,000+ years

By reacting with CO2, these materials mineralize and form carbonates, thereby trapping and storing the carbon dioxide for geological timespans. Offering a pathway to transform the environmental impact of an entire industry while utilizing industrial byproducts and waste materials such as steel slag mine tailings and alkaline waters.

Enhanced Rock Weathering

1,000+ years

A process that accelerates natural rock weathering that usually takes thousands of years. Rock weathering begins with the reaction between water, carbon dioxide and silicate rocks which breaks down the rock to then form biocarbonates, a durable for of carbon. When spread on agricultural land, the rock can be highly beneficial and can increase crop yields.

Geologically Stored Carbon [BECCS, DAC]

1,000+ years

Carbon capture processes such as Direct Air Capture (DAC) and Bio-energy Carbon Capture Storage (BECCS) with geological storage, such as direct injection of CO2 into deep geological formations. Puro.earth methodology only allows the capture of CO2 directly from the air or from biogenic sources, not from fossil fuels.

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The verification process


To be issued CORCs under the Puro Standard, carbon removal suppliers go through a rigorous verification process by independent, accredited third-party Validation and Verification Bodies to confirm that their products are truly carbon net-negative.

A supplier makes a claim on the net negativity of their products or process by presenting evidence via a Lifecycle Assessment (LCA) or Environmental Product Declaration (EPD) which attests that the product has removed more CO2 than it has emitted.

Based on this evidence, compliance to Puro Standard methodology requirements is audited by independent assessors trained by Puro.earth, who visit the production facility, validate the accuracy of data and issue an audit statement. To remain independence, the costs of verification are covered by Puro.earth instead of the supplier.

The verified volume of extra carbon absorbed in the products or process is then issued CO2 Removal Certificates (CORCs) for every metric ton of CO2 removed and stored.

Suppliers are free to sell their CORCs at any venue, marketplace, broker or directly to companies who want to neutralize their emissions by removals and reach net zero and beyond.

Puro Standard Governance


The distinguished panel of carbon removal experts that compose Puro.earth's external Advisory Board oversees Puro Standard methodologies. Their mandate is to ensure high carbon credit integrity and robust principles for a science-based carbon removal standard.

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Puro Registry


For transparency and to prevent double counting, CORCs are issued in the Puro Registry, where their entire lifecycle is tracked from creation to use. To support corporate climate goals, buyers designate a beneficiary for the CORCs and retire them in the registry, ensuring no one else can claim them. Visit the Puro Registry to see corporations making carbon removal claims, along with supplier issuances and project details.   

The latest retirements by corporations on their journey to net zero

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Date Retired Crocs Credit Type Methodology Beneficiary
2024-04-04 28 CORC Construction Materials Methodology (discontinued) Cloverly, Inc.
2024-04-04 15 CORC Biochar Pledge Earth Technologies Ltd
2024-04-04 198 CORC Biochar Pledge Earth Technologies Ltd
2024-04-04 220 CORC 100+ Biochar Carbonfuture GmbH
2024-04-03 600 CORC 100+ Biochar Shopify Inc.

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Purchase CO2 Removal Certificates (CORCs) issued under the Puro Standard by browsing our supplier listings


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