Finland-headed Puro.earth, a leading market infrastructure provider for engineered carbon dioxide removal (CDR), has announced that Frontier, an advanced market commitment to buy US$1.8 billion of permanent carbon removal between 2022 and 2040, has approved Puro.earth's Enhanced Rock Weathering (ERW) 2025 methodology for use by Frontier suppliers.
It is the second Puro.earth methodology to earn Frontier’s approval, following Frontier’s 2024 approval of Puro.earth’s Geologically Stored Carbon methodology.
This ERW approval allows Frontier suppliers to use this methodology to certify ERW credits as part of Frontier commitments. It recognises the close collaboration between Puro.earth and the scientific community on Puro.earth’s updated 2025 ERW methodology to ensure rigorous, accountable delivery.
The ERW 2025 methodology brought a significant update to Puro.earth’s approach to certifying ERW projects, and was developed in collaboration with experts from academia, industry, and the non-profit sector.
Key updates included more detailed quantification approaches – requiring suppliers to combine two independent measurement methods for greater reliability – alongside clearer sampling requirements, refined accounting for carbon losses, and a new framework for managing measurement uncertainty.
Second methodology approval by Frontier
Puro.earth’s ERW methodology approval follows Frontier’s approval of Puro.earth’s Geologically Stored Carbon methodology in 2024, subject to two conditions:
- For Direct Air Capture (DAC) projects, suppliers must also comply with Frontier’s clean energy procurement principles;
- For bioenergy with carbon capture and storage (BECCS) projects, approval currently applies only to projects with minimal net new biomass use.
Puro.earth was designated as a Leading Credit Issuer by Frontier in April 2025, reinforcing Puro.earth’s position as the market infrastructure of choice for suppliers pursuing high-quality engineered carbon removal.
Puro.earth received eligibility for the Integrity Council for the Voluntary Carbon Market (ICVCM) Carbon Crediting Programme in 2025. ICVCM is an independent governance body that sets a global threshold for high-integrity carbon credits.
Our ERW 2025 methodology underwent rigorous review by the scientific community, and Frontier’s approval is a strong signal that the bar we’ve set meets the most demanding procurement standards in the market for this pathway. Together with the approval of our Geologically Stored Carbon methodology, this reflects the breadth and quality of the infrastructure Puro.earth provides across the engineered CDR sector, said Jan-Willem Bode, President of Puro.earth.
