Progress achieved since the launch of the first Enhanced Rock Weathering (ERW) methodology, and the upcoming major update

Key Takeaways:

• Evolving Science, Strong Standards: Puro.earth’s ERW methodology is designed to adapt to scientific advancements to maintain rigorous verification standards.
• Quality Through Flexibility: Our approach accommodates multiple quantification methods without compromising data accuracy or credibility.
• Learning from Implementation: Close collaboration with in-the-field ERW experts has led to refinements that enhance project integrity and carbon removal credibility.
• Balancing Innovation & Verification: Scientific accuracy is the priority to ensure long-term trust in ERW solutions.
• Continuous Improvement: A new methodology update will further strengthen quantification transparency, and reliability.

Dear Members of the Enhanced Rock Weathering Community,

In 2022, Puro.earth published the first enhanced rock weathering (ERW) methodology for carbon removal. Since then, we have had the privilege of working alongside an innovative and passionate community of ERW scientists, project developers, and industry partners. Our pioneering framework was created not only to establish a benchmark for carbon removal but also to encourage the evolution of ERW science. Today, we're glad to share the progress we've made with our methodology and address the feedback that we've received.

Embracing an Evolving Science

Enhanced rock weathering is a rapidly developing field, with new innovations and refined quantification methods continually emerging. As there is not yet a universal consensus on a single best quantification pathway, our methodology intentionally accommodates multiple approaches. This flexibility is not a sign of inconsistency, but a strategic decision designed to encourage innovation and support the evolving nature of ERW science.

Rigorous Standards Underpinning Flexibility

We understand that the flexibility of our ERW framework has sometimes been misinterpreted as a being less precise. On the contrary, Puro.earth upholds the highest standards for scientific accuracy and data quality. Every project undergoes rigorous pre-audit data and document reviews, supported by detailed guidance and expert oversight. Our team, comprising scientists with first-hand experience in soil measurements and designing ERW projects, as well as a deep understanding of ERW ensures that every quantification pathway, adheres to robust, verifiable, and auditable scientific criteria.

Learning from Real-World Collaboration

Since launching our methodology, we have worked closely with scientists and project developers, gaining valuable insights into the practical challenges of operationalizing ERW. We have learned that even the best-laid plans can face obstacles in generating high-quality data. As a result, we often request revisions or additional details to ensure projects are fully prepared before moving forward with the audit. Key issues such as additionality, baseline deduction, environmental risk assessments, and uncertainty quantification remain central to our scrutiny, ensuring the integrity and credibility of our carbon removal credits.

Balancing Innovation and Robust Verification

For enhanced rock weathering to become a mainstream carbon dioxide removal solution, its certification framework must balance cost-effective deployment with robust monitoring, reporting, and verification (MRV) procedures. While we understand the urgency of buyers and other stakeholders to accelerate credit issuance, we firmly believe scientific accuracy must not be compromised in the process. Certifying projects before proven monitoring procedures are in place could ultimately undermine ERW’s credibility and its long-term potential. Puro.earth remains committed to fostering continuous dialogue with ERW investors, buyers, and key organizations. By working together, we can drive innovation while maintaining the highest scientific standards—ensuring ERW scales as a trusted, verifiable, and impactful carbon removal solution.

Ongoing and Future Developments

Our commitment to continuous improvement is unwavering. In 2024, we published an update to our original ERW methodology, integrating scientific advancements, improving transparency, and refining the granularity. Today, we are excited to announce the upcoming 2025 methodology update. As part of the Puro Standard’s regular review cycle, this update builds on our existing requirements by adding further detail, enhancing clarity, and incorporating the latest research and best practices—while maintaining consistency with our core principles to support a reliable and scalable framework for ERW certification.

Provide feedback & participate in the working group 

Looking Ahead -Together

Enhanced rock weathering holds immense promise as critical tool in the global fight against climate change. As we navigate its scientific and operational challenges, we invite all stakeholders—scientists, project developers, standard-setters, and buyers alike—to join us in a constructive dialogue. Together, by upholding rigorous scientific standards and embracing innovation, we can ensure that ERW achieves its full potential in a scalable and verifiable manner.
We deeply appreciate the support and engagement of the ERW community over the years. Your feedback is invaluable, and we remain committed to transparency, excellence, and continuous learning as we work side by side to advance the science and application of enhanced rock weathering.

Sincerely,
The Puro.earth Science Team