Puro.earth, a carbon removal crediting platform, has initiated a public consultation for its updated Enhanced Rock Weathering (ERW) methodology. The updates, launched on September 9, 2025, are designed to align the framework with new scientific and technological developments. This move is part of a broader trend within the industry to continuously refine standards and verification processes for carbon removal technologies.

The revised ERW methodology introduces five key changes aimed at enhancing rigor and clarity. The first change is a new requirement for quantifying carbon dioxide removal (CDR) via ERW. Projects must now use a combination of two approaches, where one quantifies the stored CO2 and the other validates the quantification. This is a move towards a more robust and verifiable system, similar to the increasing scrutiny on permanence and measurement in other carbon removal methods, including biocharBiochar is a carbon-rich material created from biomass decomposition in low-oxygen conditions. It has important applications in environmental remediation, soil improvement, agriculture, carbon sequestration, energy storage, and sustainable materials, promoting efficiency and reducing waste in various contexts while addressing climate change challenges. More. This comes at an important time for the carbon removal space as concern has risen surrounding the viability of Carbon Capture and Storage (CCS).

The updated guidelines also provide more detailed sampling instructions, with a particular focus on characterizing soil chemistry. The new methodology emphasizes the need for precision and accuracy in measurements, requiring the use of control plots for CO2 accounting. Modeling is also recognized as an optional tool for data collection.

A further change explicitly addresses the quantification and accounting of carbon losses. The methodology now provides clear instructions for calculating losses from factors such as secondary mineral formation, cation adsorption, plant uptake, and non-carbonic acid weathering, as well as river and ocean losses. This focus on accounting for potential losses mirrors similar advancements in the biochar sector, where new persistence equations and durability claims (such as Puro.earth’s CORC200+) are being introduced to better model and verify the long-term storage of carbon.

Finally, the new guidelines offer rules for managing uncertainty by introducing a discount and requiring comprehensive uncertainty quantification using frequentist or Bayesian approaches. The public consultation period is open until September 28, 2025. A webinar is also scheduled for September 17, 2025, to present the updates and address questions.

SOURCE: Puro.earth Starts Public Consultation On Its Updated ERW Methodology