Puro.earth has launched a public consultation period on its updated methodology for enhanced rock weathering (ERW).
The updates were introduced to ensure the methodology keeps up with the latest scientific and technological developments in this field, providing ERW suppliers and project developers with a streamlined process for delivering high-quality results.
To make sure the updated methodology is practical and relevant to field stakeholders, Puro.earth engaged with experts from academia, industry, and the non-profit sector, hosting three workshops and interviewing relevant field entities.
The resulting updated ERW methodology aligns with the latest edition of the Puro General Rules, as well as with the ICVCM CCP, and it comes with five key changes to the previous version.
It provides an in-depth description of six approaches eligible for measuring the carbon dioxide removal (CDR) achieved via ERW, requiring the combined use of two approaches, where one serves to quantify the stored CO2, and the other validates this quantification.
Additionally, it offers clear sampling guidelines with special attention to detailed soil chemistry characterization. It also emphasizes the precision and accuracy of measurements, demanding the rigorous use of control plots for CO2 accounting.
Another change is that modeling is recognized as an optional tool for gathering data from site-specific CDR quantification measurements.
This updated Puro.earth ERW methodology explicitly addresses losses, providing clear instructions on their quantification and accounting. The CO2 losses covered in it are secondary mineral formation, cation adsorption, plant loss, and non-carbonic acid weathering, as well as river and ocean losses.
Relevant: The Carbon Drawdown Initiative Unlocks Testing Innovation For ERW Effectiveness
Lastly, this set of scientifically rigorous guidelines offers rules on managing uncertainty by introducing an uncertainty discount and requiring comprehensive uncertainty quantification via frequentist or Bayesian approaches for the different components of the CDRl calculation.
Interested parties are encouraged to fill in the feedback form on the updated ERW methodology and send their comments to contact@puro.earth by Sep 28, 2025.
In the meantime, on September 17, Puro.earth is hosting a webinar to present the methodology and answer questions related to the newly introduced updates.
Read more: New Map Shows Locations of Enhanced Rock Weathering Projects Worldwide
