Sustainable Finance Initiative is a cross-campus effort of the Precourt Institute for Energy.

Work program 4: Scientific measurement, verification (audits) and financially credible removals products

As noted more generally in workstream 1, strong accounting foundations that rely on accurate and cost-effective measurement of data reporting carbon capture and storage dynamics over time are critical for the credibility and growth of carbon (dioxide) removal (CDR) markets across scales, from private buy and sell associations to emerging international trade mechanisms under Article 6 of the Paris Agreement. Academic evaluation describes prevailing accounting methods for carbon stocks and flows, data measurement and quality that often rely on subjective system boundary definitions, static and uncertain baselines, and simplifying assumptions that obscure the connection between credited removals and actual atmospheric outcomes (Michaelowa et al., 2019; Grubert and Talati, 2024, Cullenward et al., 2023). These practices generate significant risks, particularly for biomass-based CDR, where classifying inputs as “waste” can allow actors to ignore upstream emissions (Kamusoko, 2021; Cai, 2025), inflating removal estimates and compromising both corporate net-zero strategies and international credit transfers.

Simultaneously, carbon management systems differ significantly across jurisdictions and scales—in reporting formats, assessment scope, and aggregation level (Poralla et al., 2022, Brander 2016)—undermining compatibility for cross-border credit brokerage and coherent bookkeeping. To overcome these limitations, CDR accounting must be (1) accurately and explicitly linked to atmospheric outcomes and (2) interoperable across systems. As climate policy drives the convergence of carbon management systems, widespread intersystem compatibility will be crucial to realizing net-zero goals. 

In response, we are developing an Objective Atmospheric Basis (OAB) for CDR accounting: a technology-agnostic, cradle-to-gate framework that explicitly tracks carbon fluxes to and from the atmosphere as liabilities and assets using a rigorous environmental ledger (Ringsby et al., in prep).  OAB requires development in three key areas: 

  1. Flux-based attribution of emissions and removals to develop explicit linkages between company-wide practices and atmospheric outcomes will be critical to net-zero alignment as markets grow.
  2. Rule-based boundary setting and allocation to adapt to an environmental ledger framework.
  3. Interoperability by offering a common quantitative language for comparing CDR claims across markets, registries, and national inventories.

Any accounting approach ultimately needs to support harmonization across systems and jurisdictions, including bilateral (Article 6.2) and multilateral (Article 6.4) carbon removal and reductions units. 

Our research seeks to develop partnerships and pilot studies to advance OAB, with the goal of ensuring that CDR strategies are compared on an equal basis and that claims align across projects/buyers, corporations and national inventories. We specifically focus on CDR strategies that involve complex production pathways, such as BCR and EW, where the science and technology of measurement is central to establishing the flux-based attribution and systems boundaries.

Workstream 4.1: Science and Technology of Biochar CDR (BCR)

Biochar is among the most promising near-term CDR pathways, with the potential for gigaton-scale removal alongside agronomic co-benefits, such as nutrient retention and improved water use. However, the durability and magnitude of CO2 sequestration are highly variable, depending on feedstock composition, pyrolysis conditions, and post-application soil processes. Market standards currently rely on bulk metrics (e.g., bulk H/C) that do not capture this complexity and current agronomic data is too inconsistent to reveal optimal deployment strategies.

To improve the scientific basis of BCR crediting and field performance evaluation, our team is developing a Trait Mapping framework that links material properties and production technologies to biochar function across diverse soils and climates. Current efforts include:

  1. Building a commercial biochar library, including physical biochar samples from known feedstocks and conversion technologies, with detailed characterization data (e.g. H/C, Random Reflectance (Ro), cation exchange capacity (CEC), pH, ash content, etc.). Spectroscopic approaches (FT-IR and Raman) will be used for select samples in the library.
  2. Development of improved chemical assays that can differentiate biochar reactivity beyond the current market standards.
  3. Implementing field trials that evaluate: (a) the response of the soil to biochar amendment (e.g., plant-available nutrients, microbial community structure, enzyme activity, pH, and water retention) and (b) cost-effective methods for monitoring biochar permanence in the field.

This research supports both carbon market integrity and agronomic optimization, with applications in credit development, soil management, and sustainability planning.

Workstream 4.2: Science and Technology of Enhanced Weathering (EW)

Enhanced weathering (EW) accelerates natural mineral dissolution by applying silicate-rich rocks (e.g., olivine, basalt or ultramafic tailings) to croplands or agroforestry systems, thereby raising soil pH and supplying key nutrients while removing CO₂ through silicate carbonation reactions. In addition to direct CDR, EW may substitute for agricultural lime and support crop productivity in acidified soils, especially in tropical regions. 

At Stanford, our EW research integrates experimental trials with geochemical modeling to evaluate process rates, uncertainties, and field implementation strategies. Current work includes:

  1. A controlled mesocosm study comparing EW feedstocks, including one synthesized mineral designed for enhanced reactivity in collaboration with the Kanan Group in Chemistry—while testing alternative MRV approaches;
  2. Reactive transport modeling of tropical oxisols to understand EW performance in base-cation depleted soils with strong surface buffering and high rainfall variability. A particular focus is placed on comparing silicate and carbonate amendments in terms of both CDR potential and soil pH remediation, with application to smallholder agriculture in Indonesia, Brazil and other tropical regions.

Workstream 4.3. Opportunities for Research Collaborations 

We envision multiple opportunities for applied research and joint demonstration projects that align with the operational priorities of corporate research partners and Stanford’s ongoing work on durable, soil-based carbon dioxide removal (CDR) strategies. The proposed collaborations focus on the incorporation of real-world data to guide the development of accounting frameworks and infrastructure in alignment with the scientific trajectory of key CDR pathways.  The overarching objective is to strengthen the environmental and market value of biochar and enhanced weathering pathways through rigorous, interoperable accounting and robust field evidence.

4.3.1 Carbon Markets and Accounting Infrastructure: OAB

As governments and voluntary registries move toward flux-based, interoperability-focused systems, the credibility of corporate and national carbon mitigation efforts in future carbon markets will depend on alignment with emerging carbon accounting frameworks.  Case studies, based on operational data, that critically evaluate the proposed next-generation credit and accounting infrastructure, including standardized ledgers, feedstock allocation rules, and open-source emissions factors, will be central to both ensuring broader scalability and traceability, and for guiding policy decisions.

Based on the OAB approach, we propose to review existing revenue streams and associated mass balance from biomass production and processing to identify efficiencies and gaps in current streams. In conjunction with the assessment of biomass waste streams, estimated emissions would be paired with the project level data. Collectively, a gap and flux analysis would establish the foundation for an accounting pilot study to assess optimization opportunities and the consequences of different flux attributions, system boundaries, and allocation rules. 

  1. Feasibility and resource optimization study: Given the distribution of resources, agronomic conditions, and potential market endpoints for field level waste, a variety of scenarios for waste utilization may be viable, from in-field residue retention to biochar pyrolysis to export to bioenergy markets. This aim will identify optimal waste utilization, guide BCR production, and set the foundation for a robust accounting pilot. Key work components will include:
    • Data collection and aggregation to inform accounting pilot feasibility and information value to corporate partners/Stanford
    • A CDR-maximizing optimization study to guide the best-case scenario for utilizing waste residues. Study outputs will also include revenue maximizing and future liability-reducing scenarios and their sensitivity to changes in biomass price and availability
    • Assessment of specific life cycle hot spots for potential biochar deployments. Certain factors, such as transportation and pre-processing needs, exert important effects on net process emissions and project viability
  2. Bioichar field study accounting pilot: With an understanding of key parameters, best use cases, and future BCR deployments, an accounting pilot can be initiated. This pilot will include:
    • Physicochemical analysis of biomass inputs and process outputs for allocation strategy design
    • Sensitivity analysis of net process emissions to disparate allocation factors and waste types
    • Real-time data collection from BCR pyrolysis facilities and creation of environmental ledgers
  3. Incentive design for liability-reducing practices: With an understanding of the ground-truth for field level CDR systems, a key next step is to assess feasibility in view of the current market and policy environment. Not all BCR projects may deliver net-negativity on an atmospheric basis. However, many of these projects may provide credible reductions to value chain emissions. In instances where removal presents “insetting” benefits (i.e., liability reductions) rather than true "offsetting" benefits (i.e., asset generation), a new nomenclature and market conceptualization is needed. A demonstration project will:
    • Provide evidence to contextualize the value of these projects on both financial and climate dimensions. This may support a framework for incentive design, project valuation, and integration in markets.
    • Enable assessment of how OAB generates incentive gaps more broadly relative to current crediting frameworks—in dollar values. This can inform near-term policy needs to support CDR. This step is critical to support rigorous, flux-based accounting while continuing to enable learning and development.

4.3.1 Outcomes: Rules-based allocation strategy for mixed feedstocks:

Our work supports carbon-based allocation; however, specific allocation for disparate wastes requires a systems-level understanding of process emissions. We envision that the field verified variety of feedstock materials (e.g., PKS, EFBs, tree waste) may provide a basis to design a comprehensive set of rules for allocating emissions across CDR inputs and configurations. This work product supports accurate, flux-based accounting to align project assessment and crediting with atmospheric outcomes. 

  • Standardized ledger templates: A standardized ledger template that tracks removals and emissions at the time and sector in which they occur is essential for consistent, credible accounting across pathways, methods, and activity scales. Real-time data from field level biochar deployments would provide critical insights into what information is realistically available and at what level of detail and precision. This practical evidence will guide the design of templates that balance accuracy and feasibility for OAB across pathways and scales—addressing interoperability needs by positioning OAB as a common language for carbon accounting. 

4.3.2 Science and Technology of Biochar CDR (BCR): Field trials in Indonesia

  1. Palm plantation trials: soil response and biochar permanence. Perennial crops like oil palm present unique opportunities and challenges for biochar application. Deep root zones and long crop cycles complicate both agronomic assessment and carbon monitoring. A collaborative field trial on GAR plantations would focus on:
    • Agronomic evaluation, targeting early indicators such as soil pH, nutrient availability, and water retention;
    • Permanence assessment, using low-cost field methods (e.g., litterbags at root depth, isotopic tracing) to estimate carbon retention in subsurface soils.

This trial would generate foundational data on biochar’s behavior in tropical plantation systems and inform application techniques, such as injection via fertilizer slurry.

  1. Smallholder trials: Yield Impacts and MRV Prototyping. Annual cropping systems on smallholder farms are less likely to be optimized and thus offer potential for enhancement based on biochar’s agronomic benefits. If GAR plans to distribute biochar locally, nearby farms could serve as field sites to assess:
    • Crop yield responses;
    • Soil chemical and physical changes (e.g., pH, organic carbon, nutrient availability);
    • Cost-effective permanence monitoring under real-world farming conditions.

These trials would not only test MRV strategies but also evaluate biochar’s potential to serve as an agronomic input in emerging markets—generating key insights for demand creation and distribution logistics. We would need to understand the feasibility of data collection and what partnerships could be built to enable the measurements. 

4.3.3 Enhanced Weathering: Lime Alternatives and Deployment Feasibility

Enhanced weathering (EW) offers potential as an agricultural lime substitute or enhancer in acidic tropical soils. We propose preliminary work in field level collaboration with corporate research partners to evaluate potential opportunities:

  • Evaluate our geochemical models of lime requirement against relevant soil data and pH responses to assess potential for (a) ag lime CDR and (b) EW substitution in plantation soil.
  • Assess the geochemical suitability of EW feedstocks under plantation conditions (e.g., pH, rainfall, redox);
  • Evaluate logistical trade-offs (e.g., quarry access, comminution requirements, transport costs) relative to conventional liming agents;
  • Explore integrated soil amendment strategies, including co-application with biochar or compost.

If initial assessment is favorable, a pilot study could test whether EW offers a viable pH management strategy for either smallholder or plantation systems and identify site-specific thresholds for viability.

4.3.2 & 4.3.3 Outstanding Questions

What production data is available at different levels of aggregation and what would be the comfort level of field level corporate researchers in sharing the data to support efforts in Research Area 2.1?

Given the remoteness of current biochar production facility, and likely restrictions on shipping soils to the U.S., are there local resources that could support measurement of agronomic consequences, both in the field and in the laboratory? 

What existing soil and crop data could be used to prototype questions around plantation biochar and EW amendments? 

4.4 2025-2027 vision for Work program 4 evolution: Objective Earth: the Stanford Biochar Project

Biochar, or the conversion of biomass into a charcoal-like substance via pyrolysis, is one of the most effective and deployed forms of carbon removal today. Blending nature-based and engineered climate solutions, biochar offers a suite of co-benefits alongside carbon removal – from soil health and agriculture to wildfire risk reduction. However, its growth is constrained by (1) scientific uncertainty around both durability and co-benefits and (2) fragmented crediting standards that put buyers and the atmosphere at risk. These barriers are intricately linked and cannot be overcome by working in isolation.

The Stanford Biochar Project would bring together an interdisciplinary team of experts and practitioners in carbon cycling, agriculture, market design and climate policy. The project would act as a vital hub for incentivizing collection of the policy-ready data, facilitating open sharing of data, and ultimately coordinating efforts across a broad spectrum of actors.

With more than 90% of delivered engineered removals now coming from biochar and biomass-related pathways, an independent data and verification architecture is urgently needed to guide research, sustain integrity and enable scale.

Our mission is to create the objective data layers – like an open geospatial backbone - for tracking, testing and trusting biochar carbon removal. We do this by sharing credit, measuring what matters, dwelling in complexity, and working with curiosity but not certainty. And, we prioritize long-term collective gains over short-term returns.

Biochar Data Platform: Existing databases curate only pieces of the biochar pipeline and as such, do not support rigorous project, market, or policy design. The Data Platform will curate market-relevant data using research-quality data standards. Analyses of feedstock availability will merge with tracking of market penetration and quality metrics. Emissions data and allocation metrics will support the implementation of high-integrity carbon accounting standards

Global Collaborative and Coordinated Field Trial: There is a nearly endless array of potential feedstocks and deployment strategies, making it difficult to evaluate the potential for any single project to deliver economic, human or physical co-benefits. In tandem with the Data Platform, the Field Trial will focus on catalyzing the development of field trials in the right places with the right materials, reducing the bias and guesswork of getting to gigaton removals and enabling predictive models. A combination of data analysis and convening will launch the field trial, followed by incentive funding to support participation for accepted projects.

Durability Works: Because current market treatments do not require in-field assessment of durability, there is no accepted measurement scheme. This pillar seeks to develop both rapid and inexpensive durability characterization and in-field measurement approaches that enable true high-integrity carbon claims.

Partnerships and Collaborative Networking

The project engages faculty from the Woods Institute’s Natural Climate Solutions Initiative and the Sustainable Finance Initiative to connect science, markets, and governance.

The biochar research and practitioner community is also immensely collaborative. Research partnerships with UC Berkeley, Colorado State University and national laboratories will bring in their strength in models and agricultural practice. International collaborations, including potential partnerships with the Danish government and projects in SE Asia and S. America, will enable global reach.  Practitioners include a host of companies, from large scale producers to small scale artisanal or decentralized producers, that have already generously provided materials, knowledge and perspectives. Finally, implementation partners may include both corporate actors and NGO’s.

Defined Outcomes and Deliverables

Project years 2025-2027

  • Launch of the open-access Biochar Data Platform and integration with existing registries.
  • Global Field Trial coordination network spanning high-priority regions defined by mapping from the Data Platform.
    • Field trials coordinated collaboratively that are designed to evaluate co-benefits in equal measure to field performance metrics relevant for specific crops and agronomic settings.
  • Release of durability testing protocol as “Durability Works v1.0” followed by development of pilot-scale deployable kits.
  • MRV standards adopted by early-stage market and policy partners.