Methodology
Framework & Standards

Biomass & Soil Carbon Stock Change Method

Net carbon removal is calculated as the change in total ecosystem carbon stock (above-ground biomass, below-ground biomass, dead organic matter, and soil organic carbon) between baseline and project periods. Baseline stocks are established through pre-intervention surveys using stratified random sampling at a minimum density of 1 plot per 2 hectares.

The methodology employs the IPCC Tier 2 approach for mangroves and the Blue Carbon Initiative Standard for seagrasses and saltmarshes. Emission factors are drawn from regional datasets calibrated for the Global South, with mandatory local validation where regional defaults deviate by more than 15%.

Monitoring, Reporting & Verification Protocol

Leakage deductions apply where mangrove restoration displaces fishing, aquaculture, or agricultural activity beyond the project boundary. Leakage zone is defined as a 5 km buffer around the project perimeter.

Eligibility, Durability & Risk

• ✓ Project area must be subject to deforestation or degradation threat (documented by satellite or official land records)
• ✓ No existing legal protection that would prevent the baseline scenario without project intervention
• ✓ Community consent documented and free, prior, and informed (FPIC protocol)
• ✓ 15% of issued credits withheld to buffer pool against reversal risk
• ! Sea level rise scenario analysis required for projects with <2 m mean elevation
• ! Salinity intrusion and storm surge risk must be assessed in the project design document

Mass Balance & Energy-Adjusted Net Removal

Net carbon removal is calculated from direct CO₂ capture mass minus all process-related emissions, including: electricity consumption (grid or dedicated supply), heat energy, sorbent or solvent manufacturing and disposal, compression, transport, and injection or mineralisation of captured CO₂.

All embedded emissions must be calculated using lifecycle assessment (LCA) methodology per ISO 14044. Projects powered entirely by non-fossil energy sources may apply reduced scope 2 emissions factors, subject to additionality documentation for the energy source. Scope 3 emissions from capital equipment manufacturing must be amortised over the project lifetime.

Metering, Data Logging & Third-Party Audit

Eligibility, Durability & Risk

• ✓ Storage formation must be geologically characterised with site-specific modelling
• ✓ No revenue from captured CO₂ sold for enhanced oil recovery (EOR) without full life-cycle accounting
• ✓ Long-term monitoring plan covering 100 years post-injection required
• ! Projects co-located with EOR operations face enhanced scrutiny and require separate accounting boundary

Carbon Stability Fraction Method (CSF-Method)

Net CDR is calculated as: (Biomass Carbon × Biochar Yield × Stable Carbon Fraction) minus (All process emissions including feedstock transport, pyrolysis energy, and application emissions). The stable carbon fraction must be determined for each feedstock-temperature combination using the H/C_org ratio per EBC or IBI standards.

Feedstock Tracking, Pyrolysis Logs & Application Records

Eligibility, Durability & Risk

• ✓ Feedstock must not displace land from food production or intact native vegetation
• ✓ H/C_org ratio must be ≤ 0.7 to qualify as stable CDR (EBC-C standard)
• ✓ Heavy metal concentrations must comply with EBC limits for agricultural application
• ! Feedstocks from dedicated energy crops require additional land-use change analysis

Cation Flux Balance & Soil Inorganic Carbon Tracking

CDR is quantified using the cation flux mass balance method: measuring the depletion of divalent cations (Ca²⁺, Mg²⁺) from applied rock relative to a conservative tracer (Sr, Zr) as a proxy for weathering-driven CO₂ drawdown. Soil pH, alkalinity, and dissolved inorganic carbon in drainage water are monitored as secondary indicators.

Geochemical Sampling & Soil Monitoring

Eligibility, Durability & Risk

• ✓ Silicate rock feedstock must not contain naturally occurring radioactive material (NORM) above background
• ✓ Trace element concentrations (Ni, Cr, As) must comply with EU Fertiliser Regulation and local soil health standards
• ✓ Application must not substitute for natural weathering processes already accounted in national GHG inventories
• ! Methodology v1.3 - under active scientific review for tropical deployment scenarios

Allometric Biomass Expansion & Soil Carbon Modelling

Above-ground carbon is quantified using species-specific and regionally calibrated allometric equations applied to diameter at breast height (DBH) and height measurements. Below-ground biomass is estimated using root-to-shoot ratios. Soil organic carbon change is modelled using RothC or equivalent carbon model validated against regional data, with periodic core sampling for model re-calibration.

Plot-Based Inventory & Remote Sensing

Eligibility, Durability & Risk

• ✓ Project land must have been non-forested for a minimum of 10 years prior to project start (IPCC Tier 1 land-use history)
• ✓ Planted species must be ≥ 80% native or provenance-appropriate to the ecoregion
• ✓ Fire risk management plan mandatory for all projects in fire-prone zones
• ✓ FPIC documentation required where community land rights apply
• ! Projects in high-fire-risk zones (FRI < 30 yr) subject to enhanced buffer contribution of 25%
• ✗ Monoculture plantations of non-native species not eligible under this methodology

Total Alkalinity Mass Balance & Air-Sea Gas Exchange Modelling

CDR is quantified as the increase in dissolved inorganic carbon (DIC) attributable to added alkalinity, modelled using the carbonate chemistry equilibrium equations and verified against direct pCO₂ observations in the treatment zone. The methodology uses a paired-site control design to isolate the treatment signal from natural variability.

Oceanographic Monitoring & Ecological Screening

Status: Beta Methodology - Enhanced Review Required

• ! OAE methodology is in beta - projects accepted under enhanced review with mandatory independent ecological risk assessment
• ! Pre-deployment environmental impact assessment required in all jurisdictions
• ✓ Projects must operate under national marine research or environmental permits
• ✓ Alkaline mineral source must be fully characterised for trace contaminants

Direct Soil Sampling & Dynamic Modelling

Soil organic carbon change is quantified using stratified soil core sampling to a depth of at least 30 cm (100 cm recommended for deep-rooted systems) combined with RothC or Century model projections for inter-sampling period interpolation. Bulk density measurements are mandatory to convert volumetric to mass-equivalent carbon stocks.

Field Sampling, Agronomic Records & Remote Sensing

Eligibility, Durability & Risk

• ✓ Practice change must be demonstrated relative to a 5-year historical practice baseline
• ✓ Whole-farm GHG balance including N₂O and CH₄ must not exceed removed CO₂ (net-negative test)
• ! Reversibility risk from drought, flooding, or land-use reversion requires enhanced buffer for projects in climate risk zones

Full System LCA: Biomass Carbon to Permanent Storage

Net CDR is calculated as the captured and stored biogenic CO₂ minus all fossil and process emissions in the supply chain: biomass growth, harvest, transport, pre-treatment, combustion or gasification, CO₂ capture efficiency losses, compression, transport, and injection. Biomass carbon neutrality must be demonstrated at the landscape scale over the project crediting period.

CEMS, Biomass Tracking & Storage Integrity

Eligibility, Durability & Risk

• ✓ Biomass must meet ISCC PLUS or equivalent sustainability certification
• ✓ No food or feed crop feedstocks permitted
• ! Bioenergy co-product (electricity or heat) must be accounted for and cannot be double-claimed with separate renewable energy certificates
• ✗ Projects using primary forest or peatland biomass ineligible

Tree Biomass & Soil Carbon Stock Change

Above-ground carbon in trees is quantified using allometric equations. Below-ground biomass and soil carbon change are estimated using regional root-to-shoot ratios and validated RothC or ICRAF-WaNuLCAS model projections. Emissions from fertiliser use, livestock, and land preparation are deducted from gross sequestration in the net CDR calculation.

Tree Inventory, Soil Sampling & Practice Records

Eligibility, Durability & Risk

• ✓ Tree integration must represent a genuine change from baseline land management (minimum 10 trees per hectare net increase)
• ✓ ≥ 50% of tree species must be native or provenance-appropriate perennial species
• ✓ Harvested timber carbon must be tracked and deducted from credits at point of harvest
• ! Silvopastoral systems with cattle: methane emissions must be included in the net GHG balance