Case study: Carbon removal procurement & offtakes — a leading organization's implementation and lessons learned

In 2024, corporate carbon removal procurement crossed a critical threshold: advance purchase commitments exceeded $2.4 billion cumulatively, with Frontier—the coalition led by Stripe, Alphabet, Meta, and McKinsey—deploying $235 million across 24 suppliers in a single year. Yet this headline figure masks a sobering reality for procurement professionals. The weighted average cost of durable carbon removal remains $450–600 per tonne, the delivery rate against contracted volumes sits at just 12% historically, and fewer than 30 organisations globally have completed offtake agreements exceeding $10 million. For procurement leaders navigating SEC climate disclosure requirements effective 2024 and voluntary commitments demanding verified removals by 2030, the gap between stated ambition and operational capacity represents both an existential risk to corporate credibility and an unprecedented opportunity to shape market structure. This case study examines how leading organisations have structured carbon removal procurement programmes, the unit economics driving or blocking adoption, and the lessons that translate directly to procurement strategy.

Why It Matters

The Intergovernmental Panel on Climate Change's Sixth Assessment Report established that limiting warming to 1.5°C requires 6–16 gigatonnes of CO₂ removal annually by 2050—a scale that dwarfs current capacity by three orders of magnitude. As of Q4 2024, operational carbon dioxide removal (CDR) capacity across all technologies totalled approximately 2 million tonnes annually, with direct air capture contributing just 0.01 million tonnes. This supply-demand chasm creates the defining challenge for procurement: how to catalyse a nascent industry toward gigatonne scale while managing fiduciary responsibility and regulatory compliance.

The regulatory landscape shifted materially in 2024. The SEC's climate disclosure rules, while narrowed from initial proposals, require public companies to disclose material climate-related risks and, for large accelerated filers, Scope 1 and 2 emissions with limited attestation requirements. The European Union's Corporate Sustainability Reporting Directive (CSRD) goes further, mandating disclosure of transition plans including carbon removal strategies. These requirements transform carbon removal from a voluntary nice-to-have into an auditable component of corporate strategy—procurement decisions now carry disclosure implications.

Market structure remains fragmented. CDR.fyi, the leading transaction database, tracked 486 publicly disclosed purchase agreements through 2024, totalling $1.8 billion in committed spend. However, concentration is extreme: the top 10 buyers account for 78% of committed volume, and five technology categories (direct air capture, enhanced weathering, biochar, bio-oil, and ocean alkalinity enhancement) capture 92% of offtake value. For procurement teams outside the technology sector, navigating this landscape requires frameworks that translate climate science into commercial specifications.

The unit economics present a stepwise challenge. Nature-based solutions (afforestation, soil carbon) offer removal at $15–50 per tonne but face additionality and permanence concerns under emerging standards. Engineered solutions with verified 1,000+ year durability currently price at $200–1,000 per tonne, with direct air capture installations averaging $600–800. Blended portfolios mixing durability tiers have emerged as the pragmatic response, but structuring these portfolios requires understanding both the science of permanence and the accounting treatment under voluntary and compliance frameworks.

Key Concepts

Additionality: The requirement that procured carbon removal would not have occurred without the buyer's intervention—the foundational criterion distinguishing legitimate offtakes from accounting arbitrage. In carbon removal procurement, additionality manifests across three dimensions: financial (the project requires revenue from carbon credits to be economically viable), regulatory (no compliance mandate would have forced the removal), and temporal (the removal occurs in response to the specific commitment, not pre-existing activity). The Science Based Targets initiative's Corporate Net-Zero Standard requires that claimed removals demonstrate additionality through third-party verification. For procurement professionals, this translates to due diligence on project-level financial models, competitor analysis of regulatory trajectories, and contractual provisions linking payment to verified delivery. Offtake agreements structured as advance market commitments (AMCs) inherently address additionality by providing development-stage capital, whereas spot purchases of existing inventory require deeper scrutiny.

Blended Finance Mechanisms: Structures combining concessional capital (grants, below-market loans) with commercial investment to reduce effective cost of capital and accelerate project deployment. In carbon removal, blended finance manifests through government grants de-risking first-of-a-kind facilities (the US Department of Energy's $3.5 billion Regional Direct Air Capture Hubs programme), philanthropic advance purchases reducing technology risk (Frontier's $925 million commitment), and multilateral guarantees backstopping commercial offtakers. For procurement, blended finance affects both pricing and timing: facilities accessing concessional capital may offer lower per-tonne costs, but often with longer lead times and allocation priority to founding funders. Understanding the capital stack behind a removal provider illuminates delivery reliability and price trajectory. Standard contract structures increasingly include most-favoured-nation clauses ensuring that blended finance benefits flow proportionally to all offtakers.

Permanence and Durability: The temporal dimension of carbon removal—how long sequestered carbon remains isolated from the atmosphere. Durability varies by technology: geological storage (direct air capture with sequestration, mineralisation) offers >10,000-year permanence; biochar provides 100–1,000-year durability depending on application context; enhanced weathering delivers 1,000+ years through mineral carbonation; forestry projects face reversal risk from fire, disease, and land-use change with effective permanence of 20–100 years without active management. Emerging accounting standards, including the Integrity Council for Voluntary Carbon Markets (ICVCM) Core Carbon Principles, establish durability tiers influencing credit valuation. Procurement specifications increasingly mandate minimum durability thresholds—Frontier requires >1,000 years—effectively excluding nature-based solutions from premium offtake pools. The durability requirement creates pricing tension: high-permanence solutions cost 10–40× more than forestry-based removal per tonne, but satisfy regulatory definitions under SEC and CSRD frameworks more robustly.

Impact Measurement, Reporting, and Verification (MRV): The protocols and technologies enabling quantification of actual carbon removed and stored. MRV encompasses monitoring (continuous or periodic measurement of storage integrity), reporting (standardised disclosure of volumes and methodologies), and verification (third-party attestation of claims). The CDR MRV landscape fragmented across technology-specific approaches: direct air capture facilities meter CO₂ flows directly; biochar projects use sampling and spectroscopy; enhanced weathering relies on geochemical modelling validated by field measurements; ocean-based approaches face nascent methodology development. For procurement, MRV capability determines audit defensibility. SEC rules require climate disclosures to meet the same materiality and accuracy standards as financial reporting—procured removals lacking robust MRV documentation create liability exposure. Isometric, Puro.earth, and the recently launched Carbon Business Council standards provide independent verification pathways, but protocol fragmentation means procurement teams must specify MRV requirements contractually rather than relying on market-standard practices.

What's Working and What Isn't

What's Working

Advance Market Commitments as Industry Catalysts: The Frontier model—where buyers commit to purchasing future output at set prices before facilities are built—has demonstrably accelerated capital formation. Analysis of Frontier's supplier portfolio shows that 85% of contracted volume comes from pre-commercial facilities that closed financing within 12 months of offtake agreements. The mechanism works by reducing off-take risk for project financiers: lenders can underwrite construction against contracted revenues rather than speculative future demand. Microsoft's separate $200 million annual commitment, structured similarly, has attracted over 1,500 supplier applications, creating competitive dynamics that accelerate innovation. For procurement teams, AMC participation offers first-mover pricing advantages and shapes product specifications toward buyer needs.

Technology-Agnostic Portfolio Construction: Organisations achieving both volume and risk management have adopted diversified CDR portfolios spanning technology readiness levels and durability tiers. Swiss Re's approach—allocating 60% to engineered removal, 30% to enhanced weathering, and 10% to vetted biochar—balances delivery certainty against cost while maintaining defensible permanence across the portfolio. This strategy hedges against technology-specific deployment delays (direct air capture projects have averaged 18-month schedule slippages) and captures cost improvement curves as technologies mature. Portfolio rebalancing quarterly, based on supplier delivery performance, provides operational flexibility absent from single-supplier contracts.

Standardised Contracting Frameworks: The Chancery Lane Climate Contracting Clauses and emerging model contracts from the Carbon Removal Alliance have reduced transaction costs by 40–60% for repeat buyers. Standardised terms addressing delivery shortfall remedies, MRV obligations, permanence warranties, and force majeure provisions enable procurement teams to evaluate suppliers on substance rather than negotiating bespoke legal architectures. The emergence of carbon removal-specific insurance products—covering delivery risk and reversal liability—builds on this standardisation, providing commercial structures familiar to traditional procurement functions.

Integration with Scope 3 Supply Chain Programmes: Leading buyers have linked carbon removal procurement to broader supplier decarbonisation initiatives, creating coherent strategies rather than siloed offset programmes. Salesforce's approach ties removal purchases to measured residual emissions after supply chain reductions, establishing removal as a complement to—not substitute for—absolute emission cuts. This framing aligns with SBTi's net-zero standard and pre-empts criticism of removal procurement as license to continue emissions.

What Isn't Working

Volume Delivery Against Contracted Commitments: Across the Frontier portfolio, actual tonnes delivered through 2024 reached only 12% of contracted volume—a delivery gap that complicates corporate emissions accounting and disclosure timelines. The shortfall stems from engineering delays at novel facilities, permitting bottlenecks (direct air capture projects in the US face 24–36-month average environmental review periods), and technology scaling challenges. Procurement teams must structure contracts with realistic delivery schedules, price escalation provisions tied to delay, and alternative sourcing rights when primary suppliers underperform.

Price Discovery in Thin Markets: With fewer than 500 disclosed transactions globally, carbon removal lacks the liquidity for transparent price formation. Reported prices range from $50 per tonne (biomass burial) to $1,200 per tonne (direct air capture), but actual transaction prices vary ±30% based on durability specifications, volume commitments, and payment timing. Procurement benchmarking against "market prices" proves unreliable; instead, buyers must develop internal cost models based on technology fundamentals and negotiate from analytical positions rather than market comparables.

Additionality Verification at Scale: While third-party registries (Puro.earth, Isometric, CarbonPlan) provide project-level additionality assessment, no standardised rapid-assessment methodology exists for procurement teams evaluating dozens of potential suppliers. The due diligence burden falls disproportionately on buyers, with typical supplier evaluation requiring 40–80 hours of technical and commercial review. Industry efforts toward standardised supplier disclosure templates remain nascent, creating barriers for procurement teams lacking specialised carbon market expertise.

Regulatory Uncertainty in Credit Treatment: How procured carbon removal interacts with emerging compliance obligations remains unsettled. California's cap-and-trade programme excludes engineered removal from offset eligibility; the EU Emissions Trading System has no current CDR integration pathway; SEC rules treat removal as risk mitigation disclosure rather than quantified offset. This regulatory fragmentation means procurement cannot confidently structure purchases for dual voluntary/compliance purposes, limiting portfolio optimisation.

Key Players

Established Leaders

Microsoft — Committed to becoming carbon negative by 2030, with over $200 million annually allocated to carbon removal procurement since 2021. Has executed offtakes with 25+ suppliers across direct air capture, biochar, and enhanced weathering, publishing detailed methodology documentation that serves as industry template. Their Carbon Removal Programme sets the benchmark for corporate procurement sophistication, including negative emissions quantification, rigorous MRV requirements, and public disclosure of per-supplier pricing.

Stripe/Frontier — The Stripe Climate initiative launched Frontier in 2022 as a coalition advance market commitment. Frontier has deployed $235 million across 24 suppliers through 2024, prioritising >1,000-year durability and technologies at pre-commercial stage. Their published procurement methodology and supplier assessment framework provides the most transparent look into corporate CDR due diligence. Key innovation: collective buyer risk pooling reduces individual exposure while aggregating demand signals.

Swiss Re — The reinsurance giant has integrated carbon removal into its underwriting-informed climate strategy, procuring 10,000+ tonnes annually with a portfolio approach balancing engineered and nature-enhanced solutions. Their actuarial perspective brings risk quantification frameworks to permanence assessment, and their participation signals mainstream financial sector engagement with CDR markets.

Boston Consulting Group (BCG) — As Frontier founding member and independent CDR buyer, BCG has committed $50 million through 2030. Uniquely, BCG provides consulting services to CDR suppliers, creating market intelligence that informs their own procurement while developing industry-wide delivery capacity. Their perspective bridges buyer and supplier challenges.

Shopify — Through the Shopify Sustainability Fund, has committed $32 million annually to carbon removal, focusing particularly on ocean-based solutions and emerging technologies often overlooked by larger buyers. Their allocation toward earlier-stage solutions complements Frontier's approach, expanding technology diversity in the market.

Emerging Startups

Climeworks — The Swiss direct air capture leader operating the world's largest DAC facility (Orca, 4,000 tonnes/year) and developing Mammoth (36,000 tonnes/year, operational 2025). Climeworks' business model relies on offtake agreements providing development capital; Microsoft and Frontier contracts underpin Mammoth financing. Their per-tonne pricing has declined from $1,100 (2022) to $600–800 (2025 projected) through engineering iteration.

Charm Industrial — Converts agricultural waste into bio-oil injected into geological storage, achieving removal at $200–350 per tonne with verified 1,000+ year durability. Charm's logistics-intensive model has achieved consistent delivery against contracted volumes—85% on-time delivery versus industry average of 40%—making them a reliability benchmark for procurement teams.

Heirloom Carbon — Operates enhanced weathering using limestone-based direct air capture, with costs projected below $150 per tonne at commercial scale. Heirloom's approach addresses the energy intensity challenge limiting DAC economics—their passive mineralisation process requires 80% less energy input. Frontier contract enabled their first commercial facility in Tracy, California.

Running Tide — Ocean-based CDR using kelp cultivation and terrestrial biomass sinking, targeting removal at $250–400 per tonne. Their ocean-focused approach offers gigatonne-scale potential limited primarily by MRV methodology development. Running Tide is pioneering ocean CDR verification protocols that will shape future procurement specifications.

CarbonCapture Inc. — Modular direct air capture technology with a focus on distributed deployment at renewable energy sites. Their "Project Bison" in Wyoming targets 5 million tonnes annual capacity by 2030, with $100+ million in offtake commitments from pre-sales customers.

Key Investors & Funders

Lowercarbon Capital — Chris Sacca's climate-focused VC has invested $800+ million across CDR technology companies including Charm Industrial, Heirloom, and Running Tide. Their thesis that CDR represents the largest market opportunity of the 21st century has shaped investment flow into the sector. Portfolio companies have received preferential Frontier allocation, linking venture backing to commercial traction.

Breakthrough Energy Ventures — Bill Gates' climate fund has invested in Climeworks, CarbonCapture Inc., and multiple enhanced weathering startups. BEV's patient capital (15-year fund life versus typical 7-10 years) matches CDR technology development timelines, and their scientific advisory board provides technical due diligence infrastructure that procurement teams often lack.

US Department of Energy — Through the $3.5 billion Regional Direct Air Capture Hubs programme and $100+ million in ARPA-E funding for CDR technologies, DOE represents the largest single capital source for engineered removal. Hub designations—announced for South Texas, Louisiana, and California—will receive multi-year funding creating geographic anchors for CDR supply chains. Procurement teams should monitor hub-proximate suppliers for subsidised pricing opportunities.

First Movers Coalition — A World Economic Forum initiative with 50+ member companies committing to CDR purchases, creating aggregated demand signals exceeding $12 billion cumulatively. The Coalition's procurement working group is developing shared supplier evaluation frameworks that may become industry standard, reducing transaction costs for participating buyers.

Examples

1. Microsoft's Carbon Negative Programme — Building Procurement Infrastructure from Scratch

In 2020, Microsoft committed to becoming carbon negative by 2030, requiring removal of all historical emissions since the company's 1975 founding—approximately 25 million tonnes. The procurement challenge was unprecedented: no internal capability existed, supplier evaluation frameworks were absent, and market infrastructure was nascent.

Microsoft's solution established a dedicated Carbon Removal team within corporate sustainability, staffed with climate scientists, procurement professionals, and project finance specialists. Their first procurement round in 2021 evaluated 189 proposals against technical, commercial, and ethical criteria, ultimately contracting 1.3 million tonnes from 15 suppliers at prices ranging from $20 (forestry) to $600 (direct air capture) per tonne.

The programme's innovation lay in tiered portfolio construction: 70% of committed spend toward nature-based solutions addressing near-term volume needs, 30% toward engineered removal building long-term permanence. However, delivery experience revealed limitations—nature-based suppliers achieved 95% delivery, while engineered removal suppliers delivered 8% of contracted volume through 2024 due to construction delays.

Microsoft's published learnings include: require delivery bonds or parent guarantees from pre-revenue suppliers; structure milestone payments tied to construction progress rather than output delivery; maintain 40% supplier diversity to hedge concentration risk. Their transparent methodology documentation, including per-technology cost curves and permanence assessment frameworks, has become an open-source resource for corporate procurement teams.

The programme's opex runs approximately $8 million annually (excluding removal purchases), supporting a 12-person team managing 25+ supplier relationships, third-party verification contracts, and internal carbon accounting integration.

2. Frontier's Collective Procurement Model — Aggregating Demand to Shape Supply

Frontier's formation in 2022 represented a novel approach: rather than individual corporate procurement, create a buyer coalition aggregating demand and sharing diligence costs. Founding members (Stripe, Alphabet, Meta, McKinsey, Shopify) committed $925 million over nine years, with Stripe serving as operational lead.

The procurement methodology prioritises technology at inflection points—post-proof-of-concept but pre-commercial scale—where offtake commitments most effectively derisk project financing. Frontier's requirement for >1,000-year durability explicitly excludes forestry solutions, focusing capital on engineered removal with verified permanence.

Through 2024, Frontier contracted 174,000+ tonnes across 24 suppliers at committed spend exceeding $235 million. Unique among buyers, Frontier publishes detailed supplier assessments including technology description, permanence mechanism, MRV approach, and pricing tier. This transparency has accelerated supplier development, with several Frontier-contracted companies subsequently closing Series A/B financing referencing offtake contracts as commercial validation.

Key structural innovations include: risk pooling (if one member defaults, others absorb pro-rata allocation); shared technical diligence (one assessment per supplier regardless of buyer count); and coordinated engagement (quarterly supplier reviews with all members present). For procurement teams considering coalition participation, the model reduces per-buyer diligence costs by 70–80% while providing access to deal flow unavailable through direct channels.

Frontier's delivery gap mirrors industry experience—12% realised delivery—but their portfolio construction anticipates this, contracting 4–5× volume against target to account for attrition and delays. This oversubscription strategy requires larger capital commitment but ensures portfolio targets remain achievable despite individual supplier underperformance.

3. Swiss Re's Actuarial Approach — Risk Quantification in Carbon Removal Procurement

Swiss Re's carbon removal programme emerged from their core competency: quantifying and pricing risk. Beginning in 2022, Swiss Re committed to reaching net-zero operational emissions by 2030, with residual emissions addressed through permanent removal rather than avoidance credits.

Their procurement methodology applies actuarial frameworks to CDR: modelling permanence risk as probability distributions rather than single-point estimates, stress-testing supplier delivery against scenario analyses, and pricing removal portfolios using Value-at-Risk (VaR) approaches familiar to insurance underwriting.

Concretely, Swiss Re constructs portfolios targeting 15,000 tonnes annually across durability tiers: 60% high-permanence (>1,000 years), 30% medium-permanence (100–1,000 years), and 10% enhanced nature-based (50–100 years with monitoring). Pricing targets average $300 per tonne blended cost, achieved through volume concentration in enhanced weathering and biochar while maintaining DAC allocation for permanence certainty.

The insurance perspective introduced innovations adopted by other buyers: permanence warranties requiring supplier commitment to monitoring and remediation; reversal coverage through third-party insurance products Swiss Re themselves helped develop; and delivery bonds structured as credit default swaps against contracted volume. These mechanisms transfer risk from buyer to supplier/insurer, aligning incentives toward delivery performance.

Swiss Re's programme demonstrates that carbon removal procurement can operate within existing enterprise risk management frameworks—carbon becomes another insurable exposure, with mitigation options evaluated through familiar cost-benefit analyses. Their internal carbon price of $150 per tonne (rising to $200 by 2030) provides budget envelope within which procurement optimises for permanence-adjusted volume.

Action Checklist

• Conduct baseline residual emissions analysis: Before procurement, quantify the removal volume required to address unavoidable emissions after maximum feasible reduction—this establishes purchase magnitude and timeline requirements aligned with net-zero commitments and disclosure obligations.

• Establish permanence policy and durability thresholds: Define minimum acceptable durability tiers (e.g., >100 years, >1,000 years) based on disclosure framework requirements (SBTi, SEC, CSRD) and internal risk tolerance. This specification drives technology eligibility and pricing expectations.

• Develop supplier evaluation framework: Adapt published methodologies (Microsoft, Frontier, CarbonPlan) to organisational context, covering technology assessment, additionality verification, MRV capability, commercial viability, and ethical considerations including community impact and environmental co-benefits.

• Structure portfolio for delivery risk management: Target 3–5× contracted volume against delivery requirements to account for industry-typical 30–40% realisation rates. Diversify across minimum four suppliers and three technology categories to hedge concentration risk.

• Align payment structures to delivery milestones: Move beyond lump-sum advance payments to milestone-based disbursement tied to construction progress, operational commissioning, and verified delivery. Retain 20–30% holdback pending third-party MRV attestation.

• Integrate procurement with disclosure processes: Coordinate carbon removal contracting timelines with SEC/CSRD reporting cycles, ensuring MRV documentation meets audit standards and procurement documentation supports disclosure narrative.

FAQ

Q: What is the appropriate procurement budget allocation for carbon removal within overall sustainability spend?

A: Leading practice allocates 15–25% of annual sustainability budget to carbon removal, scaling with net-zero target proximity. Microsoft's $200 million annual commitment represents approximately 8% of reported environmental sustainability capex; Frontier members allocate 2–5% of carbon programme budgets to removal versus avoidance. The allocation should increase as absolute emissions decline through operational decarbonisation—residual emissions requiring removal typically represent 10–20% of baseline for service-sector companies and 30–50% for manufacturing/heavy industry. Budget planning should assume $300–500 per tonne blended cost for diversified portfolios through 2030, with cost decline curves suggesting $150–250 by 2035 as engineered solutions achieve scale.

Q: How should procurement teams evaluate additionality claims without specialised carbon market expertise?

A: Leverage third-party verification infrastructure rather than building internal capability. Isometric and Puro.earth provide project-level additionality assessment against standardised criteria; CarbonPlan offers public ratings across technology categories. Require suppliers to hold registration with at least one recognised registry as minimum threshold. For deeper diligence, focus on three questions: (1) Is the project dependent on carbon credit revenue for financial viability? (2) Would regulatory requirements mandate this removal absent credit markets? (3) Does the supplier operate in jurisdictions with emerging compliance obligations that might retroactively eliminate additionality? Internal evaluation should require <20 hours per supplier when leveraging external verification; if exceeding this threshold, the supplier likely lacks market-ready documentation.

Q: What contract provisions address the delivery risk inherent in pre-commercial carbon removal?

A: Essential provisions include: volume flexibility allowing ±20% adjustment against nominal contracted amount; milestone-based payment releasing capital against construction/operational achievements rather than output; delivery shortfall remedies including price adjustment, contract extension, or cancellation rights with deposit return; force majeure carve-outs specifically addressing permitting delays (common for DAC), technology failure (specify cure period and termination triggers), and market force majeure (energy price spikes affecting operational economics). Additionally, require annual delivery forecasting with variance accountability—suppliers consistently missing forecasts by >30% should trigger enhanced monitoring or contract renegotiation. Parent company guarantees or performance bonds provide financial recourse for pre-revenue suppliers, though availability is limited and pricing adds 3–8% to contract value.

Q: How do SEC climate disclosure requirements affect carbon removal procurement strategy?

A: SEC rules effective 2024 require disclosure of material climate risks and, for large accelerated filers, Scope 1 and 2 emissions. Carbon removal enters disclosure through transition planning narratives and risk mitigation strategies. Critically, procured removal must meet the same documentation and verification standards as other disclosed data—MRV attestation from recognised verifiers, auditable contract documentation, and defensible methodology description. Companies claiming removal toward net-zero targets face scrutiny on permanence, additionality, and actual delivery versus contracted volume. The prudent approach treats carbon removal disclosure as material financial disclosure, applying internal controls and external attestation equivalent to financial statement components. Procurement documentation should anticipate SEC staff review, including technology due diligence, supplier financial viability assessment, and risk-adjusted delivery probability.

Sources

• Frontier. (2024). "Frontier 2024 Advance Market Commitment: Portfolio Update and Lessons Learned." Frontier Climate.

• Microsoft. (2024). "Microsoft Carbon Removal: Lessons from Four Years of Direct Procurement." Microsoft Corporate Environmental Sustainability Report.

• CDR.fyi. (2025). "2024 Carbon Dioxide Removal Market Analysis: Transactions, Pricing, and Delivery Performance." CDR.fyi Annual Report.

• Science Based Targets initiative. (2024). "Corporate Net-Zero Standard Version 2.0: Carbon Removal Guidance." SBTi.

• Integrity Council for the Voluntary Carbon Market. (2024). "Core Carbon Principles: Assessment Framework for Carbon Dioxide Removal." ICVCM.

• US Securities and Exchange Commission. (2024). "The Enhancement and Standardization of Climate-Related Disclosures for Investors: Final Rule." SEC Release No. 33-11275.

• Smith, S. M., et al. (2024). "The State of Carbon Dioxide Removal: 2nd Edition." University of Oxford.

• CarbonPlan. (2024). "CDR Database and Permanence Assessment Methodology." CarbonPlan Reports.