The Defensibility Question: Carbon Credit Buying in the Age of Accountability

Carbon Credit Buying in the Age of Accountability

December 2025

The voluntary carbon market in 2025 tells two stories. In one, transaction volumes have contracted from their 2023 peak, prices have softened, and headlines about junk credits continue to erode public confidence. In the other, retirement activity has held steady, a quality tier is emerging around the Integrity Council's Core Carbon Principles, and the price premium for high-quality credits has never been higher. Both stories are true. What matters for corporate buyers is which side of the divide their portfolio sits on.

This analysis examines what actually happened in the market this year—who bought what, how quality differentiation is playing out, and what the patterns suggest about the road ahead.

I. The Landscape Has Changed

The voluntary carbon market contracted in 2024-2025, but the headline decline in trading volume obscures a more nuanced story. Transaction volumes fell significantly compared to 2023. Yet credit prices declined only modestly, and retirement volumes—the ultimate measure of demand—remained remarkably stable.

The divergence suggests a market in transition, not collapse. What's happening is less a retreat from carbon credits than a flight to quality. Buyers are purchasing fewer credits, but the credits they're buying command higher prices.

The market is bifurcating. Credits that meet emerging quality standards—particularly the ICVCM Core Carbon Principles—trade at substantial premiums. Credits that don't are becoming increasingly difficult to use in corporate claims without reputational risk.

Key 2025 Market Indicators (VCM.fyi data):

• 7,255 distinct buyers active in the past 12 months

• 1,616 buyers active in the past 60 days

• 62,783 retirement transactions recorded YTD 2025

• Transaction pace approximately matches 2024 volumes

II. What Corporate Buyers Actually Did in 2025

VCM.fyi tracks retirement activity across the major registries—Verra, Gold Standard, American Carbon Registry, Climate Action Reserve, ART TREES, and others. The buyer data reveals patterns that aren't visible from registry-level statistics alone.

The Top 10 Buyers by 12-Month Volume

The list is dominated by two sectors: oil & gas and aviation. Both face distinct pressures—oil majors are managing scope 3 emissions claims while navigating court challenges to their climate strategies, while aviation is preparing for CORSIA compliance.

Category Composition: The Forest Paradox

Forest credits remain the dominant category among large buyers, despite years of negative press about REDD+ projects. This creates an apparent paradox: the credit type with the most reputational baggage is still the credit type major buyers are acquiring in bulk.

The explanation lies in availability and price. High-quality removal credits—biochar, enhanced weathering, direct air capture—remain scarce and expensive. Buyers with large volume needs can't source enough removal credits at prices their procurement budgets can absorb.

Departures Worth Noting

Several notable buyers have gone quiet:

• Delta Air Lines: Last purchase April 2022. Total historical volume: 11M credits. The portfolio was predominantly renewable energy credits—a category now considered lower-quality.

• Telstra: Last purchase March 2023. Nearly 6M credits retired, primarily renewable energy, then stopped.

• AUDI AG: Last purchase December 2023. 7M credits retired, mostly forest, then silence.

The pattern suggests companies are reassessing their offset strategies rather than simply scaling back. When a buyer with millions of annual retirements goes dark for 2+ years, it's rarely a budget issue. It's a strategy shift.

Meanwhile, new entrants in 2025 include several aviation-linked entities preparing for CORSIA compliance obligations.

III. The Quality Tier Takes Shape

The Integrity Council for the Voluntary Carbon Market (ICVCM) spent years developing the Core Carbon Principles—a benchmark framework for credit quality. In 2025, that framework became operational. The question is: how much of the market actually meets it?

VCM.fyi Project Database Quality Indicators:

The numbers are sobering. Less than 2% of projects in the database carry CCP labels. CORSIA eligibility—required for aviation compliance—covers only 224 projects. Article 6 authorization, which involves host country approval under the Paris Agreement, is vanishingly rare.

This creates a supply-demand mismatch. Buyer demand is shifting toward quality-tier credits, but quality-tier supply remains a sliver of the market.

Geographic Distribution

Quality-tier projects cluster in specific geographies:

• United States: Leads in CCP-labeled projects, particularly ODS destruction and landfill methane

• Latin America: Strong in CORSIA-eligible forestry

• Southeast Asia: Large volume but limited quality certification

• Africa: High volume but quality certification lags

Indonesia—the top source country for several major buyers—has significant forest carbon volume but limited CCP or CORSIA certification. This geographic concentration creates portfolio risk for buyers dependent on single-country sourcing.

IV. Case Studies in Scrutiny

Visibility invites scrutiny. The buyers with the largest public footprints face the most intense examination of their carbon credit claims.

Shell: Volume Leader, Litigation Target

Shell has retired 37.7 million credits since 2018—more than any other corporate buyer in the VCM.fyi database. The portfolio is heavily weighted toward Indonesian forest projects and averages 2017 vintage.

Shell faces ongoing legal pressure in the Netherlands over its climate strategy, including the role of offsets. The company has scaled back its "carbon neutral" product claims in some markets.

The Shell case illustrates the paradox facing large buyers: significant investment in carbon credits has not insulated the company from legal or reputational challenge. If anything, the scale of purchasing has invited more scrutiny, not less.

Delta Air Lines: The Quiet Exit

Delta's trajectory tells a different story. Between 2015 and 2022, the airline retired 11 million credits, branded itself "the world's first carbon-neutral airline," and invested heavily in marketing the claim.

Then came the lawsuit. A class action accused Delta of greenwashing, alleging its carbon neutrality claims were misleading because the offsets it purchased did not represent real emissions reductions.

Delta hasn't retired a single credit since April 2022. The company's carbon neutral claims have disappeared from marketing materials. The lawsuit is ongoing, but the strategy has already shifted.

The Pattern

Both cases share common elements: high-visibility companies, large offset volumes, portfolios concentrated in project types now considered low-quality or high-scrutiny, and eventual legal or reputational challenge.

The lesson is not that carbon credits don't work. It's that credit quality and claim framing matter enormously—and that yesterday's acceptable portfolio may be tomorrow's litigation exposure.

V. The Regulatory Trajectory

The regulatory environment for carbon credit claims has tightened considerably since 2023. Corporate legal and sustainability teams are navigating a shifting landscape.

EU Green Claims Directive

The EU's directives on green claims restrict environmental assertions including carbon neutrality. Key implications:

• Claims of carbon neutrality based solely on offsets face heightened scrutiny

• Companies must demonstrate emissions reductions before relying on offsets

• Third-party verification of claims becomes standard

ICVCM Core Carbon Principles

The Integrity Council's CCP framework establishes threshold quality requirements for carbon credits. The market increasingly treats CCP certification as a floor for acceptable credit quality.

Article 6 and Corresponding Adjustments

The Paris Agreement's Article 6 framework—governing international carbon credit transfers—became operational following COP28. Under Article 6.2, countries can authorize credits for international use, with "corresponding adjustments" preventing double-counting.

For corporate buyers, Article 6 authorization adds a layer of legitimacy. But the scarcity of Article 6 supply means it remains a niche rather than a solution at scale.

What Corporate Teams Are Asking

Based on market patterns, the questions now reaching procurement leads include:

1. "Can we still make carbon neutral claims on products in the EU?"

2. "What happens if a project in our portfolio gets investigated?"

3. "Do we have documentation to defend our credit purchases?"

4. "What would a 'safe' portfolio actually look like?"

These aren't hypothetical questions. They reflect the risk calculus every corporate buyer now faces.

VI. Portfolio Implications

The patterns in the data suggest several risk dimensions corporate buyers should consider.

Credit Type Risk Spectrum

Lower Risk:

• CCP-labeled removal credits

• Article 6 authorized credits

• CORSIA-eligible projects

Higher Risk:

• Standard REDD+ without additional certification

• Renewable energy credits (wind/solar)

• Older vintage credits without recent verification

Vintage Risk

Older vintages face increasing scrutiny. Credits from 2014-2016—common in portfolios of buyers who made early "carbon neutral" commitments—are now nearly a decade old. This raises questions about baseline assumptions, monitoring continuity, and maintained additionality.

Geographic Concentration

Buyers dependent on single-country sourcing face concentrated risk. If a major source country's projects face investigations or regulatory action, portfolios concentrated there have no diversification.

Documentation

The ultimate question for any portfolio: can you document why each credit was purchased and defend the quality determination that was made?

In an environment of increasing scrutiny, the paper trail matters.

The voluntary carbon market in late 2025 is neither dead nor dying. Retirement activity continues at pace. Thousands of buyers remain active. New entrants are joining, particularly in aviation ahead of CORSIA compliance.

But the market is bifurcating—and rapidly. A quality tier is emerging around CCP labels, CORSIA eligibility, and Article 6 authorization. Price premiums for this tier are substantial and rising. Credits outside the quality tier face declining demand and increasing reputational risk.

For corporate buyers, the strategic question is straightforward even if the execution is complex: does your portfolio sit on the right side of this divide?

The data suggests that doing nothing is itself a choice—and increasingly, a risky one.

Data sources: VCM.fyi registry database (11,093 projects tracked), public company disclosures and litigation filings.

Analysis by VCM.fyi. For questions: [email protected]