VCM 101: How the Voluntary Carbon Market Evolved From Kyoto to Today

From the Clean Development Mechanism to Core Carbon Principles — three decades of carbon market evolution explained.

By Abhishek Das • March 2026 • 8 min read

The Clean Development Mechanism under the Kyoto Protocol established the fundamental carbon market architecture that still underpins carbon markets today. For the first time, there was a global standardised system: project developers would implement emissions reduction or removal projects in developing countries, independent auditors would verify the reductions, a registry would issue and track credits, and buyers would retire them. Over 7,800 CDM projects were registered across 100+ countries, issuing 2.4 billion Certified Emission Reductions (CERs). It was a triumph of protocol engineering.

But the CDM was built for governments. Annex I countries (developed nations) had binding reduction targets and could use CDM credits to help meet them. Companies with no legal obligation began buying voluntarily, creating a gap that gave birth to the Voluntary Carbon Market as a distinct ecosystem. This nascent market had no standards, no consistency, and no guarantee of quality. It would take another decade to build the infrastructure of trust.

Independent standards bodies filled the void. Verra's Verified Carbon Standard (VCS) became the dominant framework for voluntary offsets. Gold Standard focused on projects with co-benefits — renewable energy, cookstoves, clean water. Project types diversified: renewables, REDD+ (forest protection), landfill gas, energy efficiency. Corporate sustainability functions matured simultaneously. GRI frameworks emerged, CDP (formerly Carbon Disclosure Project) launched, and companies began asking: what are we actually offsetting? And for how much?

Registries became the backbone of the market. Verra, Gold Standard, and others set standards, vetted projects, issued credits with unique serial numbers, and tracked retirements to prevent double-counting. Annual VCS issuance rose from a few million tonnes in 2010 to over 43 million tonnes by 2017. The voluntary market had found its legs.

The Paris Agreement shifted the conversation entirely. No longer just about regulatory compliance, net-zero became the North Star. Article 6 created a framework for international carbon trading — a path from voluntary markets toward integration with compliance markets. SBTi was founded in 2015 to translate net-zero ambition into corporate targets. Climate Action 100+ mobilized investor pressure. Race to Zero launched to mobilize non-state actors. Carbon credits evolved from Corporate Social Responsibility tools to strategic components of climate strategies.

Annual VCM credit retirements exceeded 70 million tonnes by 2019. The market was accelerating, riding the wave of a simple realization: the climate math does not allow for 90%+ direct reductions in all sectors by 2050. Residual emissions would have to be addressed. The question was how.

COVID-19 paradoxically accelerated corporate climate commitments. Microsoft announced carbon negative by 2030. Unilever, BMW, Apple, Google followed with ambitious net-zero pledges. McKinsey estimated a 15-fold growth in VCM credit demand by 2030 would be necessary. Prices surged. Trading platforms proliferated — Bloomberg, ICE, Refinitiv, new fintech startups. Carbon credits became an asset class. Hundreds of millions of dollars flowed into carbon startups. TSVCM (Taskforce on Scaling Voluntary Carbon Markets) published its blueprint for market transformation.

Retirements exceeded 150 million tonnes in 2021. The infrastructure, however, could not keep pace with the ambition. Project quality was inconsistent. Additionality claims were difficult to verify at scale. And as demand accelerated, greenwashing allegations surfaced.

Investigative reporting exposed over-crediting in REDD+ projects. The Guardian and Die Zeit published investigations showing that forest protection credits were being issued for forests that faced no realistic risk of deforestation. The findings were devastating to market confidence. But they also catalyzed reform.

The Integrity Council for the Voluntary Carbon Market (ICVCM) published the Core Carbon Principles (CCPs) — ten science-based criteria for credit quality. Programmes began submitting methodologies for assessment. By the end of 2025, eight programmes and 36 methodologies had been assessed. CCP-labelled credits commanded approximately 25% price premiums over non-certified credits. Verra launched a revised REDD+ methodology (VM0048) to address baseline rigor. Sylvera, BeZero, and Calyx Global emerged as independent credit rating agencies, bringing third-party due diligence to project evaluation.

VCMI released its Claims Code of Practice and Scope 3 Action Code in May 2025, setting standards for corporate carbon neutrality claims. The market shifted from avoidance-focused strategies (REDD+, methane) toward removals (reforestation, engineered carbon dioxide removal). SBTi-aligned companies allocated 47% of retirements to forestry and afforestation, almost entirely abandoning waste and landfill gas credits.

The road ahead is defined by three structural shifts. First: the growing primacy of carbon removals. Atmospheric removal of CO2 is increasingly recognised as unavoidable. Supply of high-quality avoidance credits is constrained. Engineered CDR technologies — biochar, direct air capture (DAC), enhanced rock weathering — are scaling rapidly. Microsoft signed commitments for approximately 45 million tonnes of removal credits through 2025. Puro.earth became the eighth CCP-eligible programme in early 2026, focused entirely on engineered removals.

Second: Article 6 convergence. International carbon market rules are being operationalised. Corresponding adjustments (host countries track and adjust for exports), Letters of Authorization (LoAs) for project hosting, and voluntary-compliance market integration are creating new linkages between VCM and compliance markets. The EU 2040 climate target could create hundreds of millions of tonnes of additional demand.

Third: data and technology transformation. Satellite monitoring of forest cover and project impacts is reducing additionality uncertainty. AI-driven verification systems are accelerating due diligence. Blockchain and distributed registries are improving transparency and preventing double-counting. The next generation of market infrastructure will look nothing like the CDM — it will be real-time, AI-assisted, and globally distributed.

References

ICVCM Core Carbon Principles Impact Report 2025. VCMI Claims Code of Practice & Scope 3 Action Code 2025. UNFCCC — Paris Agreement Article 6. SBTi Corporate Net-Zero Standard. Verra VCS Programme. Gold Standard Foundation.