Biochar Carbon Credits: How They Work and Why They're Durable

Biochar carbon credits represent one of the most promising carbon dioxide removal technologies available today. Produced by heating organic waste in low-oxygen environments, biochar locks carbon into a stable form that persists in soil for centuries to millennia, making it a high-integrity solution for corporate climate strategies.

What Is Biochar and How Does It Remove Carbon?

Biochar is a carbon-rich solid material created through pyrolysis, a process that heats biomass (agricultural residues, forestry waste, or organic byproducts) in the absence of oxygen. This transforms the carbon captured by plants during photosynthesis into a highly stable form that resists decomposition.

When applied to soil, biochar stores carbon that would otherwise return to the atmosphere through natural decay. Unlike fresh biomass, which decomposes within years, biochar's fused aromatic carbon structures make it remarkably resistant to microbial breakdown. Projects can also embed biochar in construction materials or use it for environmental remediation.

Why Biochar Credits Are Considered Durable

Permanence is central to biochar's value as a removal credit. According to IPCC guidelines and established carbon market methodologies, approximately 80% of biochar carbon remains stored after 100 years. Recent research suggests the durability may be significantly higher.

High-quality biochar produced at temperatures above 550°C contains about 75% polycyclic aromatic carbon, which persists for over 1,000 years regardless of soil type or climate. The key quality indicator is the hydrogen-to-carbon (H/C) ratio: biochar with H/C below 0.4 demonstrates the highest permanence.

Puro.earth's 2025 methodology update reflects these scientific advances, extending the credited durability period to several centuries. Standards like Verra's VM0044 and Isometric's Biochar Protocol use similar benchmarks to ensure credits represent genuinely durable carbon storage.

Verification and Market Standards

Robust MRV systems underpin biochar credit integrity. Leading registries require third-party audits, feedstock verification (ensuring biomass would otherwise decompose or combust), and documentation of production parameters including temperature and residence time.

In 2025, the Integrity Council for the Voluntary Carbon Market approved three biochar methodologies: Verra VM0044, Isometric Biochar Production and Storage, and Climate Action Reserve's U.S./Canada Biochar protocol. In December 2025, ICVCM also confirmed Puro.earth as CCP-Eligible, allowing its biochar methodology to be assessed for CCP labeling. These endorsements confirm biochar meets Core Carbon Principles for high-integrity credits.

Major corporate buyers have responded: demand for biochar credits has doubled each of the last two years. Microsoft has committed to 1.24 million tonnes over ten years, while Google, Swiss Re, and JPMorgan have secured substantial offtake agreements. Puro.earth alone issued over 1.38 million total carbon removal certificates by December 2025, with biochar representing a major share. Biochar accounted for 89% of all durable CDR credits actually delivered in Q2 2025, reflecting its operational maturity and faster time-to-delivery compared to alternatives like BECCS or DAC.

Key Takeaway

Biochar offers a scalable, scientifically validated pathway for durable carbon removal. With ICVCM-approved methodologies, major corporate adoption, and storage timescales measured in centuries, biochar credits provide buyers with high confidence in climate impact. As demand grows and supply tightens (with roughly 40% of 2026 high-quality supply already contracted), early engagement with quality biochar projects becomes increasingly strategic.