Biochar & Carbon Drawdown

How biochar stores carbon

When biomass (wood, agricultural residues, organic feedstocks) decomposes naturally, the carbon it contains returns to the atmosphere as CO₂ within months or years. Pyrolysis is the term for heating biomass in a low-oxygen environment to around 400–700 °C and then this converts that biomass into biochar. The carbon in biochar is in a structurally stable form that resists biological and chemical breakdown, so it persists in soil for hundreds to thousands of years rather than being recycled back to the atmosphere.

The European Biochar Certificate (EBC) and the IPCC use the term carbon-removal pathway (or “carbon drawdown”) to distinguish this from industrial Carbon Capture & Storage (CCS), which involves capturing CO₂ from flue gases and injecting it into geological formations. Biochar achieves a similar outcome which is net removal of carbon from the active carbon cycle but by stabilising plant-fixed carbon rather than capturing gas.

What biochar does not do

A few things worth being clear about:

• Biochar does not actively adsorb atmospheric CO₂ after it is applied to soil. The carbon storage is locked in at the point of pyrolysis. Biochar’s porosity benefits soil health (water retention, nutrient cation exchange, microbial habitat) rather than ongoing CO₂ capture from the air.
• Biochar is not a renewable resource that can be reused. Its value as a carbon-drawdown pathway is precisely that it stays put.
• “Carbon Capture & Storage” in its regulatory and engineering sense refers to industrial CCS at point sources (power stations, cement works). Biochar is a separate, complementary pathway which is described in the literature as biochar carbon removal (BCR) or carbon drawdown.