Biochar is a carbon negative, charcoal based, soil amendment that can be designed to help reclaim and improve marginal soils by increasing soil water holding capacity and enhancing fertility, while also generating high-value renewable energy co-products during its production.
　　If deployed correctly, the biochar process is carbon negative: it removes net carbon from the atmosphere. When a green plant grows, it takes CO₂ out of the air to build biomass. All of the carbon in the plant came from CO₂ taken out of the air, and returns to the air when the plant dies and decomposes. When the biomass is instead pyrolyzed—heated in the absence of oxygen—it produces charcoal, which is called biochar when it is buried in the ground. Over 40% of the total carbon from the waste biomass is retained in biochar and sequestered in the soil for thousands of years, effectively removing that carbon from the atmosphere.

The carbon in 1 ton of biochar is equivalent to about 3 tons of CO₂.