Biochar is a charcoal-like substance produced by burning organic material from agricultural and forestry wastes (like wood chips, crop residues, or manure) under low-oxygen conditions.
This process, known as pyrolysis, cooks the organic matter at high temperatures which transforms it into a stable, carbon-rich solid.
The end product is a fine-grained, highly porous biochar that is similar to naturally occurring charcoal.
Just like charcoal, biochar is rich in carbon content but remains stable against decomposition for hundreds or even thousands of years.
This makes biochar an incredibly effective means of sequestering carbon long-term and removing CO2 from the atmosphere.
Ancient Amazonians First Discovered Biochar
While this may seem like a novel climate solution, its use actually dates back thousands of years. In the Amazon Basin, indigenous people produced biochar through burning biomass in pits and early kilns.
They would then bury the biochar in the soil, resulting in the extremely fertile Terra Preta soils that still remain today.
These ancient Amazonians likely stumbled upon the agricultural benefits unintentionally. However, they realized its ability to retain nutrients and moisture while promoting soil fertility.
Modern scientists are now rediscovering biochar’s potential from these remnants of ancient land management.
How Biochar Sequesters Carbon
When biomass like wood waste is burned under normal conditions, its energy gets released as carbon dioxide (CO2) into the air.
In contrast, pyrolysis limits oxygen, stopping full combustion from occurring. This incomplete burning stabilizes around 50% of the initial carbon into biochar.
Unlike CO2 which easily escapes, carbon in biochar remains locked away for centuries. Adding biochar to fields mimics the processes that created fossil fuels, effectively storing carbon underground.
This makes biochar a carbon-negative solution. For every ton of biochar produced, approximately 3 tons of CO2 are sequestered.
Biochar Offers Benefits Beyond Carbon Sequestration
While biochar’s climate mitigation potential is impressive, its benefits don’t stop there. Biochar introduces a range of advantages when added to soil:
- Improves soil nutrient retention
- Increases moisture holding capacity
- Creates beneficial microbial habitat
- Reduces nitrogen leaching
- Boosts crop productivity
By enhancing soil health and fertility, biochar enables resilient, abundant agriculture while decreasing reliance on fertilizers and irrigation.
The integrated effects also allow for sustainable farming even on degraded or vulnerable lands.
Given all these benefits, biochar is an exciting opportunity to address climate change while also regenerating soils worldwide. No wonder it’s being rediscovered centuries after indigenous Amazonians first unlocked its secrets.