In the current search for sustainable solutions, biochar has shown great promise as a tool for enhancing environmental health. This unique carbon-rich material is derived from organic materials – such as plant residues, wood or agricultural waste – through a controlled process called pyrolysisPyrolysis is the thermal decomposition of waste at high temperatures (typically 200–400°C or more) in an oxygen-limited environment. The result is a stable, porous carbonaceous product that is central to the fight against land degradation and the climate crisis.

Climate role and carbon sequestration

Biochar is key to climate change mitigation because it represents one of the negative emissions technologiesDuring pyrolysis, the carbon that was originally in the biomass is locked in a stable form, preventing it from quickly returning to the atmosphere as CO₂ during normal decomposition.

Studies show that biochar production itself can prevent the release of 66–130 billion metric tons of CO₂ equivalent over the century. A significant portion of this reduction (approximately 50 %) is attributed to the long-term carbon sequestration capabilities of biochar. Biochar can retain carbon in the soil for centuriesThe average residence time of carbon in soil is approximately 556 ± 483 years. This long lifetime makes biochar an important resource for sustainable land management practices.

Benefits for agriculture and soil

The application of biochar in agriculture brings multifaceted benefits that reduce farmers' carbon footprint and support adaptation to climate change:

1. Improving soil health: Adding biochar improves soil structure, significantly increases its ability to retain water (retention capacity) and nutrient availability.
2. Alternative to fertilizers: Biochar serves as a slow-release fertilizer, reducing the need for expensive and polluting chemical fertilizers and minimizing the risk of nutrient leaching.
3. Reducing emissions from soil: It can reduce methane and nitrous oxide emissions from agricultural soils by altering microbial processes.

In addition to agriculture, biochar also has uses in the remediation of highly polluted industrial sites, in water filtration, in the built environment (for example, in cement or asphalt), and contributes to the circular economy by converting waste biomass into a valuable resource.

Risks and Obstacles to Mass Adoption

Despite its environmental benefits, biochar faces several challenges:

• Production risks: If the pyrolysis process is not precisely controlled, it can generate CO₂ and nitrogen oxides (NOx) emissions, which contribute to air pollution.
• Contamination: If the feedstock (biomass) is not adequately cleaned, biochar may contain harmful substances such as heavy metals or dioxins, posing environmental and health risks.
• Economic barriers: High initial investment in production facilities and the need for extensive distribution networks limit the availability and affordability of biochar.
• Lack of awareness and regulation: A lack of understanding of its benefits and application methods, as well as changing regional regulations, hinder its faster adoption.

The importance of moderate use

Although biochar improves soil, its moderate application is key. Excessive use, especially when applied alone (pure biochar), can negatively affect the soil. It can lead to an increase in soil alkalinity (change in pH) and can cause competition for nitrogen as it increases microbial activity, leading to less availability of nutrients to plants. The recommended optimal use is 5–10 kg of biochar per square meter.

Biochar has the potential to transform agricultural systems and be a cornerstone for a sustainable future. However, to unlock its full potential, investment in research, public education, and policy support is needed. JRi