Biochar: Carbon Mitigation from the Ground Up

Environmental Health Perspectives

As multibillion-dollar projects intended to sequester carbon dioxide (CO2) in deep geological storage continue to seek financial support, the fertile black soils in the Amazon basin suggest a cheaper, lower-tech route towards the same destination.

Scattered patches of dark, charcoal rich soil known as terra preta (Portuguese for “black earth”) are the inspiration for an international effort to explore how burying biomass-derived charcoal, or “biochar” could boost soil fertility and transfer a sizable amount of CO2 from the atmosphere into safe storage in topsoil.

Although burial of biochar is just beginning to be tested in long-term field-scale trials, studies of Amazonian terra preta show that charcoal can lock up carbon in the soil for centuries and improve soil fertility.

David J. Tenenbaum

Brogan & Partners, 2009