Biochar is a solid fine-grained material obtained from the carbonization of biomass under oxygen-limited conditions. Biochar may be applied directly to soils to improve soil functions and to reduce emissions from biomass. Due to its stability, biochar has an important role in carbon sequestration (the process of capturing CO2 before it escapes into the atmosphere). This 2,000 year-old practice converts agricultural waste into a soil enhancer that can hold carbon, boost food security, increase soil biodiversity, and discourage deforestation. The process creates a fine-grained, highly porous charcoal that helps soils retain nutrients and water. Biochar is found in soils around the world as a result of vegetation fires and historic soil management practices. Intensive study of biochar-rich dark earths in the Amazon (terra preta), has led to a wider appreciation of the unique properties of biochar as a soil enhancer.