But because the carbon in biochar so effectively resists degradation, it also can sequester carbon in soils for hundreds to thousands of years, effectively making it a permanent "sink"-a natural system that soaks up carbon dioxide from the atmosphere. Soils containing biochar made by ancient Amazon people still contain up to 70 times more carbon than surrounding soils and have a higher nutrient content. Steiner said scientists estimate biochar from agriculture and forestry residues can potentially sequester billions of tons of carbon in the world's soils.
Biochar also avoids the disadvantages of other bioenergy technologies that deplete soil organic matter, said Steiner.
"Removing crop residues for bioenergy production reduces the organic matter accumulating on agricultural fields and thus the soil organic carbon pool, which depends on constant input of decomposing plant material. In contrast, pyrolysis with biochar carbon sequestration produces renewable energy, sequesters CO2 and cycles nutrients back into agricultural fields."
This unique system ideally utilizes waste biomass, and thus does not compete with food production," said Steiner. Currently most waste biomass decomposes or is burned in the field. Both processes release carbon dioxide stored in the plant biomass-for no other use than getting rid of it. Biochar can capture up to 50 percent of the carbon stored in biomass and establishes a significant carbon sink, as long as renewable resources are used and biochar is used as a soil amendment.
To address our world's climate change dilemma, said Steiner, "We need a carbon sink in addition to greater energy efficiency and renewable energy. Acceptance of the UNCCD proposal in Poland is a first step to make carbon trading based on biochar a reality.
"This has not only consequences for mitigating climate change, but also for agricultural sustainability, and could provide a strong incentive to reduce deforestation, especially in the tropics."
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Adapted from materials provided by University of Georgia.
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MLA University of Georgia (2008, December 20). Ancient Soil Replenishment Technique Helps In Battle Against Global Warming. ScienceDaily. Retrieved December 20, 2008, from
http://www.sciencedaily.com /releases/2008/12/081217190439.htm