Biochar as a tool to fight climate change

Environment News Service: …[S]cientists, environmental groups and policymakers forging the next world climate agreement see the charred organic material that they have dubbed "biochar" as a tool for replenishing soils and as a tool for combating global warming.

Christoph Steiner, a University of Georgia-Athens research scientist in the Faculty of Engineering, was a contributor to the biochar proposal submitted by the UN Convention to Combat Desertification at a side event held last week at the UN climate change conference meeting in Poland. The new climate change agreement will replace the Kyoto Protocol, which expires in 2012. "The potential of biochar lies in its ability to sequester - capture and store - huge amounts of carbon while also displacing fossil fuel energy, effectively doubling its carbon impact," said Steiner, a soil scientist whose research in the Amazon Basin originally focused on the use of biochar as a soil amendment.

….Steiner explains that almost any kind of organic material - peanut shells, pine chips and even poultry litter - can be burned in air-tight conditions in a process called pyrolysis. The byproducts are biochar, a highly porous charcoal that helps soil retain nutrients and water, and gases and heat that can be used as energy.

Because the carbon in biochar resists degradation, it can sequester carbon in soils for hundreds of years, making it a permanent sink - a natural system that soaks up the greenhouse gas carbon dioxide from the atmosphere.…Steiner said scientists estimate biochar from agriculture and forestry residues can potentially sequester billions of tons of carbon in the world's soils.

…"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," Steiner said. "In contrast, pyrolysis with biochar carbon sequestration produces renewable energy, sequesters CO2 and cycles nutrients back into agricultural fields."…

A comparison of "terra preta" in the Amazon (on the right) with conventional soil in the region. Shot by Bruno Glaser, Wikimedia Commons, under the terms of the GNU Free Documentation License, Version 1.2