Combating Global Warming
Former inhabitants of the Amazon Basin enriched their fields with charred organic materials – biochar, and transformed one of the earth's most infertile soils into one of the most productive. These early conservationists disappeared 500 years ago, but centuries later, their soil is still rich in organic matter and nutrients. Now, scientists, environmental groups and policy makers, forging the next world climate agreement, see biochar not only as an important tool for replenishing soils, but as a powerful tool for combating global warming.
Christoph Steiner, a University of Georgia research scientist in the Faculty of Engineering, was a major contributor to the biochar proposal that was submitted by the United Nations Convention to Combat Desertification at the United Nations Climate Change Conference meeting in Poland. The new climate change agreement will replace the Kyoto Protocol, which expires in 2011.
Steiner, a soil scientist whose research in the Amazon Basin originally focused on the use of biochar as a soil amendment, believes in the potential of biochar and its ability to sequester, capture and store huge amounts of carbon while also displacing fossil fuel energy, effectively doubling its carbon impact. At UGA's Bio refinery and Carbon Cycling Program, he now investigates the global potential of biochar to sequester carbon. He also serves as a consultant to the UNCCD, a sister program to the climate change convention.
Steiner explains that almost any kind of organic material -- peanut shells, pine chips and even poultry litter can be burned in air-tight conditions, a process called pyrolysis. The by-products are biochar, a highly porous charcoal that helps soil retain nutrients, water, gases and heat that can be used as energy. 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. Scientists estimate that biochar from agriculture and forestry residues can potentially sequester billions of tons of carbon in the world's soils.
Unlike other bio-energy techniques, biochar does not deplete the soil organic matter. Bio energy production reduces the organic matter accumulating on agricultural fields, by removing crop residues, and thus the soil organic carbon pool, which depends on constant input of decomposing plant material. Pyrolysis with biochar carbon sequestration, in contrast, produces renewable energy, sequesters CO2 and cycles nutrients back into agricultural fields.
"This unique system ideally utilises waste biomass, and thus does not compete with food production," said Steiner. Currently most waste biomass decomposes or is burned in the fields. 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 per cent 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, Steiner believes in setting up a carbon sink in addition to greater energy efficiency and renewable energy. The acceptance of the UNCCD proposal in Poland will be the 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," added Steiner.
