Biochar Offered as Climate Change Reduction Tool

Now, scientists, 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.

At UGA's Biorefinery and Carbon Cycling Program, he now investigates the global potential of biochar to sequester carbon. Steiner also serves as a consultant to the UN Convention to Combat Desertification, UNCCD, a treaty parallel to the climate change convention.

In Poland, the secretariat of the desertification convention proposed that biochar management be included in the Kyoto Protocol's Clean Development Mechanism as a way for industrialized countries to earn certified emissions reduction credits towards meeting their greenhouse gas limits. The CDM already includes afforestation and reforestation.

Biochar is applied to land in Indonesia. (Photo courtesy biochar.org)

The global carbon trade market must be made accessible to land managers, especially in the tropics where sustaining soil organic carbon and soil fertility is most challenging and CO2 emissions due to land use change are highest, secretariat proposes.

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.

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.

Despite the fact that the world's soils hold more organic carbon than that held by the atmosphere as carbon dioxide and vegetation combined, land as a factor in carbon sequestration has remained under-recognized.

As the Earth is placed under more stress to produce food, fiber and energy, more carbon is removed from the ground and emitted into the atmosphere. A side effect of this ongoing global carbon cycle is the reduction of the soil's fertility.

Biochar, or charcoal, is one solution to slow down and reverse the process. 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," Steiner said. "In contrast, pyrolysis with biochar carbon sequestration produces renewable energy, sequesters CO2 and cycles nutrients back into agricultural fields."

Inside the UGA biorefinery (Photo courtesy UGA)

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.

In partnership with Eprida, a private company in Athens, Georgia, UGA's Biorefinery and Carbon Cycling Program hosts a pilot thermochemical biorefinery on the university's Athens campus. The biorefinery converts peanut hulls to hydrogen and to biochar.

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," he said, "and could provide a strong incentive to reduce deforestation, especially in the tropics."

To view the UN Convention to Combat Desertification proposal on biochar presented in Poland, click here.

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