What’s a promising way of removing carbon from the atmosphere? Scientists attending climate talks in Poznan, Poland, are trying to sell the idea of biochar, a type of charcoal produced when biomass like agricultural and forest residue is “baked” in the absense of oxygen. This process, called pyrolysis, also produces syngas and bio-oil that can be used as a renewable fuel. But it’s the char or “black carbon” that’s capturing scientists’ imagination. The pyrolysis process locks carbon into the char, which remains stable for hundreds, potentially thousands of years.
The char, when mixed with earth, is excellent at helping soils retain nutrients. Farmers can put the char back on the land to improve crop yield (and reduce dependence on fertilizers) or the char can be used to help revive depleted lands. In this way the char both permanently sequesters the carbon and improves the ability of soils to grow more carbon-absorbing plant life.
The end result: Carbon Negativity
Scientists supporting this approach to carbon sequestration are hoping it will be recognized as part of Kyoto talks and qualify as carbon-offset projects. They argue the potential is huge, though it remains to be seen if, in practice, it could ever achieve meaningful scale. That said, interest is growing. Next week Canadian scientists, government officials and academics are meeting in Montreal for the first meeting of the Canadian Biochar Initiative, a national branch of the International Biochar Initiative.