Fowles says that there would be an incentive for farmers, logging communities, and small towns to convert their own dedicated crops, agricultural and forest residues, and municipal biowaste into char if a high enough price emerged for the sale of carbon offsets. “Every community at any scale could pyrolyse its biowaste … motivated by doing their bit against global warming,” he says.
Fowles believes that storing black carbon in soil carries less risk, would be quicker to implement, and could be done at much lower cost than burying carbon dioxide in old oil fields or aquifers. And he says the secondary benefits to agriculture could be substantial: “Biochar reduces the soil’s requirement for irrigation and fertilizer, both of which emit carbon.” Fowles adds that it has also been shown to reduce emissions of greenhouse gases from decay processes in soil. This would include nitrous oxide, a potent greenhouse gas. “Biochar has been observed to reduce nitrous-oxide emissions from cultivated soil by 40 percent.”
David Layzell, an expert on bioenergy and plant sciences at Queen’s University, in Kingston, Ontario, says that finding the right balance between energy generation from biomass and sequestration of its char is a major area of research with global implications. “The issue of how much you should burn and how much should go back to the land is partly an economic issue and partly a sustainability issue. We don’t have the full answers to this, but that’s the kind of research we need.”