Can biochar reduce greenhouse gas levels?
Carbon in biochar resists degradation, decay and digestion, and can sequester carbon in soils hundreds to thousands of years. Photosynthesis unites CO2 with water to make carbohydrates, or sugar. If biochar is made in a burner, some carbon returns to the air as CO2, but 20 to 60% of the carbon remains as biochar. In soil, biochars carbon-carbon bonds dont break down, and stay in soil for centuries. So, CO2 fixed by photosynthesis is now an inert form, safely stored long-term. Thus, biochar in soil is a true carbon-negative strategy. Biochar remains in soil far longer than other organic matter, such as compost, plant residue or manure that oxidize quickly. Biochar is one of our few ways to permanently sequester carbon. Robert Brown at Iowa State University, with a $1.8-million USDA grant, calculates corn stalk pyrolysis into biochar on a 250-hectare farm can sequester 1,900 tons of carbon a year. NASA climate scientist James Hansens August 2008 paper estimates that applied worldwide, so
