Agrichar

Another up and coming method for carbon storage provides both fertilizer for farmlands as well as an oil with potential use for fuel. This carbon-negative process is called agrichar. According to an article in the New York Times (also cited in yesterday's blog), the method involves burning agricultural plant waste at very high temperatures in an oxygen free environment. One product is an oil that can be converted to fuel for vehicles, and the other is a mineral-rich charcoal that, when incorporated into soil, can increase water retention and nutrient capacity of agricultural lands.

For more information, I turned to the International Biochar Initiative (IBI), a U.S. based non-profit organization that was formed at the International Agrichar Conference in 2007 with the goal of advancing R&D, deployment, and commercialization of this method. The IBI website explains that agrichar (agrichar and biochar are synonymous) is a carbon-negative process because it generates energy and sequesters carbon from plant material. As was explained in yesterday's post, plants pull CO2 from the atmosphere, so sequestration of their carbon back into the soil as charcoal (which will store the carbon for hundreds to thousands of years) results in a net flux of carbon from the atmosphere back to the earth. Additionally, agrichar is an effective fertilizer, stimulating more plant growth and consequently more draw-down of CO2 from the atmosphere.

A particularly interesting aspect of this method is that it has been in use for thousands of years. In the Amazon Basin, ancient people created what is called Terra Preta, or dark earth, through the process of burning agricultural waste and tilling it back into the soil. Today, thousands of years later, the soils are still fertile and carbon rich, a testament to the long-term effectiveness of this carbon storage technique.