Carbon down

Climate-monitoring stations in the Arctic recently measured atmospheric carbon-dioxide levels at more than 400 parts per million (ppm), which is higher than the 350 ppm many scientists have said is the highest level of atmospheric CO2 that is safe. It’s also 125 ppm higher than CO2 levels present before the Industrial Revolution. In fact, according to climate scientists, it’s been at least 800,000 years since the Earth had CO2 levels in the 400s.

CO2, as most people know, is considered a “greenhouse gas,” one that traps heat in the atmosphere and contributes to global warming. The present upward trend of atmospheric CO2 is troubling.

It is partly in response to the need to lower the amount of CO2 in the atmosphere that study and discussion of biochar—“a solid material obtained from the carbonization of biomass,” as the International Biochar Initiative (IBI) describes it—has picked up steam of late. Biochar—which can occur naturally from forest fires or be manufactured in a controlled, pyrolitic process—has the ability to sequester atmospheric carbon in the soil, while amending the soil at the same time. The production process of biochar also creates clean, renewable biogas and oil products and heat as a side benefit.

“Very simply, biochar is a charcoal that is usable in the soil,” said Kelpie Wilson, a Chico State graduate in mechanical engineering living in Cave Junction, Ore., who has worked as IBI’s communications editor for the past four years. Amending soil with charcoal “goes way back,” Wilson said, pointing to information presented in Charles C. Mann’s award-winning 2005 book, 1491: New Revelations of the Americas Before Columbus.

“Researchers looked at soils in the Amazon Basin and tried to figure out why there were large areas of black, carbon-rich soils [known as “terra preta”],” she explained. As it turned out, this fertile, anthropogenic soil was the result of native inhabitants adding charcoal from fires to the soil for thousands of years: “They found artifacts in the [terra preta] soil dating back to 6,000 years ago. … And the soil is still incredibly rich 500 years after those people were extirpated.”

The state of Iowa, added Wilson, has “the richest soils in the country, because of a high percentage of biochar from naturally occurring prairie fires.” Conversely, soil in various places around the country (and world) are becoming depleted “because they have been worked and tilled, which puts oxygen in and speeds up decomposition of the organic matter in it. The soil ends up being very carbon-depleted. Biochar acts like a sponge—it holds onto fertilizer and moisture.”

Hand in hand with providing boosted fertility, an abundance of carbon in soil aids plants in drawing excess carbon dioxide from the atmosphere into the soil where it can be sequestered for hundreds to thousands of years.

Biochar, said Wilson, cooperates with the natural carbon cycle of plants to convert some of the CO2 drawn in from the atmosphere by the plants’ tissues “into solid form. It takes the cellular carbon from the plant and converts it into a stable fused carbon” that remains sequestered in the soil.

Additionally, “in the baking process, gases such as methane and hydrogen are released that can be burned to provide energy. At the very least, you can use that energy to continue with the biochar-making process. At any rate, it doesn’t take fossil fuel to make biochar.”

Wilson is part of a growing group of voices extolling the virtues of biochar. Locally, Colusa resident Thor Bailey, of the Agricultural Biomass Center (ABC), sees the production of biochar as an effective way to transform agricultural green waste (orchard clippings and so on) into something environmentally useful. In addition to acknowledging its ability to sequester carbon and amend soil, Bailey also praises biochar for its ability to filter water going into aquifers (See CN&R Greenways story “Biomass-energy dreams,” May 3, 2012). Bailey and ABC are working to help facilitate the creation of local plants that would produce biochar. He noted that the market for biochar currently outstrips the amount available.

On a bigger front, climate-change activist and former Vice-President Al Gore has praised the use of biochar as “[o]ne of the most exciting new strategies for restoring carbon to depleted soils, and sequestering significant amounts of CO2 for 1,000 years or more.”

Widely known writer and environmental activist Bill McKibben put it this way: “If you could continually turn a lot of organic material into biochar, you could, over time, reverse the history of the last two hundred years. … We can, literally, start sucking some of the carbon that our predecessors have poured into the atmosphere down through our weeds and stalks and stick it back in the ground. We can run the movie backward. We can unmine some of the coal, undrill some of the oil. We can take at least pieces of the Earth and—this is something we haven’t done for quite a while—leave them better than we found them.”

Wilson is excited about the upcoming four-day U.S. Biochar Conference, which will be held at Sonoma State University in Rohnert Park from July 29 to Aug. 1. Among the topics covered at the conference will be an overview of the physical and chemical characteristics of biochar, information on growing sustainable biomass for use in making biochar and the economics of biochar (head to www.2012.biochar.us.com to learn more and to register).

“There is going to be a lot of discussion about the use of biochar on working farms,” Wilson said.

“Registration is open to anyone,” she added. “It will be a wonderful conference for anyone who really wants to learn about biochar.”