Biochar has been used in agriculture for millennia, but it is now in high demand due to industrial applications and a growing climate crisis. California is dealing with a methane problem. The state's dairy industry is the largest in the country, but those dairy cows produce more than milk.
Manure slurry ponds with foul odours dot the Central Valley, and methane-producing bacteria thrive in these lagoons, releasing the powerful greenhouse gas into the atmosphere.
However, researchers at the University of California, Merced, are looking into a potential emissions mitigation tool for dairy farmers in the climate-conscious state: biochar, a feather-light, pure black material that smells like charcoal and has the structure of a sponge.
Biochar for Good Climate
Biochar, which has long been advocated by soil scientists, has also become a darling of the climate mitigation movement due to its ability to sequester carbon, as the effects of climate change have become more visible and destructive.
"It's a really ancient technology," Rebecca Ryals, an agroecologist at the University of California, Merced, said. Indigenous communities in the Amazon have been burying charcoal for generations, transforming the region's notoriously nutrient-depleted soils into pockets of dark, fertile earth known as terra preta.
Biochars are now produced by burning wood, crop, and other organic waste at high temperatures and low oxygen levels, a process known as pyrolysis, which results in a super stable structure capable of storing carbon for hundreds or even thousands of years.
Biochar is currently the only technologically and economically feasible "negative emissions technology" that the United Nations climate panel believes humanity requires to pull carbon from the atmosphere and avoid catastrophic global warming.
According to research from Cornell University's Johannes Lehmann, biochar as a soil amendment could reduce up to 12% of global annual emissions while improving soil health, water retention, and crop yields for farmers. However, it has yet to live up to its full potential.
Completely New World
Fortunately, researchers are discovering a plethora of other applications for biochar aside from croplands, such as construction materials, orphaned oil wells, and stormwater filtration sites. It can replace sand and other aggregates in concrete, asphalt, and other composite materials, allowing for lighter and more fire-resistant materials than traditional concrete.
Furthermore, all of these applications have the potential to increase not only the use of biochar but also its potential as a carbon sink. The carbon sequestered in biochar can also offset some of the massive carbon footprints of the cement industry, which accounts for a full 8% of global emissions.
According to Draper, the market for biochar-infused materials is already flooded. She has used biochar in the plaster walls of her own home in upstate New York, and she has added more than a tonne of biochar to the ground around her septic system in place of sand.
For generations, Indigenous communities in the Amazon put charcoal into the ground, transforming the region’s notoriously nutrient-poor soils into pockets of dark, fertile earth known as terra preta.
Draper is currently collaborating with the Environmental Protection Agency on a project to replace gypsum in drywall with biochar—a mineral that is typically mined or sourced from coal mines and flue stacks. The market potential is enormous. Biochar has been added to asphalt, tyres, plastics, and even beauty products, in addition to building materials. With so many possible end products, one might be concerned that there won't be enough biochar to go around. But, according to Draper, this is not the case.
This is because biochar is a waste management tool in and of itself, and the United States has no shortage of waste. California, for example, has an infinite supply of forest biomass from wildfire fuel reduction and agricultural waste from the Central Valley, which produces one-quarter of the country's food.
