Biochar 101: Climate Savior or False Hope?

If someone told you a charred black substance could help save the planet from the worst ravages of climate change, it'd be hard to believe, yet foolhardy to ignore.

Biochar, a form of carbon sequestration, has been sold by its promoters as an almost magical way to reverse climate change. Yet not only was the marketing protocol that would help scale up biochar production in the U.S. rejected by science peer reviewers in March 2015, but big oil companies like ConocoPhillips and ExxonMobil — among the biggest climate change culprits — also have made a big bet that they can use biochar to “offset” their carbon pollution footprint.

Biochar's most enthusiastic promoters have touted it as a panacea to humanity's increasing carbon woes. Some enthusiasts go so far as to refer to the substance as “black gold.” Some may recall the 2008 Time Magazine feature story promoting this curious form of charcoal, produced by burning organic matter under low oxygen conditions.

In reality, the science of biochar is nowhere near a consensus point, with some studies actually calling the entire premise into question. Further, well-intentioned biochar advocates have seen their optimism paired with individuals and businesses — including Big Oil — standing to make a major profit before the science is settled on the risks and consequences. 

But first, the basics: what is biochar and what do proponents say it can do?

Biochar 101

Biochar is a type of biomass or biofuel, meaning it's derived from living or recently living organisms. That's juxtaposed, of course, with fossil fuels, derived from ancient, long-dead organisms.

The 2008 Time Magazine article describes biochar in layman's terms: 

Burn almost any kind of organic material — corn husks, hazelnut shells, bamboo and, yes, even chicken manure — in an oxygen-depleted process called pyrolysis, and you generate gases and heat that can be used as energy. What remains is … biochar.

The Permaculture Research Institute of Australia provides a more technical description:

Biochar is … charcoal, produced by burning organic matter such as wood, grasses, crop residues and manure, under conditions of low oxygen (pyrolysis). A number of different pyrolysis techniques exist depending on temperature, speed of heating, and oxygen delivery, resulting in different yields of biochar and co-products, ‘bio-oil’ (with energy content value approx 55 percent that of diesel fuel by volume) and ‘syn-gas’ (a mixture of hydrogen, carbon dioxide, carbon monoxide, and hydrocarbons), which can be used to generate electricity, or as low-grade fuel for ships, boilers, aluminum smelter and cooking stoves.

Biochar is as much a process as a product. The new biochar-promoting academic textbook, Biochar for Environmental Management: Science, Technology and Implementation, describes it this way:

Biochar is the product of heating biomass in the absence of or with limited air to above 250°C, a process called charring or pyrolysis also used for making charcoal. The material distinguishes itself from charcoal or other carbon products in that it is intended for use as a soil application or broader for environmetnal management.

And even with these few definitions, what is and what isn't biochar (or “biochars,” but more on that later) sits very much at the center of the scientific debate over whether the substance can serve as a credible climate solution.

“Biochar” vs. “Biochars”

At the 2013 North American Biochar Symposium attended by DeSmog, Cornell University professor and International Biochar Initiative board vice-chairman Johannes Lehmann explained these oft-used definitions are overly simplistic in nature.

Lehmann's main beef: It's wrong to refer to “biochar” as a singular thing. That's due to the myriad soils it can be placed in and the various substances from which it can be made. Lehmann prefers the term “biochars.”

“They can be so variable that it's almost useless to talk about biochar in the singular,” Lehmann said during his keynote address.

A Feb. 6, 2014 article published by Capital Press seconded Lehmann.

“Biochar is the umbrella term used to describe the material created with the application of heat and pressure,” the piece explains. “The process also produces heat and gas. The properties of biochar vary depending on the process and the ag material used.”

The Ohio State University Professor Rattan Lal, a former Nobel Peace Prize winner, agreed with the more broad-sweeping definition in his study titled, “Biochar and Soil Carbon Sequestration,” and published in April 2016 in the book, Agricultural and Environmental Applications of Biochar: Advances and Barriers.

“In fact, biochar is not a unique product, but is composed of a wide range of materials ranging from slightly charred organic material to highly condensed refractory soot, including char, charcoal, bone char, carbon ash, carbon black, activated carbon, and other carbonized materials,” wrote Lal. “Biochar is simply biomass-derived charcoal used as a soil amendment.”

The Sales Pitch: Too Good to Be True?

Some biochar promoters say they model the substance's development after the Terra Preta methods of ancient farmers in the Amazon basin. 

These farmers burned agricultural wastes (the “bio” part of the equation) at a high heat with little oxygen, producing a dark, carbon-rich charcoal (the “char”). This dark, solid byproduct was then planted back into the fields, enriching the soil.

Some proponents also say biochar has potential to improve agricultural yields, produce clean energy, and mitigate climate change by sequestering carbon, killing three birds with one stone. The sales pitch works like this:

1) Biochar is a valuable soil enricher for agriculture, thus a boon for both small- and large-scale agribusiness.

2) The ”bio-gas,” “bio-oil,” or syngas produced alongside the biochar is a form of climate-friendly, clean fuel. 

3) The process is not only carbon neutral, in that it doesn't add hydrocarbons into the atmosphere when burned, but it's actually carbon negative. That's because its proponents say biochar effectively sequesters carbon into the soil that would otherwise be emitted into the atmosphere when burned or decomposed.

4) Biochar stoves can be used both to heat homes and to cook without the burning of fossil fuels.

Yet translating the successes of ancient farmers to a modern-day industrial scale isn't so cut and dry, and critics say the Terra Preta of hundreds of years ago is not the biochar of today. 

That hasn't stopped promoters from trying to market the product, though. One of the most egregious examples came in the form of Mantria Corporation, indicted in 2015 by the U.S. Department of Justice (DOJ) for running a biochar ponzi scheme, which recently pled guilty

“The scheme alleged in this indictment offered investors the best of both worlds — investing in sustainable and clean energy products while also making a profit,” U.S. Attorney Zane Memeger said in a DOJ news release. “Unfortunately for the investors, it was all a hoax and they lost precious savings. These defendants preyed on the emotions of their victims and sold them a scam.”

Enter Big Oil

It may seem odd that there's a concerted effort to scale up biochar before there's even a centrally agreed upon definition of what the substance actually is. Couple that with the fact the science is far from sound on biochar's climate change mitigation potential and it seems odder still.

That is, until one realizes that some of biochar's biggest fans are — or are closely tethered to — major oil companies and developers of both Canada's tar sands and North American shale basins, where oil and gas is obtained via hydraulic fracturing (“fracking”). Big money rides on profiting off of biochar and greenhouse gas offsets markets. 

Is biochar the way forward? Or are those with a financial stake in the game jumping on the biochar bandwagon before the technology proves itself? Continue to Part 2 and bookmark DeSmog's investigative series on biochar and climate change.