For biochar’s fiercest promoters, the sky’s the limit for the seemingly mystical product — or at least that’s been the pitch for years, ever since TIME Magazine referred to it as “black gold” in a December 2008 feature story. To some, it could do it all: pull carbon out of the atmosphere, enrich the soil, and be refined into a clean and green fuel source.

Yet a peer-reviewed study conducted by the American Carbon Registry (ACR) analyzing the science bolstering the biochar lobby’s business plan calls all of these claims into question. Released in March 2015, the review concluded that “the scientific literature does not provide sufficient evidence of the stability of soil carbon sequestration in fields.”

The release of the carbon registry’s peer review serves as a launching point for DeSmog’s investigative series on biochar as a false climate change solution touted by the industry’s lobby and other vested interests. 

American Carbon Registry

Making matters worse for biochar promoters, the American Carbon Registry is actually a proponent of controversial and hotly contested greenhouse gas offsets regimes and carbon markets, but didn’t buy the science when it came to biochar.

ACR dubs itself the first voluntary greenhouse gas registry and accounting mechanism in the world. It is often turned to for reviews and oversight of carbon offset mechanisms, such as the one proposed by IBI, and is most well known for the verification work it did for the California Air Resources Board for the state’s cap-and-trade program.

The carbon registry has given the International Biochar Initiative (IBI) — an industry lobbying and advocacy group which presented the protocol alongside Prasino Group — “the opportunity to revisit approval of the methodology at such time as there is clearer scientific consensus behind the approach proposed for methods to measure, monitor and verify biochar carbon stability.”

But after years of IBI putting its head down and pushing for a biochar protocol that could be used as a blueprint for carbon markets worldwide, it appears that those efforts haven’t panned out — at least for now. According to IBI‘s 2013 and 2014 U.S. Internal Revenue Service (IRS) 990 reports, developing this protocol was among the initiative’s top funding priorities. 

Image Credit: U.S. Internal Revenue Service (IRS)

Some biochar proponents have critiqued the ACR‘s peer review. But before getting to the rebuttal, first we’ll look at what the peer review said about the proposed bioichar offset protocol to begin with. We slogged through it so that you don’t have to.

IBI Protocol Peer Review

The review itself is a dense 115 pages, including reviewer comments, responses, subsequent responses from reviewers, and a final chance for rebuttal from IBI and Prasino Group. While much of the review centers around non-climate change related matters, a large chunk of it takes on IBI‘s climate change claims head-on.

Biochar and Climate Change

It starts with a bang.

“This protocol is promoting the potential use of biochar amended soil as a means of carbon sequestration. The overall impression is that the science is not at a level yet to recommend that this methodology be accepted,” wrote the reviewers. “There are numerous problems that should be addressed based on the estimation — in particular research is needed on the other pathways of degradation that are occurring as well in the field setting: physical and chemical degradation.”

The “pathways of degradation” comment calls into question biochar promoters’ claims that biochar can remain sequestered in the soil for 100 years. Questions about this claim also played a prominent role in a 2013 study published in the journal Science.

IBI has disputed the Science study, calling the 100-year mean residence time estimate a “conservative” one. 

“We know biochar degrades in the environment,” IBI wrote in response. “If the biochar remained in the laboratory serum bottles, then it might still be there in 100 years. Once biochar is mixed with soil, nature is very brutal and the physical weathering forces degrade every structure — even rock which has mechanical strengths well above charcoal — degrades under these forces.”

The American Carbon Registry called that response “unsatisfactory.”

Lab testing, as opposed to field testing, plays a central role in IBI‘s protocol and its proof of concept for marketing biochar on a mass scale.

Calling that premise  “very troubling,” ACR wrote that, “Overall, the science of biochar stability in soils is a very complex process.”

“The authors of the proposed methodology have based their conclusion solely on laboratory-derived degradation rates. The likelihood of laboratory derived rates properly representing true degradation rates is very slim.”

Keith Driver of Prasino Group, who helped write the protocol, told DeSmog that field testing is a “non-starter” for those aiming to insert biochar into carbon offset protocols.

The biochar is mobile (to some degree) and the sampling program would be prohibitive. As such, with the distributed application of biochar, sampling would have to be at the sites where it is applied (i.e. in the garden of the people that buy it at Whole Foods?). Further, no matter how the biochar mobilizes, the IBI calculation methodology takes into account the extent of potential outcomes (within any sense of reason).

Also, we can model the biochar with accuracy similar to that of other protocols (such as nitrogen management protocols, forestry, etc.). Modelling (rather than direct sampling) is a broadly accepted methodology for calculating GHG [greenhouse gas] reductions from a wide range of activities. However, the reviewers did not seem willing to consider that approach and the relative standard.

Past as Prologue

Biochar enthusiasts often harken back to past use of Amazonian Terra Preta of centuries past when discussing biochar’s roots. Often left out of that story, however, is the science the peer review panel pointed to about the history of the “human hazards of the biochar production process,” perhaps the most damning part of the entire review.

“These are well established in the literature from past pyrolysis efforts, and can lead to significant air emissions which would easily offset any environmental benefit of the biochar that is produced,” ACR wrote, citing a 1980 study titled, “Toxicity of emissions from combustion and pyrolysis of wood.”

Another real-life biochar crucible took place in Brazil and, as the peer reviewers point out, the results weren’t pretty.

Pointing to a 2012 study about biochar’s health impacts in Brazil, the reviewers relay that massive amounts of smoke often coincide with biochar’s mass production, which they say “constitutes a serious health hazard for anyone in the neighborhood of the carbonization facility.”

IBI rebutted these concerns by saying they would “meet industrialized country emissions requirements,” not mentioning these regulations often aren’t enough to stop damage from taking place to begin with and even more often aren’t enforced by regulatory agencies. See hydraulic fracturing (“fracking”) as a case in point.

Potential for Fraud

Fraud and the potential for it has long remained a central concern for critics of carbon markets, cap-and-trade, and offset schemes. ACR, itself existing to promote  carbon trading, also took a critical posture in examining biochar’s ability to do what it says it can do with regards to offsetting.

“Allowing the project proponent to take all samples presents an opportunity for fraud,” wrote the reviewers. It also “relies on the honesty and integrity of the project proponent to take representative samples of the biochar, and to present these samples for analysis in a timely manner. There does not appear to be a requirement for analysis at a third party accredited laboratory.”

IBI Protocol Public Comments

The public comments coming from critics preceding the ACR peer review raised many of the same points as later seen in the peer review. The most fierce round of critiques came from the duo of New Zealand University Professor Jim R. Jones and Ruy Korscha, his advisee and author of a Ph.D. thesis entitled, “Biochar systems for carbon finance – an evaluation based on Life Cycle Assessment studies in New Zealand.”

Korscha and Jones also critiqued the assumption of 100 years as mean residence time for biochar in the soil, which is baked into the protocol, as well as the lack of monitoring.

“Since the methodology focuses on the production of biochar and not on the fate of biochar, there are no methods in place to monitor, report, and verify that a minimum fraction of biochar carbon will physically remain 100 years in the soils or in the ocean floor for that matter,” they wrote.

Life Cycle Analysis

The “conservative” nature of the estimates of biochar’s climate change mitigation potential — or lack thereof — also plays a central role in the tale of the biochar development protocol.

Korscha and Jones both believe that IBI used the word “conservative” incorrectly and improperly. Alternatively, they say IBI should have performed a total life cycle analysis of biochar’s climate change and ecological footprint.

“While it is practical it is not conservative to exclude impacts arising from feedstock production,” they wrote. “Since biomass residues have a value, the activities associated with the production of biomass should be allocated proportionally in mass or economic terms to the main crop as well as to the residues.”

“This is convenient for carbon accounting purposes but it is not conservative … While it might sound semantic here, the use of the word ‘conservative’ is confusing since carbon sequestration needs to be permanent to ‘offset’ fossil fuel-derived greenhouse gas emissions and biochar will eventually decompose.”

IBI responded that because — they claim — biochar could last much longer than 100 years under the ground in some cases, the estimate is “conservative” by definition. Also, 100 years is the “accepted timeframe considered to be “permanent” for carbon marketers, IBI explained, another reason why they say their estimates fit the “conservative” billing. 

In his April 2016 study, Rattan Lal of Ohio State came out in concurrence with Korscha and Jones. 

“There are numerous reports claiming the environmental, climatic, ecologic, and economic benefits of using biochar as a soil amendment…[but]…most of them are based on greenhouse or laboratory studies,” wrote Lal. “There are few long-term field experiments, which have credible data in support of these claims. Thus, there are not enough data from long-term field studies to support any strong sequestration benefits being attributed to the soil application of biochar.”

California’s Placer County “Wrinkle”

ACR‘s peer review has clearly struck a nerve in the biochar community. But everyone DeSmog spoke to thinks it’s just a bump in the road, and not a fatal blow. They might well be correct.

“I have no doubt that biochar will be tradable, especially if compost is already tradable. While one can argue about the quality of the review process, it is certainly not the last word spoken on this but an ongoing conversation in society, academy, and industry,” said one industry source who requested anonymity for this story.

Calling the ACR review “just another wrinkle,” Driver of Prasino Group pointed to California’s Placer County, which recently approved a biochar offsets development protocol (outsourced to Prasino Group, IBI, and The Climate Trust). Driver predicts the approval by the Board of the California Air Pollution Control Officers Association (CAPCOA) signifies that a U.S.-based biochar greenhouse gas offsets program will arise in the not-too-distant future.

IBI, in a press release, agreed with Driver’s assessment. 

“We are ecstatic that CAPCOA’s Board has recognized the important contribution that biochar projects can make in reducing greenhouse gases while also contributing to clean air through pyrolysis of biomass that would otherwise have been burned,” said IBI’s Board Chair, Marta Camps. “It is our intent that this methodology serve as demonstration of the technical requirements to produce biochar and quantify its carbon offset potential.”

DeSmog has received and reviewed the public comments and biochar offsets protocol published by Placer County.

The public comments share many of the same exact critiques found in the ACR review. Most of them this time around came from Kevin Bundy, climate legal director for the Center for Biological Diversity. 

“As currently written the Protocol fails to account for all relevant [carbon] emissions,” wrote Bundy. “Even if biochar were capable of being produced and used in a manner that would guarantee permanent sequestration, the biochar production process at best sequester only a fraction of the carbon in the original biomass feedstock.”

Bundy also noted the lack of science on biochar’s ability to stay in the ground for decades or centuries, to which the developers of the Placer County biochar offsets development protocol responded, as with the ACR review, that IBI‘s “methodology has been designed to provide a conservative estimate of the stability of biochar.”

The “conservative estimate,” Bundy argues, actually comes in the form of Placer County’s biochar greenhouse gas emissions lifecycle analysis. Its accounting, Bundy says, should have actually been much more liberal in the other direction. 

Image Credit: Placer County Air Pollution Control District

Perhaps most importantly, Bundy points to Placer County’s own numbers. Those numbers convey that the proposed Cabin Creek Biomass Facility, an appendage of which would intake biochar, “will emit 26,526 metric tons of CO2-equivalent greenhouse gases per year, nearly all of it CO2.” That’s the equivalent of 5,600 vehicles driven for an average year.

Biochar Soiled

California and Alberta carbon markets aside, Thayer Tomlinson, communications director for IBI, said that for the majority of biochar promoters, carbon markets and cap-and-trade will remain a sideshow for now. Biochar, then, is not dead but will have a different emphasis than carbon sequestration.

Tomlinson told DeSmog:

All the producers I know that are producing biochar sell it for a number of purposes — mainly as a soil amendment, an addition to composting processes, a water filtration device, soil remediation, etc; and although they may highlight the carbon sequestration potential, I know of no producer who is using climate as the main selling point for consumers.

With a nascent carbon market and uncertain pricing for carbon, we see producers potentially interested in participating in carbon markets in the future but currently building their business around other benefits to biochar. Our Industry survey finds the same results—carbon sequestration is a great side benefit but not the main benefit for biochar in terms of marketing and consumer demand.

Korscha concurred with Tomlinson, saying he believes biochar may have a future, but it is likely in sustainable land and soil management, having no place at the present moment as a climate change solution and certainly not in a cap-and-trade or carbon offset plan.

Numbers and figures appear to support that trend, with IBI‘s budget at an all-time low of $78,836, according to its 2014 IRS 990 report. In years past, its budget has hovered closer to the $550,000 level.