We’ve all heard the quotes circulating around the internet–
“We’ve experienced a 300% improvement in crop yield from adding <500kg of biochar/ hectare!”
“My biochar stove will burn any type of waste biomass with zero emissions!”
“Biochar is [insert any number of miraculous claims]!”
We in the biochar community are all excited and enthusiastic about the possibilities for biochar and biochar-producing equipment. Unfortunately, excitement often makes people overzealous, and can lead us to jump to conclusions too quickly. The consequences of making unfounded claims in the nascent field of biochar are potentially disastrous. We should all be familiar with the overarching claims made by Mantria, which ended with an SEC investigation and was recently labeled the “biggest green scam in America.” However, there is a greater danger lurking than investor fraud. Each time an unfounded claim is made about biochar or biochar technologies, it severely weakens the credibility of the entire industry.
At a recent dinner in Kisumu, Kenya, the re:char team met with Prof. Johannes Lehmann (Chair of the International Biochar Initiative) and his team from Cornell University. Subsequently, we paid a visit to the UK Biochar Research Centre at University of Edinburgh. In each case, a hot topic of conversation was the recent critical review of biochar by a UK-based group called Biofuelwatch. While this report lacks peer-review or significant scientific justification, it does point out some (unfortunately) legitimate issues surrounding biochar. The consensus of the re:char team and our academic friends, is that the content of the Biofuelwatch is largely a response to the unregulated, unfounded and sometimes fraudulent claims made by some members of the biochar community.
In an effort to clear the air (no pun intended), we are publishing the following points to explain what is currently known about biochar, and what still needs to be determined. We do not consider any claims valid that are not peer-reviewed according to traditional academic practices. We are also working closely with IBI and UKBRC to promote a unified message from the biochar community. So here’s what we feel confident in saying:
- Biochar improves crop yield in oxisols: There are now hundreds of peer-reviewed studies on the agronomic benefits of biochar. These papers have shown a variety of yield improvements across a variety of soil types and crops. We are confident that biochar is effective in tropical and/or weathered soils typically found in Africa in Latin America. For other soil types and crops, there is still much research to be done.
- It takes a lot of biochar to see an effect: Current academic consensus is that farmers must apply >500kg of biochar to every hectare of soil in order to see any crop yield improvement. However, most studies at these low concentrations were conducted in pots, which do not accurately mimic in-field conditions. The majority of field trials show yield improvements at concentrations between 3 and 6 tonnes/ha, with some as high as 20 T/ha. We need an order of magnitude more trials across a variety of soil types, with variations in concentration and application technique.
- Few (if any) biochar technologies have had their emissions rigorously tested: The unavoidable truth is that any device which combusts or pyrolyzes biomass will generate emissions. Even so-called ‘clean cookstoves’ generate emissions. There is no such thing as a ‘zero emission’ biomass stove. We are currently going through the process of having our kiln’s emissions measured by our friends at the UKBRC. It is a long and involved procedure, but we recommend it to any and all biochar technology companies.
- Carbon credits for biochar could be dangerous in places like Africa: Through our work in Kenya and East Africa, we have witnessed firsthand the enthusiasm for carbon credit funding around biochar. Unfortunately, as new markets develop there is the potential for abuse. Kenya has been plagued by a rash of potentially dubious carbon offsets. We urge those touting the benefits of offsets for biochar to exercise caution until markets have sufficiently developed.
We believe that biochar represents a growing industry with gigaton-scale potential. By maintaining a strict code of ethics, and abiding by scientific principles, we can sustainably grow the industry and all benefit. We urge other members of the biochar community to follow-suit and promote transparency.