Biochar: Black Gold or Just Another Snake Oil Scheme?




In an interview with Naomi Klein, published in the Autumn 2013 issue of Earth Island Journal, she referred to the American fondness for “win-win solutions.” I had to giggle, having on many occasions sat in on industry-led events, where the speakers, wildly animated, blather on about their latest “win-win-win” technofix, certain to resolve everything that ails humanity, from climate change to poverty, to deforestation to toxic pollution to nuclear waste. Who could be against such hopeful, all-in-one miracle cures?  Perhaps only the skeptics who know the smell of snake oil. Which, I guess, includes me.


Photo by potaufeu/flickrField trail results fly in the face of repeated claims that biochar will sequester carbon in soils for
tens, hundreds or even thousands of years.

I came to such deep skepticism not by nature but from years of experience. One formative experience has been following the hype around biochar. Biochar enthusiasts are a hopeful bunch. They claim that charred biomass will be a win for climate, a win for soils and crop yields, hence a win against hunger and poverty, and a win for renewable energy generation. They are convinced that burning “biomass,” that is, trees, crop residues, animal manure or what have you, (some even advocate burning garbage ortires), could solve our energy, food, and climate woes.

Right away, there is good reason to be skeptical. Burning anything at all seems an unlikely cure for an overheating planet. No matter how it is done, or what is burned, combustion creates pollution — air pollution, particulates, ashes, various toxins and soot, the second largest warming agent after C02. Nonetheless, there are many who embrace biochar and specifically advocate burning things under oxygen starved conditions, via process called pyrolysis, to maximize the production of charred residues. Biochar, they claim, is “black gold.”


The first key “win” of biochar, proponents say, is that if buried in the ground, the char, which consists largely of carbon, will more or less permanently “sequester” that carbon and therefore help to cleanse the atmosphere. In an article published in the journal, Nature, some of the leading biochar enthusiasts claimed that it could offset global greenhouse gas emissions by a whopping 12 percent annually. All that would be required is collecting most forest and agriculture residues and animal manures from across the globe, as well as converting over half a billion hectares (an area larger than India) of land to producing dedicated burnable crops. After collecting it, the biomass would be transported to pyrolysis facilities, burned, then the char would be collected and transported back around the globe where it would be tilled and buried into soils over millions of acres. Year after year.

The problem with this idea isn’t just the massive scale of the project, for which there seems little social or political will. It is even more fundamental: There is really little basis for assuming that biochar carbon really will store carbon reliably in soils. A Biofuelwatch review of peer-reviewed field trials as of 2011 showed some remarkably unimpressive results. We only looked at peer-reviewed field trials in order to distinguish clearly between hype and actual results, and to discern how biochar acts in the real world, with living biodiverse soils, rather than sterile, laboratory conditions. Field trails proved rare; only five such studies were found, which between them tested biochar on 11 different combinations of soil and vegetation. In only three cases did biochar result in any additional carbon sequestration. In most cases, there was either no measurable difference in soil carbon, or even a reduction in soil carbon. These results from short-term studies —none spanned more than four years — fly in the face of repeated claims that biochar will sequester carbon in soils for tens, hundreds or even thousands of years.


Photo by crustmania/flickrBiochar enthusiasts claim it can improve the quality of the soil and hence improve crop yields and
thereby help reduce desertification and deforestation,

More recently, two important reviews (you can read themhere and here) of soil carbon showed that the stability of soil carbon is not so much determined by the molecular structure of the carbon itself, but rather by surrounding soil ecosystem properties. That makes reliable carbon storage very difficult to predict or assume.

Win number two, biochar enthusiasts claim, is that biochar will also improve the quality of the soil and hence improve crop yields, thereby help reduce desertification, deforestation, hunger, and poverty. Again, Biofuelwatch’sreview of peer reviewed field trials showed unimpressive and erratic results. Since then, a recent synthesis review of impact on crop yields found that in half of published studies, there was either no effect whatsoever on crop yields, or biochar actually reduced yields.

The third win, according to advocates, is generating renewable electricity and heat during pyrolysis. But so far, virtually all biochar has been produced without doing so. That’s because pyrolysis is difficult to control and remains largely unproven for commercial application. Another reason is the inherent trade off: If you want more biochar less biomass will be converted to heat and power, and vice versa.

None of these trial results have dampened the hopes of biochar enthusiasts, who still see wins everywhere they look. They continue to promote biochar as a means to reduce fertilizer demand, agricultural runoff, clean up waste water, reclaim mine sites, and offset fossil fuel pollution. Some have even advocated feeding it to cows to make them emit less gas, and one company even claims that biochar will make it possible for consumers to reduce greenhouse gas emissions even while driving big gas-guzzling cars. (see below).

In her Journal interview Klien also spoke about climate geoengineering, which she referred to as a proverbial “escape hatch” providing a way to avoid the consequences of our failure to reduce greenhouse gas emissions. This is indeed one of the most perilous hazards of the geoengineering mindset. Widespread doubts about geoengineering have resulted in a push to accept “more benign” technologies, including large-scale biochar and bioenergy with carbon capture and storage (BECCS). Both biochar and BECCS require burning lots of biomass — trees and crops, as well as municipal solid waste. Staggering quantities would have to be harvested and burned to have any measureable impact on the global atmosphere. Studies have shown that capturing just one billion tonnes of carbon per year would require conversion of up to 990 million hectares of land to plantations. The consequences for land, water, soils, biodiversity, would very likely render the treatment worse than the disease.

What is already painfully evident is that demand for biomass, even at the current smaller scale is already stripping Earth of her remaining biodiverse ecosystems, and replacing them with industrial, chemically-dependent monoculture deserts.

Another article in the Journal’s recent issue, “Modified Stands,” talks about the push for genetically engineered trees. The impetus behind GE trees is a projected dramatic increase in demand for wood, in large part for bioenergy. This demand is a result of subsidies and supports for renewable energy that fail to distinguish between the kind of renewable energy that requires constant inputs of fuel (wood etc) and combustion, and the kind that does not. The lion’s share of subsidies and supports has gone to bioenergy, including biofuels and biomass burning for electricity, which can conveniently be done 24/7 in coal plants, or stand alone facilities. Windmills and solar panels are more fussy, expensive, and their production cycles are intermittent.

To get a sense of the scale and impact of using bioenergy, consider that in the United Kingdom alone, current and proposed biomass burning for energy would require over 80 million tons of wood, more than eight times the amount of wood produced for all purposes domestically. There is now an expanding international trade in wood chips and pellets to satisfy this voracious demand from the UK and other European countries. Tree plantations and native forests in the southeastern United States and Canada are being cut, pelletized and shipped to Europe to be burned as “renewable energy.” The wood pellet industry is booming, and fast growing monoculture plantations — which could soon include GE trees, are in great demand.

Biochar enthusiasts usually insist they won’t cut forests or convert ecosystems to provide burnable biomass. Just like the biomass electricity industry, they prefer to talk about burning “wastes and residues.” But there is no such thing as “waste” in a forest ecosystem — all is recycled, via decay, to support regeneration and regrowth. In many places, definitions of waste have been expanded to include virtually any wood that is not valued as sawlogs, so timber harvests are more intense and destructive. In agriculture, there are often better options for residues, such as compost, mulch, animal fodder, and bedding. In any case, industrial forestry and agriculture practices have already wreaked havoc on ecosystems. Creating a market for the waste products of unsustainable practices hardly seems a step in the right direction.



Photo by Engineering for ChangeA biomass briquette. There is an inherent trade off between using biomass to produce biochar
vs using it to produce energy: If you want more biochar less biomass will be converted
to heat and power, and vice versa.

So far, biochar has not gained the subsidies and investments needed to scale it up commercially. Biochar advocates initially worked to gain funding from carbon markets, arguing that biochar could “offset” fossil fuel pollution, but with the recent decline of global carbon markets they have largely retreated seeking carbon financing. Instead, they are now pushing biochar as a niche product for small-scale and organic farmers.
The good news is that most small-scale farmers are closely attuned to what works on their farms and will judge for themselves. The bad news is that they are largely unaware that they are to some extent being used to promote an eventual massive scale-up of the  biochar industry.

In 2008-09, for example, a high-profile biochar project in Cameroon run by Biochar Fund, a Belgian nonprofit, promised to alleviate poverty and improve nutritional status of poor farmers by improving crop yields. The farmers donated land and labor, and were told they would be compensated with finance from carbon markets. The first set of trials were proclaimed wildly successful without any independent verification. Then the trials were abandoned without even informing the farmers. Biochar Fund moved on and was granted funds for yet another set of trials in Congo. This time the claim was that biochar would enable slash and burn agriculturalists to do less slashing and burning because the soils would be enriched with biochar. So far, there are no reports of the status of those trials. (Read Biofuelwatch’s investigative report about the Cameroon project here.)

Just as with biomass electricity, biochar enthusiasts claim that burning biomass is “carbon neutral” – that the carbon released during combustion will be reabsorbed by new trees or crops. This claim has been soundly and repeatedly refuted. Trees take years to regrow, assuming that they even do so. Cutting natural forests for biomass electricity, or biochar, or any other use results in a massive “carbon debt” that can take decades or even centuries to repay (i.e. for an equivalent amount of carbon to be reabsorbed in new tree growth). Biochar advocates continue to cling to the carbon neutral myth nonetheless. In fact, they take it a step further. Burying the carbon char in soils, they say, will permanently store some of the carbon, so regrowth will absorb additional (not just replacement) carbon. This, they say, makes it carbon negative.

This misguided logic is what lies behind claims by companies like Cool Planet that consumers can clean the atmosphere by driving more. The California-based biofuel and biochar company seeks to make transportation fuels from wood, which they say is “carbon neutral,” and then bury the char residue from their production process, thus renderning the entire process “carbon negative.” By Cool Planet’s logic, driving more could actually reduce carbon emissions. That kind of “win” has an especially outstanding appeal. Cool Planet has won significant corporate backing from BP, ConocoPhillips, General Electric, and Google among others, and is now looking at opening two new facilities in Louisiana.

The logical conclusion for biomass electricity or biochar, from a purely carbon accounting perspective is that we should burn things that grow faster and therefore incur a shorter “carbon debt.” GE eucalyptus perhaps?  Clearly it is not very helpful to reduce the whole affair of climate change to counting carbon molecules. Forests, soils, ecosystems all are far more than agglomerations of carbon. They are intricate, multidimensional, interconnected, and complex beyond our imaginings and hence beyond our ability to measure, manipulate, and control.

The reductionist mindset that carbon accountants engage with is a dead end that only serves to blind us to the full scope and range of Earth as a whole. It fails to see that this planet is more than the sum of its parts. If we are really serious about preserving life on Earth, we will have to relearn how to envision the whole, embrace humility in the face of our ignorance about how life-supporting earth systems work. No amount of biochar, no climate geoengineering tricks, no technofixes or markets or “private sector engagement” or fancy carbon accounting will be a “win win win” for us. By far the winning strategy would be to allow Earth to restore, regenerate and recover, on her own terms.

Rachel Smolker 
Rachel Smolker is codirector of Biofuelwatch and a climate justice activist. She has a Ph.D. in biology from the University of Michigan, and worked previously as a field zoologist.

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Tried reading the articles regarding the Good & Bad information on Bio Char.

I will this Spring Inoculate some Bio Char with some Steer Manure and a little Soil Amendment.  I do this as I have been unsuccessful in growing Tomatoes the past 3 years. After all living in the most productive Agricultural area of the world one should be able to grow LOWLY TOMATOES.  I put my lack of success down to the lack of life in the Soil.
If I succeed I hope to post a rewrite later in the summer as to my success or failure.

By Philip Treanor on Sat, March 14, 2015 at 11:15 am

I first took an interest in biochar six years ago, and as it did not appear to be commercially available, decided to have a go at making my own.  I had a small supply of wood shavings available, and have tried three different methods of making it.  My current method does leave some shavings uncharred, but this will compost in the garden.  Its use Is in raised beds totalling 16 sq.meters. All beds had been newly formed.  In the first year there seemed little change in crop performance, then l realised that the biochar was probably absorbing nutrients from the soil.  All additions over the next 5 years was immersed in various solutions of liquid fertiliser.  This year has been my best crop ever. e.g runner beans over a trench of biochar produced a larger crop from a shorter row (reduced by 10%).  Total amount of biochar in the beds would probably equal about 2.5 per cent.  I look at soil as if it is a community of all sorts of life forms.  The first year of adding biochar was bit like adding a factory building but no machinery or workers.  after that workers and machinery were added and production was started and improved year on year.  Garlic and shallots showed little difference, but maybe the biochar used could develops to their specific needs.  But that now starts to ask more questions than give answers.  Developing specialist areas; would that increase disease risks.  Just as an example.  newly

By Alan Free on Thu, December 18, 2014 at 2:41 pm

This article is misleading. It also distorts genuine information to add impact to the authors point of view. It should be pointed out that the whole reason Biochar is on the scene at all is because of the amazonian terra preta. These anthropogenic (human made) soils have been around (and quite fertile) for a few thousand years. and the carbon is stable in these soils for reasons we still don’t understand. Much like how the recipe for cement was lost when the dark ages hit only to be discovered again in the 18th century. The biochar initiative began as a hopeful way to recreate the terra preta and all it’s beneficial properties. Unfortunately capitalism is getting in the way and biochar is becoming this poster child for soil improvements when in fact it is

biochar + compost + ??? + ??? = Terra Preta Nova

We still don’t know the recipe, and it’s incredibly difficult to reverse engineer a 2500 year old anthropogenic soil. So yes when the haters of biochar talk about how it doesn’t work they are right. it doesn’t work BY IT”S SELF. Just like you can’t put wheat stalks in the oven and expect to get bread.

By Nick Avila on Mon, November 10, 2014 at 8:01 am

Sorry that I did not find this article nearly a year ago when it came out.  As one who has been doing research on this subject since 2009, I must say that much of your imformation has been somewhat sensationalistic and misleading.  There is much research going on and I realize that journalist often have little time to get into something in any real way, and given that I think that your attitude is somewhat arrogant.  It is evident that you do not understand what is meant by “neutral carbon”  Our problems with climate change and carbon buildup in the atmosphere are due almost solely from carbon that is not neutral, in other words fossil fuels (coal and oil) that was sequestered in the ground 300 Million years ago in the Carbonacious period.  Carbon dioxide released from plants in our own time will be resequestered in new growth.  Any botanist can tell you that.  That’s just one example of your miscomprehension.  If you decide to get serious and do some real research on the matter, I think that you will come up with a quite different out come

By J. E. Bush on Sat, August 09, 2014 at 3:42 pm

I dug charcoal into my vegi garden and was able to get 3 crops of carrots ,1 after the other without adding any chemical or organic fertilizer. The best part was the taste, usually organic grown food will taste earthy but not when charcoal was add , all you taste is the vegetable. Everyone i gave them to couldn’t believe the taste. You really need to do your home work as mass biochar producers capture the creosote and paraffin oil that is a byproduct of producing charcoal and doesn’t go into the atmosphere.

By Richo on Wed, June 25, 2014 at 1:18 am

In your article you claim “Burning anything at all seems an unlikely cure for an overheating planet. No matter how it is done, or what is burned”.

Are you suggesting that flaring methane from a piggery has no value even though it converts the gas from a 21x CO2e into a 1xCO2e.

Perhaps you need to reconsider using hysterical generalisations

By Greg Butler on Tue, October 29, 2013 at 6:47 pm

That EOE link stopped working without subscribing, So here is the official Umass platform;

Agricultural Geo-Engineering; Past, Present & Future

By Erich J. Knight on Fri, September 27, 2013 at 4:35 pm

Dear Pip,
Narrow Minded??, did you not read what Char does for Composting?, That they are tracking down the ill effects that GMO forages and RoundUp has on enteric microbiology? Given Ms Smolker’s dire concerns about GMO’s, I wonder why she disparages this important tool for remediation.

All the long term field trials you seek are in my citations, along with the broader implication to cool the planet, in my upcoming Umass presentation;

“Agricultural Geo-Engineering: Past, Present & Future”
posted at The Encyclopedia of Earth;

By Erich J. Knight on Fri, September 27, 2013 at 4:10 pm

I am still studying, but feel correct preparation and utilisation of charcoal in soils has merit, perhaps mainly by acting as a ‘refuge’ for micro-organisms within the soil. The fine pore structure denies entry to both predators and grazers, allowing a reserve of soil improving bacteria and fungi to survive which can then re-populate and colonise soils after adverse conditions. Restoring biological activity to soils will then stimulate the formation of stable humic and fulvic acids and colloids which stably store carbon.

By Susannah Batstone on Fri, September 27, 2013 at 8:01 am

Of increasing concern is the effects of biochar introduction into the habitats of micro soil fauna – little research has been carried out thus far and that which has is proving to be inconclusive and on occasion detrimental due to the myriad of systems involved all of which need to be studied also. It is very much on a par with pesticides in so far that heavy lobbying (biochar articles always seem to attract trolls who point to research that is far too narrow minded) is pushing the product way before the practitioners on the ground are ready for it – as with deforestation the intention is simply to profit before we realise what is actually there and how beneficial it is. As some in France, Italy and elsewhere are realising the terroir systems or landscape approach is paying well and has remained untouched by fluctuating markets with a steady increase in profit for the last 30 years and more – careful soil protection is the key to this profit. Any significant population changes in soil fungi or fauna betray a reality that the soil itself is becoming more fragile – why would we want to accelerate this in anyway?

By Pip Howard on Fri, September 27, 2013 at 7:37 am

Biologically structured Carbons from Biomass; Charcoal, Plant-Coal, the elemental Carbon of the basic plant cell structure, is the pyrolitic Carbon which has held my interest for the past seven years.  A renown New Zealand climate scientist, the late, Dr. Peter Read coined the term “Biochar” for charcoal used in the soil and calculated the soil carbon building potentials to draw-down CO2e. This term embraced has made Google filtering to follow the exponential rates of publications in the last few years a simple task.

Animal feed supplements, as practiced by the European and Japanese, allow this Black Revolution for agriculture to be fermented by our livestock. In the EU, 90% of the Biochar produced is passed through livestock before composting and field application. On Swiss Farms they have eliminated manure odor and closed the nutrient loop by retaining Nitrogen in Char/Compost.  Dr. Ron Leng have shown cattle fed char reduced enteric methane emissions 40%, enhancing feed conversion 25%!, this has to be one the greatest advances in bovine nutrition in the last few decades

The Delinat Institute’s Ithaka Journal;
The use of biochar in cattle farming

By Erich J. Knight on Wed, September 25, 2013 at 7:59 pm

That’s strange. I never heard of the carbon sequestration of biochar, or using it to add organic fertilizer to the soil. What I know of biochar is that it acts like an activated carbon filter. The same stuff used in air and water filtration. I didn’t hear that mentioned at all. As far as I know if a tree falls in the forest and breaks down slowly over time with fungi and microbes doing all the work to make nutrients available is how nature has done this for billions of years. I’m sorry but burning trees, rubbing them with organic fertilizer, and then burrying them is not any answer to our co2 problem. If you want to filter small amounts of water to make it drinkable, that’s all I know is practical for biochar

By Daniel on Wed, September 25, 2013 at 8:27 am

My issue with the term “bio-char” is it is NOT defined. Most of the time people use the term to mean pyrolized wood/waste whereas “bio-char” has a VERY specific meaning. Bio-char is pyrolized cellulistic waste in a char form, that has been steam quenched and then LOADED with LIFE!

Char is NOT bio-char. I have seen some few trials where TRUE bio-char is added to intensive vegetable production at rates of around 1000#/acre. Not 10 tons per acre of sterile char, with no compost or time for the soil to adjust to the char.

It’s way past time to conduct REAL trials using fully loaded bio-char, complete with trace minerals and organic NPK. Ideally, you want to quench the char with trace mineral laden steam and then compost the char using some form of organic fertilizer, such as Mighty Grow Organics 3-3-3 with trace minerals and beneficial microbes. Or a good quality compost with additional NPK can be used.

I don’t have a financial dog in this hunt, other than as the manufacturer of an organic fertilizer. I do not sell bio-char, but I am using it in trials at my production facility in Alabama.

Good luck growing from a man outstanding in his field.

By Michael on Fri, September 20, 2013 at 12:06 pm

You’re right, I think it’s easy to latch onto an idea and get carried away with the idea that might fix everything. That type of thinking is tempting, but it just doesn’t address the real problems that we have.

In terms of biochar, I think there’s a lot of enthusiasm, but the boots on the ground efforts are looking a lot more stubbornly realistic and practical than your article implies.

I see biochar as something we generate as a byproduct of a healthy renewable energy system. It’s expensive to make and I think we should use it strategically. There’s great research being done that shows that it adsorbs (sticks to metals) and can be used in stormwater filters to keep zinc from roofs out of rivers, and along our roadways to keep copper from brake pads of cars out of our waterways.

Biochar is best agriculturally where it latches onto rainwater and organic fertilizers, and makes that water and nutrient source available to plants. That means that farmers can use less water and fertilizer, and their plants will survive drought conditions. In New Zealand they noticed that biochar sprinkled on cow pasture keeps excess nitrogen from filtering into waterways. I see a lot of potential for biochar, as a part of improving existing farming practices, to help us keep expensive fertilizers in the root zones of plants, and away from the Gulf of Mexico. That would be a gain for the farmers and for our ecosystem.

These are big problems, and there aren’t easy answers. Sustainability and bringing our ecosystems back into balance are important issues, and to the extent that we can do that intelligently with natural materials, I think we should try.

By Erin Rasmussen on Wed, September 18, 2013 at 3:49 pm

Biochar production does NOT burn the elemental carbon in Biomass. Only the Hydro-Carbons, Syn-Gas & Bio-Oils.

The exponential growth of biochar studies proves that Ms Smokler has not done her homework, and has cherry picked the studies that serve her agenda.

The Accounting of soil carbon as the base measurement of sustainability and aligning incentives to get a farmer paid for his good works, is where all carbon markets should grow from. The farmer will always have the lowest cost system for sequestration of carbon and it is about time that the carbon markets recognize that as their very foundations. A foundation far more secure than any other market.

We need every molecule of CO2,(over 350PPM), returned to the Soil.

The cascade of ecological services resulting in increased NPP, with increased cloud forming aerosols emitted from leaves & soil fungi cool the planet while we feed off the Agricultural bounty.

Husbandry of of the vast soil microbiom, to do the heavy lifting of Climate remediation, is the best way forward. All political persuasions agree; Building Soil Carbon is Good.

Please review;

Agricultural Geo-Engineering; Past, Present & Future

Erich J. Knight
Shenandoah Gardens
1047 Dave Berry Rd. McGaheysville, VA. 22840

Policy & Community Committee Chair,
2013 North American Biochar Symposium

By Erich J. Knight on Wed, September 18, 2013 at 3:48 pm