Biochar
Sam Carana
carbon ends up in the atmosphere. By encouraging growth of vegetation,
biochar also achieves that additional carbon is drawn from the
atmosphere, in a self-reinforcing cycle that can expand over a growing
areas. These points are related and reinforce each other.
The suggestion that growing biomass for biochar competed with food and
biofuel is a non-argument. We need to move away from biofuel in the
first place, and instead use electricity produced in safe, sustainable
and clean ways, such as with solar, wind, hydro, wave, tide and
geothermal facilities. Secondly, we should use less land for meat.
Biochar PLUS food (wood+fruit, if you like, that rhymes better) can
both be produced in complementary ways from the vegetation that should
grow on land that is currently taken for meat production. Indeed,
biochar and (good) food go hand in hand in many ways.
Here are some further points to take into account:
- Biochar can be produced from current farm and forest waste, and
subsequently be stored in the soil, thus avoiding that the carbon
ended up in the atmosphere. Not doing so would simply mean that a lot
of CO2 would end up in the atmosphere. Putting carbon in the soil is a
safe way to store it for long periods.
- Pyrolysis produces not only biochar, but also hydrogen and syngas,
which can be captured and used in ways that avoid CO2 and soot
emissions that would otherwise occur.
- Biochar stored in the soil also increases soil fertility and the
capacity to retain water, resulting in vegetation growth. Biochar also
prevents soil erosion and other forms of soil degradation. The ability
to improve land quality makes that biochar is an essential part of a
comprehensive approach to deal with global warming.
- Apart from obtaining char from biomass input by means of pyrolysis,
carbon can also be captured from ambient air and stored in the soil.
The term agrichar better reflects such applications than biochar.
- We're not just talking about using waste from existing farmland to
produce biochar. We should also look beyond making existing farmland
more fertile. One recent study alone estimates that vegetation in the
deserts could draw some 8 Gt C p a from the atmosphere. If we started
counting at 2020, that would add up to 640 Gt C by 2100.
http://bit.ly/afforestation
- For an overview of the potential of biochar, also have a look at:
http://bit.ly/biochar
Cheers!
Sam Carana
On Sun, Sep 27, 2009 at 4:20 AM, Peter Read <pre...@attglobal.net> wrote:
> Ken, Manu,
>
> I did not go into primary data but had in front of me one or two respectable
> secondary sources that led to the "about 15Gt" number
>
> Strand and Benford , 2008 Env Sci and Tech, quote 4.98 Pg/yr for residues
> from maize, wheat, soybeans, sugar cane, rice, sugar beet and barley. Jason
> Clay in World Agriculture and the Environment (Island Press 2004) provides
> additional data for Cassava, Potatoes, Sorghum, Bananas, Sweet Potatoes,
> Plantain and Millet which I did not trouble to add in. Hall, et al in
> Renewable Energy (Eds Johansson et al, Island Press 1993) turn it all into
> EJ to get 35EJ for Maize, Wheat, Rice and Sugar Cane residues only, 41EJ for
> animal dung, (excluding human dung which pyrolyzes fine) and 35 EJ for
> timber residues. Roughly 3 x 4.98 led to 15Gt
>
> Haberl et al must have it wrong since the global food yield for Strand and
> Benford's seven crops only (with an average harvest index of 0.44) is about
> 4 Pg/yr or ~2PgC
>
> 9.5 Gt is actually about one sixth of global net primary productivity, not
> one tenth, but one must be cautious of treating global NPP as a given, as
> many ecologically focused writers seem to do.
>
> Nature (and much subsistence agriculture) optimises on resilience to secure
> survival of the fittest and is not productively efficient.
>
> Read and Parshotam, 2007, cited in the RS report, provide Illustrative
> calculations which show that, if managed efficiently, and with plausible
> technological progress, only about 2.2GHa is needed (at a take up rate of
> .088 GHa for 25 years) to shift 1120Gt from linked ocean and atmosphere (in
> ratio ~45:55) by 2060, leading to pre-industrial levels around mid-century.
>
> I do not favour the vast monocultural developments that may seem to be
> implied, but rather a wider dissemination of carbon conservative and
> productively efficient management methods to land users worldwide. The
> obstacle is not shortage of land but shortage of investment in land (and in
> land users' human capital) -- investment on a scale comparable with current
> investments in ever harder to get fossil fuels (i.e. tilling for bio-oil not
> drilling for fossil oil).
>
> Peter.
>
> ----- Original Message -----
> From: Ken Caldeira
> To: Manu Sharma
> Cc: Peter Read ; sime...@gmail.com ; geoengineering
> Sent: Sunday, September 27, 2009 8:18 PM
> Subject: [geo] Re: Manifesto for Geoengineering
>
> How many watts per square meter of solar energy can be used to reduce carbon
> that can be stored as biochar? How many watts per square meter is needed to
> process this organic matter?
>
> Do you really think it reasonable to think that 10% of global primary
> productivity of land plants can be stored as biochar?
>
> Note that Haberl et al (2007) estimate that total global total food harvest
> is about 1.7 GtC / yr and global wood extraction is about 1 GtC / yr, so the
> 9.5 PgC / yr number cited by Lehmann et al (2006) represents carbon flows
> that are more than 5 times bigger than all the food harvesting in the world
> and more than 9 times bigger than all wood extraction in the world. These
> kinds of flows may be physically possible, but I remain skeptical regarding
> the practical feasibility of producing biochar at this scales.
>
> Haberl, H., K.-H. Erb, F. Krausmann, V. Gaube, A. Bondeau, C. Plutzar, S.
> Gingrich, W. Lucht, M. Fischer-Kowalski, 2007. Quantifying and mapping the
> human appropriation of net primary production in earth’s terrestrial
> ecosystems. Proceedings of the National Academy of Sciences of the USA 104,
> 12942-12947.
>
> ___________________________________________________
> Ken Caldeira
>
> Carnegie Institution Dept of Global Ecology
> 260 Panama Street, Stanford, CA 94305 USA
>
> kcal...@ciw.edu; kcal...@stanford.edu
> http://dge.stanford.edu/DGE/CIWDGE/labs/caldeiralab
> +1 650 704 7212; fax: +1 650 462 5968
>
>
>
> On Sat, Sep 26, 2009 at 8:32 PM, Manu Sharma <orang...@gmail.com> wrote:
>>
>> Thank you, Peter. Your arguments are well made.
>> Have you considered making a formal submission to the Royal Society for a
>> review of their position on this issue?
>> Manu
>>
>> On Sat, Sep 26, 2009 at 5:50 PM, Peter Read <pre...@attglobal.net> wrote:
>>>
>>> Ken, Simon
>>>
>>> As it was I that said it, I had best front up.
>>>
>>> My objection on first reading was to the passage immediately following
>>> Simon's quote, which is a gratuitous shift from policy relevance to
>>> policy
>>> prescription, viz:
>>> "Biochar and other forms of sequestered biomass have not yet been
>>> adequately
>>> researched and characterised, and so should not be eligible for carbon
>>> credits under the UNFCCC flexible mechanisms until there is a reliable
>>> system in place for verifying how much carbon is stored, and the wider
>>> social and environmental effects have been determined. Substantial
>>> research
>>> will be required to achieve these conditions for methods other than
>>> BECS".
>>>
>>> However, as regards the words that Simon quotes, one concern is a matter
>>> of
>>> emphasis, interpretation and tone. For instance, there are in aggregate
>>> about 15Gt p.a. crop and forestry residues and animal dung, which may be
>>> expected to rise to 20Gtp.a. (with ~10Gtp.a. C content) with population
>>> increase to 9billions. If the lot were pyrolyzed with 50 per cent C
>>> capture, and the product used for soil improvement, that would yield the
>>> lower end of the Lehman et al quoted range without any growth at all "in
>>> the
>>> resources devoted to producing" [[not "biofuels" but biochar is
>>> presumably
>>> intended]]. There would not be conflict with the use of agricultural
>>> land
>>> but synergy, with improved soil leading to increased crop yield.
>>>
>>> In a single sentence the RS writer manages to state that "using crops
>>> [PRESUMABLY HE/SHE MEANS CROP RESIDUES] for renewable fuels would be in
>>> conflict with using agricultural land for the production of food AND/OR
>>> BIOFUELS" !! Beyond the circular non-sequitur, the sentence is about
>>> biofuels and not about biochar at all.
>>>
>>> Next, a negativistic sentence "However, unless the sustainable
>>> sequestration
>>> rate exceeds around 1 GtC/yr, it is unlikely that it could make a large
>>> contribution." contains a false premise [as per the numbers above] which
>>> is
>>> then carried through to a prominent conclusion of low effectiveness in
>>> table
>>> 2.4
>>>
>>> As regards final sentence that Simon quotes "might increase the cost and
>>> reduce the availability of food crops" is precisely the opposite of what
>>> would happen with conversion of currently largely wasted or inefficiently
>>> used farm and forestry residues to soil productivity enhancing biochar.
>>>
>>> As Ron Larson has noted, there is an extraordinary failure to quote the
>>> enormous positive literature on biochar, conveniently referenced and
>>> summarized in book format published in London IN MARCH 2009, within 2
>>> miles
>>> of the RS Carlton House Terrace headquarters [Biochar for Environmental
>>> Management, Eds J Lehmann and S Joseph, Earthscan] which contrasts
>>> strangely
>>> with the Report's favourable attitude to BECS where the literature is
>>> sparse
>>> (possibly a convenience) and where success is entirely dependant on the
>>> infant CCS technology. There is not the slightest doubt that we know how
>>> to
>>> pyrolyze.
>>>
>>> As regards the gratuitous policy prescriptive paragraph, the
>>> establishment
>>> of a reliable system for verifying how much C is stored through
>>> commercial
>>> biochar application to soil is no different from estimating fossil fuel
>>> emissions - quantities and quality assay will.become available through
>>> normal accountancy procedures and can be aggregated in the same way as is
>>> done for coal, except the movement is down into the gropund rather than
>>> up
>>> out of it. As biochar is "finely divided pyrolyzed biomass prepared
>>> [expensively] for soil improvement" purchasers are not going to waste if
>>> for
>>> fuel (especially as preparation will likely involve wetting and doping
>>> with
>>> nutrients and/or fungal spores etc., somewhat spoiling combustion
>>> properties). Nobody is talking about carbon credits for increased labile
>>> soil C resulting from increased productivity or about unregulated
>>> backyard
>>> operations, though much valuable experimentation is going on in that way.
>>> As regards the RS concern over "the wider social and environmental
>>> effects
>>> " it would be good to see the same applied to already large scale
>>> bioenergy before getting too excited about the (likely beneficial) social
>>> and environmental effects of infant biochar.
>>>
>>> While I do not generally favour ad hominem arguments it may be noted that
>>> there is not a single member of the working group and review panel that
>>> has
>>> a publishing record in the field of biochar.
>>>
>>> Hope that helps
>>> Peter