CLIMATE CHANGE AND AGRICULTURE REPORT N0.1 Biochar – a climate smart solution? by Almuth Ernsting About this paper series Climate change is one of the biggest challenges facing our globalized world today. The poor population in developing countries will be particularly affected by global warming, of which developed countries are the major drivers. Science clearly indicates that a global temperature rise of 2°C above pre-industrial levels may change the face of the world irreversibly. A range of mitigation solutions is needed to avoid exceeding the 2°C limit. The need for truly sustainable and climate-friendly development is clear. A glance at global mitigation potentials shows that changes in agriculture and land use, including defor- estation in tropical areas, currently account for one-third Figure 1 Waste Photo: Meissner/MISEREOR 3 % Land-Use-Change Deforestated areas in Brazil. & Forestry 18 % Electricity & of global greenhouse gas emissions (see Figure 1). In- Heat creasingly, therefore, agriculture is being recognized as 27 % part of the problem in international climate negotiations. Agriculture While developed countries’ emissions result mostly from 13 % industry, energy consumption and transport, FAO fi gures 74 Industrial reveal that % of all agricultural emissions originate in Processes developing countries, and 70% of the agricultural miti- Manufactoring 3 % gation potential can be realized in these same countries. & Construction Could agriculture therefore be part of the solution, par- 11 % Other ticularly in developing countries? Globally, three-quar- Energy Sector ters of all malnourished people depend on agriculture 13 Transportation % and would be directly affected by international mitiga- 12 % tion agreements aimed at agriculture. Various “climate- friendly” agricultural solutions have already been pro- Figure 1: Sources of Global Greenhouse Gas Emissions. Agriculture is posed: they include biochar and no-tillage agriculture. the primary driver of land use change and deforestation. Source: EarthTrends, 2008; using data from the the Climate Analysis Against this background, MISEREOR uses this series of Indicators Tool (CAIT) papers to examine whether these solutions actually lead to climate-friendly and equitable agriculture with a clear commitment to a pro-poor approach. Table of contents About this paper series . Table of Contents, Imprint . Executive Summary . 4 1. What is biochar? . 5 1.1 Terra preta . 5 2. Biochar use today . 6 2.1 Traditional charcoal use in agriculture today . 7 2.2 Who is behind the biochar lobby? . 7 3. Is biochar really climate friendly? . 8 3.1 How does biochar affect soil carbon? . 8 3.1.1. Western Kenya trial . 9 3.1.2. Colombia study . 10 3.2 Likely climate impacts of a large biomass demand for biochar . 11 3.3 Biochar effects on other greenhouse gas emissions from soil . 12 3.4 Small airborne biochar particles . 12 4. Biochar – benefi ting the poor? . 13 4.1 Potential health impacts of biochar . 13 4.2 Can biochar be relied upon to raise crop yields? . 14 4.3 How much biomass is required to make biochar? . 15 4.4 Land-grabbing for biochar? . 15 4.5 What do biochar cook stoves offer to rural households? . 16 5. Biochar for carbon markets? . 17 5.1 Who would benefi t from biochar carbon credits? . 18 5.2 Who has profi ted from biochar so far? . 19 6. Conclusion . 20 References . The author . Imprint Published by: Edited by: Nicole Piepenbrink, Anika Schroeder, MISEREOR Bischöfl iches Hilfswerk MISEREOR e.V. Photo (front page): Achim Pohl/MISEREOR Mozartstraße 9, 52064 Aachen, Germany Tel.: +49 (0)241 442 0, Fax: +49 (0)241 442 188 Art work and printing: www.misereor.de, www.misereor.org VISUELL, Werbung und Kommunikation, Aachen Author: Almuth Ernsting As at: December 2011 CLIMATE CHANGE AND AGRICULTURE Biochar – a climate smart solution? Executive Summary Biochar, or fi ne-grained charcoal added to soils, is being sawdust or green manure, are applied. The reasons promoted as a way of sequestering carbon in and re- are complex and not fully understood and are likely to ducing greenhouse gas emissions from soils whilst, at the include a combination of biochar carbon turning into same time, making soils more fertile. This briefi ng fi rst CO2, biochar causing microbes to turn pre-existing soil introduces the different methods for producing bio- organic carbon to turn into CO2, and biochar carbon char and looks at the (very limited) uses of biochar and eroding. Furthermore, if fi ne biochar particles become traditional uses of charcoal in agriculture. It then explores airborne they can cause additional warming in the same who are the interest groups behind biochar and its main way as soot does. Similarly, fi eld studies show that advocacy group, the International Biochar Initiative, be- the impact of biochar on crop yields is highly variable, fore discussing what the science shows about the impacts negative in some cases, and cannot be predicted based of biochar on climate and especially soil carbon. It then on current knowledge. This means that small farmers discusses the likely impacts on poor communities should using biochar would carry a signifi cant risk, which would biochar be commercialised on a wider scale, by looking be even greater if they had to bear even part of the cost at biochar impacts on crop yields, the potential health of producing or procuring biochar. Biochar-making cook impacts of biochar, the claims made about ‘biochar cook stoves have been promoted as being particularly suitable stoves’, and the possibility of a future larger biochar for rural families, however there is a lack of independent demand resulting in land-grabbing. Finally, proposals to data about how well they work, with strong indications include biochar in particular and soil carbon in general that they require more biomass fuel to provide the same into cabon markets are explored. heat for cooking as similar stoves that do not produce As the briefi ng shows, optimistic claims about biochar biochar. Furthermore, the amount of biochar produced offering a reliable way of mitigating climate change, mainly by such stoves is very small compared to amounts used by sequestering carbon in soils, and of raising crop yields in fi eld trials. Those most likely to benefi t from any are not backed by the science. The limited number of peer- future inclusion of biochar into carbon markets are likely reviewed fi eld studies shows that adding biochar to soils to be agribusiness and plantation companies and other cannot be relied on to result in higher overall soil carbon larger organisations and companies who can offer eco- compared to plots where only mineral fertilisers are used nomies of scale and afford the transaction costs, not or ones where different organic amendments, such as small farmers. Photo: Michael Mondry/MISEREOR Biochar, the product of pyrolysed biomass 4 What is biochar? What is biochar? 1 Biochar is essentially fi ne-grained charcoal applied to and is still the early research and development stages. soils, which is being promoted primarily for climate change It appears to be most signifi cant in the nanotechnology mitigation and for raising soil fertility. Like all charcoal, it context. This report therefore focuses on biochar made is made by exposing wood, grasses, crops, plant residues through pyrolysis. or other biomass to high temperatures but with limited Modern pyrolysis facilities range from large indus- oxygen, a process called ‘pyrolysis’. The term biochar trial pyrolysis plants to cooking stoves. Modern pyrolysis was invented in 2005, by one of the most outspoken plants are still largely in the development stages, most advocates of its large-scale use, the late Peter Read, who of them confi ned to research institutions and commer- defi ned it as ‘fi nely divided pyrolysed biomass prepared cial pilot plants. for soil improvement’.1 This is why the vast majority of the research so far has Wood or other biomass charred and blackened after not looked at biochar produced with modern pyrolysis. an open air fi re will have been at least partly pyrolysed Instead, most studies have used crushed traditional char- and any type of charcoal is, in chemical terms, the result coal, or charcoal produced through wildfi res and swidden of pyrolysis. The carbon in all types of charred biomass, cultivation, some of it decades or centuries old. This is or in coal for that matter, is called black carbon. How- problematic because, as the UK Biochar Research Centre ever different types of charred biomass have very explains: “The function of biochar in soil is strongly different properties and chemical structures, depending infl uenced by formation conditions, and [traditional] on the temperature and the length of time for which they charcoal may only provide an insight into some general were charred and the type of biomass used. During principles of biochar function in soil.” traditional charcoal production, neither the energy which is released nor any of the air pollutants are captured, causing signifi cant pollution. Biochar advocates gener- 1.1 Terra preta ally eschew traditional charcoal production and instead support modern pyrolysis methods. Highly fertile and carbon-rich soils in Central Amazonia, In modern pyrolysis, energy produced from the com- called terra preta, meaning ‘black earth’ are widely cited bustion of biomass is captured in gaseous (“syngas”) as evidence that biochar works, i.e. that charcoal addition and/or liquid (“bio-oil”) form, leaving behind char as to soils sequesters carbon and makes soils more fertile a byproduct. Generally around 10-40% of the original over long periods. Terra preta soils are found in patches volume of biomass is left behind as char depending on of 1-80, usually 20, square metres mostly along the what is used and how it is burned 2. Syngas can be used Amazon and its tributaries and are surrounded by rela- like natural gas, although the energy content per unit of tively infertile soils which contain little carbon.4 Accord- volume is considerably lower, which means that far more ing to the Food and Agriculture Organisation (FAO), many of it has to be used to produce the same heat or elec- terra preta soils are 500-1,500 years old but some are tricity3.