Biochar as multi-purpose sustainable technology: experiences from projects in Tanzania

Abstract

Biochar was recently included as a promising negative emissions technology (NET) in the Special Report on Global Warming of 1.5 °C published by the Intergovernmental Panel on Climate Change. Unlike other NETs, it can potentially be used to mitigate global climate change while adding to local resilience in countries highly exposed and sensitive to impacts of climate change, such as least-developed countries (LDCs). The study is as an empirical contribution to the, as of yet, underdeveloped literature on deployment of negative emissions technologies in LDCs in general and on biochar use in developing countries and LDCs specifically. Nine historical and existing biochar projects in Tanzania are mapped in order to analyse problems, goals and common trade-offs associated with smallto medium-scale biochar production in LDCs. The mapping is based on a literature and document study, interviews with project actors, and on-site visits to biochar projects during 2019. The paper gives support to the observation made in the biochar literature that while biochar has many potential socioeconomic and environmental benefits, combining them in one single project is difficult. It is concluded that implementing biochar projects in Tanzania will likely involve trade-offs between the development and subsistence strategies and needs of local communities, the motivational forces of different project participants, and the uneven regulatory capacity of the state. We end by reflecting on the use of biochar projects to offset carbon emissions made elsewhere.

Socio-Economic Determinants for Biochar Deployment in the Southern Highlands of Tanzania

“…These focused on achieving food security, environmental conservation, and climate change adaptation. Similar results were also reported by the authors of [6,11], which are confirmed in this study with greater empirical underpinning. The total adoption of biochar technology may result in larger harvests.…”

“…Improving soil structure was another motive (see Section 3). This is in line with the author of [11], who argued that biochar improves the biological properties of soil, due to the morphology and heterogeneity of pore-size distribution in biochar providing a habitat for soil organisms. Biochar protects organisms from predation and desiccation.…”

“…The final motive for engaging in biochar technology was mitigating the impacts of climate change (see Section 3). This is in line with the author of [11], who argued that biochar improves the biological properties of soil, due to the morphology and heterogeneity of pore-size distribution in biochar providing a habitat for soil organisms. Biochar application reduces emissions of non-CO 2 greenhouse gases, e.g., reducing CH 4 emissions on grassland and in the production of soya beans; reducing the emission of N 2 O by over 500% from municipal waste, and ammonia emissions by up to 64%, and reducing total N losses by up to 52% during the composting of poultry litter [3,20].…”

“…Many of the original initiatives have been terminated, not least because of a lack of sustained development aid or a viable business model. One example is notable: the biochar production and application initiative in the Southern Highlands of Tanzania [11]. Previous research has shown that biochar deployment in developing countries is influenced by socio-economic factors [12].…”

“…Through 41 interviews with participants in nine biochar initiatives in Tanzania, complemented with seven field visits to production and application sites, this study shows that lack of education and financial means among farmers hindered the spread of the technology. For example, the biochar produced was left to be used as cooking fuel instead of a soil amendment [11]. The author of [27] revealed that men played a central role in deciding about biochar, i.e., building kilns, mobilizing feedstocks, operating pyrolysis, and applying biochar in farms in Haiti, Costa Rica, and India.…”