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Expansion in access to clean cooking in Sub-Saharan Africa remains well below the UN's Sustainable Development Goal objectives. In particular, clean and modern forms of cooking have struggled to attract commercial funding at scale. The use of bioethanol in cooking is not new, but until recently, its application has been confined exclusively to small-scale projects. However, a new bioethanol cooking utility in Kenya has now reached mass-market adoption, serving more than 950,000 households with cooking fuel since its launch in late 2019. Its success was made possible by a significant investment in technology to facilitate safe, convenient, and affordable fuel distribution. It is funded by climate finance, which is based on bioethanol fuel replacing the charcoal normally used for cooking; a leading cause of African deforestation. This development is so recent that it has not been widely discussed in the academic literature. More broadly, the health, environmental, and economic impacts of bioethanol for cooking have not been systematically assembled in one place. The main aim of this study is to identify how KOKO Networks has managed to overcome the traditional barriers to scalability, achieving impacts with bioethanol for accelerating energy transitions for cooking. The results show that bioethanol for cooking supports 13 out of 17 SDGs and has significant positive impacts on health, the environment, and the wider economy. The affordability of bioethanol has been made possible because of KOKO Investments in high-tech electronic fuel dispensing machines and through the use of climate financing. KOKO relies both on local and imported fuel to offer reliability and security of supply, as well as to grow commercial bioethanol demand to support the growth of the local bioethanol industry. Bioethanol for cooking also suffers from unfavorable tax regimes. This is because historically, in many countries, ethanol has been imported for use in the beverage industry. In addition, an appropriate commercial supply chain and delivery model which boosts the scalability of business and offers customer convenience is essential. For these conditions to take place, an enabling policy environment is key. [ABSTRACT FROM AUTHOR]

Hydrogen has recently been proposed as a versatile energy carrier to contribute to archiving universal access to clean cooking. In hard-to-reach rural settings, decentralized produced hydrogen may be utilized (i) as a clean fuel via direct combustion in pure gaseous form or blended with Liquid Petroleum Gas (LPG), or (ii) via power-to-hydrogen-to-power (P2H2P) to serve electric cooking (e-cooking) appliances. Here, we present the first techno-economic evaluation of hydrogen-based cooking solutions. We apply mathematical optimization via energy system modeling to assess the minimal cost configuration of each respective energy system on technical and economic measures under present and future parameters. We further compare the potential costs of cooking for the end user with the costs of cooking with traditional fuels. Today, P2H2P-based e-cooking and production of hydrogen for utilization via combustion integrated into the electricity supply system have almost equal energy system costs to simultaneously satisfy the cooking and electricity needs of the isolated rural Kenyan village studied. P2H2P-based e-cooking might become advantageous in the near future when improving the energy efficiency of e-cooking appliances. The economic efficiency of producing hydrogen for utilization by end users via combustion benefits from integrating the water electrolysis into the electricity supply system. More efficient and cheaper hydrogen technologies expected by 2050 may improve the economic performance of integrated hydrogen production and utilization via combustion to be competitive with P2H2P-based e-cooking. The monthly costs of cooking per household may be lower than the traditional use of firewood and charcoal even today when applying the current life-line tariff for the electricity consumed or utilizing hydrogen via combustion. Driven by likely future technological improvements and the expected increase in traditional and fossil fuel prices, any hydrogen-based cooking pathway may be cheaper for end users than using charcoal and firewood by 2030, and LPG by 2040. The results suggest that providing clean cooking in rural villages could economically and environmentally benefit from utilizing hydrogen. However, facing the complexity of clean cooking projects, we emphasize the importance of embedding the results of our techno-economic analysis in holistic energy delivery models. We propose useful starting points for future aspects to be investigated in the discussion section, including business and financing models. [ABSTRACT FROM AUTHOR]

In many regions of Sub-Saharan Africa, charcoal plays an important role as energy source but is widely perceived as a major driver of deforestation and forest degradation. This narrative, however, is mostly based on research within primary production regions. Though space-borne remote sensing applications can be useful in monitoring such large-scale production modes, environmental effects of household-level production are less easy to assess. Therefore, the present study employs an unmanned aerial system (UAS) to assess the impact of small-scale charcoal production on the vegetation density in the immediate vicinity of production sites. The UAS data was complemented by field measurements and very high-resolution WordView-2 satellite imagery. This approach revealed only small differences between charcoal production sites and reference plots which were usually evened out after 20–25-m distance to the plot centre using a concentric ring analysis. Results further show that a distinction between different land-use practices is difficult, even with the high spatial resolution provided by a UAS. Thus, more research and new approaches are needed to evaluate the role of small-scale charcoal production in deforestation and forest degradation processes against the background of other human activities. However, to exploit the full potential of UAS for monitoring environmental effects in charcoal producing areas, official regulations need to be clearer and more reliable. [ABSTRACT FROM AUTHOR]

Traditional combustion devices and fuels such as charcoal, wood and biomass, are widely utilised in rural and urban households in Africa. Incomplete combustion can generate air pollutants which are of human toxicological importance, including polycyclic aromatic hydrocarbons (PAHs). In this study, portable multi-channel polydimethylsiloxane rubber traps were used to sample gas phase emissions from cooking devices used in urban and rural households in Bomet and Narok counties of Kenya. A wide range of total PAH concentrations was found in samples collected (0.82 – 173.69 µg/m3), which could be attributed to the differences in fuel type, combustion device, climate, and nature of households. Wood combustion using the 3-stone device had the highest average total PAH concentration of ~71 µg/m3. Narok had higher indoor total gas phase PAH concentrations averaging 35.88 µg/m3 in urban and 70.84 µg/m3 in rural households, compared to Bomet county (2.91 µg/m3 in urban and 9.09 µg/m3 in rural households). Ambient total gas phase PAH concentrations were more similar (Narok: 1.26 – 6.28 µg/m3 and Bomet: 2.44 – 6.30 µg/m3). Although the 3-stone device and burning of wood accounted for higher PAH emissions, the charcoal burning jiko stove produced the highest toxic equivalence quotient. Monitoring of PAHs emitted by these cooking devices and fuels is critical to public health and sustainable pollution mitigation. [ABSTRACT FROM AUTHOR]

East African ecosystems have been shaped by long-term socio-ecological–environmental interactions. Although much previous work on human–environment interrelationships have emphasised the negative impacts of human interventions, a growing body of work shows that there have also often been strong beneficial connections between people and ecosystems, especially in savanna environments. However, limited information and understanding of past interactions between humans and ecosystems of periods longer than a century hampers effective management of contemporary environments. Here, we present a late Holocene study of pollen, fern spore, fungal spore, and charcoal analyses from radiocarbon-dated sediment sequences and assess this record against archaeological and historical data to describe socio-ecological changes on the Laikipia Plateau in Rift Valley Province, Kenya. The results suggest a landscape characterised by closed forests between 2268 years before present (cal year BP) and 1615 cal year BP when there was a significant change to a more open woodland/grassland mosaic that continues to prevail across the study area. Increased amounts of charcoal in the sediment are observed for this same period, becoming particularly common from around 900 cal year BP associated with fungal spores commonly linked to the presence of herbivores. It is likely these trends reflect changes in land use management as pastoral populations improved and extended pasture, using fire to eradicate disease-prone habitats. Implications for contemporary land use management are discussed in the light of these findings. [ABSTRACT FROM AUTHOR]

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When the COVID-19 pandemic unfolded, public health measures were implemented globally. Early on, concerns grew that lockdowns and travel restrictions could have severe consequences, especially for marginalized communities in the Global South. In Sub-Saharan Africa, wood charcoal is not only an important cooking fuel, but provides income for many rural households. Despite its economic value, the charcoal sector is, however, largely unregulated and viewed exclusively as an environmentally damaging industry by policy makers and the public who make it responsible for large-scale deforestation. The present study employs a sustainable livelihood framework to assess the ability of charcoal producers in northwestern Kenya, to cope with a short-term shock such as the COVID-19 pandemic and preventive measures. It furthermore compares their access to health information to that of non-producers. A street survey of 139 respondents allowed to gain rapid insights into the realities of a group not accessible via online or telephone surveys. The results show that 87 % of charcoal producers face severe decline of this economic practice because of limited market access. These losses cause them food insecurities, while non-charcoal producers are more worried about social consequences of the restrictions. Though charcoal producers and non-producers feel equally well informed about the pandemic, producers are less likely to access reliable information channels than non-producers, resulting in an uneven distribution of health information across the community. By investigating the response of producers to an external shock and limited market access this study adds to the understanding of local vulnerabilities and the sustainability of rural livelihood strategies. This research argues for inclusive policy response to ensure consideration of the informal sector in crisis response as well as to provide adequate and low-threshold access to health information. [ABSTRACT FROM AUTHOR]

Forest incomes in the form of both timber and non-timber forest products are an important source of livelihood for many communities in Africa. A major forest resource is charcoal, which contributes to the livelihoods of millions across the region. While incomes from charcoal are used to meet a wide spectrum of needs within rural livelihoods, the role of charcoal production on livelihoods of small-scale producers is not well understood. Therefore, we provide an example on the importance of charcoal on livelihoods in an agropastoralist community in a semi-arid region in Kenya. Based on a household questionnaire targeting 150 charcoal and 150 non-charcoal makers, as well as focus group discussions, we assessed the determinants for participation in charcoal production and developed a household typology based on charcoal income dependence. We also determined the role of charcoal in income equalization and poverty reduction. Our study shows that charcoal contributes about 20% of the household income in the study area. Gender, land size and the number of food-scarce months are the key determinants of participation in charcoal production. Based on the poverty analysis, we conclude that even though charcoal income does not lift the producers out of poverty, it can mitigate the impacts of poverty by reducing the poverty gap and poverty severity. Based on our findings, we recommend a multipronged approach to address sustainable rural livelihoods including a more explicit acknowledgement of charcoal production as a source of rural income. We also recommend broadening of the local livelihood base and a more active management of the woodland to ensure the sustainability of the income. [ABSTRACT FROM AUTHOR]

• We combine stakeholder engagement and agent-based modelling to assess risks and uncertainties of sustainable charcoal policy. • Stakeholders valued the ability to access detailed information and compare scenarios on financial flows and biomass extraction. • Model results for the sustainable charcoal pathway showed sharp decline in overharvesting and increase in fiscal revenues. • The overall approach was sufficiently general to apply elsewhere in sub-Saharan Africa. As cities in East Africa keep growing, so too will demand for charcoal – the region's preferred urban fuel – placing increasing pressure on rural landscapes where it is produced. How can charcoal production and supply be made sustainable? What are the implications of sustainable charcoal policies and practices for achieving a low-carbon pathway and protecting the environment? This paper presents case study research focusing on Kitui County, one of the main charcoal production areas in Kenya. Risk and uncertainty of sustainable charcoal policies in Kitui were assessed using complementary methods of stakeholder workshops, informant interviews and agent-based modelling. This interdisciplinary approach combined policy research and simulation modelling, where local perspectives and data were included directly in the modelling. These methods facilitated critique of behaviour concerning agency and corruption. Stakeholders valued the ability to access detailed information on micro-interactions and consider policy performance regarding both financial flows and biomass extraction. [ABSTRACT FROM AUTHOR]

In developing countries, household energy use is highly variable and complex, yet emissions arising from fuel combustion indoors are typically poorly quantified. Polycyclic aromatic hydrocarbons (PAHs) are emitted during the combustion of organic fuels such as charcoal and biomass. In the present study, multichannel polydimethylsiloxane rubber traps were used for gas‐phase PAH sampling and extracted using a low–solvent volume plunger‐assisted solvent extraction method. Sixteen US Environmental Protection Agency priority PAHs, primarily in the gas phase, were investigated in indoor air of rural and urban residential homes in coastal Kenya (Mombasa and Taita Taveta Counties) using typical combustion devices of each area. Average gaseous PAH concentrations per household were higher in rural (ranging 0.81–6.09 µg m–3) compared to urban (ranging 0–2.59 µg m–3) homes, although ambient PAH concentrations were higher in urban environments, likely attributable to traffic contributions. The impact of fuel choice and thereby combustion device on PAH emissions was very clear, with the highest concentrations of PAHs quantified from wood‐burning emissions from 3‐stone stoves (total PAH averages 46.23 ± 3.24 µg m–3 [n = 6]). Average benzo[a]pyrene equivalent total concentrations were evaluated for the priority PAHs and ranged from not detected to 43.31, 88.38, 309.61, and 453.88 ng m–3 for gas, kerosene, jiko, 3‐stone, and improved 3‐stone stoves, respectively. Environ Toxicol Chem 2020;39:538–547. © 2019 SETAC [ABSTRACT FROM AUTHOR]

There are a growing number of market-based providers of clean cooking solutions in sub-Saharan Africa that rely on use customer fuel sales to subsidise upfront cost of equipment. These business models can widen access to clean cooking but are undermined by the continued use of polluting fuels, known as "fuel stacking", which limits provider revenues whilst perpetuating the negative impacts of cooking with traditional fuels. This study aimed to design and test a fuel stacking intervention with commercial pay-as-you-go LPG customers in Kisumu, Kenya. It consisted of three main phases: developing and testing a survey tool for diagnosing drivers of stacking (n = 99); using an intervention design framework (the Behaviour Change Wheel) to design an intervention consisting of the bundled provision of a pressure cooker, chapati pan and training; and testing the intervention in a small (n = 19) pre-post study. There was high uptake of the intervention, with the pans being used by all participants on roughly two-fifths of days. Target foods were cooked more frequently on LPG in the intervention phase, resulting in a significant increase in PAYG LPG use and an insignificant decrease in charcoal use. A third of participants stopped cooking with charcoal altogether, but some residual charcoal usage continued amongst the remainder. The results show that targeted stacking interventions can simultaneously promote sustained use of clean fuels and dis-adoption of polluting ones, resulting in commercial gains for clean cooking fuel providers. This could address the wicked problem of fuel stacking and accelerate progress towards Sustainable Development Goal 7. [Display omitted] • Developed and tested a quantitative survey tool for diagnosing drivers of stacking. • Used the results of the survey to design a stacking intervention for PAYG LPG users. • The intervention successfully increased LPG use and decreased charcoal use. • Targeted stacking interventions can promote sustained use of clean cooking fuels. [ABSTRACT FROM AUTHOR]

Background: Relatively clean cooking fuels such as liquefied petroleum gas (LPG) emit less fine particulate matter (PM 2·5 ) and carbon monoxide (CO) than polluting fuels (eg, wood, charcoal). Yet, some clean cooking interventions have not achieved substantial exposure reductions. This study evaluates determinants of between-community variability in exposures to household air pollution (HAP) across sub-Saharan Africa., Methods: In this measurement study, we recruited households cooking primarily with LPG or exclusively with wood or charcoal in peri-urban Cameroon, Ghana, and Kenya from previously surveyed households. In 2019-20, we conducted monitoring of 24 h PM 2·5 and CO kitchen concentrations (n=256) and female cook (n=248) and child (n=124) exposures. PM 2·5 measurements used gravimetric and light scattering methods. Stove use monitoring and surveys on cooking characteristics and ambient air pollution exposure (eg, walking time to main road) were also administered., Findings: The mean PM 2·5 kitchen concentration was five times higher among households cooking with charcoal than those using LPG in the Kenyan community (297 μg/m 3 , 95% CI 216-406, vs 61 μg/m 3 , 49-76), but only 4 μg/m 3 higher in the Ghanaian community (56 μg/m 3 , 45-70, vs 52 μg/m 3 , 40-68). The mean CO kitchen concentration in charcoal-using households was double the WHO guideline (6·11 parts per million [ppm]) in the Kenyan community (15·81 ppm, 95% CI 8·71-28·72), but below the guideline in the Ghanaian setting (1·77 ppm, 1·04-2·99). In all communities, mean PM 2·5 cook exposures only met the WHO interim-1 target (35 μg/m 3 ) among LPG users staying indoors and living more than 10 min walk from a road., Interpretation: Community-level variation in the relative difference in HAP exposures between LPG and polluting cooking fuel users in peri-urban sub-Saharan Africa might be attributed to differences in ambient air pollution levels. Thus, mitigation of indoor and outdoor PM 2·5 sources will probably be critical for obtaining significant exposure reductions in rapidly urbanising settings of sub-Saharan Africa., Funding: UK National Institute for Health and Care Research., Competing Interests: Declaration of interests We declare no competing interests., (Copyright © 2024 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license. Published by Elsevier Ltd.. All rights reserved.)

Fuel wood is the main source of cooking and heating energy in developing countries. However, it is combusted in inefficient cookstoves, leading to more fuel use and human health problems resulting from exposure to smoke. Thus new, efficient cooking systems that can address some of these problems are required. This study examined gasifier cookstove use in Kwale County, Kenya, and factors influencing adoption. Gasifier stoves were issued for free to 50 households, which were surveyed after 2–3 months of use. The results showed that the stove was used by 96% of the households at varying frequencies, 40% of them used it almost every day with 4% switching to only using the new stove. All the users appreciated it because it saved fuel, produced less smoke, and produced charcoal to use for either cooking or soil amendment. Compared with the traditional three-stone open fire, the gasifier stove was reported to be easier to clean (98% of respondents), easier to adjust the heat (88%), easier to handle (58%), caused less exposure to heat (96%) and was cleaner for pots and the kitchen (98%). Another reported benefit of the gasifier stove was that it needed no tending (i.e., adjusting wood and blowing to keep the flames burning). The gasifier stove was mainly used to cook foods that required a short cooking time and many preferred to use it to cook dinner. However, the households encountered some challenges with using the gasifier stoves. For example, fuel preparation, reloading, and lighting were reported as challenges by 42%, 77% and 19%, respectively, of the 83% of households who reported challenges. These challenges could be overcome by improving stove design and by devising innovative ways of cutting fuel into small pieces. • Gasifier is appreciated for saving fuel, producing charcoal and less smoke. • Gasifier was used at varying frequencies depending on household cooking needs. • The gasifier was mostly used for food with short cooking time. • Need to cook foods with varying cooking time caused stove stacking by gasifier users. • Difficulties in lighting, fuel preparation and reloading may limit stove adoption. [ABSTRACT FROM AUTHOR]

The use of charcoal is associated with indoor air pollution where users are continually exposed to combustion pollutants with detrimental effects to their health. This study analyzed the emission profiles of selected domestically used charcoal produced by different pyrolysis methods. Charcoal samples from three tree species Acacia polyacantha, Acacia xanthophloea and Eucalyptus grandis, produced by both efficient and traditional pyrolysis were collected from charcoal producers in rural Kenya. The volatile organic compounds were collected using a fabricated chimney placed on clay cook stove such that smoke was vented to a glass cannula and condensed. Extracted volatiles were analyzed by gas chromatography-linked mass spectrometry. Twenty-two polycyclic aromatic hydrocarbons were identified together with other hydrocarbons. Polycyclic aromatic hydrocarbons found in the smoke extracts with known health effects included naphthalene, 1-methylnaphthalene, 2-methylnaphthalene, fluorene, phenanthrene, anthracene, 1-methylphenanthrene, fluoranthene, benzo(a)anthracene and chrysene. There were significant differences in the concentrations of fluorine, naphthalene and pyrene emitted from Acacia polyacantha and Acacia xanthophloea prepared by traditional pyrolysis. From Acacia polyacantha, concentrations were naphthalene (110 µg/g), fluorine (72 µg/g) and pyrene (60 µg/g), while from Acacia xanthophloea, concentrations were naphthalene (140.42 µg/g), fluorene (97.35 µg/g) and pyrene (71.82 µg/g). Charcoal prepared by traditional pyrolysis emitted the highest number of polycyclic aromatic hydrocarbons and also had higher concentration of polycyclic aromatic hydrocarbons relative to the accepted 0.1–0.2 mg/m3 levels, while those prepared by efficient pyrolysis produced the lowest concentration. Therefore, there is need to use efficient pyrolysis methods of charcoal production. [ABSTRACT FROM AUTHOR]

The promotion of agroforestry as a mitigation practice requires an understanding of the economic benefits and its acceptability to farmers. This work examines the agroecological and socio-economic factors that condition profitability and acceptance of agroforestry by smallholder farmers in Western Kenya. We differentiate the use of trees according to the permanence of carbon sequestration, introducing a distinction between practices with "high mitigation benefits" (timber) and practices with "low mitigation benefits" (fuelwood). This study goes beyond the analysis of incentives to plant trees to identify incentives to plant trees that lead to high mitigation outcomes. We show that environmental factors shaping the production system largely drive the choice for planting trees with high mitigation benefits. Most trees in the area are used for fuelwood, and the charcoal economy outweighs economic factors influencing planting of trees with high mitigation benefits. Larger households tend to produce more fuelwood, while high mitigation uses are positively related to the education level of the household head, and to the belief that trees play a positive role for the environment. Where trees contribute significantly to incomes, the norm is that they are owned by men. We conclude that although agroforestry is not perceived to be more profitable than traditional agricultural practices, it plays an important economic and environmental role by supporting subsistence through provision of fuelwood and could relieve pressure upon common forest resources. In areas with high tree cover, it also represents a way of storing capital to deal with risks and cope with uncertainty. [ABSTRACT FROM AUTHOR]

Abstract Kenya is one of the leading countries in the development and commercialization of clean bioenergy stoves in Sub-Sahara Africa. However, due to a series of interconnected factors, the adoption and sustained use of clean bioenergy stoves remains low in the country. This study synthesizes the current knowledge about clean and efficient bioenergy stoves in Kenya through a comprehensive review that brings together the disparate knowledge about the context, status, adoption and impacts of clean bioenergy stoves in Kenya. We start by outlining the main national policies technological, options and stakeholders involved in the clean bioenergy stove value chain such as government agencies, private companies, research organisations, and the civil society. Despite their different roles and interests, there is a shared expectation among all involved stakeholders that clean bioenergy stoves will curb the negative sustainability impacts of traditional cooking options on energy security/poverty, human health, rural livelihoods, gender equality, and the environment. However, a series of factors affect the adoption and sustained use of clean bioenergy stoves such as market structure, consumer awareness, stove design/performance, and the socioeconomic status and cultural practices of stove users. We develop a conceptual framework that illustrates the interlinkages between these factors of adoption and impacts, and outline their varying degree of importance in Kenya. We finish this review by suggesting six policy and practice domains that need to be targeted by policies and research if an effective transition towards universal clean cooking is to be achieved in Kenya. These include to (a) adopt integrated policy approaches and enhance stakeholder collaboration; (b) raise awareness of the benefits of clean bioenergy cooking options; (c) facilitate access to funding and establish appropriate economic incentives; (d) implement quality assurance mechanisms; (e) facilitate behavioural change among stove users; (f) enhance research, development, and technical capacity. Highlights • The promotion of clean cookstoves is a major policy priority in Kenya. • Clean bioenergy stoves have been promoted extensively in last decades in Kenya. • Various interlinked factors affect the adoption of clean bioenergy stoves in Kenya. • Clean bioenergy stoves have multiple environmental and socioeconomic impacts in Kenya. • Coordinated policy support and stakeholder engagement is needed to scale up clean stove adoption. [ABSTRACT FROM AUTHOR]

The charcoal sector constitutes an important source of employment and revenue for many tropical agroecosystems. Better understanding of the effects of charcoal-making is thus warranted to guide actions aimed at minimising environmental externalities. Conversion of trees to charcoal eliminates canopy effects associated with the living trees while at the same time creates new conditions in and around spots where the charcoal is produced due to increased concentration of pyrogenic organic matter (PyOM). It is unclear, whether such unintentional PyOM additions play a role in the abundance and distribution patterns of soil macrofauna. A study was conducted in South Nandi (Kenya) to assess effects of PyOM on soil macrofauna, taking advantage of abandoned traditional earth-mound charcoal kilns, where Croton megalocarpus Hutch. and Zanthoxylum gilletii (De Wild.) P.G.Waterman trees were used in charcoal making. Soil and soil macrofauna samples were collected at increasing distances from the centre of the spots. Total C, non-pyrogenic C (non-PyC) and total N progressively increased with increasing distance from the centre of the spots, whereas soil pH, pyrogenic C (PyC), available P and exchangeable K decreased. The number of earthworms and centipedes in Z. gilletii spots (119 and 14 individuals m −2 , respectively) was twice as high as in kilns where C. megalocarpus was used. Notably, while the number of earthworms in spots rich in Z. gilletii PyOM significantly increased with increasing distance from the centre of the spots, the opposite trend was observed for centipedes. In contrast, no significant differences in the spatial distribution of earthworms or centipedes were found in spots rich in C. megalocarpus PyOM. Furthermore, beetles, termites and crickets were significantly higher in C. megalocarpus than Z. gilletii spots, but sampling distance also had no significant influence. As hypothesised, source of PyOM played a major role in determining soil properties and macrofauna distribution patterns thus showing the value of abandoned charcoal-making spots in contributing to a mosaic of soil conditions that could ultimately affect soil productivity in tropical agricultural systems. [ABSTRACT FROM AUTHOR]

Woodlands in Kenya are undergoing land cover change and degradation leading to loss of livelihoods. Uncontrolled charcoal production, although a livelihood source for communities living in woodland areas of Kenya, leads to woodland degradation. We used Landsat imagery, field plot data and household interviews to describe land cover change and the role of charcoal production in woodland degradation. An unsupervised classification was used to determine land cover change from woodland to open/farmland, and five 16-km transects were used to investigate the extent of charcoal production in the target woodlands. Semi-structured interviews were conducted on 117 households to understand their perceptions on woodland cover change and the role of charcoal production. The overall accuracy of our classification was 86%. Woodland areas decreased by 24% between 1986 and 2014. The trend of woodland area change compared well between remote sensing and interview data. The density of kilns, a proxy for charcoal-led woodland degradation, varied across the sample plots. Despite charcoal providing a livelihood for 66% of the households, the community felt that their environment, wealth and social relations have been affected by land cover changes caused by charcoal production. Based on these results, we recommend that appropriate measures aimed at improving the productivity of agriculture, adapting to climate change and reducing dependence on charcoal for sustenance should be encouraged to mitigate woodland cover loss and degradation. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Prosopis juliflora is an invasive alien leguminous tree introduced as a way of combating desertification, deforestation, and improving soil fertility. Over time, the tree has reported significant negative externalities to farmers. Different strategies such as management through utilization and complete eradication have been proposed to reduce these externalities. We investigate the various factors associated with adherence to these strategies. In the first place, we assess the correlates of charcoal production, beekeeping, and willingness to completely eradicate Prosopis. We then examine the welfare effects of charcoal production and beekeeping. We use survey data from 530 smallholder households in the Baringo county of Kenya who are currently contending with infestation from the invasive tree. Besides other factors, we show that a positive perception about Prosopis invasion increases the probability of engaging in charcoal production and is adversely related to beekeeping and the willingness to completely eradicate Prosopis. Delving into welfare and poverty effects of these activities, we find charcoal production to be income increasing. We argue that a blend of both management and eradication of Prosopis could offer a win-win solution to both improving the welfare and socio-economic conditions of households while also ensuring environmental and ecological safeguards, with implications for broad-based sustainability. • Prosopis juliflora is an invasive alien multipurpose leguminous tree. • A positive perception about Prosopis invasion increases the probability of engaging in charcoal production. • A positive perception about Prosopis is adversely related to beekeeping and the willingness to completely eradicate Prosopis. • Charcoal production is income increasing. • A blend of both management and eradication of Prosopis could offer a win-win solution to both economic and environmental concerns. [ABSTRACT FROM AUTHOR]

Drawing from a holistic research approach, this paper contributes to the studies of land cover change and sustainable development in Kenya, and to the planning of sustainable future in Dakatcha Woodland, SE Kenya. as an unprotected global hotspot for biodiversity, Dakatcha Woodland has suffered from the unsustainable use of forest resources. The relation of charcoal production to land cover change and its socioeconomic impact are studied in detail. a supervised land cover classification formed using four SPOT satellite images from 2005-2006 and 2011 revealed that the woodland is fragmenting and that the Important Bird area (IBA) demarcation should be reconsidered. Through in-situ observation, household questionnaires and semi-structured expert interviews, it was found that more than half of the 90 households assessed are involved in charcoal production - a higher figure than peer studies have suggested -, and that, while the charcoal network offers income to many, it bears an negative impact on the environment. It was also discovered that, like in Kenya, in Dakatcha Woodland the demand for woodfuels (charcoal and fuelwood) is one of the key drivers of deforestation and land degradation. as such, woodfuel energy is a cross-cutting issue, tying together forest resources, livelihoods and sustainable development, and thus demands further research. Forest management of Dakatcha Woodland must be planned in accordance with all stakeholders in a sustainable manner, drawing from agroforestry and participatory forest management systems, and keeping environmental factors in mind for the maintenance of ecosystem services. [ABSTRACT FROM AUTHOR]

In sub-Saharan Africa, 72 per cent of urban and 98 per cent of rural households use fuelwood for energy. In Kenya use of charcoal in urban areas has risen by 64 per cent in two decades. Despite the charcoal industry providing employment to 500,000 people and generating over US$427 million that benefits grassroots communities, it has been kept out of the formal economies of this country. This review presents the status of the charcoal industry in Kenya, highlighting its contribution to livelihoods, production, utilisation, and implications for the environment; policy issues; and stakeholders' involvement. The review also proposes strategies to improve the sustainability of this sector. La production de charbon de bois au Kenya et des stratégies pour l'augmentation de sa durabilité Dans l'Afrique subsaharienne 72 pour cent de ménages urbains et 98 pour cent de ménages ruraux se servent du bois combustible pour leur propre énergie. Au Kenya l'usage de charbon de bois dans les secteurs urbains a augmenté par 64 pour cent au cours de deux décennies. Malgré le fait qu'elle fournit un emploi à 500,000 personnes et qu'elle génère plus de US$427 million de bénéfice aux collectivités populaires, l'industrie du charbon de bois reste écartée des économies formelles de ce pays. Cet examen présente la situation de l'industrie du charbon de bois au Kenya, en soulignant sa contribution aux moyens d'existence, à la production, et à l'utilisation ainsi que les implications pour l'environnement ; des questions concernant la politique ; et l'implication des parties prenantes. L'examen propose également des stratégies pour l'amélioration de la durabilité de cette industrie. Producción de carbón y estrategias para aumentar su sostenibilidad en Kenia En el África subsahariana, 72% de los hogares urbanos y 98% de los hogares rurales utilizan la leña como fuente de energía. En las áreas urbanas de Kenia, el uso de carbón ha aumentado 64% en dos décadas. A pesar de que la industria de carbón crea empleo para 500 mil personas, generandous$427 millones en beneficios para las comunidades de base, se la ha marginado de las economías formales de este país. El presente artículo examina la situación de la industria de carbón en Kenia, analizando, por un lado, su contribución a los medios de vida, y por otro, su forma de producción y su utilización, así como sus implicaciones para temas de política ambiental, además de la participación de los actores en la misma. Asimismo, el artículo propone estrategias para mejorar la sostenibilidad del sector. Produção de carvão e estratégia para aumentar sua sustentabilidade no Quênia Na África Subsaariana, 72 por cento de famílias da zona urbana e 98 por cento de famílias da zona rural utilizam lenha como fonte de energia. No Quênia,o uso de carvão nas áreas urbanas cresceu 64 por cento em duas décadas. Apesar da indústria de carvão proporcionar emprego a 500.000 pessoas e gerar mais de US$427 milhões que beneficiam comunidades de base, ela tem sido deixada de fora das economias formais deste país. Esta revisão apresenta o status da indústria de carvão no Quênia, destacando sua contribuição para os meios de subsistência, produção, utilização e implicações para o meio ambiente; questões de políticas e envolvimento dos stakeholders. A revisão também propõe estratégias para melhorar a sustentabilidade deste setor. [ABSTRACT FROM PUBLISHER]

Kenya generates about 1.6 million tones of sugarcane bagasse which has enormous potential for exploitation in modern commercial applications. Due to rising fossil fuel prices, availability in large quantity and rapidly growing interest in bio-energy as well as technological advances and environmental concerns , bagasse could be utilized for the formulation of charcoal briquettes for household use to supplement wood charcoal. In this study briquettes were formulated using carbonized bagasse, clay as a binder and molasses as a filler. Bagasse was obtained from sugar factories for carbonization. Carbonization was carried out using a brick-built kiln while blending used a manually operated drum mixer. A piston type briquetting press fitted onto a universal strength testing machine was used for the production of briquettes. The most optimum parameters that produced briquettes which complied to current charcoal specifications for household use were in the ratio of 1:1:40 for molasses, clay and carbonized bagasse respectively at 0.50N/mm2 pressure. At this formulation, briquettes were produced whose ash content, volatile matter and calorific energy were 36.4%, 27.2% and 4.390 Kca/g respectively. The briquettes produced burnt without sparks and were smokeless, producing no irritating smell. They ignited easily and took relatively long before they extinguished. They were recommended for household use in Kenya. [ABSTRACT FROM AUTHOR]

Pollen, microscopic charcoal and radiocarbon data are used to document changes in vegetation dynamics during the late Holocene from Namelok Swamp in the Amboseli Basin (Kenya). The data reveal changes in savanna vegetation composition driven by an interaction of climate change, anthropogenic and herbivore activities. The abundance of Celtis, Podocarpus and Syzygium reflects a relatively moist climate from around 3000 to 2400 cal. yr BP. Increased abundance of Acacia, Amaranthaceae/Chenopodiaceae and Poaceae suggest a drier and/or warmer climate from 2150 to around 1675 cal. yr BP. The expansion of Syzygium within the catchment and decrease in Amaranthaceae/Chenopodiaceae reflect a relatively wet phase from around 1675 to about 550 cal. yr BP - superimposed on this is a large increase in Poaceae from 1400 to 800 cal. yr BP indicative of a drier environment. The dominance of Amaranthaceae/Chenopodiaceae and Poaceae with an associated decrease in Syzygium from 550 cal. yr BP is thought to correspond to a drier climate. The uppermost samples, dating to the last 150 years, record a large increase in Acacia, Amaranthaceae/Chenopodiaceae and Poaceae with decrease in Syzygium and are attributed to recent land-use changes associated with increased sedentary settlement. The increased presence of Cannabis sativa, Cereal and Ricinus communis pollen, combined with charcoal in the sediment record, particularly from 2500 but more constantly from 1600 cal. yr BP, indicate a long history of human-ecosystem interaction in the Amboseli Basin that has implications for future management of the area. [ABSTRACT FROM AUTHOR]

Abstract: Pollen and charcoal data generated from a 1469cm core, radiocarbon dated to 26,430 14C yr BP, recovered from Rumuiku Swamp on the southeast of Mount Kenya, are used to document changes in the distribution and composition of montane vegetation and fire regimes over the Late Quaternary. Throughout the transition from the Last Glacial Maximum (LGM), high resolution (sub-centennial scale) analysis documents a highly dynamic ecosystem and fire regime. The pollen record shows that under a cool, but rather moist LGM climate, Ericaceae and Stoebe species shifted down-slope more than 1000m relative to the present day. Rather than simple altitudinal lowering of current vegetation zonation, these taxa formed a vegetation assemblage that mixed high altitude components with relatively lowland taxa; in particular Juniperus that is presently found at altitudes lower than the study site, but on the drier side of Mount Kenya. There is noticeable addition and co-dominance of Hagenia to the ecosystem from 20,500 14C yr BP, until around 14,000 14C yr BP when a mix of Ericaceous Belt and upper montane forest taxa, such as Artemisia, Polycias, Schefflera and Stoebe, dominated the initial development of montane forest. Reduced levels of Hagenia, Juniperus, Olea and Podocarpus are recorded about the time of the Younger Dryas with highly variable presence of more mesic taxa such as Polyscias and Schefflera. This development of montane forest over the Late Pleistocene to Holocene transition reflects a significant reorganization of the ecosystem composition that was heavily influenced by a variable fire regime. Shifts in vegetation composition reflect the onset of a warmer moist climate from the beginning of Holocene, as mixed montane forest became more established. The latter part of the Holocene registers human impact and forest clearance with increased anthropogenic impact marked by a transition to open vegetation and increased fire frequency. [Copyright &y& Elsevier]

Abstract: Current carbon accounting methodologies do not accommodate activities that involve emissions reductions from both land-use change and energy production. This paper analyzes the climate change mitigation potential of charcoal production in East Africa by examining the impact of changing both land management and technology. Current production in a major charcoal producing region of Kenya where charcoal is made as a by-product of land clearance for commercial grain production is modeled as the “business-as-usual” scenario. Alternative production systems are proposed based on coppice management of native or exotic trees. Improved kilns are also considered. Changes in aboveground, belowground, and soil carbon are modeled and two distinct baseline assessments are analyzed: one is based on a fixed area of land and one is based on the quantity of non-renewable fuel that is displaced by project activities. The magnitude of carbon emissions reductions varies depending on land management as well as the choice of carbonization technology. However, these variations are smaller than the variations arising from the choice of baseline methodology. The fixed-land baseline yields annualized carbon emission reductions equivalent to 0.5–2.8tons per year (ty−1) with no change in production technology and 0.7–3.5ty−1 with improved kilns. In contrast, the baseline defined by the quantity of displaced non-renewable fuel is 2–6 times larger, yielding carbon emissions reductions of 1.4–12.9ty−1 with no change in production technology and 3.2–20.4ty−1 with improved kilns. The results demonstrate the choice of baseline, often a political rather than scientific decision, is critical in assessing carbon emissions reductions. [Copyright &y& Elsevier]

Black carbon (BC) is a quantitatively important C pool in the global C cycle due to its relative recalcitrance compared with other C pools. However, mechanisms of BC oxidation and accompanying molecular changes are largely unknown. In this study, the long-term dynamics in quality and quantity of BC were investigated in cultivated soil using X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared (FTIR) and nuclear magnetic resonance (NMR) techniques. BC particles and changes in BC stocks were obtained from soil collected in fields that were cleared from forest by fire at 8 different times in the past (2, 3, 5, 20, 30, 50, 80 and 100 years before sampling) in western Kenya. BC contents rapidly decreased from 12.7 to 3.8 mg C g−1 soil during the first 30 years following deposition, after which they slowly decreased to a steady state at 3.5 mg C g−1 soil. BC-derived C losses from the top 0.1 m over 100 years were estimated at 6,000 kg C ha−1. The initial rapid changes in BC stocks resulted in a mean residence time of only around 8.3 years, which was likely a function of both decomposition as well as transport processes. The molecular properties of BC changed more rapidly on surfaces than in the interior of BC particles and more rapidly during the first 30 years than during the following 70 years. The Oc/C ratios (Oc is O bound to C) and carbonyl groups (C=O) increased over the first 10 and 30 years by 133 and 192%, respectively, indicating oxidation was an important process controlling BC quality. Al, Si, polysaccharides, and to a lesser extent Fe were found on BC particle surfaces within the first few years after BC deposition to soil. The protection by physical and chemical stabilization was apparently sufficient to not only minimize decomposition below detection between 30 and 100 years after deposition, but also physical export by erosion and vertical transport below 0.1 m. [ABSTRACT FROM AUTHOR]

Black carbon (BC) is a quantitatively important C pool in the global C cycle due to its relative recalcitrance compared with other C pools. However, mechanisms of BC oxidation and accompanying molecular changes are largely unknown. In this study, the long-term dynamics in quality and quantity of BC were investigated in cultivated soil using X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared (FTIR) and nuclear magnetic resonance (NMR) techniques. BC particles and changes in BC stocks were obtained from soil collected in fields that were cleared from forest by fire at 8 different times in the past (2, 3, 5, 20, 30, 50, 80 and 100 years before sampling) in western Kenya. BC contents rapidly decreased from 12.7 to 3.8 mg C g−1 soil during the first 30 years following deposition, after which they slowly decreased to a steady state at 3.5 mg C g−1 soil. BC-derived C losses from the top 0.1 m over 100 years were estimated at 6,000 kg C ha−1. The initial rapid changes in BC stocks resulted in a mean residence time of only around 8.3 years, which was likely a function of both decomposition as well as transport processes. The molecular properties of BC changed more rapidly on surfaces than in the interior of BC particles and more rapidly during the first 30 years than during the following 70 years. The Oc/C ratios (Oc is O bound to C) and carbonyl groups (C=O) increased over the first 10 and 30 years by 133 and 192%, respectively, indicating oxidation was an important process controlling BC quality. Al, Si, polysaccharides, and to a lesser extent Fe were found on BC particle surfaces within the first few years after BC deposition to soil. The protection by physical and chemical stabilization was apparently sufficient to not only minimize decomposition below detection between 30 and 100 years after deposition, but also physical export by erosion and vertical transport below 0.1 m. [ABSTRACT FROM AUTHOR]

Interactions between Holocene environmental changes and human subsistence strategies in semi-arid parts of eastern Africa are relatively poorly understood because of a paucity of sites where contemporaneous archaeological and palaeoenvironmental records are preserved. This paper presents new AMS 14C-dated palaeoenvironmental evidence of mid- to late-Holocene vegetation changes, in the form of pollen, charcoal, mineralogical and δ13Cbulk data, from a floodplain location on the Laikipia Plateau, Kenya, and in the context of information on modern plant–environment relationships, existing and new archaeological and historical data, and published palaeoclimatic records. Although relatively poorly resolved, the evidence indicates more wooded and relatively humid conditions compared with the present from before c. 6600 BP to c. 1900 BP. Evidence for vegetation changes over the last two millennia is more finely resolved and indicates increased burning and the expansion of fire-modified Acacia bushland c. 1900 BP and grassland c. 1700 BP. Burning to improve and extend pasture, and possibly to eradicate disease-prone habitats, may have been facilitated by prolonged periods of moisture deficits that might also have facilitated the spread of food production technologies. Vegetation changes c. 700 BP are associated with evidence for the occurrence of fires locally and could represent the activities of people and their animals close to the study site. [ABSTRACT FROM AUTHOR]

Non-equilibrium processes in savannas are poorly understood because little data is available on how tree abundance has changed over long periods of time. Here I analyse fossil pollen and charcoal from Kanderi Swamp in Tsavo National Park, Kenya in order to investigate patterns of vegetation change over the past 1400 years. I compare the results with the predictions of cyclical, phase and transition and stochastic non-equilibrium models. Fourier analysis of the pollen data provides evidence of cyclical changes in tree abundance with a periodicity of 250–500 years, but the pollen data also suggests that the vegetation surrounding Kanderi swamp remained in a prolonged woodland phase, as predicted by phase and transition models, from approximately 770–1520 a.d. In addition, the results provided evidence of much shorter term changes in tree/grass abundance, perhaps reflecting stochastic variations in rainfall. The charcoal data suggests a link between vegetation change and fire history, possibly mediated through the effects of rainfall variation on the accumulation of combustible biomass in the herb layer. There was also evidence of extreme fires occurring twice in the past 1400 years. The results suggest that at the local scale, the vegetation near Kanderi Swamp has been mainly influenced by localised disturbance, rather than climatic shifts or the Rinderpest epidemic, and that elements of cyclical, phase and transition and stochastic models are needed in order to fully understand the observed pattern of vegetation change. [Copyright &y& Elsevier]

The article reports on the challenges to the authority of Somali President Hassan Sheikh Mohamud. They include disputes over the management of Kismayo port, which was recovered from Al Shabaab by the Kenya Defence Forces. Another challenge is the handling of charcoal stockpiled at the port by Darod/Ogadeni businessmen.

Incorporation of phosphorus (P) into an organic matrix may be an effective strategy to increase plant P use efficiency in high P-fixing soils. The objective of this work was to evaluate the effect of biochar-based fertilizers (BBFs), produced from poultry litter (PLB) and coffee husk (CHB) enriched with phosphoric acid and magnesium oxide, in combination with triple superphosphate (TSP) on plant growth and soil P transformations. Treatments were prepared as: TSP, CHB, PLB, CHB + TSP [1:1], CHB + TSP [3:1], PLB + TSP [1:1] and PLB + TSP [3:1]; with numbers in brackets representing the proportion of BBF and TSP on a weight basis. Cultivations were: Mombasa grass, maize, and common bean interspersed with fallow periods. After cultivations, a sequential extraction procedure was employed to determine P distribution among different P pools. A kinetic study was performed and revealed that TSP released approximately 90% of total P, and BBFs less than 10% in the first hour. BBF alone or in combination with TSP presented higher or similar biomass yields, relative agronomic effectiveness, and P uptake when compared with TSP. As for the soil, BBFs increased non-labile P fractions, which can be due to pyrophosphate formed during pyrolysis. According to these results, BBFs could totally or partially replace conventional soluble P fertilizers without compromising crop yield either in the short and long-term., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

The feasibility of using biowaste for the production of biochar and its use in agriculture depends on its environmental and economic performance. This paper quantifies environmental and economic life cycle impacts of biochar production and agricultural use in six developing and middle-income countries (Ethiopia, Indonesia, Kenya, Peru, Vietnam, and China). Two types of production technologies typical for rural and urban areas were investigated (flame curtain kiln and gasifier, respectively), and comparisons were made with composting (either home composting or windrow composting) as alternative biowaste management systems. The results showed that both pyrolysis systems performed better than composting and both were expected to bring environmental benefits. The largest environmental benefits were observed for the gasifier systems, mainly due to the substitution of electricity production from the grid. Damage to ecosystems and human health ranged from -1 × 10 -7 to -2 × 10 -8 species×yr and from -1 × 10 -5 to -5 × 10 -6 DALY per kg of biowaste treated, respectively (negative scores indicating environmental benefits). However, net economic benefits were only achieved when low-cost simple kilns were used in countries with low labor cost, like Ethiopia, Kenya and Vietnam (net profit from 0.01 to 0.08 USD per kg of biowaste treated). Further, high investment and operating costs and relatively small electricity revenue from substituting the grid electricity resulted in gasifier scenarios being economically unsustainable (net loss from 0.29 to 1.58 USD per kg of biowaste treated). Thus, there are trade-offs between positive environmental impacts for society and net market loss for the individual decision-maker (company or individual farmer) that should be considered when making decisions regarding the implementation of biochar technology in developing and middle-income countries. The use of simple kilns in countries with relatively low labor costs appears to be favorable., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Woodland resources provide livelihoods for millions of people in Africa. Concerns about the impact of human utilization of woodlands have led to vigorous debates on woodland degradation. Ecological and socio-economic empirical data and understanding of the socio-ecological system have been synthesized in an agent-based model (ABM) to explore different woodland management options for a dynamic, semi-arid region in Kenya. In our simulations we accounted for the impacts of drought frequency, charcoal price changes, improved management practices and taxation of charcoal for a 20-year period to assess woodland changes in a spatially explicit way and evaluate the numbers of actors that can benefit from charcoal harvesting as a livelihood option. The model is based on an agent typology derived from 150 household interviews that focused on livelihood strategies and decision-making processes. Furthermore, the model integrates knowledge from vegetation plots and focus group meetings. From the model simulations we learn that favorable prices, improved management and taxation do not directly have the anticipated impact on woodland resources, as the improved conditions lead to fewer constraints on involvement in charcoal making. This reduces the positive impacts of these measures on the woodland quality but, at the same time, allows a larger number of actors to benefit from charcoal harvesting. Results show a very strong decrease in woodland area under the base scenario thereby reducing possibilities for households to supplement their incomes with charcoal making. Increased droughts and low prices for charcoal lead to early depletion of woodlands and reduction in livelihood options. Taxation stabilizes the number of charcoal producers but does not stop the depletion of woodland area. Woodland loss can only be prevented by controlling the number of charcoal makers and the amount of charcoal harvesting. • The effect of charcoal production dynamics on sustainable woodland management are explored in Kenya. • An agent based model is developed to explore human-environment interactions. • Charcoal makers and woodland area decrease over the 20 year modelling period. • Limiting ability of charcoal makers to change agent type reduces woodland area decline. • ABM add value to empirical research on socio-economic and ecological aspects of charcoal production. [ABSTRACT FROM AUTHOR]

Lake Nakuru in Kenya, located south of the equator on the East African Plateau, is one of themany modern, shallow saline lakes in the East African Rift System (EARS). Despite today’slake composition throughout the EARS, many of these lakes were instead deep, freshwaterlakes 15,000 to 5,000 years ago during the African Humid Period (AHP), due to achange in earth’s precession causing increased moisture throughout the region. Thissensitive reaction to even moderate moisture changes categorizes these lakes as"amplifier lake" systems, but beyond the existence of such lakes during the AHP,little is known about them. This is especially evident in the lack of understandingregarding their transitional speed in and out of wet phases as well as their internalstability/instability during the AHP. Here we present a high-resolution multiproxy record forthe last 25,000 years including diatom identification and geochemical and physicalparameters. Samples were retrieved from the upper 8 m of two duplicate, 17 m drill corestaken by the Lake Naivasha Coring Project (LNCP) in 2004. The chronology of thecores is based on 11 AMS 14C ages measured on charcoal and two 40Ar/39Ar agesfrom separate tephra layers. Beyond providing a new high-resolution record ofpaleolimnological changes at Lake Nakuru over the past 25,000 years, this study willcontribute to knowledge regarding the impact of moisture changes both during and alongthe transitions of dry-wet-dry cycles on the amplifier lake systems of the EARS.Furthermore, the new record will resolve a regional data gap of the synchronicity oflake level changes and its associated impact on past humans and their migrations. [ABSTRACT FROM AUTHOR]

Background : Pica, the craving and purposeful consumption of nonfoods, is poorly understood. We described the prevalence of pica among women on Mfangano Island, Kenya, and examined sociodemographic and health correlates. Methods : Our cross-sectional study included 299 pregnant or postpartum women in 2012. We used a 24-h recall to assess pica, defined as consumption of earth (geophagy), charcoal/ash, or raw starches (amylophagy) and built multivariable logistic regression models to examine sociodemographic and health correlates of pica. Results : Eighty-one women (27.1%) engaged in pica in the previous 24 h, with 59.3% reporting amylophagy and 56.8% reporting geophagy, charcoal, and/or ash consumption. The most common substances consumed were raw cassava ( n = 30, 36.6%), odowa, a chalky, soft rock-like earth ( n = 21, 25.6%), and soil ( n = 17, 20.7%). Geophagy, charcoal, and/or ash consumption was negatively associated with breastfeeding (OR = 0.38, 95% CI: 0.18-0.81), and amylophagy was associated with pregnancy (OR = 4.31, 95% CI: 1.24-14.96). Pica was more common within one of six study regions (OR = 3.64, 95% CI: 1.39-9.51). We found no evidence of an association between food insecurity and pica. Conclusion : Pica was a common behavior among women, and the prevalence underscores the need to uncover its dietary, environmental, and cultural etiologies.