Electronic Theses and Dissertations (PhDs)

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    Peat dynamics in the Angolan Highlands
    (University of the Witwatersrand, Johannesburg, 2023-03) Lourenco, Mauro Cesar; Woodborne, Stephan; Fitchett, Jennifer
    The Angolan Highlands is a war stricken, threatened, and under-studied area. The region is hydrologically and ecologically important and supports extensive tropical peatland deposits. Peatland preservation has been acknowledged to address climate change, is sensitive to drought and fire, and is directly influenced by vegetation and hydrological conditions. However, little research has been conducted in the Angolan Highlands. This study addresses gaps in the literature through four key contributions. The first is a critical review of peat definitions: the implications of disparate definitions are detailed, and a new proposed definition for peatlands in the interest of climate science is provided. The second is the first map of peatland extent in the Angolan Highlands, containing details on the age and growth dynamics. The study presents a conservative estimate of peatland extent that is much larger than previously estimated for Angola and is a crucial first step in facilitating the preservation of this deposit. The third contribution is the first historical assessment of drought and vegetation response in the region. This contains a 40-year drought and 20-year vegetation history, demonstrating that drought occurrence is increasing and there is a strong relationship between precipitation and the peatland vegetation region. The fourth contribution is the first assessment of the contemporary (2001-2020) fire regime of these peatlands, and reveals that among all land cover classes, peatlands burn more frequently and at a higher proportion. Investigation into the peat dynamics of the Angolan Highlands indicate that they have critical importance and are naturally resistant to both droughts and fire. Failure to preserve these deposits will have direct implications on the communities, environment, and surrounding areas.
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    The political geography of hemp Cannabis in South Africa: A development critique
    (University of the Witwatersrand, Johannesburg, 2023-06) Moore, Wendell; Mnwana, Sonwabile; Wafer, Alex
    The discourse on Cannabis that is generally understood in the public domain, revolves mostly around its recreational uses and more recently its medicinal potential. The plants industrial usages and overall worth to society are often framed in relation to these more popular parts of Cannabis. The study focuses its attention on hemp Cannabis to tell a different story but acknowledges that all the uses of Cannabis are interlinked. Using an extensive desktop analysis, Cannabis webinars and conferences, as well as autoethnography, the thesis shows that there is in fact more to the plant than what first meets the eye. It especially illuminates two important dimensions of Cannabis that are often overlooked when discussing the plant. Firstly, by its nature Cannabis is political, which is deeply embedded in how the plant is understood in the geographic diaspora of the Global South. Secondly, it shows that any serious social scientific analysis of contemporary Cannabis development must think through how the ways of knowing, produced during prohibition, will become a part of the plant’s future. This thesis therefore argues for an appraisal and maintenance of the historical resistances of Cannabis used prior to legalization, if its development in the legal era is to be successful. To be sure, such innovative and alternative models of practical development should become a standard part of the geographies of all work economies. Moreover, making use of these forms of resistance is not about Cannabis gaining the approval from ‘the market’. In fact, the skills learnt while labouring for Cannabis, when it was prohibited, has become such a permanent feature of its development that liberal democratic consent is not an option. Therefore, the thesis proposes that Cannabis development delink from the prohibition narratives inscribed onto the plant. It continues by showing that the current medicalisation of Cannabis only updates gatekeeping models. Hence, an agrarian alternative was suggested that consolidates all the uses of Cannabis without undermining any one part of the plant. Lastly, the thesis documents the possibilities of gaining access into the industry for black people, the poor working class and women. What it argues is that ownership, just employment and leadership of Cannabis industries in South Africa must be repurposed so that ordinary people can also play a part in making sure the plants contemporary development is truly sustainable. Taken together, this is the critique of development that the political geography of hemp Cannabis in South Africa reveals.
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    The role of institutional arrangements in post-flood disaster management in South Africa, focusing on Kwa-Zulu Natal Province, Mphela Township and Ncakubana Communities
    (University of the Witwatersrand, Johannesburg, 2023-10) Nyide, Sindisiwe; Grab, Stefan; Simatele, Mulala Danny
    South African officials and communities grapple with various matters after flood disasters. This thesis used a combination of qualitative and quantitative data collection approaches to explore possible systematic and structural weaknesses in addressing post-flood disasters in South Africa. The study investigated whether post-disaster management in disaster-vulnerable urban and rural communities contributes towards disaster resilience and adaptive capacity to achieve sustainable development. The need stemmed from the Country's high frequency and magnitude of disasters, including floods, droughts, and fires. The Government implemented different policies and strategies after 1994 to address flood disasters. While acknowledging some success in managing these disasters with the current adaptive measures, the frequency and intensity of disasters have increased, causing significant loss of life, environmental damage, and properties, particularly among the vulnerable population. Since this was a national study, participants came from across South Africa. The random sampling selected 35 Ncakubana Village and Mphela Township community members. Other selected participants were seven and six focus group members, respectively. In contrast, purposive and snowball samples chose 34 disaster management officials. Moreover, the purposive sampling selected two ward councillors and six advisory forum members. There were open-ended and closed-ended questions in the interview schedules and questionnaire surveys. The researcher also used observation to gather information on variables of interest during transect walks in the study areas. The study conducted an intensive documentary analysis to obtain more information. Descriptive statistical techniques, Microsoft Excel, and Statistical Package for the Social Sciences were employed to examine the quantitative data. Thematic analysis was for qualitative data analysis to review data from open-ended questions and literature. The study employed Atlasti software for inductive content analysis to identify research codes and themes and the Word Cloud tool to visualise textual data. For quantitative results, 33 disaster management officials responded that disaster-specific Acts and Policies are in place. According to 21 disaster management officials, or 62% of all participants, their organisations have vulnerable groups' specific policies. Multistakeholder complications were the most frequently mentioned challenge by participants. They mentioned them 23 times, 68% of the total participants. Challenges stated, among others, included funding and administrative matters. Most of the respondents, 75% identified funding as the biggest problem. Qualitatively, the thesis uncovered that disaster management is a multi-sectoral and multidisciplinary field. Although various institutional arrangements exist, they do not seem appropriate for assisting vulnerable groups post-disaster. Floods appeared to be the most frequent natural disaster in South Africa. Floods severely affected vulnerable people, particularly women, the elderly, children, and people with physical disabilities. While officials have made some progress on implementing post-flood disaster projects, they appear inadequate to assist vulnerable groups in dealing with floods. Furthermore, regrettably, despite the level of success in addressing disasters, most measures have failed to achieve the intended results for various reasons. The participants identified multiple tangible and intangible opportunities. They subsequently proposed that Disaster Management Centres develop various noteworthy documents, intensify the dissemination of post-disaster information across numerous platforms, obtain post-disaster funding and adequate personnel, and establish or revitalise structures. The suggested consolidated long-term measures by the participants yielded a proposed South African Post-flood Disaster Checklist or Model, which was non-existent in South Africa. By implementing more effective and efficient post-disaster measures, the proposed tool can help policymakers and strategic partners standardise post-disaster resilience and adaptive capacity in various sectors' sustainability contexts. The aim is to have post-flood disaster resilient communities with adaptive capacity to achieve sustainable development.
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    Cartographic History, the Post-Colonial Landscape and the Agricultural Settlement Scheme: A Case Study of Citizen-Based Mapping in Northeastern Ibadan Rural Hinterland
    (University of the Witwatersrand, Johannesburg, 2023-10) Ogundiwin, Babatunde Adedayo; Wafer, Alex
    Maps of economic imagination provide visual insights into alternative agrarian spatial thought. This thesis examines visual contribution to reconstituting agricultural subjectivity. It explores the potential of citizen-based mapping in consolidating alternative visions of the agricultural settlement scheme. Visualisations are integral in the discursive technologies of post-colonial state policies that produce modern agricultural subjectivity. On one hand, these state cartographic strategies involve othering practices of subaltern agriculture. On the other hand, there are resurgent ideas of community-based agricultural schemes verbalised amongst subaltern groups. Hence, there is an ongoing political-economic struggle of visions mediated by visualisation and verbalisation. Drawing upon theoretical literature in spatiality, postcolonialism and governmentality, the thesis explores taken-for-granted knowledge, sites of economic difference and silenced voices/visions on the post-colonial agricultural landscape. Using Northeastern Ibadan rural hinterland of Oyo State, Southwest Nigeria, as a case study, the thesis argues that visualisation offers insight into counter-narratives and alternative reframing of the agricultural settlement scheme. This study employed a multi-method qualitative approach involving the critical historical reading of state maps, ethnographic analyses and mapmaking techniques to visualise and summarise developmental concerns and aspirations. The thesis demonstrates that state imaginative geographies strive in shaping agricultural identities and subjectivities. Recently, these cartographic legacies of state rationalities seek the active consent of the citizenry in the drive toward state-sanctioned neoliberal imaginary. The study contends that the post-colonial state in Nigeria envisions a large-scale agricultural development rather than supporting smallholder subaltern agriculture. Hence, there is intentional and unintentional involvement in visual disinformation and engagement in anti-political economic imaginations of subaltern agriculture. However, the visualisation of verbalised counter-narratives contesting state developmental visions and alternative imaginations of the agricultural settlement scheme unveil anticipatory spatialities desiring a break from economic decline and stagnation in rural hinterlands. This transformation of imaginaries into visual images emphasises new perspectives and new insights renegotiating the political subjectivity of subalterns. This thesis demonstrates that visual geographies of subaltern aspirations offer alternative visions of the agricultural settlement schemes.
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    Climate Variability and Asset Adaptation of Small-scale Farmers in Zimbabwe's Gokwe South District:A Search for Knowledge Integration Approach
    (University of the Witwatersrand, Johannesburg, 2023-05) Chatsiwa, Jaison; Simatele, Mulala Danny
    Globally, climate change and variability threaten food production and security for an unforeseeable future leaving millions of people vulnerable to hunger and malnutrition related diseases. Climatic models are projecting that Zimbabwe’s climate will be hanging drastically with a high possibility of experiencing extreme weather patterns impacting the livelihoods of small-scale farmers who rely on rain-fed agriculture for their livelihoods. This study aims to investigate the role of asset portfolios in reducing the climate vulnerability of small-scale farmers of Gokwe South in Zimbabwe. Zimbabwe’s agricultural production both crop and livestock production has been negatively impacted due to the dwindling rainfall and increase in temperature and climate related risks and disasters. The quality and quantity of asset portfolios determine the adaptive strategies and their success against the challenges of climate variability. Despite these effects, small-scale farmers in the Gokwe South district are using their asset portfolios to increase their adaptive capacity and resilience to fight against the challenges of climate variability. Therefore, this thesis revealed a paradigm shift from asset vulnerability to pro-poor asset adaptation. The paradigm shift crafted the ‘Theory of Change’ which is useful for climate variability adaptation strategies in the Gokwe South district as the small-scale farmers change from asset vulnerability to asset adaptation. The Theory of Change encourages contextual analysis of the area and theme under study. A Theory of Change is a method that explains how a given intervention, or set of interventions, is expected to lead to specific development change, drawing on a causal analysis based on available evidence. This study used the Participatory Climate Change Adaptation Appraisal (PCCAA) as the primary data collection tool and the Participatory Rural Appraisal (PRA) known as the emancipatory methodology, to collect data in rural areas. A mixed methodological approach involving qualitative and quantitative was applied. We used thematic content analysis to analyse qualitative data collected during the data collection exercise. During the study period, computer-Aided Qualitative Data Software was used to store data in a sorted manner. The parametric variables were coded using the Predictive Analytic Software. This enabled to performance of statistical analysis and obtaining descriptive statistical outcomes were obtained. The assessment of the effect of the factors on climate adaptation strategies was done through the Likert scale. Indigenous knowledge remained widely used as a source of climate knowledge in the Gokwe South district. The research results showed that indigenous knowledge (IK) is unpredictable, productive assets and adaptive assets are inadequate, technoscience and institutional support are poor support to implement viable adaptation strategies is lacking, and poor distribution and dissemination of climate and weather information to small-scale farmers in the Gokwe South district is poor and asset portfolios and asset mix is poor. The available asset portfolios determine the adaptation strategies used in the Gokwe South district. Results show that climate vulnerability varies spatially and temporally across the Gokwe South district. The studied five constituencies for the Gokwe district have a mean vulnerability index of 3.04 with the highest index being 5 as being well adapted. Sengwa and Mapfungabutsi are highly vulnerable to the vagaries of climate variability in the Gokwe South district. The researchers recommend strong institutional support from the government. The fact that small-scale farmers should integrate their IK and modern science climate knowledge small-scale farmers in the Gokwe South district should adopt proactive or anticipatory adaptation, government climate-smart agricultural policies, and a bottom-up approach to climate variability. The quality and quantity of asset portfolios are key resources affecting the level of vulnerability to climate variability. The asset mix was seen to be significant in reducing the vulnerability of small-scale farmers in Sengwa and Mapfungabutsi, constituencies worst affected due to poor asset endowment of farmers in the Gokwe South district. The results have shown that the financial asset is the most important asset affecting vulnerability because it can be converted into other assets through buying. Weak institutional intervention renders many small-scale farmers helpless to climate variability, and the government is not fully supporting small-scale farmers to increase their adaptive capacity and resilience.
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    Social vulnerability in the adaptation of rural communities to climate change in Imo State, Nigeria
    (University of the Witwatersrand, Johannesburg, 2024) Okoro, Franklin Chimaobi; Knight, Jasper
    Rural communities in developing countries such as Nigeria are faced with frequent extreme weather/climate events that impact their economy, health, and environment due to the combination of high social vulnerabilities, low social resilience, and low adaptive capacities. The aim of this study is to investigate the root causes of social vulnerability in rural communities in Nigeria and how rural households use their social capital and networks to adapt to the impacts of climate change. The study used ten (10) social vulnerability indicators (factors) to ascertain their influence on social resilience and adaptive capacity during climate related disasters. To achieve this purpose, three communities in Imo State, Southern Nigeria were selected, and distributed 240 structured questionnaires to rural household heads, interviewed 18 local stakeholders and climate change actors (government agencies), and conducted three (3) Focus Group Discussions (FGDs) with group of farmers from the three selected communities. The questionnaire survey, interview, and FGD guides contained open-ended questions that allowed participants to report freely. The quantitative data derived from the questionnaire survey were subjected to descriptive analysis using SPSS while the qualitative data were subjected to thematic analysis to derive relevant themes for discussions. The result of the study shows that social vulnerability is a function of age, gender, education, household size, income, sources of livelihood, disability, means of transport, access to healthcare, and alternative accommodation being available during climate emergencies. The study further shows that social vulnerability of rural residents was exacerbated by societal vulnerability influenced by political, economic, cultural, and social factors. Although there are other weather/climate extreme events (disasters), however, the most prominent is floods, constituting 48.3% of the weather/climate events experienced in the study area with its impacts requiring more efficient climate adaptation strategies other than the traditional measures like relocation/migration, use of early maturing crop varieties, early planting and harvesting. However, rural households drew support from government, NGOs, and oil companies but the help from family members, friends, neighbours, social group members (social networks) were more beneficial and helped more rural residents to improve their social resilience. The study recommends that rural residents be encouraged to join social groups since their memberships in such groups will help to improve their social resilience, and that government and its agencies should engage multi-stakeholders in their genuine efforts to develop more effective measures for climate change adaptation.
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    Palynological insights into an 11,700-year sequence of vegetation change in mashishing, Mpumalanga, northeastern South Africa
    (University of the Witwatersrand, Johannesburg, 2023) Olatoyan, Jerry O.; Schoeman, Alex; Neumann, Frank; Sievers, Christine; Orijemie, Emuobosa; Evans, Mary
    In this thesis, the issue of distinguishing anthropogenic and climatic drivers of vegetation change was explored through the analysis of pollen, phytoliths and microcharcoal in core sediment records from Mashishing Fen in the Thaba Chweu Municipality, Mpumalanga province, northeastern South Africa, that date from ca. 11.2 – 11.7 ka BP to the present. In southern Africa, generally, the distinction between the contributions of anthropogenic and climatic factors to vegetation changes poses a complex challenge in palaeoenvironmental research. This difficulty often arises due to limited, well-dated palaeoenvironmental sequences suitable for correlations between archaeological and palaeoecological records. For the last 2000 years, there has been a scarcity of direct evidence for farming, such as grains and other domesticated plants, and pastoralism. A further difficulty is that some plant taxa may be indicators for intense droughts but also signify anthropogenic disturbances. At the centre of the thesis are three papers. The first comprises a synthesis of existing literature of archaeobotanical evidence that was done to evaluate the relationship between climate, anthropogenic activities, and vegetation change during the first millennium CE in southern Africa. I focussed on this context in the paper because it is a time in which the arrival of pastoralism and farming in the region makes it the most likely period during which distinct anthropogenic vegetation change occurred. The published data demonstrates that microfossil assemblages are potential indicators of anthropogenic activities of pre-European pastoralists and farmers of the region, with patterns including a decline in tree pollen and increases in microcharcoal, spores of coprophilous fungi, open land/disturbance indicators, and ruderal species. The second paper addresses some of the limitations of palynology as a method. A modern pollen- and phytolith-vegetation study was conducted on surface sediment samples linked to the botanical survey of five vegetation survey plots at and around Mashishing Fen to investigate the relationships between the modern pollen and phytoliths in the surface samples and the contemporary vegetation within the area. The results support the accepted view that pollen and phytoliths often do not track similar vegetation signals. The modern pollen assemblages clearly track forest and wetland vegetation, and the modern phytolith assemblages reflect grassland vegetation in the area. The study confirmed that differential phytolith and pollen production, dispersal and preservation substantially influence the proxy records and that combining phytolith and pollen data provides a more accurate basis for plant fossil interpretations in palaeoenvironmental studies. The results of this paper constrained my interpretation of the pollen data used in the third paper. Finally, pollen, spores and microcharcoal data from the core sediment records from Mashishing Fen (formerly the Lydenburg Fen) provide palaeoenvironmental records for approximately the last 11,2 to 11,7 ka years–most of the Holocene. The data is interpreted through the patterns identified in the first paper, including potential indicators of anthropogenic activities. The data of the earlier period provide a backdrop to possible anthropogenic change in the first millennium CE; the extended data illustrate paleoenvironmental changes that took place in a region occupied by hunter-gatherers but predate any possible anthropogenic influences by pastoralists or farmers. The core data suggests that the early Holocene began with moist and warm conditions that were followed by fluctuations between wet and dry conditions during the mid-Holocene and the decline of trees with the dominance of open-land indicators during the later Holocene, thereby providing the basis for correlating the palaeoecological records with the archaeological records in the region
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    Assessing livelihood vulnerability and adaptation to climate variability and change among farming households in Plateau State, north-central Nigeria
    (University of the Witwatersrand, Johannesburg, 2024) Hassan, Buhari; Knight, Jasper
    It has been projected that sub-Saharan Africa would be severely affected by climate change in form of persistent and increasing climate variability. Nigeria’s situation as a developing country coupled with the fact that agricultural activities are primarily rainfed, provides a suitable case study in which to assess the vulnerability of farming households to climate variability and change. Lack of data on the nature and extent of vulnerability to climate variability (particularly annual changes in rainfall and temperature patterns) on food production systems and livelihoods in Nigeria hinders the development of effective policies to mitigate the adverse impacts of climate change and variability. The study aims to improve understanding of the socio-economic, institutional, biological and physical factors that contribute to vulnerability of farming households to climate change and variability in Nigeria. By combining descriptive, participatory and statistical analysis as well as field observations, this research develops a holistic approach to assess the level of exposure, sensitivity and adaptive capacity of farming households. Multistage sampling was used to purposely select communities in Bokkos Local Government Area, Plateau State, for the study, while farming households were randomly selected for the household questionnaire survey within four communities. Purposive sampling was used to identify key informants for interviews. Observation and taking photographs of farmers’ activities were used to complement the other data collection methods. Qualitative data was analysed using descriptive and content analysis, while the quantitative data was analysed using the Statistical Package for Social Sciences (SPSS) (v 27) and Microsoft Excel (v2020). The level of vulnerability of farming households was determined using the Sustainable Livelihood Approach. Results show that farmers are exposed to climate variability in form of changing rainfall patterns which includes late onset of rains, dry spells, and early cessation of rains and crop loss due to pests and disease infestation. Results show that the vulnerability of farming households can be linked to access to household livelihood capital assets and that households are characterised by low levels of financial, social and physical capital. Smallholder farming households adopt a range of on-farm and off-farm adaptation strategies including changing planting time, crop diversification, engaging in irrigation farming, intensifying the use of fertilizers, manure and agro-chemicals to boost crop yield, and planting of disease-resistant and drought-tolerant crop varieties. Farming households experience a number of challenges which include a lack of financial resources which has a strong influence on enhancing other capital assets such as physical and natural capitals; poor access to mechanised agricultural equipment, lack of training on how to deal with climate change and variability, limited access to improved crop varieties as well as a lack of institutional support, which constitute serious barriers to adaptation to climate variability. In applying these results to climate change adaptation it is recommended that policymakers need to institute specific and implementable climate change adaptation policies that will enable farmers to utilize their capital assets on effective adaptation measures and also engage in viable alternative livelihood diversification strategies, enhance agricultural productivity and resilience and improve institutional support including access to information and training
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    From Coal to Renewable Energy: Perspectives on South Africa's Energy Transition for a Sustainable Future.
    (University of the Witwatersrand, Johannesburg, 2024) Sebele, Temperance; Simatele, Mulala Danny
    South Africa has been experiencing an unstable electricity supply for years, leading to periods of load shedding from 2007 up to the present date. The electricity shortages have been attributed to distinct reasons, ranging from inefficient coal supply, skills shortages, sabotage by employees and lack of maintenance for nearly sixteen years. In addition to the electricity supply shortages, coal-fired electricity generation is responsible for roughly 80 per cent of South Africa’s total greenhouse gas emissions due to fossil fuel dependence, leading to many health, climate, and environmental challenges. To address the challenges related to fossil fuel dependency, moving to Renewable Energy sources that are climate and environmentally friendly is a necessity. The aim of this study was to investigate the optimal approaches that South Africa can embark on for a successful transition from coal to renewables. The institutional, policy, and strategic frameworks that exist within which South Africa can embark on for a successful transition were explored. Furthermore, the study sought to identify the challenges, and opportunities that exist or hinder the transition in South Africa. Lastly, the study explored how developments in the international policy frameworks influence South Africa’s ambitions to transition to renewables. The study is best suited to the pragmatism approach, and data were collected through the reviewing of literature, key-informant interviews, and questionnaires. A mixed-methods strategy that involved gathering both qualitative and quantitative data was employed and primary and secondary sources of data were used. The primary data sources used included key informants from various private and public institutions with an interest in South Africa’s energy matters such as ESKOM, SANEDI, SANEA, SAREC, SAPVIA, SAWEA, SAIPPA and NECSA. The non-probability sampling method was used in the participants’ selection from the sampled study institutions, with a combination of judgmental, snowballing and convenience sampling procedures employed at distinct phases of the research. Data collected was analysed both quantitatively and qualitatively, with interviews text data transcribed and analysed through manual tabulation and thematic analysis, and presented in graphs generated from Microsoft Excel, and the data from questionnaires analysed through the IBM Statistical Package for the Social Sciences (SPSS) software. The study revealed that the government played mainly four leading roles in the energy transition, which were providing financial support, legislative direction, institutional direction, and project oversight. Financial support is provided through financing projects and setting up financing policies that promote renewable energy investment, and legislative direction is provided through policy development and ensuring efficient implementation. Providing institutional direction is ensured through ensuring coordination across all spheres of government and capacitating institutions involved in the transition, and project oversight is provided through setting out renewable energy capacity determinations. The study further identified key energy transition elements, namely infrastructure, governance, legislation, stakeholders’ perceptions, and skills and strategies for a successful transition, which included channelling adequate financial resources to the renewable energy sector, privatisation of the electricity utility, diversification, rolling out bid windows, improving the legislative framework, improving grid access and integration, skills development, localisation of RE components manufacturing, providing incentives, and increasing consumer awareness about renewables. Several barriers to the transition were also identified, which included political interference and corruption, lack of financial investment, policies/legislation inadequacy, inconsistency in rolling out bidding windows, ESKOM’s monopoly, high cost of renewables, deficiency of incentives, skills and technology, labour unions, and deficiency of awareness on alternatives. The study recommends multisector reskilling of employees, since not all employees in the coal value chain may be interested in or able to be absorbed in the Renewable Energy sector. Furthermore, the government should fund and support progressive technologies and business models, improve the quality of institutions through merit-based appointments and uprooting corruption, privatisation of ESKOM to create opportunities for new entrants in the electricity market and improve stakeholder engagement and community support programmes. The UNFCCC must develop and ensure the implementation of enforcement strategies for holding countries accountable for their climate commitments for the transition to be realised
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    Mapping and assessment of informal settlements using object-based image analysis, a case study of Mamelodi, Tshwane, South Africa
    (University of the Witwatersrand, Johannesburg, 2024) Mudau, Naledzani; Mhangara, Paida
    The social and environmental challenges faced by people living in informal settlements or slums are widely recognized by development agendas including United Nations Sustainable Development Goals, Agenda 2063 and National Development Plans. The study aims to investigate informal settlement dynamics and spatial characteristics to generate an understanding of housing informality and environmental conditions for designing innovative sustainable solutions. The study assessed the use of 12 spectral indices and textural measures, and object-based image analysis (OBIA) technique to detect informal settlements from WorldView 2 images. A growth indicator that uses informal settlement extent and impervious surface was developed and used to assess informal settlement growth patterns between 2005 to 2020. Unmanned aerial vehicle image products, and landscape metrics were used to assess the spatial characteristics and patterns of backyard shacks and free-standing informal settlement structures. In addition, a settlement surface ecological index was developed and used to assess the ecological conditions of informal settlements. Lastly, the assessment of the location characteristics of informal settlements was done using ancillary data. The results show that the use of built-up index, coastal blue index and first order statistics mean textural measures and OBIA technique detected informal settlements with producer and user accuracies of 95% and 82% respectively. The developed informal settlement growth assessment indicator shows that informal settlement in 2020 had a slightly lower density of impervious surfaces than in 2005. The Euclidean Nearest-Neighbour Distance, Aggregation Index and Cohesion Index show that backyard shacks are less connected, less dense, and more isolated than freestanding informal settlement structures. Some informal settlements have better surface ecological conditions than some of the formal settlements. A higher extent of informal settlements continued to develop closer to formal settlements, rivers and railway lines between 2015 and 2020. The information demonstrated in this study can be used by local authorities to better understand and manage informal settlement developments, prioritize settlement upgrade projects and improve the environmental conditions and resilience of informal settlements