4. Electronic Theses and Dissertations (ETDs) - Faculties submissions

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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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    Examining the technologies and practices that can help SA mining industries meet carbon blueprint reductions
    (University of the Witwatersrand, Johannesburg, 2023) Lakhna, Adheesh; Oro, Ufuo Oro
    Mining has always been regarded as a black sheep due to its legacies of environmental accidents, pollution, and safety incidents. However, for economies to grow, they need energy and energy requires metals to generate, transmit and store power. These metals are mostly sourced from mining and so as the world changes to cleaner and greener energy options, it is only fitting that mining equipment also becomes more environmentally friendly and keep up with the times. Heavy mining equipment such as ultra class dumptrucks and face shovels have 2-3MW diesel engines which can easily burn hundreds of litres of diesel per hour (Komatsu, 2022). Diesel has been the fuel of choice for many years due to its developed supply chains, ease of storage, high energy density and reliable engines. High fuel consumptions coupled with increasing fuel prices and deepening mines means that in addition to increasing expenses and pressure from environmental organisations, South African mines are becoming more and more carbon intensive. In December of 2015, at the 21st Conference of the Parties (COP21) to the United Nations Framework Convention on Climate Change (UNFCCC) held in Paris, an international treaty on climate change was adopted by 195 parties. This treaty also known as the Paris agreement was a landmark agreement since this was the first legally binding treaty aimed at fighting climate change (United Nations Climate Change, 2015). The Paris agreement covered many items but these are some of the most crucial ones; Long-term temperature goals with the aim of restricting global temperature increases to below 2 degrees Celsius or even further to 1.5 degrees Celsius; National Adaptation Plans which outlines plans and actions for different nations based on their needs and priorities; Finance, technology and capacity-building support that addresses developed countries providing financial assistance to less endowed countries for adaption and accelerating technology development