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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Development of techniques for the assessment of climate change impacts on estuaries : a hydrological perspective.

Davis, Nicholas Savile. January 2012 (has links)
Global climate change is a naturally occurring phenomenon, influencing weather and climate patterns. However, the greatest cause for concern at present is the rate at which climate change is currently occurring. Natural shifts in climate take place over a period of many thousands of years, not in a matter of decades, which is what is occurring at present. In South Africa, climate change is projected to have different regional effects, which in turn could impact on the components of the terrestrial hydrological system, such as land use. The alteration of the catchment upstream of the estuaries could affect the quantity and quality of streamflows entering estuaries. This could impact negatively upon estuaries, thereby reducing the considerable biodiversity in estuaries and the ecosystems goods and services provided by estuaries which would reduce the significant revenue provided by these systems. The research undertaken in this project investigates the possible effects of climate change, and changes in upstream land use on freshwater inflows into estuarine ecosystems using a daily hydrological model. Owing to the regionality of climate change in South Africa 10 estuaries in different climatic regions were selected for this investigation. Climate output from five GCMs under the SRES A2 climate scenario for the present (1971 – 1990), intermediate (2046 – 2065) and distant future (2081 – 2100) periods was used as input for the selected climate input. Results of these simulations show that the eastern regions of South Africa may experience considerable increases in the occurrence of high intensity rainfall events into the future. This could influence the abiotic factors of the system which may impact upon the biotic components of estuaries, as these systems are physically controlled. In the western regions the difference of the magnitude of flows between present and projected future is minimal. However, projected increases in temperature could influence evaporation, thereby decreasing future flows into estuaries. This, in some instances, may result in systems turning hyper-saline, which could have far reaching implications, both ecologically and economically. Additionally, an investigation, as to the possible effects of irrigation and climate change combined on flows entering and breaching events of the Klein estuary, was undertaken. Hence, simulations including and excluding irrigation routines have been completed. Results from these simulations illustrate the detrimental effects of irrigation into the future periods, especially during 1 in 10 low flow years, when flows into the Klein estuary cease completely. Breaching event results illustrate that climate change could have a negative impact on this estuarine system as the number of events decreases into distant future period. The addition of agricultural abstractions decreases the number of breaching events markedly. Therefore, the link between the marine and terrestrial hydrological systems is lost which could, if this estuary is isolated from the ocean for an extended period of time, become extremely detrimental to the ecological integrity of the Klein estuary. This highlights the value and vulnerabilities of estuarine ecosystems in South Africa to future climate and upstream land use changes. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2012.
42

Projected impacts of climate change on water quality constituents and implications for adaptive management.

Ngcobo, Simphiwe Innocent. January 2013 (has links)
The past few decades have seen, amongst other topical environmental issues, increased concerns regarding the imminent threat of global warming and the consequential impacts of climate change on environmental, social and economic systems. Numerous groundbreaking studies conducted independently and cooperatively have provided abundant and conclusive evidence that global climates are changing and that these changes will almost certainly impact natural and socio-economic systems. Increased global change pressures, which include, inter alia, climate change, have increased concerns over the supply of adequate quality freshwater. There is an inadequate body of knowledge pertaining to linking basic hydrological processes which drive water quality (WQ) variability with projected climate change. Incorporating such research into policy development and governance with the intention of developing adaptive WQ management strategies is also overlooked. Thus, the aim of this study was the assessment of projected climate change impacts on selected WQ constituents in the context of agricultural non-point source pollution and the development of the necessary adaptation strategies that can be incorporated into WQ management, policy development and governance. This assessment was carried out in the form of a case study in the Mkabela Catchment near Wartburg in KwaZulu-Natal, South Africa. The research involved applying climate change projections derived from seven downscaled Global Circulation Models (GCMs) used in the Fourth Intergovernmental Panel on Climate Change (IPCC) Assessment Report, in the ACRU-NPS water quality model to assess the potential impacts on selected water quality constituents (viz. sediment, nitrogen and phosphorus). Results indicated positive correlations between WQ related impacts and contaminant migration as generated from agricultural fertilizer applications. ACRU-NPS simulations indicated increases in runoff and associated changes in WQ variable generation and migration from upstream sources in response to downscaled GCM projections. However, there was limited agreement found between the simulations derived from the various downscaled GCM projections in regard to the magnitude and direction (i.e. percent changes between present and the future) of these changes in WQ variables. The rainfall distribution analyses conducted on a daily time-step resolution for each selected GCM also showed limited consistency between the GCM projections regarding rainfall changes between the present and the future. The implication was that since hydrological and climate change modelling can inform adaptation under climate change. However, adaptation to climate change in water quality management and policy development is going to require approaches that fully recognise the uncertainties presented by climate change and the associated modelling thereof. It was also considered crucial that equal attention be given to both climate change and natural variability, in order to ensure that adaptation strategies remain robust and effective under conditions of climate change and its respective uncertainties. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2013.
43

The effect of climate change on Durban Consumers' buying behaviour.

Punchee, Vijay Anand. 01 October 2013 (has links)
The green market is now one of the biggest markets in the world and green marketing is one of the major trends in modern business. This is a chance for businesses to take advantage of this opportunity by providing environmental solutions whilst at the same time contributing towards reducing the carbon footprint. To effectively achieve this, green manufacturers and marketers need to understand the perceptions, attitudes and behaviours of consumers towards green products and the factors that encourage and discourage their green purchases. Hence this study attempts to understand Durban’s consumers in this regard to enable local businesses to develop strategies around green product design, development, marketing and sales. The research objectives and questions were answered by sampling 450 consumers in Durban. A convenience sampling design was used as an appropriate sample frame could not be identified. This imposed a limitation on the study in that the findings cannot be generalized to the total population. The study found that 96% of respondents believed that climate change existed and 87% believed that it was having a major impact on the planet. Nevertheless, environmental issues did not weigh heavily in the buying decisions of the respondents. Instead quality and cost were the main factors. However, the study identified a significant market for green cars whilst a significant number of respondents were willing to pay a premium for green products. Furthermore, the respondents indicated that eco-labeling of products would encourage them to buy more green products. Moreover, the study found that green marketers should target the White female segment of the market as they were most conscious of environmental issues. It was also recommended that the pricing of green products needs to be more competitive, green products need to be promoted as the norm and not the exception, and consumers need to be educated to go green. Government, consumers and industry all need to work together to ensure the sustainability of the planet. / Thesis (MBA)-University of KwaZulu-Natal, Westville, 2011.
44

Inter-individual variability and phenotypic plasticity : the effect of the environment on the biogeography, population structure, ecophysiology and reproduction of the sandhoppers Talorchestia capensis and Africorchestia quadrispinosa

Baldanzi, Simone January 2014 (has links)
Climatic envelope models focus on the climatic variables affecting species or species assemblages, and are important tools to investigate the effect of climate change on their geographical ranges. These models have largely been proposed in order to make successful predictions on species‘ persistence, determining which variables are likely to induce range expansion, contraction, or shifting. More recent models, including the ability and the cost for individuals to respond promptly to an environmental stimulus, have revealed that species may express phenotypic plasticity able to induce adaptation to the new environment. Consequently, understanding how species evolve to a changing climate is fundamental. From this perspective, investigating intraspecific responses to an environmental variable may contribute to better understanding and prediction of the effect of climate change on the geographical range and evolution of species, particularly in the case of widespread species. In this context, the present study aimed at establishing how environmental variables (focussing mainly on temperature) may have contributed to shape the spatial distribution, physiology, reproductive biology and connectivity of two species of Southern African sandhoppers (Talorchestia capensis and Africorchestia quadrispinosa, Amphipoda, Talitridae). Most of the work was carried out on T. capensis, due to its widespread spatial distribution. A first investigation of the biogeography of T. capensis and A. quadrispinosa, revealed that, for both species, spatial patterns of abundance, size and sex ratio were not explained by the Abundant Centre Hypothesis (greater abundance at the core of a spatial range), but rather guided by bio-physical forces. Precisely, the abundance of sandhoppers was driven by the morphodynamic state of the beach, salinity and temperatures, with strong differentiation among sites that reflected local environmental conditions. In support of these findings, strong population structure in the genetics of T. capensis was found (three main groups) when investigating its phylogeography and genetic connectivity. Although such defined structure may suggests cryptic speciation, the concomitant within-population variation in the COX1 region of mtDNA, also highlighted the importance of individual genetic variability. High individual variability was also found in the response of T. capensis to temperature, both in its physiology (thermal plasticity) and its reproductive biology (maternal effects). Since temperature is one of the main variables affecting the coastal marine systems of southern Africa and the metabolism of animals in general, its effect on the physiology and reproduction of T. capensis was therefore investigated. Thermal responses to increasing/decreasing temperatures were assessed for separated populations of T. capensis. Individual variability was reported in the oxygen consumption of T. capensis in response to temperature (high variation around the means, especially for increasing temperatures). Among population differences in thermal sensitivity were significantly correlated with air temperature variability experienced over the past 23 years, highlighting the importance of historical temperature fluctuations to the current thermal physiology of these sandhoppers. Temperature also had an important effect on the reproductive plasticity of T. capensis. Different temperatures induced mothers to adjust the size of their offspring (i.e. egg size), with larger eggs produced at lower temperatures. Interestingly, females showed strongly significant among individual variation in the size of the eggs. Given the importance of understanding rapid responses of organisms to climate change and considering the fundamental role played by phenotypic plasticity in evolution, the overall study revealed the significance of individual plasticity and variability in response to the environment and highlighted its importance. Particularly, studying the thermal physiology of separated populations and understanding within population reproductive plasticity in response to temperature, helped to clarify how differences among individual responses have important consequences at the population level, possibly explaining the widespread distribution of T. capensis.
45

Adaptive livelihood strategies of the Basarwa: a case of Khwai and Xaxaba, Ngamiland district, Botswana

Madzwamuse, Masego S January 2006 (has links)
This thesis looks into the land use and natural resource management systems of Basarwa communities in Ngamiland in the northwest of Botswana. The study specifically focuses on Basarwa communities living in and on the edges of the Okavango Delta. The link between these communities and their natural resources is explored using the Sustainable Rural Livelihoods Framework and the Adaptive Renewal Cycle. The core assumption in this thesis is that livelihood strategies are constantly renewed and adapted to promote resilience in ecological and social systems. Fieldwork data collected between May 2000 and July 2001 and secondary data is used to deliberate on this point. The thesis confirms that the Basarwa’s livelihood strategies were adaptive only in as far as traditional livelihoods are concerned. The thesis traces the changes that the Basarwa have experienced as a result of policy restrictions through the different phases of the adaptive renewal cycle. The period following Independence in Botswana saw a policy shift which resulted in the Basarwa becoming landless. With mainly land-based livelihood strategies, the Basarwa were faced with new forms of crises and vulnerability which their traditional adaptive strategies were not designed for. It comes to the conclusion that the Basarwa are currently stuck in a reorganisation phase; however, the CBNRM Draft Policy of Botswana offers a glimpse of hope as it provides an opportunity for the Basarwa to progress through the full cycle of reorganisation, renewal, conservation and release.
46

An investigation of communal farmers's livelihoods and climate change challenges and opportunities in Makonde rural district of Zimbabwe

Sango, Ishumael 27 May 2014 (has links)
As the debate on the impacts of global climate change goes on at global and regional scale, climate change impacts are already being felt at local level. The thesis aims at exploring climate change as a driver of environmental and smallholder farmers’ livelihood vulnerability in Makonde District of Zimbabwe. Specifically the study seeks to: determine climate change trends and manifestations; evaluate household-level impacts of climate change and associated environmental changes on smallholder farmers’ livelihoods and lastly; to investigate the extent of household-level coping and adaptation strategies to climate change in the Makonde rural community in Zimbabwe, especially farmers in Makonde Communal Lands. Given the fact that the subject under study is multidimensional in scope, a mix of research methods was adopted in this case study. Whilst it is largely qualitative in design, the study involved some quantitative data and thus, a triangulation of different data sources and data gathering instruments was employed. The instruments used include; key informant interviews, structured observations and a household questionnaire survey. The analysis was based on a final sample of 434 out of the originally anticipated 500 households. In addition to the households’ sample, were twenty key informants and transect walk observations. The qualitative data was analyzed by means of coding, memoing, descriptions, typologies, taxonomies and visual representations, whilst quantitative data was processed through the Statistical Package for Social Sciences (SPSS) and complimented by Microsoft Excel to generate various forms of descriptive statistics. The findings suggest that climate change in the Makonde Rural District that includes the Makonde Communal Lands has been significant during the past thirty years. The climate change has contributed to significant local environmental stresses affecting local resources such as forests, fauna, water, pastures and soil among other natural assets. The local livelihoods show high levels of vulnerability to climate change due to notable low adaptive capacity. The high level of vulnerability to changing climate is exposing the study population to increased prevalence of: poverty, crop and livestock failures, food insecurity, malnutrition, disease and rural urban migration among other impacts. The study concludes that the factors creating barriers to climate change adaptation are related those contributing to poverty and holding back sustainable local development. Among the key suggestions to enhance the community’s climate change adaptation capacity, the thesis presents an establishment of a government-driven, multi-dimensional and multi-stakeholder intervention mechanism to help local communities manage their vulnerability. / Environmental Sciences / D. Litt. et Phil. (Environmental Management)
47

The impact of glaciation and climate change on biogeochemical cycling and landscape development

Mabry, James Brice 19 March 2012 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Lake cores from Dry Lake, California and Crystal Lake, Illinois were analyzed to identify climate variability and characterize landscape response to glacial/deglacial climate transitions. Geochemical analysis of the Dry Lake sediment prior to the 8.2 kyr event revealed average values for percent total organic carbon to be 4% with a range of 0.2% to 15.2%. The average decreased to approximately 2.1% with a range of 0.4% to 5.3% during and after the event. Occluded phosphorus averaged 488 µg/g before the 8.2 kyr event and 547 µg/g after but was much lower during the event at 287 µg/g. These results were interpreted as an environment which began as warm, wet, and productive then quickly turned colder and drier during the 8.2 kyr event which resulted in a resetting of soil development. The higher temperatures returned after the 8.2 kyr event which allowed for continued soil development despite its drier climate. Previous research corroborated these conclusions. The Crystal Lake geochemical record was very different from Dry Lake. Percent total organic carbon averaged 6.7% with a range of 3.9% to 8.5% during the Younger Dryas but recorded a lower average before and after at 4.9% and 4.6% respectively. Occluded phosphorus acted similarly with a higher average during the cooling event, 2626 µg/g, and lower averages before and after, 1404 µg/g and 1461 µg/g, respectively. This was interpreted as continued productivity and soil development through the cold period which was attributed to a change in biomass.
48

Impacts of climate change : some economic considerations for decision-makers in the City of Cape Town, using Langebaan Lagoon as a case study

Haskins, Craig Ian 03 1900 (has links)
Thesis (MBA)--Stellenbosch University, 2005 / ENGLISH ABSTRACT: Strong scientific evidence suggests that global warming is altering the world's climate and that this phenomenon is being accelerated as a result of human activities. Climate change is affecting weather patterns and, in addition to demonstrated sea-level rise, these in turn have and are likely to continue having significant, mostly negative, impacts - both economic and loss of life - on governments, industries and people. Ocean levels rose between 15 and 20 centimeters in the 20th century, mostly as a result of melting glaciers and thermal expansion of the oceans. The International Panel on Climate Change (IPCC, 2001a: 16) in its 2001 estimate suggests a potential rise in average sea level from nine to 88 centimeters from 1990 to 2100. Areas of risk in the City of Cape Town are residential property, infrastructure and beaches in low-lying areas. These areas are likely to be impacted as a result of increasing sea-level rise and increasing severity and frequency of storms. This study seeks to • demonstrate that sufficient evidence exists to compel decision-makers in the City of Cape Town that climate change and the impacts of sea-level rise and increasing frequency and severity of storms need to be considered in development planning; and • test cost-benefit analysis (through climate change impact analysis) as a tool for decision-makers to consider adaptation measures, using Langebaan as a case study. The research comprises a comprehensive literature study of the impacts of climate change, particularly with respect to coastal areas. A case study based on the eroding beaches at Langebaan is used to test cost-benefit analysis as a tool for decision-makers in dealing with the impacts. Despite the uncertainties associated with the impacts of climate change (time, place and extent) the issues of sea-level rise and severe storms seem to warrant further investigation, especially at a local level. This study provides local context to a global problem and makes recommendations for decision-makers in the City of Cape Town. Climate impact analysis (incorporating cost-benefit analysis) is suggested as a tool to quantify avoided damages at vulnerable coastal sites in the City of Cape Town. In conclusion, the impacts of climate change are a complex and multivariate problem. However, there are a number of identified vulnerable areas along the coastline of the City of Cape Town and using tools like climate impact analysis and cost-benefit analysis may assist in identifying, costing and managing these economic risks before the problem becomes unmanageable - a case for quantifying avoided damage. / AFRIKAANSE OPSOMMING: Sterk wetenskaplike bewyse bestaan dat globale verwarming besig is om die wêreld se klimaat te verander en hierdie verskynsel word versnel deur die mens se handelinge. Klimaatsverandering affekteer weerpatrone en bykomend tot gedemonstreerde stygende seevlakke, sal dit waarskynlik 'n langdurige en meestal negatiewe impak - beide ekonomies en lewensverlies - op regerings, industrieë en mense hê. Seevlakke het in die twintigste eeu met tussen 15 en 20 sentimeter gestyg, meestal as gevolg van smeltende ysberge en hitte uitsetting van die oseane. Die 'International Panel on Climate Change' (IPCC, 2001a: 16) het in hul skatting 'n waarskynlike seevlak styging van tussen 9 en 88 sentimeters voorspel vir die tydperk 1990 - 2100. Risikogebiede in die Stad Kaapstad is residensiële gebiede, infrastruktuur en strande in laagliggende gebiede. Hierdie gebiede sal ge-affekteer word deur stygende seevlakke en groter en meer gereelde storms. Hierdie studie poog om • te demonstreer dat voldoende bewyse bestaan om besluitnemers van die Stad Kaapstad te oortuig dat weerveranderinge en die impak van seevlakstygings en toenemende storms in aanmerking geneem moet word in ontwikkelings beplanning; en • koste-voordeel analises (deur klimaatsverandering impak analises) te beproef as 'n hulpmiddel vir besluitnemers om aanpasbare maatreëls te oorweeg, deur Langebaan as 'n voorbeeld te gebruik. Ten spyte van onsekerhede wat saamgaan met die impak van klimaatverandering (tyd, plek en omvang) regverdig die problem van stygende seevlakke en erge storms verdere ondersoek, meer spesifiek op plaaslike vlak. Hierdie studie gee plaaslike konteks aan 'n globale probleem en maak aanbevelings aan beplanners van die Stad Kaapstad. Klimaat impak analises word as hulpmiddel voorgestel om vermybare skades by kwesbare kusgebiede in die Stad Kaapstad te kwantifiseer. Ten slotte: die impak van klimaatsverandering is 'n komplekse probleem met baie fasette. Nietemin is daar verskere sensitiewe areas langs die kus van Stad Kaapstad, en klimaat impak analises en koste-voordeel analises kan help met die identifisering, kosteberekening en bestuur van hierdie ekonomiese risiko areas, voordat dit onhanteerbaar raak.
49

Investigating the response of subtropical forests to environmental variation through the study of the Abies kawakamii treelines in Taiwan

Greenwood, Sarah January 2014 (has links)
Altitudinal treeline advance represents a sensitive and well-studied example of species response to climate warming. Although a great deal of work has been conducted globally, few studies have considered subtropical alpine treelines and little is known about their structure and function. This research aims to investigate the response of high altitude forests in Taiwan to climate variation by characterising treeline advance in the area, exploring the mechanisms driving the advance, and considering the consequences of advance for the wider community. The thesis consists of a general introduction to the topic followed by a series of papers, exploring: (1) Possible consequences of treeline shifts for biodiversity and ecosystem function. (2) The advance of the Abies kawakamii treeline through aerial photograph analysis. (3) The changes in growth rate of Abies kawakamii at treeline and the influence of altitude and temperature on growth. (4) Regeneration patterns at treeline and the importance of microclimate and topographic sheltering. (5) Consequences of the range shift for the wider forest community. The work is then concluded with a general discussion and synthesis. The main aims of this work are therefore to characterise and understand the pattern and pace of treeline advance and forest structural change throughout the Central Mountain Range of Taiwan. Treeline advance is characterised through the study of repeat aerial photographs and the mechanisms behind the observed shift are explored through the study of two key responses associated with forest advance: tree growth at treeline and seedling establishment beyond treeline. The consequences of treeline advance for the wider subalpine community are investigated through the study of epiphytic lichen communities at treeline sites. This investigation of an understudied region will allow for improved understanding of treeline response at a global scale.
50

Living with climate variability and change: lessons from Tanzania

Pauline, Noah Makula 25 May 2015 (has links)
A Thesis Submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Doctor of Philosophy May, 2015. / There is sufficient evidence supporting that climate change and variability are pervasive realities that are strongly impacting on smallholder farmers in the Great Ruaha River sub-Basin of Tanzania. This PhD study examines smallholder farmers’ vulnerability, coping and adaptation strategies to climate change and variability (including non-climatic stresses), and investigates how such coping and adaptation may be constrained or enhanced given climate variability and change. Both quantitative and qualitative data collection methods were used when engaging with smallholder farmers and government officials. Primary data collection was undertaken in two phases, with phase one using participatory tools (e.g. focus group discussions, wealth ranking, community mapping and transect walk, and historical time lines). Data collected include climatic and non-climatic extreme events, farmers’ perceptions, coping and adaptation strategies. Phase two involved detailed individual interviews (questionnaire surveys) and key informant interviews (case studies), so as to obtain in-depth information on issues of interest. Secondary data were collected from existing statistical sources, literature surveys in archives, libraries and documentation centres, and from governmental agencies (e.g. TMA). Demographic, agricultural production and livestock statistics, and rainfall and temperature records were collected. Results from selected meteorological stations and farmers’ perceptions (74%) indicate that there has been an increase in average maximum temperatures, and both dry and wet years with varying magnitudes during the past four decades. Other climatic stresses include delayed onset and later cessation of the rain seasons. The agreement between farmers’ perceptions and rainfall trends provides good evidence that the climate has become increasingly variable in the GRRB during the past four decades. Achieving sustainable livelihoods is further compounded by non-climatic stresses such as access to markets and coordinating institutions. Results indicate that vulnerability is a complex phenomenon that entails two approaches (end-point and starting-point perspectives). The end-point perspective views vulnerability as the net projected climate change impacts after adaptation has taken place, whilst the starting-point perspective looks at both the current and future multiple stresses and places much emphasis in improving the adaptive capacity. In the study villages, such a nuanced picture highlighted areas for enhanced adaptation strategies. Farmers respond by using various strategies to deal with droughts, floods and other stresses when they occur. During droughts, they mostly use irrigation (canal, pumping and cans), or plant short-term maturing crops. During food shortages, farmers use strategies such as buying food, borrowing money, temporary migration, working in other people’s farms for cash, and reducing consumption. Moreover, the farmers’ choice of adaptation and coping strategies is influenced by factors such as location, access to resources, education levels and institutions. This calls for a whole system approach, which entails defining vulnerability of smallholder farmers to climatic and non-climatic stresses and thus designing appropriate response strategies. For example, mainstreaming adaptation to such stresses when considering development plans, projects, programmes and policies at all scales.

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