MENVSC / Department of Geography and Geo-Information Sciences / Climate change has a crucial impact on livelihoods, economy, and water resources due to the occurrence of weather and climate extreme events such as floods, droughts and heat waves. Extreme weather has been increasing worldwide, hence the need to understand their nature and trends. The aim of this study was to analyse the spatial variability and long-term trends of climate extremes over the Limpopo in South Africa from 1960 to 2014. Rainfall, temperature, and circulation fields were analysed to understand the extent, nature of climate extremes over the Limpopo. Extreme value theory (EVT) is a powerful method that was also employed in this study to provide statistical models for events rarely observed. R statistical software was used for clustering analysis which has a variety of functions for cluster analysis. Any station whose value is larger than 95th for any day of the season was considered as a widespread extreme event. The results show that the study area is highly vulnerable to extreme events due to its latitudinal location and low altitude. Anomalous cut-off lows, tropical cyclones and tropical storms are the major extreme producing systems affecting the Limpopo province whilst the Botswana High becomes dominant during heat waves and drought. Extreme weather events are common in Limpopo during summertime and often coincide with mature phases of the El Nino Southern Oscillation. In this study, after the suitable model for data was chosen, the interest was in deriving return levels of extreme maximum rainfall. The computed data for return levels predicted that the 5-year return period’s return level is approximately 223.89 mm, which suggests that rainfall of 223.89 mm or more per month should occur at that station or location on the average of once every five years. / NRF / http://hdl.handle.net/11602/1485

It has become accepted that long-term global mean temperatures have increased over the twentieth century. However, whether or not climate change can be detected at a local or regional scale is still questionable. The numerous new record highs and lows of temperatures recorded over South Africa for 2003, 2004 and 2005 provide reason to examine whether changes can already be detected in southern Africa's temperature record and modelled hydrological responses. As a preface to a temperature detection study, a literature reVIew on temperature detection studies, methods used and data problems encountered, was undertaken. Simple statistics, linear regression and the Mann-Kendall non-parametric test were the methods reviewed for detecting change. Southern Africa's temperature record was thereafter examined for changes, and the Mann-Kendall non-parametric test was applied to time series of annual means of minimum and maximum temperature, summer means of maximum temperature and winter means of minimum temperature. Furthermore, changes in the upper and lower ends of the temperature distribution were examined. The Mann-Kendall test was applied to numbers of days and numbers of 3 consecutive days abovelbelow thresholds of 10th and 90th percentiles of minimum and maximum temperatures, as well as abovelbelow threshold values of minimum (i.e. 0°) and maximum (i.e. 40°C) temperatures. A second analysis, using the split sample technique for the periods 1950 - 1970 vs 1980 - 2000, was performed for annual means of daily maximum and minimum temperatures, summer means of daily maximum temperatures, winter means of daily minimum temperatures and coefficients of variability of daily maximum and minimum temperatures. Two clear clusters of warming emerged from almost every analysis, viz. a cluster of stations in the Western Cape and a cluster of stations around the midlands ofKwaZulu-Natal, along with a band of stations along the KwaZulu-Natal coast. Another fmding was a less severe frost season over the Free State and Northern Cape. While certain changes are, therefore, evident in temperature parameters, the changes are not uniform across southern Africa. Precipitation and evaporation are the primary drivers of the hydrological cycle, with temperature an important factor in the evaporation process. Thus, with changes in various temperature parameters having been identified over many parts of southern Africa, the question arose whether any changes were evident as yet in hydrological responses. The ACRU model was used to generate daily streamflow values and associated hydrological responses from a baseline land cover, thus eliminating all possible human influences on the catchment and channel. A split-sample analysis of the simulated hydrological responses for the 1950 - 1969 vs 1980 - 1999 periods was undertaken. Trends over time in simulated streamflows were examined for medians, dry and wet years, as well as the range between wet and dry years. The seasonality and concentration of streamflows between the periods 1950 - 1969 and 1980 - 1999 were examined to determine if changes could be identified. Some trends found were marked over large parts of Primary Catchments, and certainly require consideration in future water resources planning. With strong changes over time in simulated hydrological responses already evident in certain Primary Catchments of South Africa using daily rainfall input data from 1950 1999, it, therefore, became necessary to examine the rainfall regimes of the Quaternary Catchments' "driver" rainfall station data in order to determine if these hydrological response changes were supported by changes in rainfall patterns over time. A splitsample analysis was, therefore, performed on the rainfall input of each Quaternary Catchment. Not only were medians considered, but the higher and lower ends of the rainfall distributions were also analysed, as were the number of rainfall events above pre-defined daily thresholds. The changes evident over time in rainfall patterns over southern Africa were found to vary from relatively unsubstantial increases or decreases to significant increase and decreases. However, the changes in rainfall corresponded with the changes noted in simulated streamflow. From the analyses conducted in this study, it has become clear that South Africa's temperature and rainfall, as well as hydrological responses, have changed over the recent past, particularly in certain identifiable hotspots, viz. the Western Cape and KwaZulu-Natal where significant increases in temperature variables and changes in rainfall patterns were detected. These detected changes in climate need to be considered in future water resources planning. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2005.

Radiative forcing by increased atmospheric levels of greenhouse gases (GHGs) produced by human activities could lead to strongly undesirable effects on oceans and their dependent human systems in the coming centuries. Such dangerous anthropogenic interference with the climate system is a possibility the UN Framework Convention on Climate Change (UNFCCC) calls on nations to avoid. Unacceptable consequences of such interference could include inundation of coastal areas and low-lying islands by rising sea level, the rate of which could exceed natural and human ability to adapt, and ocean acidification contributing to widespread disruption of marine and human food systems. Such consequences pose daunting socioeconomic costs, for developing nations in particular. Drawing on existing literature, we define example levels of acceptable global marine change in terms of global mean temperature rise, sea level rise and ocean acidification. A global-mean climate model (ACC2), is implemented in an optimizing environment, GAMS, and coupled to an economic model (DICE). Using cost-effectiveness analysis and the tolerable windows approach (TWA) allows for the computation of both economically optimal carbon dioxide emissions pathways as well as a range in carbon dioxide emissions (the so-called ``emissions corridor'') which respect the predetermined ceilings and take into account the socio-economically acceptable pace of emissions reductions. The German Advisory Council on Global Change (WBGU) has issued several guardrails focused on marine changes, of which we find the rate and absolute rise in global mean temperature to be the most restrictive (0.2 degrees Celsius per decade, 2 degrees Celsius total). Respecting these guardrails will require large reductions in both carbon and non-carbon GHGs over the next century, regardless of equilibrium climate sensitivity. WBGU sea level rise and rate of rise guardrails (1 meter absolute, 5 cm per decade) are substantially less restrictive, and respecting them does not require deviation from a business-as-usual path in the next couple hundred of years, provided common assumptions of Antarctic ice mass balance sensitivity are correct. The ocean acidification guardrail (0.2 unit decline relative to the pre-industrial value) is less restrictive than those for temperature, but does require emissions reductions into the coming century.

Climate variability and change as well as sea level rise poses significant challenges to livelihoods, water and food security in small island developing states (SIDSs) including the Zanzibar Islands. Thus, without planned strategic adaptation, the future projected changes in climate and sea level will intensify the vulnerability of these sensitive areas. This thesis is based on research conducted in two sites located in the north eastern parts of each island, namely Kiuyu Mbuyuni, Pemba Island and Matemwe, Unguja Island. The research focused firstly on assessing the vulnerability of these two coastal communities to climate variability and change and other stressors. This included investigation of (1) the perceptions of fishers, farmers and seaweed farmers regarding climate stressors and shocks and associated risks and impacts, (2) existing and possible future water and food security issues, and (3) household's access to important livelihood assets. This was followed by an exploration of the coping and adaptive responses of farmers, fishers and seaweed farmers to perceived shocks and stresses and some of the barriers to these responses. Lastly, an analysis of the implications of the findings for achieving sustainable coastal livelihoods and a resilient coastal community was undertaken. The general picture that emerges is that local people along the east coasts of both islands are already vulnerable to a wide range of stressors. Although variability in rainfall is not a new phenomenon in these areas, increasing frequency of dry spells and coastal floods resulting from the influence of El Niño and La Niña events exert enormous pressures on local activities (fishing, farming and seaweed farming) which are the crux of the local economy. The main argument of the study is that the nature and characteristics of these activities are the main source of sensitivity amongst these communities and this creates high levels of vulnerability to climate shocks and trends. This vulnerability is evidenced by the reoccurrence of localised food shortages and the observed food and water insecurity. The study found that food insecurity is a result of unreliable rainfall, drought and seasonality changes. These interacted with other contextual factors such as poor soil, low purchasing power and the lack of livelihood diversification options. In addition to exposure to these almost unavoidable risks from climate variability, the vulnerability of the local communities along the east coasts is also influenced by the low level of capital stocks and limited access to the assets that are important for coping and adaptation. Despite this, some households managed to overcome barriers and adapt in various ways both within the three main livelihood sectors (fishing, farming and seaweed farming) as well as through adopting options outside these sectors resulting in diversification of the livelihood portfolio. However, the study found that most of the strategies opted for by fishers, farmers and seaweed farmers were mainly spontaneous. Few planned adaptation measures supported by state authorities were observed across the sites, with the exception of the provision of motorised boats which were specifically meant to increase physical assets amongst fishers, reduce pressure in the marine conservation areas and prevent overfishing in-shore. Furthermore, numerous strategies that people adopted were discontinued when further barriers were encountered. Interestingly, some of the barriers that prevented households adapting were the same ones that forced households that had responded to abandon their adaptations. To increase resilience amongst east coast communities to current and future predicted changes in climate and sea level, the study argues that traditional livelihood activities (fishing, farming and seaweed farming) need to be better supported, and access to a range of livelihood assets improved. This may be achieved through increased access to local sources of water and facilitation of rainwater harvesting, expanding the livelihood options available to people and increasing climate change awareness, and access to sources of credit.

Orientadores: Arnaldo Cesar Walter, Fernando Cardozo Fernandes Rei / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-08-16T08:10:47Z (GMT). No. of bitstreams: 1 Cunha_KamylaBorgesda_D.pdf: 6584850 bytes, checksum: f9cedaa0b7d809a1e7ca74de744ebb2c (MD5) Previous issue date: 2009 / Resumo: A presente tese teve como objetivo principal analisar o papel de Brasil, Índia e China para a efetividade do regime climático pós-2012. Para tanto, foi preciso avaliar a efetividade do regime climático atual, perscrutar sobre os desafios da efetividade do futuro regime climático, identificar as principais semelhanças e diferenças entre o Brasil, a China e a Índia, em termos de contribuição para o efeito estufa adicional, analisar a posição oficial de cada um dos três países e perscrutar o papel desejável do Brasil no regime pós 2012. De modo a cumprir o objetivo proposto, realizou-se uma breve explanação sobre os aspectos científicos das mudanças climáticas, dando-se destaque para os desafios colocados a decisão política; fez-se uma analise do regime climático vigente, de modo a se identificar os principais aspectos foco da discussão sobre o futuro regime; procedeu-se a uma analise dos principais pontos de discussão sobre o regime climático pós-2012, com destaque para a efetividade ambiental do regime, a eficiência econômica e a equidade. Tais aspectos foram então avaliados sob a perspectiva política, de modo a destacar sua inserção na evolução das negociações internacionais. Buscou-se focar nos três países avaliados, levantando-se-lhes o perfil de emissões, energia e uso da terra, dados demográficos, econômicos e sociais, assim como sua postura política nas negociações internacionais. Realizadas todas essas analises, identificou-se a importância do Brasil, da China e da Índia para a efetividade do regime climático pós-2012, seja em função de sua crescente contribuição para as emissões de gases de efeito estufa, seja por forca de seu papel econômico, tanto no que diz respeito a distribuição dos custos de mitigação quanto ao cenário atual de crescente interdependência econômica. Também se constatou a ausência de correlação direta entre as emissões brasileiras de gases de efeito estufa e o desenvolvimento socioeconômico do pais, já que a maior parte decorre de desmatamentos ilegais. Entendeu-se que a postura brasileira há de focar-se nas oportunidades da assunção de compromissos voluntários relativos a redução das taxas de desmatamento / Abstract: This study aims at analyzing the role of Brazil, India and China for the of the international post-2012 climate change regime effectiveness. In order to meet this goal, it was necessary to evaluate the present climate regime effectiveness, to identify the main similarities and differences between Brazil, India and China, in terms of their contribution to greenhouse effect, to analyze their official position in the international negotiations and to evaluate the desirable role of Brazil in the post-2012 climate regime. The scientific aspects of climate change were briefly explored, in order to highlight the main challenges faced by the political decision. The present climate change regime was analyzed, in order to pose the main aspects of climate change discussion. The post-2012 climate regime effectiveness was posed in terms of wide participation of main countries and the need to bring together two main points: economic efficiency and equity. Then, the climate change international negotiation evolution was presented. After this general approach, this study has focused Brazil, India and China national circumstances, such as their greenhouse gases emissions profile, energy and land use sectors, demographic, economic and social indicators, as well their political position in the climate change international negotiations. As a result of such analysis, it was possible to identify the importance of Brazil, India and China for the post-2012 climate change regime effectiveness, first, because of their major contribution to greenhouse gases emissions, and second, because of their economic role, both in terms of mitigation costs distribution and in terms of the international economic interdependence. It was also identified the absence of direct relationship between Brazilian emissions and the country's socioeconomic development, considering that most of Brazil's emission come from illegal deforestation. It was concluded that Brazil could benefit in a scenario of position flexibility, assuming voluntary commitments related to deforestation reduction / Doutorado / Planejamento de Sistemas Energeticos / Doutor em Engenharia Mecânica

PhD (Agricultural Economics) / Department of Agricultural Economics and Agribusiness / Climate change is a global phenomenon that has been of great concern and its tackle is of outmost importance for food security among other things. In response to climate change adaptation, the study intended to determine awareness of climate change, its critical determinants and impacts among farmers, particularly emerging farmers. The study also investigated socio-economic characteristics of farmers that play a vital role in selection of various adaptive strategies, furthermore, institutional factors that contributed in emerging farmers’ decision to either adapt or not to climate change were also investigated. The main aim of the study was to develop a model that could be used in future to enhance adaptation to climate change through various identified adaptive strategies in Limpopo province of South Africa. The study was conducted in five districts of Limpopo province, namely: Capricorn, Mopani, Sekhukhune, Vhembe and Waterberg. The study made use of structured questionnaire to collect data from 206 emerging farmers. A two-stage cluster sampling technique was employed to select participants of the study. Statistical Package for the Social Sciences (SPSS; version 25, 2017) was used to analyse the data; cross-tabulation, multinomial and binary logistic models were used for analysis. Preliminary descriptive statistics results from cross-tabulation indicated that farmers were aware of climate change; had noted various critical determinants of climate change and were aware of impacts of climate change during production seasons between 2014 and 2018. Using Multinomial Logit model, further analysis indicated that there are socio-economic characteristics that significantly influenced selection of various adaptive strategies among farmers. Variables that significantly influenced selection of various adaptive strategies were household size, farming experience, formal education, occupation, gender and monthly on-farm income. The study also discovered that institutional factors such as accessing different kinds of extension services, securing source of support and accessing climate change information such as weather forecast, positively and significantly influence farmers’ decision to adapt to climate change. Recommendations of the study were that there should be capacity building in a form of training programmes that promote climate change awareness as farmers need to be capacitated to enable them to take strategic decisions on a daily basis. Furthermore, it was also recommended that training of farmers should target illiterate farmers and farmer without off-farm occupation and specific needs of farmers should be taken into consideration when initiating adaptation initiatives as adaptation to climate change is best monitored at farm level. The study also recommended that various stakeholders such as community of practice, climatologists, and agro-meteorologists should provide various support to emerging farmers to improve farmers’ resilience towards climate change through adaptation. / NRF

MENVSC / Department of Geography and Geo-Information Science / See the atttached abstract below

The aim of this thesis is to improve the knowledgebase regarding the technical lifetime of radio circuit boards. The purpose is to create opportunities to facilitate the design of products that live up to the customers' requirements and to Ericsson's sustainable responsibility goals. The problem at hand was to look for the average temperature that has contribiuted to the performance degradation of circuit boards used in the field. The method was to measure the performance degradation of capacitors used in a power distribution function on the circuit board and combining those values with the time the circuit board has been in operation, to derive the average operation temperature with the help of the Arrhenius equation. The radio circuit board used in the field showed signs of performance degradation that could be interpreted as having reached the end of its technical lifetime after being used for 31 800 hours (3,6 years) at an average temperature of 78 °C to 79 °C. For it to be possible to interpret the temperature results of the unit used in the field, the three parameters: measured performance degradation, time of operation and average temperature at that time, had to be collected. All three parameters are key when evaluating technical lifetime since they need to be interpreted in relation to each other. The temperature results exists in a thermodynamic system that includes the capacitors, circuit board, the temperature of the surrounding environment, and the global climate. The temperature results and the measured performance degradation is a consequence of how the radio was operated, which is linked to the desired performance it was designed for. The radio circuit boards are also designed to comply with customers' requirements and the requirements based in the companys's sustainability responsibility goals. It is likely that the desired performance of radios in the future needs to be balanced with the company's sustainability responisibility goals, and the temperatures created as an effect of climate change. / Målet med detta examensarbete var att öka kunskapen om radiokretskorts tekniska livslängd. Syftet var att skapa möjligheter att främja utveckling av produkter som möter kunders krav samt de krav som följer av Ericssons strategi för hållbarhet och ansvarsfullt företagande. Problemformuleringen består av att söka efter medeltemperaturen som har bidragit till den prestandadegradering som lett till att kretskort i fält nått slutet på sin tekniska livslängd. Metoden som användes för att kunna härleda medeltemperaturen under drift var att mäta prestandadegraderingen hos kondensatorer som används i en specifik kraftfördelningsfunktion på radiokretskort och kombinera dessa mätvärden med tiden kretskortet varit i drift. Tiden och temperaturen härleddes med hjälp av Arrhenius ekvation. Den radiokretskortsenhet som användes i fält kan tolkas ha nått slutet på sin tekniska livslängd efter 31 800 timmar (3,6 år) och under tiden i drift haft medeltemperaturen på ungefär 78 °C till 79 °C. För att det skulle vara möjligt att tolka temperaturresultatet för radiokretskortet som användes i fält behövde följande tre parameterar samlas in: uppmätt prestandadegradering, tiden som radiokretskortet varit i drift samt medeltemperaturen under driftstiden. Samtliga tre parameterar behöver analyseras i relation till varandra när den tekniska livslängden ska utvärderas. Temperaturresultatet existerar i ett termodynamiskt system som består av kondensatorerna, krestkortet, temperaturen i den omkringliggande miljön samt det globala klimatsystemet. Temperaturresultatet och den uppmätta prestandadegraderingen är en konsekvens av hur radion har använts och är länkat till den den prestanda radion är designad för. Radiokretskorten är också designade för att följa kundernas krav och de krav som följer av Ericssons strategi för hållbarhet och ansvarsfullt företagande. Det är sannolikt att den önskade prestandan hos radioprodukter i framtiden behöver balanseras med de krav som följer av Ericssons strategi för hållbart företagande samt de temperaturer som skapas som konsekvens av klimatförändringarna.

MESHWR / Department of Hydrology and Water Resources / This study dealt with the influence of climate variability on flood and drought cycles and implications on rainy season characteristics in Luvuvhu River Catchment (LRC) in Limpopo of South Africa. Extreme weather events resulting in hazards such as floods and droughts are becoming more frequent due to climate change. Extreme events affect rainy season characteristics and hence have an influence on water availability and agricultural production. Annual temperature was obtained from Water Research Commission for stations 0723485W, 0766628W and 0766898W from 1950-2013 were used to show/or confirm if there is climate variability in LRC. Daily rainfall data was obtained from SAWS for stations 0766596 9, 0766563 1, 0723485 6 and 0766715 5 were used to detect climate variability and determine the onset, duration and cessation of the rainy season. Streamflow data obtained from the Department of Water and Sanitation for stations A9H004, A9H012, and A9H001 for at least a period of 30 years for each station were used for climate variability detection and determination of flood and drought cycles. Influence of climate variability on floods and droughts and rainy season characteristic were determined in the area of study. Trends were evaluated for temperature, rainfall and streamflow data in the area of study using Mann Kendall (MK) and linear regression (LR) methods. MK and LR detected positive trends for temperature (maximum and minimum) and streamflow stations. MK and LR results of rainfall stations showed increasing trends for stations 0766596 9, and 0766563 1 whereas stations 0723485 6 and 0766715 5 showed decreasing trends. Standardized precipitation index (SPI) was used to determine floods and droughts cycles. SPI results have been classified either as moderately, severely and extremely dry or, moderately, very and extremely wet. This SPI analysis provides more details of dominance of distinctive dry or wet conditions for a rainy season at a particular station. Mean onset of rainfall varied from day 255 to 297, with 0766715 5 showing the earliest onset compared to the rest of the stations. Cessation of rainfall for most of the hydrological years was higher than the mean days of 88, 83 and 86 days in 0766596 9, 0766563 1 and 0723485 6 stations. Mean duration of rainfall varied from 102 to 128, with station 0766715 5 showing shortest duration of rainfall. The results of the study showed that the mean onset, duration and cessation were comparable for all stations except 0766715 5 which had lower values. The study also found that climate variability greatly affects onset, duration and cessation of rainfall during dry years. This led to late onset, early cessation and relatively short duration of the rainfall season. Communities within the catchment must be educated to practice activities such as conservation of indigenous plants, reduce carbon dioxide emissions.

PhD (Geography) / Department of Geography and Geo- Information Sciences / One of the major challenges facing all categories of farmers globally is climate change. African smallholder farmers are the most vulnerable to changes in climate. In most parts of South Africa, empirical evidence indicates the level to which climate change has impacted negatively on agricultural production. Rising temperatures, prolonged drought and decreasing rainfall have affected local farmers’ livelihood and crop production. In the Vhembe District of South Africa’s Limpopo Province, smallholder farming predominates and its vulnerability to climate change has increased for the past decades. This study, therefore, assesses the impact of climate change and adaptation strategies on smallholder farming systems in the Vhembe District To achieve this aim, qualitative and quantitative research methodologies were employed. A questionnaire was administered to a sample of 224 smallholder farmers to elicit data on perceptions; climate change impacts, adaptation and IKS based strategies to deal with climatic shocks. Focus group discussions (FGDs), semi-structured interviews with the extension officers elicited thematic data that complemented the interview survey. Climate data were obtained from the South Africa Weather Service (SAWS) for the period 1980 to 2015. Smallholder farmers’ perceptions about climate change were validated by an analysis of climatic trends from 1980-2015. A thematic analysis of qualitative data and the Multi Nominal Logit (MNL) regression model was used based on socio-economic and biophysical attributes such as access to climate knowledge, gender, farm size, education level, and farmers’ experience, decreasing rainfall and increasing temperature as farmers’ determinants of their adaptation options to climate change. Furthermore, farmers’ perceptions tallied well with climatic trends that showed flood and drought cycles. Most of the smallholder farmers were aware of climate change and its impacts over the past decades. The study further indicated that, due to the marked climate change over this period, farmers have adopted different coping strategies at on-farm and off-farm levels. In terms of adaptation, the major adaptive strategies used by smallholder farmers included the use of drought-tolerant seeds; planting of short-seasoned crops; crop diversification; changing planting dates; irrigation and migrating to urban areas. The study recommends a framework that would include water conservation (rainfall harvesting); investment in irrigation schemes and other smart technologies that integrate indigenous knowledge systems and modern scientific knowledge to enhance crop production. / NRF