Juvenile rainbow trout were chronically exposed to acidified softwater, alone and in combination with a slight temperature increase in order to understand the possible effects of global warming and environmental acidification in freshwater fish. The second goal was to determine the role of diet in the response to acid stress and elevated temperatures. In the first two exposures, a simulated global warming scenario (+2°C) was applied for 90 days in winter (8-12 °C), in the presence and absence of sublethal acidity (pH 5.2). In the first trial, fish were fed to satiation twice daily, while in the second trial, fish were fed only 1% of their wet body weight every four days (~0.25% daily). A slight increase in temperature caused a marked increase in oxygen consumption, nitrogenous waste excretion and growth, although there did not appear to be any specific pH effects. During the Satiation Exposure, fish exposed to low pH especially at slightly elevated temperatures had increased appetites compared to non-acid exposed fish. This increased appetite suggested that NaCl losses brought about by low pH exposure, stimulated appetite in some way, thereby alleviating any ionoregulatory disturbances. During the Limited Ration Exposure, ionoregulatory disturbances occurred during low pH exposure, with more dramatic effects in fish at slightly elevated temperatures. Trout maintained on a limited diet had a higher mortality rate, lower plasma and whole body Na⁺ and Cl⁻ concentrations, and elevated cortisol levels compared with fish fed to satiation. Thus, it became clear that fish could use food to compensate for the stresses of increased temperature and low pH. The third exposure was conducted to determine whether food simply provided the necessary fuel to meet the increased cost of living in a low pH environment, or whether food directly provided the dietary salts necessary to replace branchial ion loss. Diets were formulated at two levels of energy (regular: 16.31MJ/kg or low: 9.77MJ/kg) and two levels of NaCl (regular: 263 mmols/kg or low: 43 mmols/kg) using a factorial design (2x2=4 treatments). In addition, a fifth group of fish were not fed during the exposure. All five groups of fish were challenged with pH 4.0 to induce a rapid ionoregulatory disturbance and then held at pH 5.2 for the next 28 days. During this month, fish were fed 0.6% of their body weight of one of the four diets. Fish fed the low salt diets incurred typical long-term ionoregulatory disturbances with decreased whole body Na+, K+ and Cl concentrations. These effects were not seen in fish fed regular salt diets, regardless of energy content, showing that it is the salt content of the food rather than the energy content which is critical in protecting against the deleterious effects of low environmental pH. Interestingly, fish fed the regular energy/low salt diet had high cortisol levels and increased mortality while fish fed the regular salt diets, low energy/low salt diets and starved fish did not have a high rate of mortality. These results may have been due to differences in metabolic rate and therefore oxygen consumption (M₀₂). Starved fish had the lowest M₀₂. Fish fed the regular energy diet had increased post-prandial M₀₂ due to the specific dynamic action evoked in fish by ingestion of protein-rich food. An increase in oxygen consumption may have caused an increase in branchial ion loss, thereby exacerbating the ionoregulatory deficit associated with chronic acid exposure. This is detrimental when dietary salts are unavailable to replace branchial losses. Overall, the salt content of food may play an important role in ameliorating the deleterious effects of chronic low pH, while the energy content of food may complicate the response. / Thesis / Master of Science (MS)

Quantitative information about halogenated hydrocarbons is important for understanding their impact on atmospheric ozone chemistry and climate change, their regulation, and the devising of improved substitutes. The Montreal Protocol aimed to regulate the utilization and manufacturing of hydrochlorofluorocarbon compounds (HCFCs), contributing to ozone layer depletion. The 2016 Kigali Amendment to the Montreal Protocol agreement, Annex C listed 274 HCFCs. Only 16 of them have been measured experimentally. The rest were set to zero by default. These reported global warming potentials (GWPs) play a crucial role in formulating policies for gradually reducing the usage and production of HCFCs to prevent atmospheric impact. Here we are studying 1-chloro-1-fluoro-ethane (CH3CHFCl) as a test of past theory. There are no prior experimental measurements of the reactivity of CH3CHFCl with hydroxyl (OH) radicals, which primarily determines its atmospheric lifetime, nor of its infrared (IR) spectrum. Saturated hydrofluorocarbons (HFCs) are non-ozone depleting substitutes for chlorofluorocarbons deprecated under the 1987 Montreal Protocol on Substances that Deplete the Ozone Layer, but they exhibit high global warming potentials (GWPs) and the Kigali Amendment adopted in 2016 outlines their phase down. Unsaturated HFCs offer more reactive alternatives, whose likely short atmospheric lifetimes would imply small GWPs. Because their GWPs are smaller than those for saturated HFCs by several orders of magnitude, and especially for fully fluorinated examples, several halogenated olefins are under consideration for practical application. We studied HCF2CF2CF=CF2, cis-HCF=HCF, trans HCF=HCF, CF2=CH2 unsaturated HFCs.

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This research studied the efficacy of enhancing information-based appeals with social influence strategies in order to encourage environmental activism and efficiency behaviors in response to global warming. A secondary goal was to study the relationship between pro-environment attitudes as measured by the New Ecological Paradigm (NEP) and the activism/efficiency behaviors. After hearing a 15-minute presentation about the threat of global warming, 270 participants were encouraged to take relevant action by (a) signing web-based petitions asking automakers to build more environmentally friendly cars, (b) sending web-based letters to their state senators asking them to pass legislation to curb global warming, and (c) replacing their own inefficient incandescent light bulbs with compact fluorescent light bulbs (CFLs). The primary independent variable was the intervention technique used to encourage the three behaviors. The Information Only condition received a standard informational presentation, and a Social Influence condition received a presentation enhanced by the social psychological principles of authority, social validation, and consistency. A third group—Social Influence and Commitment—received the social influence manipulations and also signed a commitment statement. Overall compliance was relatively low, with 30.7% of participants across all conditions completing one or more activism/efficiency behavior. Statistical comparisons of the compliance rates of the three groups were insignificant, and thus failed to support the efficacy of the social influence approach. Participants who held stronger pro-environment attitudes were more likely to complete the tasks. Those who completed at least one of the environmental actions scored significantly higher on a pre-presentation NEP (m = 54.9) than those who completed none (m = 50.3). In addition, political conservatism was negatively related to the NEP and task compliance. Finally, individuals who completed at least one of the requested behaviors showed a significant increase in pro-environment attitude on a second (post intervention) NEP, while the NEP scores of non-compliers remained unchanged. / Ph. D.

Thesis Ph.D. ((Applied Mathematics)) -- University of Limpopo, 2022 / The world is under threat from the devastating effects of the continued depletion of the Ozone layer. Increased global warming is causing catastrophic ecological damage and imbalance due to accelerated melting of glaciers, rampant runaway veld res, widespread floods and other extreme events. The delegates to the Cop26 Climate Change Summit were reminded that the continued burning of fossil fuels is releasing carbon into the atmosphere at an unprecedented pace and scale and that the world is already in trouble. Complete substitution of fossil fuels with clean energy sources is the only solution through which the world can be saved from the deleterious effects of global warming. However, total dependence on renewable energy sources can only be possible through novel technology that enables efficient energy utilization and conservation. For instance, the evolution of advanced techniques in manufacturing processes has led to the reduction in the size of various industrial and engineering designs that consume reduced amounts of energy. Efficient energy utilization in thermo-fluid flow systems can be achieved through entropy generation minimization. Entropy is a thermodynamic quantity that represents the unavailability of a system's thermal energy for conversion into mechanical work. In this study, thermodynamic analysis of reactive variable properties third-grade fluid flow in channels with varied geometries and subjected to different physical effects was investigated with the second law of thermodynamics as the area of focus. Entropy generation and inherent irreversibility analysis were the main focus of the study where the sensitivities of these quantities to the embedded parameters were numerically and graphically described and analysed. The semi-analytic Adomian decomposition method, the semi-implicit fi nite difference scheme and the spectral quasilinearisation method were employed to solve the nonlinear differential equations modelling the flow systems. The results reveal that the effects of the parameters on flow velocity, fluid temperature, entropy generation and inherent irreversibility cannot be neglected. In particular, conditions for entropy generation minimization were successfully established and documented. / University of Limpopo

Contrasting the day-night variation in thermal landscape, the higher local variation and irregularity on urban surface temperature pattern during daytime was observed and identified by landscape metrics compared with those of nighttime pattern. The diversity and fragmentation metrics had revealed the influence of urban development on the overall urban landscape pattern. Along with urban development, daytime pattern of urban thermal landscape presented more fragmentation, less diversity and uneven texture distribution within daytime observations. / During the process of worldwide urbanization along with high rise and high density housing development in large cities, urban warming has received growing concern among many environmental issues related to urban landscape change. Due to the complicated interplay between urban environment and local climate, it is far from certain about the urban effects on local warming. In this literature, a systematic monitoring and analysis of the spatial dependency and heterogeneity of urban thermal landscape at city scale remains inadequate. The goal of this doctoral research is to develop a research framework incorporating geospatial statistics, thermal infrared remote sensing and landscape ecology to study the urban effect on local surface thermal landscape regarding both the pattern and process. / GWR analysis offered an in-depth investigation of local effect on surface temperature variation which had been proven to be spatially varying and influenced by local weather condition with local environmental setting quantified with the referred site specific environmental factors. The local dominant factor accounted for most to the site specific surface temperature variation which varied significantly in space and time and prevented a general delineation of the relative association among environmental factors to surface temperature disparities. The effective adaptive measures could be devised locally with reference to day-night needs in the identification of this feature. / In summary, global regression analysis confirmed the relationship between environmental factors and surface temperature and gave a general overview of urban effect on local surface warming. The distinctive mechanism of dominating day-night surface warming was uncovered by regression analysis. Vegetation played the most important role which could be referred as surface cooling in average to local surface temperature variation as compared with other measures of local environment during both daytime and nighttime. Besides the dominant role of local solar radiation on surface warming, building square footage demonstrated the second important influence on local surface temperature elevation during daytime. During nighttime, population density played a dominant role on nighttime surface warming among different parameters, with the second important contribution of nighttime surface warming coming from road density. While elevation and distance from coast demonstrated obvious cooling effect on surface temperature within most nighttime models. / Located in a subtropical region, Hong Kong's development with high rise and high density housing made it a suitable site for studying urban effect on local warming. This research chose Hong Kong as the case study which hopes to enrich our knowledge regarding urban local thermal performance and add to our understanding of urban microclimate in hot-humid weather area. / Xue, Yucai. / Adviser: Tung Fung. / Source: Dissertation Abstracts International, Volume: 71-01, Section: B, page: 0185. / Thesis submitted in: September 2008. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (leaves 201-228). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. Ann Arbor, MI : ProQuest Information and Learning Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese.

Global warming is currently a major challenge facing the world. There are widespread ongoing efforts in the form of summits, conferences, etc., to find satisfactory ways of surmounting this challenge. The basic objective of all such efforts can be summarized as conception and formation of protocols to reduce the pace of global carbon levels. Game theory and mechanism design provide a natural modeling tool for capturing the strategic dynamics involved in global warming related problems. This dissertation explores for the first time the use of voting mechanisms in the context of solving the central problems, namely, allocation of emission caps and reduction quotas to strategic emitting agents (countries). The contribution of this dissertation is two-fold. The first contribution is to develop an elegant game theoretic model that accurately captures the strategic interactions among different emitting agents in a global warming setting. This model facilitates a convenient way of exploring a mechanism design approach for solving important allocation problems in the global warming context. The second contribution is to propose and explore a novel approach, based on voting mechanisms, to solve two problems: (1) allocating emission caps and (2) allocating reduction quotas to strategic agents. Our work investigates the use of voting mechanisms that satisfy four desirable properties: (1) non-dictatorship, (2) strategy-proofness, (3) efficiency, and (4) anonymity. In particular, we explore the median selection, maximum order statistic selection, and general Kth order statistic selection voting mechanisms. Our results clearly show that only trivial allocations satisfy all the above properties simultaneously. We next investigate the use of voting mechanisms for the dual problem, namely, allocation of emission reductions to emitting agents. Here, we show that non-trivial allocations are possible, however an important property, individual rationality, might be compromised. The investigations in the thesis bring out certain limitations in applying voting mechanisms that satisfy all the four properties above. Nevertheless, the insights obtained provide valuable guidelines for solving emission allocation related problems in a principled and informed way.

Northern bobwhite populations have declined concurrent with global warming. The focal period of this study was the 12-d pre-incubation period, when bobwhite eggs remain in the nest without the thermal protection of the incubating parent. This study first established the storage and thermal limits of bobwhite eggs, then investigated how global warming may impact oviparous embryos and how bobwhite embryos react to acute and chronic doses of simulated drought temperatures during pre-incubation. First, the maximum storage limit of bobwhite eggs was determined by storing eggs ≤21 d and measuring hatching success and pH of egg albumen and yolk. Hatching success of stored eggs declined after 14 d, when yolk and albumen pH reached levels detrimental to embryonic development. Secondly, thermal limits were determined by exposing bobwhite eggs to hyperthermic temperatures (38-52 °C). Bobwhite embryos survived 50 °C for 1 h, 49 °C for 3 h and 46 °C for 6 h. Results indicate an adaptation to the naturally occurring temperature extremes that can occur in the bobwhite's southern range during pre-incubation. Subsequently, bobwhite eggs were exposed to either low constant (LC), low fluctuating (LF), high constant (HC), or high fluctuating (HF) temperatures during pre-incubation to determine if the nature of temperatures differentially affected development. Although eggs exposed to high heat loads (HC and HF), and low heat loads (LF and LC) had equal heating degree-hours within groups, they exhibited differential growth during pre-incubation. Oxygen consumption, hatch timing, and hatching success were also affected by the thermal regimes. Eggs in simulated drought (HF) had a 47% lower hatch rate than eggs in simulated non-drought (LF) indicating that thermal stress during pre-incubation may contribute to population declines during drought. Finally, northern bobwhite eggs were exposed to acute or chronic doses of simulated drought temperatures, which tested for critical periods of development during pre-incubation. Collectively, data indicated that the earliest stages of bobwhite development were more affected by hyperthermic temperatures. Indeed, a critical period of development exists during the first 2/3 of pre-incubation during which exposure to hyperthermic temperatures results in aberrant development, hatching plasticity, and reduced hatch rates.

Climate change has been a topic for discussion in the IT industry. The IT (information technology) sector has been regarded as one of the contributing sectors towards climate change due to carbon emissions from IT equipment such as computers and servers. Environmental concerns are gaining incremental attention from organisations across the globe. Green IT is seen as part of the solution to this problem and has been defined and discussed by many researchers. The purpose of this study was to investigate Green IT practices that have been adopted in the NWPG (North West Provincial Government). The study focused on the three departments which fall under one central IT section in the department of the provincial treasury. A quantitative study was conducted in Mafikeng and questionnaires were distributed to collect the data and it was found that although end-users in the government sector are aware of Green IT, many still needed a lot of training on Green IT. The research concludes by suggesting strategies that might be adopted to improve IT use in the government sector. / Thesis (M.Com.(Information Systems) North-West University, Mafikeng Campus, 2014

A 2°C increase in global mean temperature (ΔTg) has been widely adopted as a benchmark for dangerous climate change. However, there has been a lack of research into the implications of 2°C, or any other degree of warming, for Africa. In this thesis changes in African temperature and precipitation associated with 1°C, 2°C, 3°C, 4°C, and beyond are investigated for the first time, using output from 350 climate model experiments: a collection of simulations from international modelling centres (CMIP3), two Perturbed Physics Ensembles (PPEs), and a group of five regional models. The models project temperature and precipitation anomalies which increase in magnitude and spatial extent as global temperature rises, including a wet signal in East Africa, and drier conditions for African rainforests. The models consistently show that the evolution of change with global warming is gradual, even at 4°C and beyond; but the amplitude and direction of precipitation change at each ΔTg increment vary between models and between datasets. The PPEs project precipitation signals which are not represented by CMIP3, in particular a large drying (>0.5 mm day-1 °C-1) of western Africa. There are also important differences between global and regional models, especially in southern and West Africa (>1 mm day-1). Analysis of atmospheric circulation responses suggests that the higher resolution projections are no more credible in this case. Some of the variation between models can be understood as the result of untrustworthy simulations, leading to constraints on the PPEs, and casting doubt on the strong drying of west Sahel; but model evaluation is found to be limited by observations in the case of the Congo Basin. The implications of global warming are different depending on which models are consulted. The findings emphasise that caution should be exercised in the application of climate model data to inform mitigation debates.