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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.
281

Impacts of primary energy constraints in the 21st century

Nel, Willem P. 25 March 2010 (has links)
D.Phil. / Global society has evolved into a complex multi-dimensional system in which it has become increasingly difficult to construct and maintain a systemic model of cause and effect. Specialisation and abstraction in the various disciplines of scientific and societal complexity has led to divergent theories of sustainability. Failure to integrate real life problems across disciplines poses a threat to modern society because the causal links between disciplines are unattended in many instances and events in one dimension could lead to catastrophic unintended consequences in another. In light of the above, this thesis contributes towards the multi-disciplinary integration of some of the most important sustainability concerns of modern society, namely Energy Security, Economic Growth and Global Warming. Analysing these real-life sustainability issues in a multi-disciplinary context leads to conclusions that are controversial in terms of established philosophical worldviews and policy trends. Firstly, the thesis establishes deterministic expectations of an imminent era of declining Energy Security resulting from the exhaustion of non-renewable fossil fuel resources, despite optimistic expectations of technology improvements in alternative energy sources such as renewable and nuclear. Secondly, the exhaustion of non-renewable fossil fuel resources imposes limits to the potential sources of anthropogenic carbon emissions that render the more pessimistic emissions cases considered in the global warming debate irrelevant. The lower level of attainable carbon emissions challenges the merits of the conventional carbon feedback cycle with the result that the predicted global warming is within acceptance limits of the contemporary global warming debate. Thirdly, the consequences of declining Energy Security on socio-economic welfare is a severe divergence from historical trends and demands the reassertion of the role of energy in human development, including Economic Growth theory. The thesis develops a novel economic growth model that treats energy as an explicit and Autonomous Factor of Production, thereby facilitating plausible predictions of future Economic Growth potential. The results challenge the sustainability of the current free-market capitalist economic system and demand strong policy responses to avoid the collapse of modern society.
282

Coping with Weather in Cape Town: use, adaptation & challenges in an informal settlement

Tabi, Kris Agbor January 2013 (has links)
Magister Artium - MA / The concern that weather variability and climate change has raised nowadays puts every society or community on the alert. This is arguably the most persistent environmental threat to global stability in vulnerable communities in recent times. City dwellers are now experiencing increased variable weather episodes such as frequent flooding, heat waves and drought with increased wind and storm activities. Unfortunately, the aftermath of these weather irregularities are felt most severely by vulnerable urban poor residents with the least mechanisms to cope. This study focused on the residents of Enkanini in Makhaza, an informal settlement in the greater Khayelitsha Township of Cape Town, South Africa. It documented the challenges they encounter with respect to weather, seeking to understand their adaptive strategies. Emphasis was also placed on the vulnerable nature of their dwellings and their ingenuity in coping with the variable weather pattern in Cape Town. Qualitative and quantitative methods were used to analyse field data, using codes derived from themes and SPSS respectively. Ethnographic methodology guided the researcher to participate overtly in the activities of the community over an extended period, watching what happened, listening to what was said and asking questions pertaining to their vulnerability to the vicissitudes of the prevailing weather in the informal settlement. Findings from the study revealed that over 62% of the dwellings do not conform to the City‟s Disaster Risk Management Centre and Fire & Rescue safety regulations and that over 80% of the residents do not adapt very well to weather-related episodes. It also identifies the most challenging weather episodes to be floods during winter and shack fires during summer; amidst other health concerns that occur all year round.
283

Climate change mitigation strategies and its effect on economic change

Roux, Louis Johannes January 2013 (has links)
Scientists started to study the relationship between changing weather patterns and the emission of carbon dioxide (CO2) and other harmful gasses. They soon discovered compelling evidence that CO2 concentration and other gases have been increasing and it was causing temperatures to increase in certain areas on the earth, which disturb historic weather patterns. Climate change has become a very popular field of study in the modern science. Europe first introduced measures to reduce carbon emissions but it was the Kyoto in 1997 where global leaders were asked to participate in a joint protocol to reduce greenhouse gases. South Africa responded to climate change challenges in 2008 with the Long term Mitigation Scenarios (LTMS). The Integrated Resource Plan for electricity to 2030 was developed from the LTMS scenarios and after some major amendments it was accepted and promulgated by Government and has recently been included in the National Development Plan to 2030 (NDP). There are concerns about the achievability of some of the objectives listed in the NDP and this study explored the IRP2010 as the proposed strategy to meet energy demand and reduce emissions. The purpose for this study was to answer this question: Is there an optimum climate change mitigation strategy for South Africa and how can the effect thereof be simulated on economic growth? Through primary and secondary research during the study it was possible to define some 32 categories of energy producing assets that are commercially active or nearly market-ready. The characteristics of the various assets and the relevant fuel are defined in mathematical equations. It was found that the three portfolios that matched the 450TWh electricity requirement would perform substantially better than the NDP portfolio in terms of cost and similar on emissions with marginally fewer employment opportunities created. The proposed electricity strategy in this study was 390TWh and 33.5 Million tonnes of oil consumption by 2030. This strategy was substantially more affordable than the 450TWh strategy. Trends in the Supply and Use tables since 1993 were studied and then forecasted to 2030 to determine consumption levels on electricity and liquid fuel into the future. It was found that electricity demand is seriously overestimated and South Africa would end up with large excess capacity in electricity infrastructures if the NDP energy strategy (IRP2010) is implemented. It is concluded that the NDP energy strategy to 2030 is based on an incorrect electricity demand forecast. It would lead to excessive investment in an electricity infrastructure. Government has confirmed that part of the new infrastructure would be nuclear. It is also found that NDP has not clearly supported nuclear as part of the strategy. Nuclear is partly the reason why the capital requirement of the NDP portfolio is so much higher than the other portfolios. It is the conclusion of this study that South Africa do not need to invest in a nuclear build programme as the electricity demand would be adequately covered by adding the new Medupi and Kusile power stations, Ingula pump storage scheme, some wind and solar renewables, electricity from cogeneration, biogas, biomass, small hydro and imported hydro from neighbour countries. To invest in electricity capacity to generate 450TWh annually by 2030 would result in excessive energy cost, GDP growth could be up to 1% lower due to underperforming capital investments in the electricity infrastructure and higher energy cost would lead to a decline in global competitiveness.
284

A New Strategy for Climate Change Litigation: Recovering the Rising Costs of Rising Sea Levels

Carrade, Elizabeth Marie 01 January 2018 (has links)
This thesis assesses the promise and potential failures of five tort cases filed in California city and county governments in 2017. The plaintiffs in these cases are suing the fossil fuel industry, claiming that the actions of the industry contributed substantially to global climate change, which is now causing sea level rise in their coastal communities. If these cases are successful, the budget-constrained city and county governments will be provided with funds necessary for climate change adaptation and mitigation measures that will allow residents to continue living in a hotter climate, with higher sea levels. As the effects of global climate change materialize, it is essential that local governments find ways to adapt.
285

Phytoremediation of Nitrous Oxide: Expression of Nitrous Oxide Reductase from Pseudomonas Stutzeri in Transgenic Plants and Activity thereof

Wan, Shen January 2012 (has links)
As the third most important greenhouse gas, nitrous oxide (N2O) is a stable greenhouse gas and also plays a significant role in stratospheric ozone destruction. The primary anthropogenic source of N2O stems from the use of nitrogen in agriculture, with soils being the major contributors. Currently, the annual N2O emissions from this “soil–microbe-plant” system is more than 2.6 Tg (one Tg equals a million metric tons) of N2O-N globally. My doctoral studies aimed to explore innovative strategies for N2O mitigation, in the context of environmental microbiology’s potential contribution to alleviating global warming. The bacterial enzyme nitrous oxide reductase (N2OR), naturally found in some soils, is the only known enzyme capable of catalyzing the final step of the denitrification pathway, conversion of N2O to N2. Therefore, to “scrub” or reduce N2O emissions, bacterial N2OR was heterologously expressed inside the leaves and roots of transgenic plants. Others had previously shown that the functional assembly of the catalytic centres (CuZ) of N2OR is lacking when only nosZ is expressed in other bacterial hosts. There, coexpression of nosZ with nosD, nosF and nosY was found to be necessary for production of the catalytically active holoenzyme. I have generated transgenic tobacco plants expressing the nosZ gene, as well as tobacco plants in which the other four nos genes were coexpressed. More than 100 transgenic tobacco lines, expressing nosZ and nosFLZDY under the control of rolD promoter and d35S promoter, have been analyzed by PCR, RT-PCR and Western blot. The activity of N2OR expressed in transgenic plants, analyzed with the methyl viologen-linked enzyme assay, showed detectable N2O reducing activity. The N2O-reducing patterns observed were similar to that of the positive control purified bacterial N2OR. The data indicated that expressing bacterial N2OR heterologously in plants, without the expression of the accessory Nos proteins, could convert N2O into inert N2. This suggests that atmospheric phytoremediation of N2O by plants harbouring N2OR could be invaluable in efforts to reduce emissions from crop production fields.
286

Permafrost Changes Along the Alaska Highway Corridor, Southern Yukon, from Ground Temperature Measurements and DC Electrical Resistivity Tomography

Maxime Arsène, Duguay January 2013 (has links)
Permafrost temperatures were measured by the Geological Survey of Canada (GSC) in 1977-1981 at boreholes along a proposed pipeline route in the southern Yukon. Analysis of climate station records indicate that mean annual air temperatures in the region have since increased by 0.5-1.0˚C. Renewed interest in the pipeline and the need to develop adaptation strategies for existing highway infrastructure have meant that information on permafrost and geotechnical conditions must be updated. To accomplish this goal, a total of eight GSC boreholes ranging in depth from 5-9 m were located, unblocked of ice and instrumented with thermistor cables and data-loggers to permit renewed ground temperature monitoring. Manual temperature measurements were also taken at four other shallow boreholes. Electrical resistivity tomography (ERT) surveys were conducted at each site. MAGTs below 1 m at permafrost sites in the study area range from -0.2˚C to -1.5˚C with permafrost depths greater than 25 m. The permafrost at the study sites can be classified as sporadic discontinuous and extensive discontinuous. Ground temperatures indicate that permafrost can persist under warmer climatic conditions as long as it remains protected by its ecosystem properties. Thermal monitoring for 2011-2012 shows an average increase of 0.5-1.0˚C when compared to the original 1978-1981 ground temperatures. This slow rate of ground warming is mainly attributed to a combination of limited climate change, especially in the south of the study area, ground temperatures close to 0˚C, and the possible disturbance of sites from the removal of vegetation prior to the original measurements being made. ERT surveys conducted at most borehole sites show deeper thaw or taliks where the cleared cut-line used for geophysical work in the 1970s is crossed. These results indicate the impacts of climate change and environmental change in the study area over the past three decades. They appear to match the relatively slow rates of ground warming observed elsewhere in northern Canada where permafrost temperatures are close to 0˚C and where warming also requires changes in latent heat due to internal thaw. TTOP equilibrium modelling suggests that if climate change is responsible for the ground warming, most of the change can be attributed to the step-like MAAT increase that occurred between 1975-1976.
287

Neudržitelnost ekonomického růstu / Sustainability of economic growth

Follprecht, Štěpán January 2009 (has links)
Thesis evaluates sustainability of economic growth in current conditions from three main points of view: impacts of mankind to enviroment especially in form of global warming, growth of human population and availability of energy sources. Thesis offers possible scenario of solving the situation and analyses, how had situation been solved till now and tries to find reasons why were these solutions succesfull or not, and proposes possibilities to solve the situation.
288

Impact du réchauffement climatique sur le krill en milieux polaires : thermotolérance et réponse Hsp70 / Global warming impact on polar krill : thermal tolerance and Hsp70 response

Cascella, Kévin 17 October 2014 (has links)
Les zones polaires sont les premières à subir les effets du réchauffement climatique.L'estimation de l‟impact physiologique d‟une augmentation de température sur les espèces de ces régions est capitale afin de prédire l'évolution des écosystèmes polaires. Les conséquences physiologiques de l‟augmentation des températures peuvent affecter les capacités de résistance et de survie des organismes. Le krill constitue un maillon clé des écosystèmes polaires, il est aussi à la base de la chaine trophique de ces régions. Dans ce contexte, une étude comparative de la thermotolérance de trois espèces de krill polaires a été effectuée. Deux espèces d‟Antarctique Euphausia superba et Euphausia crystallorophias, et une espèce d‟Arctique, Thysanoessa inermis. La détermination de la température limite de tolérance (CT50) a été estimée sur ces 3 espèces. E. superba et T. inermis présentent des tolérances thermiques similaires, alors que E. crystallorophias a une CT50 légèrement inférieure. Cinq isoformes d‟Hsp70 ont été caractérisées, pour chaque espèce. Leur expression génique a été suivie au cours d‟augmentations de la température du milieu. Le suivi de ces biomarqueurs a permis d‟estimer la température limite à laquelle les premiers dommagescellulaires apparaissent. Les cinétiques d‟expressions de chaque espèce se sont révéléesdifférentes : une forte réponse Hsp70 a été observée chez T. inermis, alors que chez E.crystallorophias celle–ci est beaucoup plus faible. Aux mêmes températures E .superba ne développe pas de réponse Hsp70, malgré sa forte thermotolérance. La multiplication des expériences de choc thermique sur cette espèce (intensité et durée) n'a pas révélé de réponseHsp70, mais confirmé sa grande thermotolérance pour un organisme antarctique. / Polar regions are the first to be impacted by global warming. The physiological impact appraisal of a temperature increase over local species is critical to foresee future evolutions of polar ecosystems. Physiological consequences of temperature rises can affect organisms both in their hardness and survival. Krill stands as a key component for polar ecosystems and therefore constitutes the core diet of local predators. In such context, a thermal tolerance comparative analysis of three distinct polar krill species has been carried out: two Antarctic species Euphausia superba and Euphausia crystallorophias, and one Arctic species,Thysanoessa inermis. The determination of thermal tolerance (CT50) was conducted on these three species. E. superba and T. inermis analysis showed similar thermal tolerances, while E.crystallorophias CT50 was slightly lower. Five isoforms of Hsp70 have been characterized foreach species. Their gene expression has been monitored through temperature increases of their environment. This biomarkers monitoring allowed an estimation of the critical temperature at which cellular damages appear. Kinetic expressions vary for each species: a strong response was observed in Hsp70 T. inermis, whereas response is much lower in E.crystallorophias. For similar temperatures, E .superba does not provide any Hsp70 response,despite its high thermal tolerance. The accumulation of heat shock experiments on this species, in intensity and duration, still did not provide any Hsp70 response, although it confirmed its highly noticeable heat tolerance for an Antarctic organism.
289

Incertezas associadas à temperatura do ar no contexto das mudanças climáticas: determinação das causas e efeitos de heterogeneidades e discussão das implicações práticas / Uncertainties associated with the air temperature in the context of climate change: determination of the causes and effects of heterogeneities and discussion of the practical implications

Marcos José de Oliveira 08 October 2010 (has links)
O registro da temperatura terrestre é um indicador fundamental nas análises de mudanças do clima global. A presente investigação tratou da verificação e quantificação dos efeitos de heterogeneidades (erros) em séries da temperatura do ar obtidas em estação climatológica localizada em Itirapina, SP, Brasil. As principais causas de heterogeneidades estudadas foram: mudanças dos horários de observação e cálculos da temperatura média diária; mudanças dos tipos de instrumentos utilizados (convencionais e automáticos) e mudanças nos abrigos meteorológicos. A metodologia aplicada consistiu em comparar, em diferentes escalas temporais, várias séries de temperatura do ar em relação a uma série de referência, assumida como mais confiável. As diferenças obtidas, em termos de desvios, resultaram em valores nas seguintes ordens de grandeza, de acordo com cada escala: 10,0ºC na escala das medições horárias; 5,0ºC na escala das médias diárias; 2,0ºC, na escala mensal; 1,0ºC na escala anual; e 1,5ºC na escala de normal climatológica (30 anos) de exibição dos valores médios da temperatura do ar. Conclui-se que em escalas reduzidas (horárias e diárias) existem erros de alta magnitude de variação, porém de baixa frequência de ocorrência. Com o aumento da escala, a magnitude dos desvios diminui. As causas de heterogeneidades, de acordo com os desvios observados, ficam classificadas, na ordem de menor para a maior intensidade de influência: mudanças dos abrigos; mudanças dos cálculos das médias diárias; e mudanças dos instrumentos. No contexto da discussão do aquecimento global, na ordem de 0,6ºC no último século, a ocorrência de erros e incertezas de mesma ou maior magnitude pode comprometer o uso da temperatura do ar como uma evidência confiável de mudanças do clima, uma vez que mudanças não-climáticas interferem significativamente nas medições. O uso da evidência é discutido no contexto da interação entre a Ciência, Política, Mídia e Economia. Foi identificado que, neste âmbito externo ao meio científico, as incertezas são diminuídas e ignoradas, tanto devido ao processo de simplificação da informação para sua difusão, quanto devido a interesses que norteiam a manipulação intencional e tendenciosa do tema. Devido à disputa de diferentes interesses, foi feita uma breve discussão de alguns aspectos controversos, permeando a atuação de cientistas céticos à crença da contribuição humana significativa nas mudanças climáticas. / The instrumental temperature record is a key indicator in the analysis of global climate change. This research dealt with the verification and quantification of the effects of heterogeneities (errors) in air temperature series obtained from a climatological station located in Itirapina, SP, Brazil. The main causes of heterogeneity studied were: changes on the times of observation and on the daily mean air temperature calculation; changes on the types of instruments (conventional and automatic); and changes in thermometer screens. The methodology consisted of comparing, at different time scales, several series of air temperature series in relation to a reference series, assumed to be more reliable. The differences obtained, in terms of deviations, resulted in the following orders of magnitude, according to each scale: 10.0ºC in the range of hourly measurements, 5.0ºC in the range of daily mean, 2.0°C in monthly scale, 1.0°C in the annual scale and 1.5°C in the climatological normal scale (30 years). It follows that at small scales (hourly and daily) exist errors of high magnitude of change, but low frequency of occurrence. With increasing scale, the magnitude of the deviations decreases. The causes of heterogeneity, according to the observed deviations, are ranked in order of lowest to highest extent of influence: changes on screens, changes on daily mean air temperature calculation, and changes of the instruments. In the context of the discussion of global warming, on the order of 0.6ºC over the last century, the occurrence of errors and uncertainties in same or greater magnitude can compromise the use of air temperature as a reliable evidence of climate changes, since non-climatic changes significantly interfere the measurements. The use of evidence is discussed in the context of the interaction between Science, Politics, Media and Economics. It was identified that, outside the scientific environment context, the uncertainties are reduced and neglected, both due to the simplification process for the information dissemination, as due to concerns that guide the intentional and biased manipulation on the subject. Due to the competition of different interests, there was held a brief discussion of some controversial aspects, permeating the work of skeptical scientists on the belief of the significant human contribution to the climate change.
290

Curvar-se diante do existente: o apelo às mudanças climáticas pela preservação ambiental / The construction of the modern discourse involving global climate change

Daniela de Souza Onça 05 June 2007 (has links)
Esta pesquisa tem por objetivo investigar a construção do discurso moderno envolvendo as mudanças climáticas globais. Tal discurso, que podemos observar em diversos tipos de publicações, eventos e atitudes, apregoa em geral a noção de que as mudanças climáticas globais já são uma realidade auto-evidente, com efeitos devastadores mundo afora, com um aquecimento progressivo e provocadas pelo homem, por meio do lançamento indiscriminado de poluentes na atmosfera. Sendo assim, fazem-se apelos apaixonados pela preservação da saúde do planeta, pela redução da emissão de poluentes, pois do contrário sofreremos graves conseqüências em nossas vidas, por exemplo, na agricultura, no abastecimento de água, no conforto térmico e na disseminação de doenças. Entretanto, no interior da comunidade científica, ao contrário do que possa parecer à primeira vista, não existe um consenso quanto às causas, conseqüências e mesmo quanto à realidade do aquecimento global. Constrói-se, dessa forma, um discurso que toma hipóteses por certezas, doutrinador pelo medo e, principalmente, que não rompe com as bases da concepção de mundo que gerou a degradação ambiental. Idealiza a possibilidade de uma harmonia entre a sociedade e natureza mas, ao mesmo tempo, conserva o mesmo tipo de racionalidade com relação a medidas mitigadoras e mantém seu utilitarismo - devemos proteger o meio ambiente porque o homem necessita dos recursos naturais para sobreviver. Enfim, faz o \"jogo do inimigo\", pois o apelo às graves conseqüências do aquecimento global é de forte impacto e tem maiores chances de agregar partidários e surtir algum efeito prático de mitigação. Acreditamos que, embora tal atitude possa até funcionar, não é o melhor caminho para a construção de uma autêntica consciência ecológica por manter fundamentalmente inalterada a mentalidade criticada. Sugerimos, assim, a construção de um argumento ético, a saber, o do valor intrínseco da vida e necessidade de respeito por ela, ao invés de insistir numa argumentação utilitarista e amedrontadora. A proteção à natureza não necessita de falsas premissas climáticas para sustentá-la, pois sua necessidade é auto-evidente. / This research aims to investigate the construction of the modern discourse involving global climate change. Such discourse, which we can observe in different kinds of publications, events and attitudes, generally proclaims the notion that global warming is already a self-evident reality, with its devastating effects worldwide, with a progressive warming and man-induced, via the indiscriminate launching of pollutants in the atmosphere. This way, passionate appeals for the planet\'s health preservation and the reduction of pollutants emission are made, otherwise we will suffer serious consequences in our lives, for example in agriculture, water supply, thermal comfort and dissemination of diseases. However, in the scientific community, instead of what we may think at first sight, there is no consensus about causes, consequences and even the reality of global warming. It is constructed, this way, a kind of discourse which takes hypothesis for certainties, indoctrinates by fear and, above all, does not break with the basis of the worldview that engendered environmental degradation. It idealizes the possibility of harmony between society and nature but, at the same time, conserves the same kind of rationality regarding mitigation measurements and keeps its utilitarianism - we must protect the environment because man needs natural resources to survive. In a word, it \"plays the enemy\'s game\", since the appeal to the serious consequences of global warming is powerful and has greater possibilities of aggregating partisans and producing some practical mitigation effect. We believe that, although this kind of attitude may work, this is not the best way to construct an authentic ecological consciousness because it keeps basically unchanged the criticized mentality. We suggest, thus, the construction of an ethical argument, to wit, the one about intrinsic value of life and the need of respecting it, instead of insisting on a utilitarian and frightening argument. The protection of nature does not need false climatic premises to support it, as its necessity is self-evident.

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