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Diagnosing Mechanisms for a Spatio-Temporally Varying Tropical Land Rainfall Response to Transient El Niño Warming And Development of a Prognostic Climate Risk Management FrameworkParhi, Pradipta January 2020 (has links)
Assessing and managing risks posed by climate variability and change is challenging in the tropics, from both a scientific and a socio-economic perspective. While our understanding of the tropical land rainfall variability and its future projection is highly uncertain, most of the vulnerable countries with a limited adaptation capability are within the tropical band. This dissertation combines a process-based physical understanding with observational analysis to characterize the spatio-temporal changes in the tropical land rainfall during a transient El Niño evolution, with an emphasis on the risk management of the dry and wet extremes. The broad objectives are two-fold: 1) To make better sense of the higher uncertainty in the tropical rainfall response to warming and 2) to improve climate risk management strategies in the tropical developing countries.
An ENSO teleconnection mechanism, referred to as the tropical tropospheric temperature or TTT mechanism provides a theoretical framework to study the remote tropical land rainfall behavior during a transient El Niño warming. The TTT mechanism postulates that the tropic-wide free tropospheric warming interacts locally with the deep convection to modulate remote tropical climate. During the growth phase, anomalous free tropospheric temperature causes direct and fast atmospheric adjustments leading to tropospheric stability to deep moist convection and a drier response. Subsequently, during mature phase, a recovery of the initial rainfall deficit follows due to indirect and slower adjustments in surface temperature and humidity fields. In chapter 2 and 3 of this dissertation, the changes in the observed tropical land rainfall characteristics and other climate fields conditional on the growth and mature phase of El Niño warming are investigated and the role of dynamical and thermodynamic mechanisms as hypothesized by the TTT mechanism are elucidated. In chapter 4, an El Niño forecast based early action investment strategy is developed to reduce the socio-economic impacts of rainfall extremes at sub-seasonal to inter-annual lead time scales.
In the part I (chapter 2), the analysis is conducted at a regional scale over the tropical Africa. Using the TTT mechanism, a physical explanation is provided for the contrasting rainfall response over the Western Sahel and tropical Eastern Africa during an El Niño. The study finds that the Western Sahel’s main rainy season (July-September) is affected by the growth phase of El Niño through (i) a lack of neighboring North Atlantic sea surface warming, (ii) an absence of an atmospheric column water vapor anomaly over the North Atlantic and Western Sahel, and (iii) higher atmospheric vertical stability over the Western Sahel, resulting in the suppression of mean seasonal rainfall as well as number of wet days. In contrast, the short rainy season (October-December) of tropical Eastern Africa is impacted by the mature phase of El Niño through (i) neighboring Indian Ocean sea surface warming, (ii) positive column water vapor anomalies over the Indian Ocean and tropical Eastern Africa, and (iii) higher atmospheric vertical instability over tropical Eastern Africa, leading to an increase in mean seasonal rainfall as well as in the number of wet days. While the modulation of the frequency of wet days and seasonal mean accumulation is statistically significant, daily rainfall intensity (for days with rainfall >1 mm/day), whether mean, median, or extreme, does not show a significant response in either region. Hence, the variability in seasonal mean rainfall that can be attributed to the El Niño–Southern Oscillation phenomenon in both regions is likely due to changes in the frequency of rainfall. These observed changes agree with the predictions of the TTT mechanism.
In the part II (chapter 3), a global scale analysis is performed to more generally characterize the spatio-temporal differences in remote tropical land rainfall response to El Niño warming. The principal conclusions are: 1) during the El Niño growth phase relative to the neutral phase, rainfall decreases. A significant decrease in mean accumulation can be attributed to a significant increase in proportion of dry days and decrease in median and extreme intensity. A significant descent anomaly confirms the vertical stabilization and dominance of dynamical processes. 2) During the mature phase relative to the growth phase, rainfall increases, signifying a recovery from the suppression of deep moist convection. A significant increase in mean accumulation is accompanied by a decrease in proportion of dry days and by an increase in median and extreme intensity characteristics. The significant rise in the moisture field corroborates the dominance of thermodynamic processes. These findings are expected from the TTT mechanism and generalizes the findings of part I to the global scale.
In the part III (chapter 4), an El Niño forecast based index insurance policy is developed that can be used as an early action investment instrument. The forecast insurance (FI) design framework is illustrated with an application to El Niño associated flood hazard during the January-February-March-April (JFMA) season over Piura region of Peru. In order to determine the economic utility of the system, a simple cost-loss decision model, incorporating the insurance cost, is developed. The main conclusion is that the proposed El Niño forecast insurance policy with the pre-event Niño1.2 index based trigger has significant reliability and substantial utility for a wide range of policy parameters considered. Relative to a no early action strategy, the advantage of the system generally increases with i) shortening in the lead time from 9 to 1 month, ii) increase in El Niño severity level from 10 to 50 year return period and iii) increase in avoidable loss to cost ratio (LCR) ratio from 1 to 1000. These results and the forecast insurance modeling and utility evaluation frameworks have implications for designing optimal contingent financial instruments for disaster risk reduction and climate change adaptation.
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Barriers to and enablers of climate change adaptation in four South African municipalities, and implications for community based adaptationSpires, Meggan Hazel January 2015 (has links)
The focus of this study is on understanding the multiple and interacting factors that hinder or enable municipal planned climate change adaptation, here called barriers and enablers respectively, and their implications for community based adaptation. To do this I developed a conceptual framework of barriers to and enablers of planned climate change adaptation, which informed a systematic literature review of barriers to planned community based adaptation in developing countries. In this framework barriers were grouped into resource, social and physical barriers. I then conducted empirical case study analysis using qualitative research methods in four South African municipalities to understand what barriers and enablers manifested in these contexts. In light of the reflexive nature of my methodology, my framework was adjusted based on my empirical findings, where contextual barriers were found to better represent the empirical results and subsumed physical barriers. I found my framework useful for analysis, but in the empirical cases, barriers and enablers overlaid and interacted so significantly that in reality it was often difficult to separate them. A key finding was that enablers tended to be more about the way things are done, as opposed to direct opposites of barriers. Comparison of barriers and enablers across the case studies revealed a number of key themes. Municipalities struggle to implement climate change adaptation and community based adaptation within contexts of significant social, economic and ecological challenges. These contextual barriers, when combined with certain cognitive barriers, lead to reactive responses. Existing municipal systems and structures make it difficult to enable climate change adaptation, which is inherently cross‐sectoral and messy, and especially community based adaptation that is bottom‐up and participatory. Lack of locally applicable knowledge, funding and human resources were found to be significant resource barriers, and were often underlain by social barriers relating to perceptions, norms, discourses and governance challenges. Enablers of engaged officials, operating within enabling organisational environments and drawing on partnerships and networks, were able to overcome or circumvent these barriers. When these enablers coincided with windows of opportunity that increased the prioritisation of climate change within the municipality, projects with ancillary benefits were often implemented. Analysis of the barriers and enablers identified in the literature and case studies, informed discussion on whether municipalities are able to implement community based adaptation as defined in the literature, as well as the development of recommendations for how municipal planned climate change adaptation and community based adaptation can be further understood and enabled in the future. These recommendations for practice and research include: (a) To acknowledge and understand the conceptual framings of municipal climate change work, as these framings inform the climate change agenda that is pursued, and hence what municipal climate change adaptation work is done and how it was done. (b) The need for further research into the social barriers that influence the vital enablers of engaged officials, enabling organisational environments, and partnerships and networks. (c) To learn from pilot community‐level interventions that have been implemented by municipalities, as well as from other disciplines and municipalities. (d) To develop top‐down/bottom‐up approaches to enable municipal planned climate change adaptation and community based adaptation, that benefits from high level support and guidance, as well as local level flexibility and learning‐by‐doing. (e) To develop viable mechanisms for municipalities to better engage with the communities they serve.
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Investigating climate change intervention strategies in opencast mining contracting and plant hire companies: a case of mutual construction company group of companies, South AfricaMatangira, Peace Aaron 06 1900 (has links)
Climate change has come to be understood as a deleterious phenomenon, which threatens business, society and ecological systems, thus making it imperative to understand its impact on human, social and economic activities as well as the impact of these activities on climate change. Against this background, this research sought to determine climate change intervention strategies in the mining supply chain in general, specifically focussing on opencast mining contracting and plant hire companies’ practices. This focus on the mining industry was driven by its importance in South Africa and globally, despite its significant direct and indirect contribution to climatic changes.
The mixed-methods multiple case study focused on the climate change management of the Mutual Construction Company Group of Companies (MCCGC), an open cast toll mining firm and equipment supplier. Limited to two sites, Pilanesberg Platinum Mines (PPM) and Tharisa Minerals (Tharisa) Mines, the researcher gathered data through interviews, questionnaires, observations and document review. Data was analysed through deductive content analysis. The research made three major findings: (i) the MCCGC, like its principals PPM and Tharisa, does not have an explicit climate change management strategy. Instead, climate change is managed indirectly through implicit strategies seeking to manage environment, health and safety concerns of the mines, (ii) as a contractor, the MCCGC has had to adopt PPM and Tharisa’s implicit approach to climate change management strategies to meet contractual obligations, instead of an explicit approach and, (iii) the MCCGC and its principals’ commitment to environment, health and safety management, and implicitly climate change management, is not mere rhetoric but is being put into practice.
The research concluded that MCCGC’s lack of expressed climate change management intentions and practices exposed the firm to climate change risks, most notably financial risks and reputation risks. Financial risks arise from possible ex post climate change liability. In addition, MCCGC is risking its contract tenures, particularly if the two mines change ownership and the new owners insist on an explicit rather than implied climate change strategy with all its suppliers. Reputational risks arise from the possible failure to attract new clientele and investors who may perceive MCCGC as a risky partner, due to an inept climate change intervention strategy / College of Agriculture and Environmental Sciences / M. Sc. (Environmental Management)
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Intergrating environmental risk into bank credit processess : The south African banking contextBimha, Alfred 09 1900 (has links)
The impact of climate change on the financial performance of companies is of concern
to bank credit processes. The main objective of this research was to develop a South
African contextualised credit process that incorporates environmental risk. The
research methodology comprised of a mixed-method being content analysis – the
qualitative portion and the Probability of Default prediction using a Merton Model and
the Hoffmann and Busch (2008) carbon risk analysis model - the quantitative portion.
A content analysis of the banks’ Annual Reports, Integrated Reports and
Sustainability Reports showed that, while South African banks follow a qualitative
approach to embedding environmental risk into their credit process, none of the four
banks that formed part of the study divulged their quantitative approach to embedding
environmental risk. The study used a proximity matrix method to examine the level of
embedding.
The second part of the study, which used prior studies as the benchmark, adopted the
following: (1) a simulated carbon tax regime as a proxy for an environmental risk, and
(2) the Hoffmann and Busch (2008) carbon risk analysis tool and the Merton Model
(1974) as the bank credit process proxies. The second part of the study used a sample
of 33 JSE-listed Carbon Disclosure Project reporting companies out of a population of
107.
The carbon risk analysis showed that the companies in the materials and energy
sector have a high carbon risk. However, the results from the Merton Model showed
that the companies have enough profit to cushion the additional carbon tax liability,
given the insignificant shift in probability of default between the three scenarios, where
financial data had (1) no carbon tax, (2) was adjusted for a carbon tax with incentives,
and (3) adjusted for carbon tax without incentives.
Triangulation of the results from the content analysis, carbon risk analysis and the
probability of default analysis confirms that South African banks do not fully integrate
environmental risk across the credit value chain or process in the 2010 to 2017 period.
However, the carbon risk analysis shows a heavy dependency on carbon sources for
critical inputs into the South African companies’ production processes, which if not
checked, will affect the credit portfolios of banks. / Finance, Risk Management and Banking / D. Phil (Management Studies)
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A structured approach to energy risk management for the South African financial services sectorBotha, Erika 07 1900 (has links)
Energy conservation, efficiency and renewable energy have become a vital part of everyday life and business. The increase in energy cost and the consequences of greenhouse gas emissions necessitates energy management and in particular energy risk management within organisations. Organisations need to manage the possible negative effect that the increased costs will have within the organisation.
The present research investigated the introduction of a structured approach to energy risk management within the financial services sector of South Africa. The research followed a quantitative, non-experimental research design by using a structured questionnaire. The questionnaire was sent to managers within the financial services sector. The research investigated the criteria for the implementation of a structured approach to energy risk management such as organisational requirements (culture, corporate social responsibility, management, and finance), governance, energy strategies (energy conservation, efficiency and renewable energy), risk identification, risk management and lastly communication and review. The research found that the structured approach to energy risk management should include the context within the organisation namely
organisational requirements, governance and energy strategies. Thereafter the risks within the energy strategies need to be identified, analysed and evaluated, and control measures need to be implemented. It is important to monitor the various energy strategies continuously in order to identify corrections and implement
preventative actions. The strategies need to be reviewed and communicated in terms of the various strategies to all stakeholders within the organisation in order to set continual improvement plans. Risk management should form part of the energy management strategies of organisations. The research showed that energy risk
management plays an important role in the overall business strategy and that the vast majority of financial services organisations have already implemented some form of energy management. There are however aspects that are still lacking within management strategies that need attention. / D. Phil. (Management Studies) / Business Management
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Drought analysis with reference to rain-fed maize for past and future climate conditions over the Luvuvhu River catchment in South AfricaMasupha, Elisa Teboho 02 1900 (has links)
Recurring drought conditions have always been an endemic feature of climate in South Africa, limiting maize development and production. However, recent projections of the future climate by the Intergovernmental Panel on Climate Change suggest that due to an increase of atmospheric greenhouse gases, the frequency and severity of droughts will increase in drought-prone areas, mostly in subtropical climates. This has raised major concern for the agricultural sector, particularly the vulnerable small-scale farmers who merely rely on rain for crop production. Farmers in the Luvuvhu River catchment are not an exception, as this area is considered economically poor, whereby a significant number of people are dependent on rain-fed farming for subsistence. This study was therefore conducted in order to improve agricultural productivity in the area and thus help in the development of measures to secure livelihoods of those vulnerable small-scale farmers.
Two drought indices viz. Standardized Precipitation Evapotranspiration Index (SPEI) and Water Requirement Satisfaction Index (WRSI) were used to quantify drought. A 120-day maturing maize crop was considered and three consecutive planting dates were staggered based on the average start of the rainy season. Frequencies and probabilities during each growing stage of maize were calculated based on the results of the two indices. Temporal variations of drought severity from 1975 to 2015 were evaluated and trends were analyzed using the non-parametric Spearman’s Rank Correlation test at α (0.05) significance level. For assessing climate change impact on droughts, SPEI and WRSI were computed using an output from downscaled projections of CSIRO Mark3.5 under the SRES A2 emission scenario for the period 1980/81 – 2099/100. The frequency of drought was calculated and the difference of SPEI and WRSI means between future climate periods and the base period were assessed using the independent t-test at α (0.10) significance level in STATISTICA software.
The study revealed that planting a 120-day maturing maize crop in December would pose a high risk of frequent severe-extreme droughts during the flowering to the grain-filling stage at Levubu, Lwamondo, Thohoyandou, and Tshiombo; while planting in October could place crops at a lower risk of reduced yield and even total crop failure. In contrast, stations located in the low-lying plains of the catchment (Punda Maria, Sigonde, and Pafuri) were exposed to frequent moderate droughts following planting in October, with favorable conditions noted following the December planting date. Further analysis on the performance of the crop under various drought conditions revealed that WRSI values corresponding to more intense drought conditions were detected during the December planting date for all stations. Moreover, at Punda Maria, Sigonde and Pafuri, it was observed that extreme drought (WRSI <50) occurred once in five seasons, regardless of the planting date.
Temporal analysis on historical droughts in the area indicated that there had been eight agricultural seasons subjected to extreme widespread droughts resulting in total crop failure i.e. 1983/84, 1988/89, 1991/92, 1993/94, 2001/02, 2002/03, 2004/05 and 2014/15. Results of Spearman’s rank correlation test revealed weak increasing drought trends at Thohoyandou (ρ = of 0.5 for WRSI) and at Levubu and Lwamondo (ρ = of 0.4 for SPEI), with no significant trends at the other stations. The study further revealed that climate change would enhance the severity of drought across the catchment. This was statistically significant (at 10% significance level) for the near-future and intermediate-future climates, relative to the base period.
Drought remains a threat to rain-fed maize production in the Luvuvhu River catchment area of South Africa. In order to mitigate the possible effects of droughts under climate change, optimal planting dates were recommended for each region. The use of seasonal forecasts during drought seasons would also be useful for local rain-fed maize growers especially in regions where moisture is available for a short period during the growing season. It was further recommended that the Government ensure proper support such as effective early warning systems and inputs to the farmers. Moreover, essential communication between scientists, decision makers, and the farmers can help in planning and decision making ahead of and during the occurrence of droughts. / Agriculture, Animal Health and Human Ecology / M. Sc. (Agriculture)
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