Thesis (Ed.D.)--Teachers College, Columbia University, 1995. / Typescript; issued also on microfilm. Sponsor: Warren E. Yasso. Dissertation Committee: O. Roger Anderson. Includes bibliographical references (leaves 95-109).

The attribution of recent global warming to anthropogenic emissions is now well established. However, the relation of recent changes in other properties of the climate system to human activities is not as clearly understood. The aim of this thesis is to improve our understanding of this relation in the case of two of these properties, namely the diurnal temperature range (DTR) and modes of tropospheric variability. The DTR, the difference between daily maximum and minimum temperatures, has decreased over global land areas at a rate comparable to the mean warming. Model simulations including the effects of human emissions produce a comparable change, albeit of smaller magnitude. This decrease results from increased reflection of solar radiation by clouds moderated by decreasing soil moisture, mostly through its effect on the ground heat capacity. Recent trends in indices of some modes of atmospheric variability suggest the possibility that forced climate change may manifest itself through a projection onto these pre-existing modes. Model simulations indicate that this is plausible in the case of sea level pressure, but only partly so in the case of surface air temperature. On the interannual time scale examined in this thesis, these projections are consistent with a linear interpretation, rather than a nonlinear one. These results are, however, sensitive to the representation of small scale processes in the models. For instance, the DTR response depends strongly on the representation of cloud and land surface processes. Further examination of the response of one of the tropospheric modes, namely the Southern Annular Mode which represents the meridional shift of the mid latitude jet in the Southern Hemisphere, indicates that it is sensitive to the parametrisation of sub-grid scale mixing in the ocean. Nevertheless, these results suggest that the recent changes are consistent with enhanced greenhouse warming, and indicate that they are likely to continue into the foreseeable future. / Graduate

The Community Earth System Model (CESM) is a coupling of five different models which are combined to simulate the dynamic interactions between and within the Earth's atmosphere, ocean, land, land-ice, and sea-ice. In this work, the installation and testing of CESM on Portland State University's Cluster for Climate Change and Aerosol Research (CsAR) is described and documented, and two research applications of the model are performed. First, the improved treatment of cloud microphysics within recent versions of CESM's atmospheric module is applied to an examination of changes in shortwave cloud forcing (SWCF) and results are compared to output from older versions of the model. Second, the CESM model is applied to an examination of the effect that increased methane (CH4) concentrations have had on the catalytic destruction of stratospheric ozone (O3) by ozone depleting compounds (ODCs) such as chlorofluorocarbons (CFCs) and nitrous oxide (N2O).

This study focuses on two main broad areas of active research on climate: climate variability and climate change and their implications on regional precipitation characteristics. All the analysis is carried out for a climate change-sensitive region, the state of Florida, USA. The focus of the climate variability analysis is to evaluate the influence of individual and coupled phases (cool and warm) of Atlantic multidecadal oscillation (AMO) and El Niäno southern oscillation (ENSO) on regional precipitation characteristics. The two oscillations in cool and warm phases modulate each other which have implications on flood control and water supply in the region. Extreme precipitation indices, temporal distribution of rainfall within extreme storm events, dry and wet spell transitions and antecedent conditions preceding extremes are evaluated. Kernel density estimates using Gaussian kernel for distribution-free comparative analysis and bootstrap sampling-based confidence intervals are used to compare warm and cool phases of different lengths. Depth-duration-frequency (DDF) curves are also developed using generalized extreme value (GEV) distributions characterizing the extremes. ... This study also introduces new approaches to optimally select the predictor variables which help in modeling regional precipitation and further provides a mechanism to select an optimum spatial resolution to downscale the precipitation projections. New methods for correcting the biases in monthly downscaled precipitation projections are proposed, developed and evaluated in this study. The methods include bias corrections in an optimization framework using various objective functions, hybrid methods based on universal function approximation and new variants. / by Aneesh Goly. / Thesis (Ph.D.)--Florida Atlantic University, 2013. / Includes bibliography. / Mode of access: World Wide Web. / System requirements: Adobe Reader.

In this work over 200 temperature proxy data sets have been analyzed to determine if periodic and or quasi-periodic patterns exist in the data sets. References to the journal articles where data are recorded are provided. Chapter 1 serves an introduction to the problem of temperature determination in providing information on how various proxy data sources are derived. Examples are given of the techniques followed in producing proxy data that predict temperature for each method used. In chapter 2 temperature proxy data spanning the last 4000 years, from 2,000 BCE to 2,000 CE, are analyzed to determine if overarching patterns exist in proxy data sets. An average of over 100 proxy data sets was used to produce Figure 4. An overview of the data shows that several “peaks” can be identified. The data were then subjected to analysis using a series of frequency modulated cosine waves. This analysis led to a function that can be expressed by equation 3. The literature was examined to determine what mathematical models had been published to fit the experimental proxy data for temperature. A number of attempts have been made to fit data from limited data sets with some degree of success. Some other papers have used a sinusoidal function to best fit the changes in the temperature. After consideration of many published papers and reviewing long time streams of proxy data that appeared to have sine wave patterns, a new model was proposed for trial. As the patterns observed showed “almost” repeating sine cycles, a frequency modulated sine wave was chosen to obtain a best fit function. Although other papers have used a sinusoidal function to best fit the changes in the temperature, the “best fit” was limited. Thus, it was decided that a frequency modulated sine wave may be a better model that would provide a more precise fit. This proved to be the case and the more than 240 temperature proxy data sets were analyzed using Equation 3. In chapter 3 the time span for the proxy data was extended to cover the period of time 12,000 BCE to 2000 CE. The data were then tested by using the equation above to search for periodic/quasi-periodic patterns. These results are summarized under select conditions of time periods. In chapter 4 the interval of time is extended over 1,000,000 years of time to test for long period “periodic” changes in global temperature. These results are provided for overall analysis. The function f(x) as described above was used to test for periodic/quasi-periodic changes in the data. Chapter 5 provides an analysis of temperature proxy data for an interval of time of 3,000,000 years to establish how global temperature has varied during the last three million years. Some long-term quasi-periodic patterns are identified. Chapter 6 provides a summation of the model proposed for global temperature that can be expected if similar trends continue over future years as have prevailed for the past few million years. Data sets that were used in this work are tabulated in the appendices of this paper.

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.

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