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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.
1

Assessing the effects of urban development and climate change on flooding in the Greater Port-Harcourt watershed, Niger Delta, Nigeria

Dan-Jumbo, Nimi Gibson January 2018 (has links)
Developing countries have been rapidly urbanising over the last decades, resulting in major environmental pressures and increased vulnerability to natural disasters. A complex combination of factors, including climate change, land use change, poorly implemented regulation and a lack of integrated planning has often resulted in environmental degradation and disproportionate impacts of natural disasters affecting millions worldwide, particularly in tropical cities. The main aim of this study is to understand the effects of land-use and climate change on flooding in the Greater Port-Harcourt watershed. The specific research objectives were: to understand the historical and future land use /land cover changes; to understand the magnitude of change in hydrologic and hydraulic conditions due to land-use and climate changes; to assess the influence of different forest mitigation scenarios on peak-discharge; and to make recommendations on how to improve future planning using insights from this study. Methodologically, the post-classification change detection method was applied to examine the extent and nature of historical LULC changes using remotely sensed data. Future LULC changes were estimated by superimposing the 2060 digitised Masterplan map on the year 2003 baseline imagery. Hydrologic changes were assessed using HEC-HMS model, while changes in the hydraulic condition were assessed using HEC-RAS model. Model output was further used to map flood hazards, flood zones and damage potential. Priority areas and infrastructure at risk were identified by means of their location in flood zones and exposure to floods with high damage potential. On the extent of change, this study revealed that urbanisation and loss of agricultural land had been the dominant and intensive land use change in the watershed. Urbanisation is projected to almost double its 2003 extent by 2060 and is likely to remain the dominant force of land use change. On the nature of change, this study found that urban land was the most dynamic in terms of gross gain and net change. It exhibited the grossest gain (about 9% of the watershed) and the grossest loss leading to a high net change of about 8.6%. In fact, the most prominent transition was the conversion of agricultural land (about 422km2) to urban land, and roughly 93.3% of all conversions to urban land resulted from agricultural land. On the process of change, urban land mainly experienced a net-type of change (change in quantity), whereas changes in agricultural land was more of a swap-type of change (change in location). Importantly, the study reveals that the impact on flood flow was historically significant (about 68%) and is projected to amplify in future, however, these changes are largely attributed to increased storm size. Urbanisation is likely to have little or no impact on annual maximum peak flow at the watershed scale; however, urbanisation is projected to have a considerable impact on peak flow in a number of subbasins, which could have severe implications for flash flooding in those subbasins. Similarly, afforestation could have little or no impact on future maximum peak flow when assessed at the watershed scale. Although some subbasins experienced changes in peak flow, the effect of forest is variable. The study concludes that although the impact of urbanisation is projected to be insignificant at the watershed scale, it could also increase flood risk due to increasing developments in floodplains and channel encroachment. Priority infrastructure and areas requiring urgent flood risk management include the Port-Harcourt seaports, Onne seaport, the University of Science and Technology and cement factory. Priority areas in the Masterplan are mainly in the south (Phase 3), comprising of the Air force base and the residential area near Onne seaport. Lastly, approximately 8.1km and 189m of road and rail network are at greater risk of flooding by means of their exposure to floods with the highest damage potential. Based on this study, I have furthered understanding by showing that the transition to urban land category was dominated by net changes (i.e. changes in quantity). I have also furthered understanding by showing that substantial changes in future urban land-use may not have significant effect on flood parameters. My main contribution to knowledge is that despite the high rate of urbanisation in the GPH watershed and its minimal impact on flooding (which could be due the large size of the storm and watershed), urbanisation could still increase flood risk due to greater exposure of elements at risk in the flood plains to damaging floods. Based on the results, the study recommends that the development authorities should integrate both structural measures (mainly for flood defence around existing developments) and non-structural measures (primarily for future developments). For flood risk management research, this study recommends that conclusions about the effects of urbanisation should not be made solely on the basis of changes in hydrology and river hydraulics, however researchers should also consider the exposure of important elements at risk within the floodplains under study to better understand the effects of urbanisation. Moreover, to better understand urbanisation effects on runoff dynamics in other watersheds, this study recommends that research efforts should be concerted in understanding subbasin-scale changes given that the effects of urbanisation are more pronounced in smaller basins.
2

Vulnerability of biodiversity to land use change and climate change in Mexico

Mendoza Ponce, Alma Virgen January 2016 (has links)
Biodiversity in Mexico is threatened by Land Use/Cover Change (LUCC) and Climate Change (CC). Identifying what sites will be most vulnerable to these threats can help to prioritise conservation, mitigation and adaptation strategies and target limited resources. Therefore, the aims of this study are 1) to identify the most vulnerable sites to LUCCs under different socio-economic and CC scenarios, and 2) to assess the vulnerability of endemic and threatened vertebrate species to establish prioritization strategies for biodiversity conservation. Spatially explicit socio-economic scenarios were created at national and subnational level (Chapter 3). National LUCC models were then developed using the DINAMICA EGO software (Chapter 4). These models were run for three future time slices (2020s, 2050s and 2080s) and two contrasting future climate and socio-economic scenarios to determine biodiversity vulnerability (Chapter 5). Vulnerability was estimated by quantifying the exposure, sensitivity and adaptive capacity to LUCC and CC. This framework integrates national information about the priority sites of biodiversity conservation and their future extent of natural covers under future socio-economic and climate conditions. Finally, the vulnerability framework was also applied in a regional case-study in three municipalities of southern Mexico (Chapter 6). Results reveal that temperate forest is the most vulnerable ecosystem type in Mexico, followed by natural grasslands and tropical evergreen forests. Agriculture is the driver of this threat, which is projected to expand to feed an increasing population under dryer climatic conditions. More than 40% of endemic and endangered mammals are in places ranking from medium to extremely high vulnerability, followed by the 28% of the amphibians, 25% and 23% for reptiles and birds, respectively. These vertebrates are principally distributed on temperate forests and tropical dry forests. In the regional scale, rain-fed agriculture (RfA) and anthropogenic grasslands are the principal LUCC drivers, threatening 31 species of endangered vertebrates. A local strategy for creating corridors between patches close to rivers from the south to the north of one municipality is supported as conservation priority for the regional biodiversity. This research presents a novel approach for prioritising conservation strategies in highly biodiverse countries using readily available data sources, demonstrated at different spatial and temporal scales.
3

Det gröna gapet : Kommunikation för hållbar förändring / The green gap : Communication for sustainable change

Tsakova, Krasimira January 2022 (has links)
Today a great focus is placed on consumer’s choices and how those affect climate change and global warming. At the same time, messages about the climate crisis and mass extinction are circulating in the public. A lot of the responsibility for making better and more educated choices in order to reverse climate change is being placed on the individual and their actions. This can trigger a sense of helplessness or even increase psychological resistance. In climate- and sustainability communication there is often the assumption that people lack knowledge and are therefore unable to change their attitudes or behaviours. Many people arethough aware of climate change and the ways it affects our lives and future. There is however a gap between our green intentions and our current actions– the so-called, green gap. Climate- and sustainability communication are limited in how much they can achieve on their own. Political action and engagement is therefore a crucial part of communicating climate change and influencing the public’s knowledge, attitude and perception.
4

Climate change adaptation and tourism in the Mexican Caribbean

Matus Kramer, Arnoldo January 2011 (has links)
The Mexican Caribbean tourism sector is highly exposed to hurricane activity, yet coastal tourism is also a major driver influencing regional biophysical and social vulnerability to climate risks. Drawing on a political ecology approach and a vulnerability assessment, this study asks how experiences with extreme hurricane events in the Mexican Caribbean shape climate change adaptation in the regional tourism sector. This study uses multiple methods, scales and field sites to (a) examine how biophysical vulnerability to extreme hurricanes affects the tourism sector, (b) explain the changing conditions of social vulnerability linked to hurricane damage in the tourism sector and (c) assess the present and future opportunities and obstacles for adaptation planning. The main findings show that the region is experiencing a phase of unprecedented high intensity hurricanes. It is uncertain, however, whether changes in hurricane activity exceed natural multi-decadal variability. Tourism is one major driver of land use changes which have resulted in some of the world’s fastest increase in coastal urban sprawl. Most tourism infrastructure is located in areas with the greatest exposure to hurricanes. Hurricane Wilma which hit the region in 2005 is the most expensive natural disaster in the history of the Mexican insurance industry. Hotels have showed a high ability to recover operations after hurricanes. There is a high penetration of insurance ownership in hotels and there is substantial mobilization of public and private financial and human resources during hurricane disasters. Hotel responses to hurricanes, however, tend to be reactive and autonomous. One important consequence of hurricanes is that hoteliers in the interest to reduce operational costs, fire those workers with the weakest labour rights. Thus, hotel workers suffer from ‘double exposure’, a situation where hotel workers are confronted with the consequences of climate change while simultaneously suffering the consequences of globalization and neoliberal policies which have reduced the power of unions and weakened access to social security. The Mexican government has created a national climate change strategy and its operational programme which has led to the consolidation of an adaptation organizational structures at the national and state levels. I conclude, however, that adaptation planning may not result in the necessary actions on the ground since local actors are not well integrated yet into such efforts. This study shows the importance of regional adaptation research that takes into account perspectives from both the physical and social sciences. This study highlights the importance of interactions between local actors, the larger socioeconomic and political economy context to inform adaptation planning and policy.
5

Climate change communications : understanding people's perceptions and evaluating the effectiveness of interventions

White, Tom January 2011 (has links)
A government-funded scheme, the UK Climate Change Communications Initiative (UKCCCI), provided money for organisations to deliver projects that attempted to impact positively on people’s attitudes towards climate change and to increase knowledge and awareness of the issue. This devolution of communications is a relatively novel approach after previous centralised campaigns. This thesis adopts a mixed-method approach; a qualitative and a quantitative study have been conducted based on three case studies of individual projects funded under the UKCCCI. The quantitative study analyses pre- and post-project surveys to assess whether the communications produced the desired changes in attitude, knowledge and awareness; results are generally mixed in relation to all three case studies as some statistics are more positive after communications, whereas some are less positive. Data from a regional UKCCCI project are compared with a nationally representative dataset; this analysis shows that attitudes, knowledge and awareness differ at regional and national scales, supporting the policy of devolving communications. Regional data are also analysed to see if there are differences between socio-demographic groups within a single target audience for communications; this analysis suggests that interventions must strike a balance between personalisation of information and the higher cost of targeting smaller groups with more specific material. The quantitative study uses conceptual content cognitive mapping (3CM) to discover the climate change-related knowledge of twenty subjects who received communications from two of the case study projects. Results suggest that people have knowledge of a wide range of issues related to climate change, but they do not possess a detailed scientific understanding. However, there is a high knowledge of how to mitigate climate change and this is expressed largely through individual actions and lifestyle choices. A template analysis was also conducted to discover what interviewees thought specifically about the communications and a range of practical recommendations are made for future projects. Implications are discussed in relation to future practical climate change communications projects, wider policy and academic research.
6

Implications of global warming for African climate

James, Rachel Anne January 2014 (has links)
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.
7

East African rainfall : classification of rain producing systems : a modelling and observation study

Pearce, Helen Elizabeth January 2013 (has links)
The study of anthropogenic climate change is a research area of vital importance for the coming decades, with rainfall change and variability expected to be keenly felt in vulnerable regions of the world, including Africa. The focus of this study is daily rainfall during the short rains season over East Africa from October to December, which has one of the most coherent increasing rainfall projections in the Coupled Model Intercomparison Project (CMIP) dataset. This thesis aims to examine the fidelity of coupled climate models over an East African domain, with the question approached through focus on the daily (rather than monthly) rainfall field. The self-organising map is used as a clustering tool to establish contemporary characteristics of daily rainfall events in reanalysis (ERA-40) and satellite (TRMM) rainfall datasets between 1971-2000 and 1998-2010 respectively for the East African short rains. Moisture flux divergence is found to be the circulation parameter that is most closely related to the presence of rainfall events or dry conditions over East Africa. Coupled climate models are poor at replicating the daily rainfall field over the domain. A key result of the analysis is the consistent overestimation of daily rainfall by climate models for days where dry conditions of suppressed convection should prevail. In contrast, the moisture flux divergence field maps well to dry nodes for days of the self-organising map array for the models. Dry days are associated with widespread anomalous moisture flux divergence and rainfall events with co-located anomalous moisture flux convergence. This is in agreement with the moisture flux divergence field in the ERA-40 dataset; it is the rainfall field where there is disagreement for days of suppressed convection. Twenty to thirty-five percent of the projected rainfall increase towards the end of the twenty-first century results from an increase in the proportion of days assigned to nodes of suppressed convection in six of the seven models and the ensemble mean. There is an accompanying projected rainfall increase associated with days assigned to these nodes. Such days in the 2090s are characterised by projected increased strength moisture flux divergence over East Africa. Given that the moisture flux field was more successfully simulated in the coupled models under contemporary conditions than the daily rainfall field, this suggests that rainfall projections under a high emissions scenario at the end of the twenty-first century are overestimated and that an important part of the key increase in the projected rainfall may not be real.
8

Options for Managing Climate Risk and Climate Change Adaptation in Smallholder Farming Systems of the Limpopo Province, South Africa

Lekalakala, Ratunku Gabriel 11 May 2017 (has links)
No description available.
9

Hold the line or give in to the sea? : deliberative citizen engagement in governance to adapt to sea level rise on the shoreline

Liski, Anja Helena January 2018 (has links)
Shorelines, including the Inner Forth in Scotland, are facing unprecedented challenges with climate change. Rising sea levels mean that stakeholders need to work closely to deliver adaptation, such as the nature-based option of intentionally realigning shorelines landwards to give the sea more space. Drawing from workshops, interviews and surveys with citizens living on the shores of the Inner Forth, and semi-structured interviews with locally active organisations and land-owners, this thesis examines the governance context and methodological issues of citizen engagement in adaptation, with a focus on the use of participatory valuation tools. In particular, I develop citizen-oriented methodological options for integrated and deliberative valuation to address issues of inclusivity and knowledge gaps. The novelty of the deliberative valuation presented here is based on the explicit consideration of awareness gaps from both expert and local perspectives. The results show that even though emerging collaborative institutions are broadening the spectrum of stakeholders engaged in shoreline governance, they do not yet include representative groups of citizens. Empirical material presented here suggests that bridging the citizen engagement gap would potentially support the uptake of nature-based adaptation options, enhance legitimacy of decision-making processes, and bring other-regarding moral principles and biocentric values into decision-making. However, as the valuation results from the citizen workshops illustrate (in resonance with the central tenets of the Intergovernmental science-policy Platform on Biodiversity and Ecosystem Services), commonly applied valuation methods may be too narrow in their framing to capture plural values and world views. Furthermore, the ability of citizens to engage in adaptation is limited by knowledge gaps regarding the local area and the pressures it is facing. The deliberative citizen-oriented approach to valuation developed here led to the emergence of clearer priorities, improved choice model fit and participant confidence, providing empirical evidence to support the premise that deliberation builds citizens' ability to engage in adaptation. In addition to contributing empirical insights on how adaptation governance is unfolding on local scales, this thesis responds to methodological discussions on the use of valuation for citizen engagement in three main ways: 1) it demonstrates that the choice of value framings impacts the engagement outcomes; 2) it illustrates how deliberative valuation can shape citizens' attitudes towards the uptake of adaptation measures; 3) it provides evidence of the specific role that local knowledge plays in improving the outcomes of deliberative valuation.
10

From Paris to Sharm el-Sheikh: : A Framing Analysis of Climate Justice / Från Paris till Sharm el-Sheikh: : En Framinganalys av Klimaträttvisa

Bryntesson, Anton January 2023 (has links)
While UNFCCC negotiations generally have adopted a neoliberal version of the contestedconcept of climate justice in the last 30 years, the acceptance of the Loss and Damage Fundduring COP27 indicates a possible shift in the climate justice discourse. To examine possibleshifts in the portrayal of climate justice, statements delivered by state representatives fromfive coalitions during COP21 and COP27 have been analyzed using a qualitative framinganalysis. The coalitions represent both victims of climate change and the causers of it. Theanalysis has been based on a theoretical framework consisting of six different climate justiceframes: neoliberal, distributive, intergenerational, rights-based, transformative, and ecologicaljustice. During COP21, a clear division appeared between ‘victim coalitions’ who portrayedtheir own vulnerability and partly described the injustice of climate change, and the ‘causercoalitions’ who foremost used neoliberal framings of the issue. During COP27, the divisionwas less obvious. Rights-based framings increased in prominence, but fragmentation withinthe coalitions was observed. The controversy did no longer seem to revolve aroundportraying vulnerability. Rather the division was split between the critical states demanding atransformative shift in the global climate regime, and the uncritical ones. The study indicatesthat alternative justice norms continue to break new grounds in the UNFCCC framework, butthe specific implications on politics are yet to be seen.

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