The overarching theme of my thesis is understanding observed variations of northern hemisphere atmospheric carbon dioxide (CO2) and methane (CH4) concentrations. I focus my analysis on high-latitude observations of these gases, as there are large stores of carbon in boreal vegetation and tundra which are vulnerable to rapid warming in the Arctic. My thesis is split into two parts. First, I use the wavelet transform to spectrally decompose observed multi-decadal timeseries for CO2 and CH4. I perform a series of numerical experiments based on synthetic data in order to characterise the errors associated with the analysis. For CO2, I analyse the phase and amplitude of the detrended seasonal cycle of CO2 to infer changes about carbon uptake by northern vegetation. I do not find a long-term change in the length of the carbon uptake period despite significant changes in the spring and autumn phase. I do find an increase in the rate of peak uptake which coincides with the observed increase in seasonal amplitude. These results suggest that the carbon uptake period of boreal vegetation has become more intense but has not changed in length, which provides evidence for an increase in net uptake of CO2 in the high latitudes. For CH4, I test the hypothesis that an increase in Arctic wetland emissions could result in a decrease in the seasonal amplitude of CH4 in the high latitudes. This hypothesis is based on the fact that the seasonal minima of CH4 roughly coincides with the peak of high latitude wetland CH4 emissions. I find that the CH4 seasonal amplitude has significantly decreased at a number of high-latitude sites. However I also find that atmospheric transport appears to drive much of the variability in high-latitude CH4 and that transport could also be responsible for the observed changes in amplitude. I show that an increase in wetland emissions is likely to have a more pronounced effect on the high-latitude CH4 seasonal cycle in the future. In the second section of my thesis, I describe a series of experiments in collaboration with the UK Astronomy Technology Centre, in which I characterise a new instrument technology for satellite applications to observe changes in CO2 from low-Earth orbit. The proof of concepts experiments were performed with a bench top hyperspectral imager. I show that the instrument is able to capture clean spectra at the wavelengths required for CO2 with low levels of scattered light between spectra.

The North-South divide is one of the central political characteristics of the UN climate change negotiations. But while the Group of 77 coalition has been the main negotiating group for the South, developing countries have often faced challenges to their unity, magnified by the recent establishment of smaller negotiating groups. How has 'the South' hung together? This thesis investigates how developing countries have formed negotiating groups over the two decades of the UN climate negotiating process. It explains the origins of the different negotiating groups that have formed over this time, as well as the timing of their emergence and the scope of their membership. In particular, while scholarly attention has focused on the G77, Alliance of Small Island States (AOSIS) and most recently the Brazil-South Africa- India-China (BASIC) coalition, this thesis corrects the relative neglect in understanding the many other negotiating groups that have formed. While conventional explanations highlights the shared material interests that underpin group formation, this thesis advances a constructivist argument that emphasises instead the importance of collective identities in shaping norms of 'appropriate association' – the social bases of whose one's friends and allies are. It highlights the regional basis for many of these negotiating groups that cut across shared material circumstances, and draws upon historical institutionalist insights on critical junctures and path dependence to place this larger pattern of Southern coalition formation in the appropriate historical and institutional context of the UN system. It demonstrates the continuing persistence of countries identifying as the 'South', where despite changing material circumstances and disagreements among developing countries, the salience of the G77 as the constitutive institution of this identity remains. Above all, in investigating the processes of coalition formation among developing countries in the climate context, this thesis deepens scholarly understanding about the contemporary meaning of the 'South'.

The most recent Intergovernmental Panel on Climate Change assessment report concludes that the Atlantic Meridional Overturning Circulation (AMOC) could weaken substantially but is very unlikely to collapse in the 21st century. However, the assessment largely neglected Greenland Ice Sheet (GrIS) mass loss, lacked a comprehensive uncertainty analysis, and was limited to the 21st century. Here in a community effort, improved estimates of GrIS mass loss are included in multicentennial projections using eight state-of-the-science climate models, and an AMOC emulator is used to provide a probabilistic uncertainty assessment. We find that GrIS melting affects AMOC projections, even though it is of secondary importance. By years 2090-2100, the AMOC weakens by 18% [-3%, -34%; 90% probability] in an intermediate greenhouse-gas mitigation scenario and by 37% [-15%, -65%] under continued high emissions. Afterward, it stabilizes in the former but continues to decline in the latter to -74% [+4%, -100%] by 2290-2300, with a 44% likelihood of an AMOC collapse. This result suggests that an AMOC collapse can be avoided by CO2 mitigation.

This thesis examines the observed and anticipated impacts of climate change on energy security. Specifically, by incorporating emergent international legal obligations and regulations governing climate change, this thesis proposes a definitional and policy framework for energy security that can assist in making Nigeria’s energy supply more secure. This, in turn, can serve to improve Nigeria’s capacity to meet current and future climate change obligations. While the principal objective of this thesis is to explore how global climate change risk regulation provides opportunities for the state to improve energy security in Nigeria, this thesis emphasizes that Nigerian law should aim to create a balance between the dual objectives of energy security and climate change responses. Using the theory of legal transplantation, further insights for integrating climate and energy security goals to develop the definitional and policy framework of energy security in Nigeria are gained through an examination of bold initiatives taken by Germany. / October 2016

The most critical hazards impacting the world today are the affects of climate change and global warming. Scientists have been studying the Earth's climate for centuries and have come to agreement that our climate is changing, and has changed, many times abruptly over the history of our planet. This research focuses on the impacts of global warming related to increased hurricane intensities and their surge responses along the coast of the State of Louisiana. Surge responses are quantified for storms that could potentially occur under present climate but 50 years into the future on a coast subjected to current erosion and local subsidence effects. Analyses of projected hurricane intensities influenced by an increase in sea surface temperatures (SSTs) are performed. Intensities of these storms are projected to increase by 5% per degree of increase in SSTs. A small suite of these storms influenced by global warming and potentially realized by abrupt climate changes are modeled. Simulations of these storms are executed using a storm surge model. The surges produced by these storms are significantly higher than surges produced by presentday storms. These surges are then compared to existing surge frequency distributions along the Louisiana coast.

<p> Understanding how to balance human well-being and ecological integrity is one of the fundamental challenges in conservation and natural resource management. As our human-footprint on ecosystems expands and deepens, we are increasingly realizing that human well-being is crucial to understanding social-ecological systems and managing them sustainably.</p><p> In my first chapter I add to this literature by extending a theoretical model to examine the effects of two biophysical stressors on a marine species. While this model was developed to understand how harvest and climate change may interact to affect species viability, the model instead emphasized the sensitivity of the results to assumptions about human behavior. This result adds to a small, but growing, body of literature that demonstrates the importance of considering resource-users&rsquo; dynamics when attempting to predict outcomes for biophysical systems.</p><p> Despite conceptual advances in linking human-wellbeing to biophysical dynamics, a major challenge exists in operationalizing these conceptual framings. In my second chapter I use the US West Coast commercial fisheries system as a case study and developed a novel network approach of linking the social system (i.e. fishing communities) to the ecological system (the fish). This approach made use of data collected by management, making it immediately operational for all managed fisheries in the US. Such a conceptual framework represents a major step forward for mapping and quantifying these linkages between social and natural systems. I add to this work by analyzing these resultant networks to show that the topological structure and modularity varied non-randomly, providing additional features that may be useful for mangers seeking to balance human well-being with sustainable populations of fish.</p><p> In my third chapter I analyzed patterns of participation across the US West Coast commercial fisheries before and after a major management change in a single fishery. Using individual- and fishing community-level analyses, using the framework described above, I show that the policy affected how fishermen shift their effort across fisheries at the individual level, but community level attributes remain unchanged. This work demonstrates how such social-ecological system level policy analysis may be conducted.</p><p> Overall this dissertation helps move us towards a set of tools managers can use to evaluate policy efficacy in commercial fisheries in the face of rapid environmental change while balancing ecological integrity and human well-being.</p>

Despite the lack of robust empirical evidence, a growing number of media reports attempt to link climate change to the ongoing violent conflicts in Syria and other parts of the world, as well as to the migration crisis in Europe. Exploiting bilateral data on asylum seeking applications for 157 countries over the period 2006-2015, we assess the determinants of refugee flows using a gravity model which accounts for endogenous selection in order to examine the causal link between climate, conflict and forced migration. Our results indicate that climatic conditions, by affecting drought severity and the likelihood of armed conflict, played a significant role as an explanatory factor for asylum seeking in the period 2011-2015. The effect of climate on conflict occurrence is particularly relevant for countries in Western Asia in the period 2010-2012 during when many countries were undergoing political transformation. This finding suggests that the impact of climate on conflict and asylum seeking flows is limited to specific time period and contexts. / Series: Department of Economics Working Paper Series

Magister Scientiae (Biodiversity and Conservation Biology) - MSc (Biodiv and Cons Biol) / Small ruminants found in pastoral dryland systems face many challenges regarding constant environmental and climate changes. These variable environments are home to many pastoralists who use the natural resources to sustain their livestock. Due to the prevailing environmental changes, these pastoralists require various adaptation strategies for the survival of their small ruminants. Adaptation is vital for all pastoralists globally, especially those living in semi-arid to arid regions as these areas are badly impacted by climate change. Farming with small ruminants that are able to constantly adapt to variable environments are a long-term and low cost resource strategy for farmers in these areas. Drought is a recurring challenge that farmers in dryland systems have to cope with and small ruminants are forced to adapt to food and water available to them as drought affects their survival, reproduction and production. This is because drought affects the environment directly as rainfall has an impact on all forage and water resources found in drylands. Thus available forage and the utilisation of this resource by small ruminants is essential for sheep and goat farmers who depend on these animals for their livelihoods. This thesis sets out to establish sheep and goat breeds found in a dryland pastoral system in South Africa focussing on their genetic differences and their diet selection during a drought period. The study was carried out in the 582 634 ha Steinkopf communal area located in the semi-arid to arid region of Namaqualand in South Africa. The dominant land use in this area is livestock farming where farmers utilise two biomes for grazing. Using mitochondrial DNA, genetic differences were investigated in small ruminants found in Steinkopf. The small ruminants that were studied were the Boer goats, Swakara sheep (Karakul) and cross-bred sheep. These were the most commonly farmed small ruminants in this area. Genetic differences and diversity found within the small ruminants in this area supports their ability to adapt to drought and changing environments. Diet selection of these small ruminants were assessed using direct forage observation during this drought period in both the Succulent and Nama Karoo biomes. Findings of the study indicate that small ruminants during a drought period will largely forage on what is available to them. Boer goats changed their diets from browser to grazers in the different biomes while sheep remained grazers in both biomes. This suggests that these animals are well adapted to changing forage availability and will adjust their feeding behaviours accordingly. Succulent plant species were utilised by all small ruminants and this can be regarded as new knowledge for small ruminants in dryland systems. Succulent species play a role in the diets of small ruminants in the Steinkopf rangeland and these animals have adapted traits that allow them to eat plants that contain high levels of phenolics and tannins, which show their high adaptability to this area. This study also revealed that indigenous and locally bred sheep in this area are crucial resources for livestock farming in this area. Swakara sheep in this area showed a low level of genetic variation while cross-bred sheep and the Boer goat had significant variation. With a long tradition of breeding small ruminants in the Steinkopf communal area that suit changing conditions, livestock keepers have accumulated detailed knowledge of their animals. Recommendations from this study were to do further studies regarding genetic variation within the cross-bred sheep as this information will be useful for breeding programs in dryland areas and it will add to the small ruminant genetics in South Africa. Because this study was conducted in a drought period, I recommend that diet selection should be observed during a regular wet and dry period as this would indicate how these animals adapt to what forage is available to them. These studies can act as management strategies for herders as it can provide information on how to use the natural resources sustainably.

The snow leopard lives in the high mountains of Asia. Threats currently facing the species are being poached for its high-valued fur and being killed by herders in retaliation for livestock predation. However, climate change also has an impact on the snow leopard’s mountain habitats as tree line height and the average temperature have increased in Asian mountains. This thesis analyzes the near-future threats from climatic changes against snow leopards and what impact human activities have on the species. Fragmentation of habitats have a huge effect on the survival of snow leopards because the connectivity routes may be reduced or lost. The general process of assessment by the IUCN was examined alongside the assessment of the snow leopard. Both anthropogenic activities and global warming lead to fragmented habitats and may isolate snow leopard populations from each other. An estimated 30 - 65 % of the snow leopard’s habitats may disappear in future scenarios. Climate change is not a threat by itself but creates new threats. Therefore, climate change needs to be taken into consideration in future assessments by IUCN due to its growing impact. The recently released IPBES report makes it apparent what destructive force human activities have on biodiversity.

Thesis advisor: Kenneth R. Himes / This project constructs a public theology of Laudato Si' with which Catholics in the United States might shape climate change discourse, policy, and action. Chapter 1 outlines anthropogenic climate change and reviews magisterial Catholic teaching about this issue. Chapter 2 argues that the Christian church should engage with the world through both secular and faith-based language in the forms of public philosophy and public theology. Chapter 3 considers Catholic public theology in the contemporary U.S. Chapter 4 considers LS as a document of public theology and demonstrates how this document both develops Catholic public theology in the social encyclical tradition and is organized according to a modified Pastoral Circle. Chapter 5 analyzes a nationally representative public opinion survey of American adults to discern the likelihood that messages based on LS might move Americans’ climate change opinions more in line with Pope Francis’s ecological vision. Chapter 6 combines these insights with the reflections in Chapter 3 to construct an American Catholic public theology of LS that might help accordingly shape American climate change discourse, policy and action. The project thus combines theological ethics and social science to engage in applied ecological theological ethics and constructively suggest the contents of an evidence-based American Catholic public theology of LS with which the church might advance Pope Francis’s ecological vision. / Thesis (PhD) — Boston College, 2017. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Theology.