Dissertations / Theses on the topic 'Evolutionary impacts of climate change'

Located at the interface between uplands and surface water networks, headwater wetlands act as a natural filter to improve downstream water quality and play a critical role in maintaining the ecological integrity of downstream aquatic ecosystems. Vulnerable to development pressure, as well as indirect impacts from land use and climate change, the loss and alteration of headwater wetlands has been linked to the loss of biodiversity and regional water quality declines worldwide. The overall goal of this dissertation is to address some of the challenges associated with the management and conservation of headwater wetlands in the coastal plain of Virginia including: the identification of palustrine forested wetlands in flat coastal landscapes (Chapter II); and improved understanding of the impacts of land use (Chapter III) and climate change (Chapter IV) on the hydrologic regime of headwater wetlands. First, a simple model of wetland distribution was developed by characterizing the depth to groundwater using widely available geospatial data, including surface water features and a high-resolution digital elevation model. Comparison with the National Wetland Inventory (NWI) and targeted field validation indicated that this model provides an effective approach to identify palustrine forested wetlands often unmapped by NWI. Results from this study indicate that there may be at least 37% more wetland area than is currently mapped within the study area; and that in the future, modeling approaches should be used in addition to NWI mapping to better understand the full extent and distribution of wetlands in forested areas. The impacts of land use and climate change were then investigated through field studies of headwater wetland hydrology and community composition. Potential differences in headwater wetland hydrology were evaluated through an index of hydrophytic vegetation occurrence, the wetland prevalence index (PI). Changes in PI between sapling and canopy strata, with respect to local land use, indicated that decreased forest cover was associated with a shift in plant community composition, and that increasing road density was associated with a shift towards more upland type species, while increasing agricultural cover was associated with a shift towards more wetland type species. The effects of climate change, including rising temperatures and altered precipitation patterns were evaluated by developing an empirical model of water table depth for coastal headwater wetlands. Wetland water levels were simulated under current and potential future conditions to evaluate the impact of climate change on the hydrologic regime of headwater wetlands. Based on the model scenarios applied in this study, it appears that decreasing water availability may lead to drier conditions at headwater wetlands by the end of the 21st century, with a substantial decline in minimum water levels and a 3-10% decline in average annual percent saturation. Collectively, the results of this dissertation provide practical insights for improving the conservation and management of coastal headwater wetlands. Improved understanding of the extent and distribution of previously unmapped forested wetlands can improve the capacity to monitor wetland loss and degradation. Additionally, clarifying the influence of land use and climate on the hydrologic regime of these wetlands, can help improve the capacity to forecast and then mitigate potential future impacts to wetland hydrology.

Climate policy has been mainly studied with economic models that assume representative, rational agents. However, it aims at changing behavior associated with carbon-intensive goods that are often subject to bounded rationality and social preferences, such as status and imitation. Here we use a macroeconomic multi-agent model with such features to test the effect of various policies on both environmental and economic performance. The model is particularly suitable to address distributional impacts of climate policies, not only because populations of many agents are included, but also as these are composed of different classes of households driven by specific motivations. We simulate various policy scenarios, combining in different ways a carbon tax, a reduction of labor taxes, subsidies for green innovation, a price subsidy to consumers for less carbon-intensive products, and green government procurement. The results show pronounced differences with those obtained by rational-agent model studies. It turns out that demand-oriented subsidies lead to lower unemployment and higher output, but perform less well in terms of carbon emissions. The supply-oriented subsidy for green innovation results in a significant reduction of carbon emissions with a slight reduction of unemployment.
Series: WWWforEurope

How and why species’ ranges shift has long been a focus of ecology but is now becoming increasingly important given the current rate of climatic and environmental change. In response to global warming, species will need to migrate northward or upward to stay within their climatic tolerances. The ability of species to migrate will determine their fate and affect the community compositions of the future. However, to more accurately predict the future extent of species, we must identify and understand their responses to past and current climatic and environmental changes. The first place change is expected to occur is within ecotones where the ranges of many species converge and individuals exist at the limits of their environmental tolerances. In montane regions, these boundaries are compressed, creating a situation in which even relatively small changes in conditions can lead to shifts in the elevational ranges of species. In this dissertation, I examine the responses of forests in the Green Mountains of Vermont to recent climatic and environmental change in an attempt to understand how future climate change will affect their location and composition. I focus on the Boreal-Deciduous Ecotone (BDE), where the high elevation spruce-fir forests converge with the lower elevation northern hardwoods. In addition to investigating adult trees within the BDE, I also examine the responses of understory herbs and tree seedlings to changes in environmental and climatic factors. Factors considered in these investigations include temperature, soil environment, light environment, invasive species, competition, disturbance and many others. I will examine the complex range of responses in forest species that results from prolonged exposure to these forces alone and in combination. I have attempted to identify the responses of forest species to environmental changes by resurveying historic vegetation plots (Chapter 2), experimentally manipulating the growing environment of tree seedlings (Chapter 3) and performing dendrochronological analyses on tree rings (Chapter 4). Through my resurvey of historic vegetation plots, I determined the degree to which understory species have shifted as individuals or as groups. I also identified a set of novel understory communities that have developed since the 1960's in response to recent climate change, acid deposition and invasive species (Chapter 2). By transplanting and artificially warming tree seedlings, I identified factors responsible for limiting the growth and survival of northern hardwood species above the BDE. Temperature was the primary factor limiting sugar maple (Acer saccharum) at high elevations, while yellow birch (Betula alleghaniensis) was limited almost exclusively by light (Chapter 3). Dendrochronological studies of sugar maples indicated that prolonged exposure to acidified soils has only recently caused growth declines and has altered their relationship to climate (Chapter 4). Together, these studies have produced a cohesive picture of how northeastern montane forests have responded to recent climate change and other anthropogenic impacts. These findings can be used to help predict future species' ranges and identify species that may not be capable of migrating fast enough on their own to keep pace with changes in climatic conditions.

Macroalgae play an important role in coastal reef systems and are often referred to as ecosystem engineers. They serve as primary producers, supporting a diverse range of organisms, and are a sink for atmospheric CO2. Water acidification and ocean warming caused by anthropogenic activities are affecting many marine flora and fauna, potentially impacting the physical and chemical performance of macroalgae and the consumption rates of associated herbivores. Many studies have focused on ocean acidification or ocean warming individually but there is an overall lack of research investigating the combined effects and the ensuing repercussions on consumer-prey relationships. Three species of ecologically important macroalgae (Ecklonia radiata, Sargassum linearifolium and Laurencia brongniartii) were subjected to elevated temperature and increased pCO2 conditions and observed for alterations in algae physiology and chemical production, in terms of growth, toughness, bleaching, density, blade mass, quantum efficiency yields, carbon: nitrogen (C:N) ratios and phenolic content. A series of feeding assays were conducted with two abundant marine herbivores, an amphipod (Allorchestes compressa) and a gastropod (Family Trochidae), to examine the indirect impact of climatic stressors on the palatability of the algae. The overall impact of climate change on macroalgae was species-specific, with each algal species having distinct physical and chemical responses to the changes in environmental conditions. S. linearifolium functioned poorly at high temperatures, exhibiting high levels of bleaching, lower quantum efficiency yields and, when ground, was less palatable to Trochidae. Overall, E. radiata was less affected by the projected climate change conditions, with only the C:N ratios being impacted in the combined increased temperature and increased pCO2 treatment. The palatability of E. radiata was also altered with the gastropod consuming a greater amount of the ground algae exposed to the combined temperature and pCO2 conditions. Finally, L. brongniartii was impacted in all the performance tests measured across all treatments, showing increases in levels of bleaching, density, and C:N ratios and decreases in growth, quantum efficiency yields, blade toughness and total phenolics. Uniquely, this study shows the vulnerability of understory red algal species, such as L. brongniartii to changes in climatic conditions. Surprisingly, these alterations in algal performance for L. brongniartii did not change the consumption rates of either herbivore. This study indicates that extreme climatic events have the potential to affect the performance and health of three abundant habitat-forming temperate algal species. The loss in health and performance seen in each species could have key implications for benthic communities in temperate Australian reefs, through processes such as changes in herbivory rates, competition with invasive species or simply through algal death. A possible implication of these stressors is the facilitation of range shifts along the west coast which could lead to the retraction of distribution ranges for many temperate Australian species.

Global climate change is projected to impact multiple levels of biodiversity by imposing strong selection pressures on existing populations, triggering shifts in species distributions, and reorganizing entire communities. The Lower Guineo-Congolian region in central Africa, a reservoir for amphibian diversity, is predicted to be severely affected by future climate change through rising temperatures and greater variability in rainfall. Geospatial modelling can be used to assess how environmental variation shapes patterns of biological variation – from the genomic to the community level – and use these associations to predict patterns of biological change across space and time. The overall goal of this dissertation is to examine potential impacts of climate change on amphibian diversity in central Africa. Geospatial modeling is used to: 1) map the distribution of the amphibian fungal pathogen, Batrachochytrium dendrobatidis (Bd) in a biodiversity hotspot in Cameroon under current and future climate; 2) assess phenotypic and adaptive genomic variation in a widespread frog species, Phrynobatrachus auritus, in order to predict areas where populations may best adapt under climate change; 3) determine how amphibian community composition may shift with climate change and which areas may experience greatest loss of functional groups. Findings show that most Bd samples belong to a globally hypervirulent lineage. However, areas of highest predicted environmental suitability for Bd are predicted to shrink under warming temperatures. Within P. auritus, most phenotypic and genomic turnover occurred across known ecological gradients and are heavily influenced by seasonal precipitation. Current amphibian beta diversity is greatest throughout the Cameroonian highlands and forest-savanna ecotones flanking the central Congolian lowland forests. Greatest shifts in community composition under climate change are predicted to occur in coastal Cameroon and its eastern border whereas the greatest predicted loss of functional richness was in central Gabon. Overall, this dissertation shows that areas of elevated environmentally-associated phenotypic, genomic, and community turnover are associated with key ecological gradients. Regions predicted to experience high genomic mismatch, large shifts in community composition, and high loss of functional richness resulting from climate change may warrant conservation attention.

Conservation is plagued by the issue of prioritization - what to conserve and where to conserve it - which relies on identification and assessment of risks. In this body of work, I identify some of the risks related to climate change impacts on biodiversity, as well as potential solutions. Climate changes are underway across nearly all terrestrial areas and will continue in response to greenhouse gas emissions over centuries. Other extinction drivers, such as habitat loss due to urbanization, commonly operate over localized areas. Urbanization contributes, at most, less than 2% of the total range loss for terrestrial species at risk when averaged within an ecodistrict (Chapter 2). Documented impacts of climate change, to date, include: extinction, population loss, reduction in range area, and decreased abundance for multiple taxonomic groups. Examining species’ and populations’ physiological limits provides insight into the mechanistic basis, as well as geography, of climate change impacts (Chapter 3). Climate changes, and the ecological impacts of climate changes, are scale-dependent. Thus, the biotic implications are more accurately assessed through comparisons of local impacts for populations. Under a scenario of climate change, equatorward margins may be strongly limited by climatic conditions and not by biotic interactions. Yet, geographic responses at poleward margins do not appear directly linked to changes in breeding season temperature (Chapter 4). New ideas on how regions with attenuated climate change (climate refugia) may be used to lower species climate-related extinction risk while simultaneously improving habitat connectivity should be considered in the context of potential future consequences (i.e. range disjunction, alternative biological responses) (Chapter 5). Contemporary climate refugia are identifiable along multiple climatic dimensions, and are similar in size to current protected areas (Chapter 6). Determining how, when, and where species distributions are displaced by climate change as well as methods of reducing climatic displacement involves integrating knowledge from distribution shift rates for populations, occurrence of climate refugia, and dispersal barriers. Such assessments, in the Yellowstone to Yukon region, identify dramatically different pathways for connectivity than assessments that are not informed by considerations of species richness and mobility (Chapter 7).

The evolutionary economic geography of climate change is concerned with the processes by which the landscapes of greenhouse gas emissions and vulnerability to climate change are transformed from within over time. Unlike neoclassical economics, evolutionary economic geography is interested in how economic change is driven by innovation and shaped by structural, historical, and contextual factors at different scales. This thesis articulates an evolutionary economic geography perspective on three debates: (1) What factors influence human systems’ capacity to adapt to climate change, and how can these factors be assessed? (2) What forces drive and inhibit economic change towards low-carbon economies, and how should governments induce and manage such shifts? (3) What role should climate finance play in promoting developing countries’ shifts to low-emitting and climate-resilient economies, and how should it be managed? The thesis includes five academic papers. The first reviews the literature on vulnerability and adaptation. It argues that the adaptive capacity of human systems is constrained by structural and historical factors, and that the rich data necessary to identify these factors can only be obtained through qualitative research methods. The next two papers offer case studies from the Global Islands’ Vulnerability Research Adaptation and Policy Development project, which assess the adaptive capacity of Soufriere, Saint Lucia and Whitehouse, Jamaica, respectively. The fourth paper examines the mechanics of three low-carbon shifts in Brazil: the diffusion of no-till agriculture, the decrease in the deforestation rate in the Amazon, and the growth of the ethanol biofuel industry. It found that the driving forces behind each of the shifts were far more varied and complex than the price-based market dynamics analysed in neoclassical economics. The final paper argues that climate finance will need to perform a variety of functions beyond attracting low-carbon private investment. It concludes that the institutional architecture governing climate finance should enable direct access to national governments to incentivise them to implement sustainable innovation policy regimes.

Climate changes have been impacting ecosystems worldwide. Southwest Western Australia (SWA) is experiencing increased drought with climate change, causing great concerns for the continuing persistence of its extraordinary plant diversity. The potential of SWA plants to adapt to increased drought through rapid evolution was investigated. Results indicate that the SWA flora has tolerated recent climate changes, with potential for tolerance of further changes; however altered fire regimes may be detrimental to further adaptation and survival.

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Myanmar is a Least Developed Nation, according to the UN, and therefore is highly vulnerable to the negative effects of a changing climate. To assess the relationship between Myanmar and climate change, this thesis analyzes projected impacts on the nation and its people, the current state of adaptation, and how Myanmar’s government has prepared. Projected impacts are viewed through the lens of the most recent IPCC reports and climate models, and discussed in relation to vulnerable areas in Burmese society and governance. This thesis concludes that Myanmar’s environment, people and society are at a significant risk; higher temperatures, altered precipitation rates, and higher sea levels will lead to reduced agriculture output, the spread of disease, and loss of habitable land. Though recent governmental action has laid the framework for suitable adaptation measures, slow progress in past decades has left Myanmar highly vulnerable to the negative impacts of climate change. Myanmar’s next election is scheduled for 2015, and the emerging leaders have the opportunity to make significant progress in climate change adaptation. Cooperation between Myanmar’s new leaders and the international community could accelerate the nation’s adaptation efforts and result in significant progress on climate change preparedness projects.

A thesis submitted in partial fulfillment of the requirements for the degree of Doctor in Information Management, specialization in Geographic Information Systems
Urban systems are not only major drivers of climate change, but also impact hotspots. The processes of global warming and urban population growth make our urban agglomerations vulnerable to chain reactions triggered by climate related hazards. Hence, the reliable and cost-effective assessment of future climate impact is of high importance. Two major approaches emerge from the literature: i) detailed spatially explicit assessments, and ii) more holistic approaches consistently assessing multiple cities. In this multidisciplinary thesis both approaches were addressed. Firstly, we discuss the underlying reasons and main challenges of the applicability of downscaling procedures of climate projections in the process of urban planning. While the climate community has invested significant effort to provide downscaling techniques yielding localised information on future climate extreme events, these methods are not widely exploited in the process of urban planning. The first part of this research attempts to help bridge the gap between the communities of urban planners and climatologists. First, we summarize the rationale for such cooperation, supporting the argument that the spatial scale represents an important linkage between urban and climate science in the process of designing an urban space. Secondly, we introduce the main families of downscaling techniques and their application on climate projections, also providing the references to profound studies in the field. Thirdly, special attention is given to previous works focused on the utilization of downscaled ensembles of climate simulations in urban agglomerations. Finally, we identify three major challenges of the wider utilization of climate projections and downscaling techniques, namely: (i) the scale mismatch between data needs and data availability, (ii) the terminology, and (iii) the IT bottleneck. The practical implications of these issues are discussed in the context of urban studies. The second part of this work is devoted to the assessment of impacts of extreme temperatures across the European capital cities. In warming Europe, we are witnessing a growth in urban population with aging trend, which will make the society more vulnerable to extreme heat waves. In the period 1950-2015 the occurrence of extreme heat waves increased across European capitals. As an example, Moscow was hit by the strongest heat wave of the present era, killing more than ten thousand people. Here we focus on larger metropolitan areas of European capitals. By using an ensemble of eight EURO-CORDEX models under the RCP8.5 scenario, we calculate a suite of temperature based climate indices. We introduce a ranking procedure based on ensemble predictions using the mean of metropolitan grid cells for each capital, and socio-economic variables as a proxy to quantify the future impact. Results show that all the investigated European metropolitan areas will be more vulnerable to extreme heat in the coming decades. Based on the impact ranking, the results reveal that in near, but mainly in distant future, the extreme heat events in European capitals will be not exclusive to traditionally exposed areas such as the Mediterranean and the Iberian Peninsula. Cold waves will represent some threat in mid of the century, but they are projected to completely vanish by the end of this century. The ranking of European capitals based on their vulnerability to the extreme heat could be of paramount importance to the decision makers in order to mitigate the heat related mortality. Such a simplistic but descriptive multi-risk urban indicator has two major uses. Firstly, it communicates the risk associated with climate change locally and in a simple way. By allowing to illustratively relate to situations of other capitals, it may help to engage not only scientists, but also the decision makers and general public, in efforts to combat climate change. Secondly, such an indicator can serve as a basis to decision making on European level, assisting with prioritizing the investments and other efforts in the adaptation strategy. Finally, this study transparently communicates the magnitude of future heat, and as such contributes to raise awareness about heat waves, since they are still often not perceived as a serious risk. Another contribution of this work to communication of consequences of changing climate is represented by the MetroHeat web tool, which provides an open data climate service for visualising and interacting with extreme temperature indices and heat wave indicators for European capitals. The target audience comprises climate impact researchers, intermediate organisations, societal-end users, and the general public.

The changing abundance and distribution of parasitic helminths has been identified as one of the greatest threats to animal health in the UK under climate change. This is due to the strong influence of abiotic conditions on parasites’ free-living stages. Planning adaptation and mitigation strategies requires predictions of parasite risk, and understanding of subtle interactions between abiotic conditions and parasite transmission. This requires development and application of a range of different modelling approaches. This thesis includes the first long-term forecast showing potential impacts of climate change on a parasitic helminth in the UK. By combining a correlative parasite risk model with UKCP09 climate projections, risk maps are generated identifying which areas of the UK are predicted to experience unprecedented levels of fasciolosis (liver fluke) risk in the future. Correlative models provide warnings of future risk, indicating where resources for monitoring and control should be targeted. To address more complex issues, and foresee consequences of subtle interactions between various components of a system under climate influence, a drive towards process-based mechanistic models is required. Consequently, a spatially explicit mechanistic model is developed, for the transmission of gastro-intestinal nematodes in a controlled grazing system. This allows investigation into how climate impacts on different elements of transmission. A non-linear relationship between climate change and parasite risk is revealed, with a distinct ‘tipping point’ in outbreaks when temperature driven processes exceed critical rates. This indicates that climate change could lead to sudden and dramatic changes in parasite risk. Through combining the models developed here with improved empirical data and a broader view of livestock systems, our understanding of future risks and opportunities can be increased. This will allow improved control of these physically and economically damaging parasites, reducing deleterious impacts on production efficiency and animal welfare.

Drylands represent the planet's largest terrestrial biome and evidence suggests these landscapes have large potential for creating feedbacks to future climate. Recent studies also indicate that dryland ecosystems are responding markedly to climate change. Biological soil crusts (biocrusts). soil surface communities of lichens, mosses, and/or cyanobacteria. comprise up to 70% of dryland cover and help govern fundamental ecosystem functions, including soil stabilization and carbon uptake. Drylands are expected to experience significant changes in temperature and precipitation regimes, and such alterations may impact biocrust communities by promoting rapid mortality of foundational species. In turn, biocrust community shifts affect land surface cover and roughness-changes that can dramatically alter albedo. We tested this hypothesis in a full-factorial warming (+ 4 degrees C above ambient) and altered precipitation (increased frequency of 1.2 mm monsoon-type watering events) experiment on the Colorado Plateau, USA. We quantified changes in shortwave albedo via multi-angle, solar-reflectance measurements. Warming and watering treatments each led to large increases in albedo (> 30%). This increase was driven by biophysical factors related to treatment effects on cyanobacteria cover and soil surface roughness following treatment-induced moss and lichen mortality. A rise in dryland surface albedo may represent a previously unidentified feedback to future climate.

Geoengineering has attracted large attention over recent years as to being a possible way to ameliorate some of the effects of climate change. One of the proposals, involving injecting sulphate aerosols into the stratosphere in order to cool Earth's temperature back to pre-industrial levels, has been assessed as one of the leading geoengineering proposals. Despite this, large uncertainties remain in both the physical and social sciences. Small scale trials of sulphate aerosol injection are not seen as ways to provide large amounts of useful data to inform on the climate response to stratospheric sulphate aerosol loading (whilst also facing many social and ethical barriers). Large scale trials involving injecting amounts of aerosol more comparable to what would be required to cool the Earth's temperature back to pre-industrial levels are viewed as too risky. Assessments of the climate effects of sulphate aerosol geoengineering by the scientific community therefore have largely relied on climate modelling studies. The thesis begins by reviewing sulphate aerosol geoengineering and the modelling that have been conducted to date. In light of the need to verify modelling results with observations the thesis seeks to understand the effects of nature's analogue to sulphate aerosol geoengineering: large volcanic eruptions. When a volcano erupts it can inject large amounts of SO2 gas into the stratosphere, which then undergo conversion to form sulphate aerosol, cooling the Earth in a way analogous to sulphate aerosol engineering. The ability of the climate models submitted to the Coupled Model Intercomparison Project 5 (CMIP5) database is assessed, with a particular focus on dynamical changes in the Northern Hemisphere winter period. These models fail to capture the observed NH dynamical response following eruptions, which is of concern for the accuracy of geoengineering modelling studies that assess the atmospheric response to sulphate aerosol geoengineering. Simulations of volcanic eruptions are then performed with high-top and low-top configurations of the HadGEM2-CC climate model. The high-top version of HadGEM2-CC, with enhanced vertical resolution and model height, gives a markedly improved and statistically significant post-volcanic winter dynamical simulation to its low-top counterpart. The post-winter dynamical simulation in the high-top model agrees with the observed response following volcanic eruptions. Accordingly, mechanisms involved in the dynamical changes are analysed and it is concluded that the HadGEM2-CC high-top model would give more confident simulations of sulphate aerosol geoengineering over its low-top counterpart. Given the identification of a more suitable model for geoengineering simulations following extensive investigation, the final chapter analyses simulations of the HadGEM2-CC high-top model for asymmetries between the climate response to an immediate onset of geoengineering and a rapid cessation of geoengineering - known as a 'termination' of geoengineering. The project is summarised and discussed, and future work is proposed, involving a large host of projects.

Diese Dissertation beschreibt die Entwicklung und Anwendung des Klimawirkungsmoduls des ICLIPS-Modells, eines integrierten Modells des Klimawandels ('Integrated Assessment'-Modell). Vorangestellt ist eine Diskussion des gesellschaftspolitischen Kontexts, in dem modellbasiertes 'Integrated Assessment' stattfindet, aus der wichtige Anforderungen an die Spezifikation des Klimawirkungsmoduls abgeleitet werden.

Das 'Integrated Assessment' des Klimawandels umfasst eine weiten Bereich von Aktivitäten zur wissenschaftsbasierten Unterstützung klimapolitischer Entscheidungen. Hierbei wird eine Vielzahl von Ansätzen verfolgt, um politikrelevante Informationen über die erwarteten Auswirkungen des Klimawandels zu berücksichtigen. Wichtige Herausforderungen in diesem Bereich sind die große Bandbreite der relevanten räumlichen und zeitlichen Skalen, die multifaktorielle Verursachung vieler 'Klimafolgen', erhebliche wissenschaftliche Unsicherheiten sowie die Mehrdeutigkeit unvermeidlicher Werturteile. Die Entwicklung eines hierarchischen Konzeptmodells erlaubt die Strukturierung der verschiedenen Ansätze sowie die Darstellung eines mehrstufigen Entwicklungsprozesses, der sich in der Praxis und der zu Grunde liegenden Theorie von Studien zur Vulnerabilität hinsichtlich des Klimawandels wiederspiegelt.

'Integrated Assessment'-Modelle des Klimawandels sind wissenschaftliche Werkzeuge, welche eine vereinfachte Beschreibung des gekoppelten Mensch-Klima-Systems enthalten. Die wichtigsten entscheidungstheoretischen Ansätze im Bereich des modellbasierten 'Integrated Assessment' werden im Hinblick auf ihre Fähigkeit zur adäquaten Darstellung klimapolitischer Entscheidungsprobleme bewertet. Dabei stellt der 'Leitplankenansatz' eine 'inverse' Herangehensweise zur Unterstützung klimapolitischer Entscheidungen dar, bei der versucht wird, die Gesamtheit der klimapolitischen Strategien zu bestimmen, die mit einer Reihe von zuvor normativ bestimmten Mindestkriterien (den sogenannten 'Leitplanken') verträglich sind. Dieser Ansatz verbindet bis zu einem gewissen Grad die wissenschaftliche Strenge und Objektivität simulationsbasierter Ansätze mit der Fähigkeit von Optimierungsansätzen, die Gesamtheit aller Entscheidungsoptionen zu berücksichtigen. Das ICLIPS-Modell ist das erste 'Integrated Assessment'-Modell des Klimawandels, welches den Leitplankenansatz implementiert.

Die Darstellung von Klimafolgen ist eine wichtige Herausforderung für 'Integrated Assessment'-Modelle des Klimawandels. Eine Betrachtung bestehender 'Integrated Assessment'-Modelle offenbart große Unterschiede in der Berücksichtigung verschiedener vom Klimawandel betroffenen Sektoren, in der Wahl des bzw. der Indikatoren zur Darstellung von Klimafolgen, in der Berücksichtigung nicht-klimatischer Entwicklungen einschließlich gezielter Anpassungsmaßnahmen an den Klimawandel, in der Behandlung von Unsicherheiten und in der Berücksichtigung von 'singulären' Ereignissen. 'Integrated Assessment'-Modelle, die auf einem Inversansatz beruhen, stellen besondere Anforderungen an die Darstellung von Klimafolgen. Einerseits muss der Detaillierungsgrad hinreichend sein, um Leitplanken für Klimafolgen sinnvoll definieren zu können; andererseits muss die Darstellung effizient genug sein, um die Gesamtheit der möglichen klimapolitischen Strategien erkunden zu können. Großräumige Singularitäten können häufig durch vereinfachte dynamische Modelle abgebildet werden. Diese Methode ist jedoch weniger geeignet für reguläre Klimafolgen, bei denen die Bestimmung relevanter Ergebnisse in der Regel die Berücksichtigung der Heterogenität von klimatischen, naturräumlichen und sozialen Faktoren auf der lokalen oder regionalen Ebene erfordert.

Klimawirkungsfunktionen stellen sich als die geeignetste Darstellung regulärer Klimafolgen im ICLIPS-Modell heraus. Eine Klimawirkungsfunktion beschreibt in aggregierter Form die Reaktion eines klimasensitiven Systems, wie sie von einem geographisch expliziten Klimawirkungsmodell für eine repräsentative Teilmenge möglicher zukünftiger Entwicklungen simuliert wurde. Die in dieser Arbeit vorgestellten Klimawirkungsfunktionen nutzen die globale Mitteltemperatur sowie die atmosphärische CO2-Konzentration als Prädiktoren für global und regional aggregierte Auswirkungen des Klimawandels auf natürliche Ökosysteme, die landwirtschaftliche Produktion und die Wasserverfügbarkeit. Die Anwendung einer 'Musterskalierungstechnik' ermöglicht hierbei die Berücksichtigung der regionalen und saisonalen Muster des Klimaänderungssignals aus allgemeinen Zirkulationsmodellen, ohne die Effizienz der dynamischen Modellkomponenten zu beeinträchtigen.

Bemühungen zur quantitativen Abschätzung zukünftiger Klimafolgen sehen sich bei der Wahl geeigneter Indikatoren in der Regel einem Zielkonflikt zwischen der Relevanz eines Indikators für Entscheidungsträger und der Zuverlässigkeit, mit der dieser bestimmt werden kann, gegenüber. Eine Reihe von nichtmonetären Indikatoren zur aggregierten Darstellung von Klimafolgen in Klimawirkungsfunktionen wird präsentiert, welche eine Balance zwischen diesen beiden Zielen anstreben und gleichzeitig die Beschränkungen berücksichtigen, die sich aus anderen Komponenten des ICLIPS-Modells ergeben. Klimawirkungsfunktionen werden durch verschiedene Typen von Diagrammen visualisiert, welche jeweils unterschiedliche Perspektiven auf die Ergebnismenge der Klimawirkungssimulationen erlauben.

Die schiere Anzahl von Klimawirkungsfunktionen verhindert ihre umfassende Darstellung in dieser Arbeit. Ausgewählte Ergebnisse zu Veränderungen in der räumlichen Ausdehnung von Biomen, im landwirtschaftlichen Potential verschiedener Länder und in der Wasserverfügbarkeit in mehreren großen Einzugsgebieten werden diskutiert. Die Gesamtheit der Klimawirkungsfunktionen wird zugänglich gemacht durch das 'ICLIPS Impacts Tool', eine graphische Benutzeroberfläche, die einen bequemen Zugriff auf über 100.000 Klimawirkungsdiagramme ermöglicht. Die technischen Aspekte der Software sowie die zugehörige Datenbasis wird beschrieben.

Die wichtigste Anwendung von Klimawirkungsfunktionen ist im 'Inversmodus', wo sie genutzt werden, um Leitplanken zur Begrenzung von Klimafolgen in gleichzeitige Randbedingungen für Variablen aus dem optimierenden ICLIPS-Klima-Weltwirtschafts-Modell zu übersetzen. Diese Übersetzung wird ermöglicht durch Algorithmen zur Bestimmung von Mengen erreichbarer Klimazustände ('reachable climate domains') sowie zur parametrisierten Approximation zulässiger Klimafenster ('admissible climate windows'), die aus Klimawirkungsfunktionen abgeleitet werden. Der umfassende Bestand an Klimawirkungsfunktionen zusammen mit diesen Algorithmen ermöglicht es dem integrierten ICLIPS-Modell, in flexibler Weise diejenigen klimapolitischen Strategien zu bestimmen, welche bestimmte in biophysikalischen Einheiten ausgedrückte Begrenzungen von Klimafolgen explizit berücksichtigen. Diese Möglichkeit bietet kein anderes intertemporal optimierendes 'Integrated Assessment'-Modell. Eine Leitplankenanalyse mit dem integrierten ICLIPS-Modell unter Anwendung ausgewählter Klimawirkungsfunktionen für Veränderungen natürlicher Ökosysteme wird beschrieben. In dieser Analyse werden so genannte 'notwendige Emissionskorridore' berechnet, die vorgegebene Beschränkungen hinsichtlich der maximal zulässigen globalen Vegetationsveränderungen und der regionalen Klimaschutzkosten berücksichtigen. Dies geschieht sowohl für eine 'Standardkombination' der drei gewählten Kriterien als auch für deren systematische Variation.

Eine abschließende Diskussion aktueller Entwicklungen in der 'Integrated Assessment'-Modellierung stellt diese Arbeit mit anderen einschlägigen Bemühungen in Beziehung.
This thesis describes the development and application of the impacts module of the ICLIPS model, a global integrated assessment model of climate change. The presentation of the technical aspects of this model component is preceded by a discussion of the sociopolitical context for model-based integrated assessments, which defines important requirements for the specification of the model.

Integrated assessment of climate change comprises a broad range of scientific efforts to support the decision-making about objectives and measures for climate policy, whereby many different approaches have been followed to provide policy-relevant information about climate impacts. Major challenges in this context are the large diversity of the relevant spatial and temporal scales, the multifactorial causation of many climate impacts', considerable scientific uncertainties, and the ambiguity associated with unavoidable normative evaluations. A hierarchical framework is presented for structuring climate impact assessments that reflects the evolution of their practice and of the underlying theory.

Integrated assessment models of climate change (IAMs) are scientific tools that contain simplified representations of the relevant components of the coupled society-climate system. The major decision-analytical frameworks for IAMs are evaluated according to their ability to address important aspects of the pertinent social decision problem. The guardrail approach is presented as an inverse' framework for climate change decision support, which aims to identify the whole set of policy strategies that are compatible with a set of normatively specified constraints (guardrails'). This approach combines, to a certain degree, the scientific rigour and objectivity typical of predictive approaches with the ability to consider virtually all decision options that is at the core of optimization approaches. The ICLIPS model is described as the first IAM that implements the guardrail approach.

The representation of climate impacts is a key concern in any IAM. A review of existing IAMs reveals large differences in the coverage of impact sectors, in the choice of the impact numeraire(s), in the consideration of non-climatic developments, including purposeful adaptation, in the handling of uncertainty, and in the inclusion of singular events. IAMs based on an inverse approach impose specific requirements to the representation of climate impacts. This representation needs to combine a level of detail and reliability that is sufficient for the specification of impact guardrails with the conciseness and efficiency that allows for an exploration of the complete domain of plausible climate protection strategies. Large-scale singular events can often be represented by dynamic reduced-form models. This approach, however, is less appropriate for regular impacts where the determination of policy-relevant results generally needs to consider the heterogeneity of climatic, environmental, and socioeconomic factors at the local or regional scale.

Climate impact response functions (CIRFs) are identified as the most suitable reduced-form representation of regular climate impacts in the ICLIPS model. A CIRF depicts the aggregated response of a climate-sensitive system or sector as simulated by a spatially explicit sectoral impact model for a representative subset of plausible futures. In the CIRFs presented here, global mean temperature and atmospheric CO2 concentration are used as predictors for global and regional impacts on natural vegetation, agricultural crop production, and water availability. Application of a pattern scaling technique makes it possible to consider the regional and seasonal patterns in the climate anomalies simulated by several general circulation models while ensuring the efficiency of the dynamic model components.

Efforts to provide quantitative estimates of future climate impacts generally face a trade-off between the relevance of an indicator for stakeholders and the exactness with which it can be determined. A number of non-monetary aggregated impact indicators for the CIRFs is presented, which aim to strike the balance between these two conflicting goals while taking into account additional constraints of the ICLIPS modelling framework. Various types of impact diagrams are used for the visualization of CIRFs, each of which provides a different perspective on the impact result space.

The sheer number of CIRFs computed for the ICLIPS model precludes their comprehensive presentation in this thesis. Selected results referring to changes in the distribution of biomes in different biogeographical regions, in the agricultural potential of various countries, and in the water availability in selected major catchments are discussed. The full set of CIRFs is accessible via the ICLIPS Impacts Tool, a graphical user interface that provides convenient access to more than 100,000 impact diagrams developed for the ICLIPS model. The technical aspects of the software are described as well as the accompanying database of CIRFs.

The most important application of CIRFs is in inverse' mode, where they are used to translate impact guardrails into simultaneous constraints for variables from the optimizing ICLIPS climate-economy model. This translation is facilitated by algorithms for the computation of reachable climate domains and for the parameterized approximation of admissible climate windows derived from CIRFs. The comprehensive set of CIRFs, together with these algorithms, enables the ICLIPS model to flexibly explore sets of climate policy strategies that explicitly comply with impact guardrails specified in biophysical units. This feature is not found in any other intertemporally optimizing IAM. A guardrail analysis with the integrated ICLIPS model is described that applies selected CIRFs for ecosystem changes. So-called necessary carbon emission corridors' are determined for a default choice of normative constraints that limit global vegetation impacts as well as regional mitigation costs, and for systematic variations of these constraints.

A brief discussion of recent developments in integrated assessment modelling of climate change connects the work presented here with related efforts.

Anthropogenic climate change will cause changes to the abundance, distribution, and survival of species in ecosystems worldwide. Kelps are foundation species that form the structure of temperate, marine ecosystems on coastlines worldwide. Kelps support highly productive communities that are ecologically and economically valuable, but are susceptible to the increases in environmental stressors associated with climate change. This susceptibility varies with life history stage, with macroscopic stages less sensitive to environmental stress than microscopic stages. I addressed the effects of climate change on the different life history stages of intertidal kelp from rocky shores on the Pacific coast of North America. I began with two studies on the interactive effects of multiple climate stressors on microscopic stages of kelp. Increasing temperature, CO₂, and UV caused mechanical and functional damage to zoospores during their motile phase, and caused further reductions in settlement, germination, and adhesion of the initial sessile phase of the life history cycle. Settlement style was also affected, with decreased time spent looking for suitable attachment locations and microenvironments, and overdispersion of spore settlement distribution, which has been shown to decrease fertilization rates and sporophyte abundance. In my final research chapter, I describe the effects of increases in frequency of extreme warming events on macroscopic juvenile and adult kelp sporophytes. I also manipulated adult density in situ to determine the stress ameliorating affect of neighbor proximity on both juvenile recruitment and seasonal adult growth along a vertical tidal gradient. Extreme warming treatments reduced recruitment and seasonal growth of adults in the upper shore when adult density was low and environmental stressors were not mitigated by neighboring individuals. All other treatment combinations showed slightly positive effects of warming on recruitment and adult size. I predict that the aforementioned population effects resulting from increases in frequency of extreme warming events will cause an overall reduction in this species’ habitable vertical space in the intertidal zone. The combined impacts of overall reductions in microscopic life history stages with decreasing recruitment and habitable space for the macroscopic life history stage indicate overall reductions in abundance of future populations of intertidal kelp species.
Science, Faculty of
Zoology, Department of
Graduate

Agriculture is the mainstay of the economy in Malawi and accounts for 40% of the Gross Domestic Product (GDP) and 90% of the export revenues. Corn (maize) is the major cereal crop grown as staple food under rainfed conditions, covers over 92% of the total agricultural area, and contributes 54% of the caloric intake. Corn production is the principle occupation and major source of income for over 85% of the total population in Malawi. Issues of hunger and food insecurity for the entire nation are associated with corn scarcity and low production. Global warming is expected to cause climate change in Malawi, including changes in temperature and precipitation amounts and patterns. These climate changes are expected to affect corn production in Malawi. This study evaluates the impacts of climate change on rainfed corn production in Malawi. Lilongwe District, with about 1,045 square miles of agriculture area, has been selected as a representative area. First, outputs of 15 General Circulation Models (GCMs) under different emission scenarios are statistically downscaled. For this purpose, a weather generator (LARS-WG) is calibrated and validated for the study area and daily precipitation as well as minimum and maximum temperature are projected for 15 GCMs for three time horizons of 2020s, 2050s and 2090s. Probability assessment of bounded range with known distributions is used to deal with the uncertainties of GCMs' outputs. These GCMs outputs are weighted by considering the ability of each model to simulate historical records. AquaCrop, a new model developed by FAO that simulates the crop yield response to water deficit conditions, is employed to assess potential rainfed corn production in the study area with and without climate change. Study results indicate an average temperature increase of 0.52 to 0.94oC, 1.26 to 2.20oC and 1.78 to 3.58oC in the near-term (2020s), mid-term (2050s) and long-term (2090s) future, respectively. The expected changes in precipitation during these periods are -17 to 11%, -26 to 0%, and -29 to -3%. Corn yields are expected to change by -8.11 to 0.53%, -7.25 to -14.33%, and -13.19 to -31.86%, during the same time periods. The study concludes with suggestion of some adaptation strategies that the Government of Malawi could consider to improve national food security under climate change.
M.S.
Masters
Civil, Environmental, and Construction Engineering
Engineering and Computer Science
Civil Engineering; Water Resources Engineering

This thesis aims to apply recent conceptual frameworks for climate change impact assessment to the road freight sector of Great Britain in order to identify potential future safety issues. The freight sector is a key component of Great Britain’s economy, and one which is particularly vulnerable to the effects of adverse weather. An assessment of the current patterns in weather related freight accidents is produced, and existing studies on accident causation are elaborated upon to arrive at relationships between key meteorological parameters and freight accident rates. These relationships are extrapolated onto various climate scenarios under low, medium and high emissions for the 2020s, 2050s and 2080s using UKICP09 climate tools to arrive at projections of possible impacts at a regional scale. This thesis also addresses a key criticism of the previous climate change impact assessment literature; that studies usually neglect the consideration of what the network will look like in the future, how it will be used, and how this will impact upon its vulnerability to meteorology. The way in which the network is designed, the resilience of the vehicles that operate on it and the split of usage between the various modes will all affect the impacts that are likely to be seen, and are all determined by the broader socio-economic pathway of the country. Delphi techniques are used for short term forecasts of growth and to identify emerging issues with the industry. UKCIP data is used to extend these projections to 2050. By combining social and physical techniques, a more holistic picture of future impacts is found. Although the confluence of safer technology and a reduction of winter road icing and summer precipitation events could potentially lead to a safer operating environment, certain scenarios which promote high emissions, a larger freight fleet and low investment in infrastructure could cause problems, especially for winter precipitation events.

Thesis: Ph. D. in Climate Science, Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2018.
Cataloged from PDF version of thesis.
Includes bibliographical references.
Recognition of stratospheric ozone depletion as a significant global danger sparked the landmark international agreement of the Montreal Protocol to control the production of ozone depleting substances (ODSs). There are now signs of stratospheric ozone recovery, and it is essential to understand whether the observed historical changes, during both the depletion and recovery eras, are directly the result of secular changes in ODSs, or influenced by other anthropogenic and natural forcings such as greenhouse gases (GHGs) and solar variability. This thesis explores the climate impacts of stratospheric ozone depletion, and how we can attribute, with high confidence, the causes of observed changes in stratospheric ozone. First, the linkages between Antarctic ozone loss and midlatitude surface climate changes are investigated. Unusually hot summer extremes in Australia, South America and Africa were found to be associated with elevated levels of ozone the previous November, and that this link has only emerged in the era of the Antarctic ozone hole. This study provides motivation for understanding the causes of ozone changes, showing direct impacts to regions where humans live. Second, a formal detection and attribution study of stratospheric ozone change is presented. A multi-satellite observational dataset and simulations from a chemistry climate model are analyzed. An improvement to conventional fingerprint attribution methodology is presented that accounts for nonlinearities in the temporal evolution of anthropogenic forcings. High confidence in the detection of ODSs upon observed stratospheric ozone change is shown. Detection of a GHG signal, in stratospheric ozone, is projected to emerge in the mid-21st century. Third, the improved attribution methodology is applied to seasonal atmospheric circulation changes. Reanalysis products and simulations from a multimodel assessment are used. Positive detection of both ODS and GHG fingerprints is found during the months of December- May, with the ODS signal dominating in the Southern Hemisphere. Ultimately, the results of this thesis further our scientific understanding of the role of ODSs in climate change, and provide new steps for future detection and attribution studies of the climate system.
by Justin Bandoro.
Ph. D. in Climate Science

The primary objective of this work was to analyse how water companies are affected by climate change and how they try to adapt to it. Therefore, a systematic literature review was being accomplished. The work is being divided into a theoretical and a methodological part. First of all an overview of the climatic changes that are projected to occur during the next years is being given. Then, resulting impacts on the water cycle are being pointed out. Furthermore, raw water sources, water companies obtain water from are being defined as well as the treatment process. Within the methodological part the approach of a systematic literature review is being applied, which includes the selection of references as well as their evaluation. The results of the literature review are that concerning the effects of climate change on water companies, the risks water providers might face, clearly predominate possible opportunities. Especially the deterioration of the raw water quality caused by increasing temperatures, floods as well as heavy rainfalls can be seen as a serious problem. Moreover, the most often mentioned adaptation strategies are dealing with quantitative water problems such as measures to increase storage as well as treatment capacity or leakage reductions. All in all it can be stated that there is still uncertainty about how climate change is going to effect water companies, especially concerning water quality changes and the treatment process.

Thesis (PhD)-- Stellenbosch University, 2012.
ENGLISH ABSTRACT: Climate change and biological invasions are major threats to biodiversity. In particular, these threats are predicted to influence terrestrial systems in the sub-Antarctic, where significant ecosystem responses to both have already been seen. In this thesis, the sub-Antarctic Prince Edward Island group is used as a model system in which to investigate key questions relating to climate change and invasive species impacts. The island group comprises two islands, Marion (MI) and Prince Edward (PEI), both of which are experiencing rapid warming, yet have different invasive assemblages and in consequence are experiencing different impacts. Variation in the patterns of invasive species richness and abundance and their underlying causes are matters of considerable ecological and conservation significance. While an increase in thermal energy availability typically results in an increase in species richness, the mechanisms underlying these patterns are poorly understood. In Chapter 2 of this thesis, these relationships are explored for springtails, an important component of the soil fauna on Marion Island. Energy explains a large amount of the spatial variation in indigenous and invasive springtail species richness. Disturbance thresholds and stressful temperatures are more important than increased population sizes in determining this variation in species richness. As both indigenous and invasive springtail species richness and abundance are strongly related to temperature, a warming climate could have far-reaching consequences for these organisms. In particular, invasive species are predicted to be at an advantage relative to indigenous species under warming conditions. One species where this seems especially likely, given its physiological responses to experimental warming and drying, is the large invasive tomocerid, Pogonognathellus flavescens. Determining whether this will be the case depends on understanding the factors underlying its range limits and abundance structure. Moreover, few studies have sought to distinguish the causal basis of abundance structure and range limits, particularly for invasive species. Thus, in Chapter 3, local microclimate variables and physiological tolerances of the invasive springtail, P. flavescens (a habitat generalist), are examined. The results suggest that the species should be widely distributed across a range of habitats on MI. However, the springtail is restricted to indigenous Poa cookii tussock grassland habitats in the southeast. The current range limits are set by dispersal limitation (i.e. contingent absences) whilst abundance structure is a function of variation in soil substrate quality. However, over time, the widening distribution of P. cookii, as a consequence of a major management intervention (the eradication of feral cats), may enable P. flavescens to colonise all suitable areas. In Chapter 4, the focus changes to what has been considered the third major response to climate change, along with range and phenological responses - changing animal body sizes. Body size is one of the most significant and obvious features of animals and is of considerable ecological and physiological importance. A prediction of the temperature-size rule (TSR) is that with warming, body size of the weevil species on both MI and PEI should decline. However, predation by mice of the weevils on MI should fundamentally affect the pattern of such change, causing it to differ from neighbouring PEI, indicating synergistic impacts between climate change and invasions. Analysis of a 24-year data set indicates a decline in the body size of all weevil species on PEI with increasing temperature. However, on MI, a negative relationship between mean annual temperature and body size is found only for Palirhoeus eatoni, a species not eaten by mice. A possible explanation for the positive relationships found for the other species could be due to higher metabolic demands imposed on mice in colder years than in warmer ones. Any increase in predation coupled with a preference for larger sizes, which the mice clearly show, would lead to a decline in the mean size of the weevil species. Due to the relationship between body size and metabolic rate and the importance of the weevils in the islands’ food webs, changes to the body size of these organisms could have significant consequences for the island ecosystems’ functioning. The thermal environment experienced by organisms also has a direct effect on survival, growth and reproduction. The physiological response of organisms to rapidly changing climates is therefore a primary concern. Organisms may respond to variable environmental conditions through phenotypic plasticity as well as behaviour. Chapter 5 of this thesis shows that of the weevil species and populations investigated on MI, most display phenotypic plasticity, the form of which is in keeping with the ‘Hotter is Better’ hypothesis. This could be due to rare extreme temperature events and the advantage for the performance curves to incorporate high temperatures experienced in the environment. Mismatches between thermal optima and preferred temperatures displayed by all species could mean that these weevils are well equipped to cope with warming conditions on MI unless the prediction of an increase of rare extreme events such as extreme temperatures is realised. Rapidly changing climates and an increase in the introduction of non-indigenous species are issues of major conservation concern. This has increased the significance of studies on the impacts of these threats. However, this thesis shows that to understand such processes, it is essential that an integration of disciplines be undertaken. This thesis thus adopts a multidisciplinary approach and highlights key issues associated with both climate change and biological invasions. The patterns and predictions of species and community responses to these environmental changes are complex. Moreover, predicting such responses is likely to be problematic, especially as multiple factors will change concurrently and how these factors might change is unclear. This highlights the importance of long-term records for understanding organism responses to such changes. Furthermore, impacts on indigenous species are likely to be exacerbated by the predicted increase in the rate of introductions with climate change. This makes the case for preventing the dispersal of invasive species to new areas all the more important.
AFRIKAANSE OPSOMMING: Klimaatsverandering en indringer spesies is belangrike bedreigings vir biodiversiteit. In besonder word voorspel dat hierdie bedreigings terrestriële sisteme in die sub-Antarktiese sal beïnvloed, waar beduidende ekosisteem reaksie aan beide reeds gesien is. In hierdie tesis word die sub-Antarktiese Prince Edward eiland groep as a model sisteem gebruik om belangrike vrae met betrekking tot klimaatsverandering en die impak van indringer spesies te ondersoek. Die eiland groep bestaan uit twee eilande, Marion (ME) en Prince Edward (PEE), wat beide versnellende verwarming ervaar, maar tog verskillende indringer samestellings het en vervolgens verskillende impakte ervaar. Variasie in die patrone van indringerspesierykheid en vollopheid en hulle onderliggende oorsake is van aansienlike omgewings en bewarings betekenis. Terwyl 'n toename in die beskikbaarheid van energie tipies lei tot 'n toename in spesierykheid, word die onderliggend meganismes van hierdie patrone swak verstaan. In Hoofstuk 2 van hierdie tesis, word hierdie verhoudings vir springsterte ondersoek, 'n belangrike komponent van die grond fauna op ME. Energie verduidelik 'n groot hoeveelheid van die ruimtelike variasie in inheemse en indringende springstert spesierykheid. Versteuringsdrempels en stressvolle temperature is meer belangrik as die toename in bevolking groottes in die bepaling van hierdie variasie in spesierykheid. Aangesien beide inheemse en indringende springstert spesierykheid en vollopheid sterk verwant is aan temperatuur, kan 'n verwarmende klimaat verreikende gevolge vir hierdie organismes hê. In die besonder word voorspel dat indringerspesies bevoordeeld sal wees relatief tot inheemse spesies onder verwarmende toestande. Een spesie waar dit veral blyk om geneig te wees, gegewe sy fisiologiese reaksie tot eksperimentele verhitting en uitdroging, is die groot indringer tomocerid, Pogonognathellus flavescens. Om te bepaal of dit die geval sal wees, hang af van die begrip van die onderliggende faktore van sy voorkomsgrense en vollopheidstruktuur. Daarbenewens is daar min studies wat gepoog het om te onderskei tussen die veroorsakende basis van vollopheidstruktuur en voorkomsgrense, veral vir indringerspesies. Dus, in Hoofstuk 3, word plaaslike mikroklimaat veranderlikes en fisiologiese toleransies van die indringer springstert, P. flavescens ('n habitat generalis), ondersoek. Die resultate stel voor dat die spesie wyd verspreid moet wees oor 'n verskeidenheid van habitatte op ME. Maar, die springstert is beperk tot inheemse Poa cookii polle grasveldhabitatte in die suidooste. Die huidige voorkomsgrense word daar gestel deur verspreidingsbeperking (dws voorwaardelike afwesighede), terwyl vollopheidstruktuur 'n funksie is van die variasie in die grond substraat kwaliteit. Maar, die uitbreidende verspreiding van P. cookii as gevolg van 'n groot bestuursingryping (die uitwissing van wilde huiskatte), kan P. flavescens in staat stel om alle geskikte gebiede te koloniseer met verloop van tyd. In Hoofstuk 4 verander die fokus na wat as die derde groot reaksie op klimaatsverandering beskou word, saam met voorkoms en fenologiese reaksies - veranderende diere liggaamsgroottes. Liggaamsgrootte is een van die beduidendste en mees voor die hand liggende eienskappe van diere en is van aansienlike ekologiese en fisiologiese belang. 'n Voorspelling van die temperatuur-grootte-reël (TGR) is dat met verwarming, liggaamsgrootte van die snuitkewerspesies op beide ME en PEE sal afneem. Hoe ookal, predasie deur muise van die snuitkewers op ME moet fundamenteel die patroon van sodanige verandering op PEE beïnvloed, wat sinergistiese impakte tussen klimaatsverandering en indringings aandui. Die ontleding van 'n 24-jarige datastel dui aan op 'n afname in die liggaamsgrootte van alle snuitkewer spesies op PEI met ‘n toename in temperatuur. Maar, op ME is 'n negatiewe verhouding tussen die gemiddelde jaarlikse temperatuur en liggaamsgrootte net gevind vir Palirhoeus eatoni, 'n spesie wat nie deur die muise geëet word nie. 'n Moontlike verduideliking vir hierdie positiewe verhoudings wat gevind is vir die ander spesies kan wees as gevolg van hoër metaboliese eise op die muise in kouer jare as in warmer jare. Enige toename in predasie, tesame met 'n voorkeur vir groter mates, wat die muise duidelik wys, sou lei tot 'n afname in die gemiddelde grootte van die snuitkewer spesies. As gevolg van die verhouding tussen liggaamsgrootte en metaboliese tempo, sowel as die belangrikheid van die snuitkewers in die eilande se voedselwebbe, kan veranderinge in die liggaamsgrootte van hierdie organismes beduidende gevolge op die eiland ekosisteme se funksionering hê. Die termiese omgewing wat deur organismes ervaar word het ook 'n direkte invloed op oorlewing, groei en voortplanting. Die fisiologiese reaksie van organismes op vinnig veranderende klimate is dus 'n primêre bron van kommer. Organismes kan reageer op veranderlike omgewingstoestande deur fenotipiese plastisiteit sowel as gedrag. Hoofstuk 5 van hierdie tesis toon dat van die snuitkewerspesies en bevolkings wat ondersoek is op ME, die meeste fenotipiese plastisiteit vertoon, die vorm wat in ooreenstemming is met die ‘Warmer is Beter’ hipotese. Dit kan wees as gevolg van seldsame uiterste temperatuur gebeure en die voordeel vir die prestasie kurwes om hoë temperature wat ervaar word in die omgewing in te sluit. Mismatches tussen termiese optima en voorkeur temperature vertoon deur alle spesies kan beteken dat hierdie snuitkewers goed toegerus is om die verhitting op ME te hanteer, tensy die voorspelling van 'n toename van seldsame uiterste gebeure soos uiterste temperature gerealiseer word. Vinnig veranderende klimate en 'n toename in die bekendstelling van nie-inheemse spesies is kwessies van groot bewarings kommer. Dit het die betekenis van studies oor die impak van hierdie bedreigings verhoog. Hierdie tesis toon egter dat om sulke prosesse te verstaan, dit noodsaaklik is dat 'n integrasie van die dissiplines onderneem word. Hierdie tesis aanvaar dus 'n multi-dissiplinêre benadering en beklemtoon die belangrike kwessies wat verband hou met beide klimaatverandering en biologiese indringing. Die patrone en voorspellings van spesies en die gemeenskapsreaksies op hierdie omgewingsveranderinge is kompleks. Verder, die voorspelling van sodanige reaksies sal waarskynlik problematies wees, veral omdat verskeie faktore gelyktydig sal verander en hoe hierdie faktore kan verander is onduidelik. Dit beklemtoon die belangrikheid van lang termyn rekords vir die begrip van organisme reaksies op sulke veranderinge. Verder, die impak van inheemse spesies is geneig om te vererger deur die voorspelde toename in die tempo van bekendstellings met klimaatsverandering. Dit maak die taak vir die bestuur van die voorkoming dat indringerspesies nuwe gebiede bereik al hoe meer belangrik.

It is vital that we develop our understanding of how crops will respond to climate change given the likely need to increase food production by 2050. The contribution of potatoes to the global food supply is increasing - consumption more than doubled in developing countries between 1960 and 2005. Analyses of climate impacts on potato compared to other major crops are relatively rare. Studies involving biotic stresses in crop modelling are also comparatively rare - around 70% of models do not incorporate pest and disease damage. This thesis simulated abiotic and biotic impacts of climate change to 2050 to identify risks and opportunities for global potato agriculture. The GLAM crop model is used to assess abiotic impacts and the SimCastMeta model is used to assess the impacts of the most important global disease of potato, late blight Phytophthora infestans. A further analysis uses pesticide data as a proxy for pest pressures, showing that warming leads to pesticide increases in temperate areas. GLAM is evaluated for potato simulation in two contrasting climates using data from Colombian regions and Aberdeen, UK. The model shows skill in simulating observed weather-yield relationships. National yield data are then used to test a global parameter configuration. Results show realistic planting dates and crop growth. Skill is low due to insignificant observed weather-yield relationships. Regional results show higher skill than global results, primarily due to more parameter detail. Global model results show skill in reproducing observed yields in Europe. Elsewhere, correlations are generally positive but low. Future climate simulations show that yields are expected to increase in most cases, primarily as a result of CO2 fertilisation, although the magnitude of increases are uncertain due to the uncertainties around future climate and CO2 fertilisation. Temperature increases in some regions result in shorter durations and reduce yield increases. Late blight is predicted to increase more in temperate regions, particularly if adaptation to climate change is considered. Taken together, abiotic and biotic impacts show potential opportunities for potato agriculture in temperate latitudes providing pests and diseases can be sustainably managed.

Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para a obtenção do grau de Mestre em Engenharia do Ambiente, perfil Gestão e Sistemas Ambientais
Significant work has been developed in defining climate change impacts, adaptation and mitigation measures both on national and worldwide scopes. In the published literature, strong references are made linking effects of mitigation and adaptation and how the two can counteract, but there is still a lack of integrated assessment of these issues. Using the optimization model TIMES_PT, calibrated and validated for Portugal, interactions between climate change, mitigation strategies, adaptation and the energy system are evaluated in this thesis. A special focus is addressed on two sectors where climate change effects are the most noticeable: hydroelectric production and energy demand. Results indicate that it is wise and cost-effective to delay the investment in new hydropower infrastructure beyond 2020 and that hydropower installed capacity could be reduced in 15% in 2050 when compared with the scenario with no climate change. Furthermore, large hydropower capacity could compromise the deployment of advanced electricity production technologies. Overall,the energy system will benefit from climate change due to useful energy demand reduction, reaching accumulated savings from 4500M€2000 to 6100M€2000 compared to the no climate change scenario.

The research presented here attempts to bridge science and policy through the quantification of climate change impacts and the analysis of a science-fed participatory process to face a sustainability challenge in the San Pedro Basin (Arizona). Paper 1 presents an assessment of a collaborative development process of a decision support system model between academia and a multi-stakeholder consortium created to solve water sustainability problems in a local watershed. This study analyzes how science-fed multi-stakeholder participatory processes lead to sustainability learning promoting resilience and adaptation. Paper 2 presents an approach to link an ensemble of global climate model outputs with a hydrological model to quantify climate change impacts in the hydrology of a basin, providing a range of uncertainty in the results. Precipitation projections for the current century from different climate models and IPCC scenarios are used to obtain recharge estimates as inputs to a groundwater model. Quantifying changes in the basin's water budget due to changes in recharge, evapotranspiration (ET) rates are assumed to depend only on groundwater levels. Picking on such assumption, Paper 3 explores the effects of a changing climate on ET. Using experimental eddy covariance data from three riparian sites, it analyzes seasonal controls on ET. An approach to quantify evapotranspiration rates and growing season length under warmer climates is proposed. Results indicate that although atmospheric demand will be greater, increasing pan and reference crop evaporation, ET rates at the studied field sites will remain unchanged due to stomatal regulation. However, the length of the growing season will increase, mainly with an earlier leaf-out and at a lesser level by a delayed growing season end. These findings - implying decreased aquifer recharge, increased riparian water use and a lesser water balance - are very relevant for water management in semi-arid regions. Paper 4, in which I am second author, explores the theory relating changes in area-average and pan evaporation. Using the same experimental data as Paper 3, it corroborates a previous theoretical relationship and discusses the validity of Bouchet's hypothesis.

Die Untersuchung der Auswirkungen des Klimawandels auf die globale Kaffeeproduktion in einem integriertem Modell war das Ziel dieser Arbeit. Der vorwiegende Teil der globalen Kaffeeproduktion stammt von zwei Arten: dem hitzeempfindlichen Coffea arabica (Arabica) Strauch und vom frostempfindlichen Coffea canephora (Robusta). Eine zunehmende Zahl Studien zeigt, dass der Klimawandel bereits heute die Produktion mindert. Maschinenlernklassifizierung wurde hier genutzt um ein Modell der globalen Klima-Kaffee-Wechselwirkungen zu entwickeln. Zur Integration der modellierten Klimafolgen mit ökonomischen Faktoren war ein detailliertes Wissen über die räumliche Verteilung der Kaffeeproduktion notwendig. Da existierende Datensätze unzureichend waren, wurde ein neuer methodischer Ansatz auf der Grundlage der maschinenlern-basierten Anbaueignungsklassifizierung entwickelt. Diese beiden Schritte waren Voraussetzung für die Inklusion eines Modells des Kaffeesektors in dem räumlich expliziten partiellen Gleichgewichtsmodell Globiom. Auf der Hälfte der heute für den Anbau geeigneten Fläche muss bis 2050 2,5-mal so viel Kaffee produziert werden um die zukünftige Nachfrage zu sättigen. Niedrigere Ernten und höhere Preise werden das Volumen des Kaffeemarktes um über 5 Mio. Tonnen pro Jahr reduzieren. Dieser Verlust entspricht dem Marktvolumen im Modellbasisjahr. Kaffeeproduktion wird zukünftig in höheren Lagen angebaut werden müssen, sofern dort landwirtschaftliche Fläche zur Verfügung steht. Die Produktion wird größtenteils innerhalb der gegenwärtigen Breitengrade bleiben, aber wichtige Produzenten, wie Brasilien und Vietnam werden Probleme haben wettbewerbsfähig zu bleiben mit weniger betroffenen Ländern in Ost-Afrika. Modellunsicherheit auf lokaler Ebene erschwert jedoch die Entwicklung eindeutiger Anpassungsempfehlungen. Es wird also auch in Zukunft Kaffee geben, aber dieser Kaffee wird von geringerer Qualität sein und mehr kosten.
To model the impacts of climate change on global coffee production in an integrated modeling framework was the objective of this thesis. The majority of coffee is produced using either one of two species which form a single market: the heat sensitive Coffea arabica (Arabica) and the cold sensitive Coffea canephora (Robusta). Recently, evidence is increasing that climate change has begun to affect production. Machine learning classification was used to develop a global biophysical impacts model for both coffee species. Integrating these biophysical effects with demand side effects required a detailed understanding of the spatial distribution of coffee production. Because existing datasets were found to be insufficient a novel methodology was developed that built upon the machine learning classification of coffee suitability. These two steps were preconditions to include a model of the coffee sector in the spatially explicit partial equilibrium modeling framework Globiom. On only half the area that is currently available for coffee production by 2050 2.5-times as much coffee will have to be produced to meet future demand. Reduced yields and increased prices were shown to reduce the coffee market by more than 5million tons per year, equivalent to the size of the baseyear market volume. Coffee production will migrate to higher elevations where area is available for agricultural production. Production will remain within current latitudinal ranges but major producers like Brazil and Vietnam will struggle to remain competitive with relatively less affected countries in East Africa. Substantial uncertainty about the impacts on local scale prevails and impedes the development of unambiguous adaptation strategies. Thus, there will be coffee on the table in 2050, but it will be of lower quality and will cost more.

Global climate model simulations indicate 1.3°C to 1.8°C increase in the Earth’s average temperature by middle of this century above the 1980 to 1999 average. The magnitude and rate of change of this projected warming is greater than the average warming during the last century. Global climate models project an even higher degree of warming later in the century also due to increasing grrenhouse gases concentrations in the atmosphere from human activity. Impacts of future climate change on viticulture are likely to be significant as viticulture requires a narrow climate range to produce grapes of suitable quality for premium wine production.In this thesis, impacts of climate change on winegrape growing conditions across the Western Australian wine regions were spatially and temporally examined by utilising fine resolution downscaled climate projections. Relationships between climate variation and grape maturity or key quality attributes of Cabernet Sauvignon, Shiraz and Chardonnay were modelled from measured fruit and climate data along a natural climate gradient encompassing a 5°C range in winegrape growing season average temperature. Potential future climate change impacts on grape quality were quantitatively evaluated by driving the grape quality models with the downscaled climate projections.Analyses of climate conditions for winegrape growth were carried out under future climate projections for the Western Australian wine regions. A total of 10 global climate models forced with an A2 emission scenario were downscaled. Of these models, the MEDRES Miroc3.2 and CSIRO Mk3.5 climate models, which indicated the low and high warming ranges (projections of these models will be referred as low and high range warming, hereafter) across the study regions, were selected to take into account the uncertainty of future climate change for impact assessment. Our results indicate increasingly warmer and drier climate conditions for the Western Australian wine regions. The current October to April average temperature (averaged across the regions) is projected to be 0.5°C to 1.5°C warmer by 2030, respectively. The magnitude of the warming will likely be uneven across the regions. For example, 0.1 to 0.3°C higher average temperature during October to April period has been projected for the northern regions than the southern regions by 2030, depending on the warming ranges. On the other hand, rainfall is projected to decrease across the regions under the future scenario we assessed in this study. By 2030, annual rainfall, averaged across the regions, is projected to decline by 5 to 8%, respectively, under the low and high warming ranges of climate change under the A2 emission scenario. Among seasons, the greatest decline in rainfall is projected to occur during spring. On average, up to 8% and 19% decline in spring rainfall is projected respectively under the low and high warming ranges by 2030.The magnitude of these changes are projected to increase as time progresses. For example, by 2070, averaged across the study regions, our modelling results show current mean temperature during October to April is projected to be between 1.1°C and 3.9°C warmer, but the annual rainfall is likely to be 15 to 24% lower than the current climate averages (1975 to 2005) under the A2 scenario.Maturity dates of the studied varieties are projected to advance asymmetrically across the study regions. For example, Cabernet Sauvignon may reach 22 °Brix total soluble solid maturity about 4 and 7 days earlier respectively for the northern and the southern regions by 2030 under the low warming range. Our results also indicate maturity date shifting a further 8 and 18 days earlier by 2070 for the northern and the southern regions respectively under the same warming range. Patterns of this maturity date shifting is likely to be similar under the high warming range. However, the magnitude of advancement is projected to be doubled.If no adaptive measures are implemented future climate change will likely reduce wine quality due to declining concentrations of berry anthocyanins and acidity under a warmer climate. The reductions of berry quality attributes are likely to be more pronounced in the warmer northern wine regions compared to the cooler southern regions. For example, Cabernet Sauvignon current median anthocyanins concentration is projected to decline by about 12% and 33% for the warmer northern regions, and about 6 to 18% for the cooler southern wine regions respectively by 2030 and 2070 under the high warming range. In contrast, the maximum decline in Cabernet Sauvignon anthocyanin concentration under the lower warming range is projected to be small, up to 5% for the cooler southern and up to 8% for the warmer northern regions by 2070. Shiraz anthocyanins concentration decrease pattern is similar to that of Cabernet Sauvignon, however, our modelling indicates the magnitude is smaller, with maximum of 18% for Swan District and about 11% for the southern regions by 2070 under the high warming range.Modelled impacts of climate change on grape titratable acidity are also region and variety specific. Among the varieties studied, Chardonnay exhibits the highest decline in median titratable acidity across the regions (17% for the Margaret River and 42% for the Swan District regions), followed by Shiraz (7% for the Margaret River and 15% for the Peel regions) and Cabernet Sauvignon (no change for Blackwood and 12% for the Swan District regions) by 2070 under high climate warming. On the other hand, the median titratable acidity levels are less impacted by low warming scenario (maximum decline is 4% for Shiraz only by 2070).Under the future warming scenarios studied in this thesis currently established wine regions and wine styles across the Western Australian wine regions are likely to be affected to the extent that some regions may not be conducive to premium wine production, while for some regions changing the variety may be the only option to adapt to the climate change. For example, by 2070, under high warming range Swan District, Perth Hills, and some parts of the Peel and Geographe regions are projected to be suited more to producing fortified wines or table grapes due to high average growing season temperature (>24°C). In this future climate the present cool climate southern regions are likely to have the same climate conditions that currently prevail in the warmer Swan District. Apparent differences in currently planted varieties between the cooler southern and warmer northern regions clearly indicate the need to adapt to the warming climate in the southern wine regions.Analysis of other potential factors that influence viticulture such as frequency of hot days, vapour pressure deficit and disease pressure were examined. The results indicated that winegrape fungal disease pressure will likely decrease across the regions due to the declining rainfall, potentially lessening the need for spraying during the growing season. On the other hand, there will likely be increased frequency of hot days and elevated vapour pressure deficit. The impacts of these, combined with the decreasing rainfall during growing season will potentially drive irrigation demand higher requiring altered water management under climate change.Climatically, most of the Western Australian wine regions are known as premium wine producing areas. The results from this study indicate potential challenges of climate change for the Western Australian wine industry. Under the future climate scenarios examined, some currently warmer regions may become less suitable for premium quality wines due to the increased temperature, which is projected to be out of the optimum temperature range for premium wine production. For most of the other regions, the challenge will likely be a decreased grape quality required to produce premium wine with the current varieties. Suitable adaptation strategies may be required to maintain the current market reputation. Furthermore, the warmer and drier conditions under climate change is likely to necessitate revised water management across the wine growing regions, especially some regions which are already limited by available water for grape production. However, the magnitude of the impacts is projected to be dependent upon the magnitude of future climate change.

1. Contextual outline of the PhD Research

Climate change is today often seen as one of the most challenging issue that our civilisation will have to face during the 21st century. This is especially so now that the most recent scientific data have led to the conclusion that the globally averaged net effect of human activities since 1750 has been one of warming (IPCC 2007, p. 5) and that continued greenhouse gas emissions at or above current rates would cause further warming (IPCC, 2007 p. 13). This unequivocal link between climate change and anthropogenic activities requires an urgent, world-wide shift towards a low carbon economy (STERN 2006 p. iv) and coordinated policies and measures to manage this transition.

The climate issue is undoubtedly a typical policy question and as such, is considered amenable to economic scrutiny. Indeed, in today’s world economics is inevitable when it comes to arbitrages in the field of policy making. From the very beginning of international talks on climate change, up until the most recent discussions on a post-Kyoto international framework, economic arguments have turned out to be crucial elements of the analysis that shapes policy responses to the climate threat. This can be illustrated by the prominent role that economics has played in the different analyses produced by the Intergovernmental Panel on Climate Change (IPCC) to assess the impact of climate change on society.

The starting point and the core idea of this PhD research is the long-held observation that the threat of climate change calls for a change of climate in economics. Borrowing from the jargon used in climate policy, adaptation measures could also usefully target the academic discipline of economics. Given that inherent characteristics of the climate problem (e.g. complexity, irreversibility, deep uncertainty, etc.) challenge core economic assumptions, mainstream economic theory does not appear as appropriately equipped to deal with this crucial issue. This makes that new assumptions and analyses are needed in economics in order to comprehend and respond to the problem of climate change.

In parallel (and without environmental considerations being specifically the driving force to it), the mainstream model in economics has also long been (and still is) strongly criticised and disputed by numerous scholars - both from within and outside the field of economics. For the sake of functionality, these criticisms - whether they relate to theoretical inconsistencies or are empirically-based - can be subsumed as all challenging part of the Cartesian/Newtonian legacy of economics. This legacy can be shown to have led to a model imprinted with what could be called “mechanistic reductionism”. The mechanistic side refers to the Homo oeconomicus construct while reductionism refers to the quest for micro-foundations materialised with the representative agent hypothesis. These two hypotheses constitute, together with the conjecture of perfect markets, the building blocks of the framework of general equilibrium economics.

Even though it is functional for the purpose of this work to present them separately, the flaws of economics in dealing with the specificities of the climate issue are not considered independent from the fundamental objections made to the theoretical framework of mainstream economics. The former only make the latter seem more pregnant while the current failure of traditional climate policies informed by mainstream economics render the need for complementary approaches more urgent.

2. Overview of the approach and its main insights for climate policy

Starting from this observation, the main objective of this PhD is thus to assess the implications for climate policy that arise from adopting an alternative analytical economic framework. The stance is that the coupling of insights from the framework of evolutionary economics with the perspective of ecological economics provides a promising way forward both theoretically as well as on a more applied basis with respect to a better comprehension of the socioeconomic aspects related to the climate problem. As claimed in van den Bergh (2007, p. 521), ecological economics and evolutionary economics “share many characteristics and can be combined in a fruitful way" - which renders the coupling approach both legitimate and promising.

The choice of an evolutionary line of thought initially stems from its core characteristic: given its focus on innovation and system change it provides a useful approach to start with for assessing and managing the needed transition towards a low carbon economy. Besides, its shift of focus towards a better understanding of economic dynamics together with its departure from the perfect rationality hypothesis renders evolutionary economics a suitable theoretical complement for designing environmental policies.

The notions of path-dependence and lock-in can be seen as the core elements from this PhD research. They arise from adopting a framework which is founded on a different view of individual rationality and that allows for richer and more complex causalities to be accounted for. In a quest for surmounting the above-mentioned problem of reductionism, our framework builds on the idea of ‘multi-level selection’. This means that our analytical framework should be able to accommodate not only for upward but also for downward causation, without giving analytical priority to any level over the other. One crucial implication of such a framework is that the notion of circularity becomes the core dynamic, highlighting the importance of historicity, feedbacks and emergent properties.

More precisely, the added value of the perspective adopted in this PhD research is that it highlights the role played by inertia and path-dependence. Obviously, it is essential to have a good understanding of the underlying causes of that inertia prior to devising on how to enforce a change. Providing a clear picture of the socio-economic processes at play in shaping socio-technical systems is thus a necessary first step in order to usefully complement policy-making in the field of energy and climate change. In providing an analytical basis for this important diagnosis to be performed, the use of the evolutionary framework sheds a new light on the transition towards low-carbon socio-technical systems. The objective is to suggest strategies that could prove efficient in triggering the needed transition such as it has been the case in past “lock-in” stories.

Most notably, the evolutionary framework allows us to depict the presence of two sources of inertia (i.e at the levels of individuals through “habits” and at the level of socio-technical systems) that mutually reinforce each other in a path-dependent manner. Within the broad perspective on path dependence and lock-in, this PhD research has first sketched the implications for climate policy of applying the concept of ‘technological lock-in’ in a systemic perspective. We then investigated in more details the notion of habits. This is important as the ‘behavioural’ part of the lock-in process, although explicitly acknowledged in the pioneer work of Paul David (David, 1985, p. 336), has been neglected in most of subsequent analyses. Throughout this study, the notion of habits has been studied at both the theoretical and applied level of analysis as well as from an empirical perspective.

As shown in the first chapters of the PhD, the advantage of our approach is that it can incorporate theories that so far have been presented opposite, partial and incomplete perspectives. For instance, it is shown that our evolutionary approach not only is able to provide explanation to some of the puzzling questions in economics (e.g. the problem of strong reciprocity displayed by individual in anonymous one-shot situations) but also is very helpful in bringing a complementary explanation with respect to the famous debate on the ‘no-regret’ emission reduction potential which agitates the experts of climate policy.

An emission reduction potential is said to be "no regret" when the costs of implementing a measure are more than offset by the benefits it generates such as, for instance, reduced energy bills. In explaining why individuals do not spontaneously implement those highly profitable energy-efficient investments ,it appears that most prior analyses have neglected the importance of non-economic obstacle. They are often referred to as “barriers” and partly relate to the ‘bounded rationality’ of economic agent. As developed in the different chapters of this PhD research, the framework of evolutionary economics is very useful in that it is able to provide a two-fold account (i.e. relying on both individual and socio-technical sources of inertia) of this limited rationality that prevent individuals to act as purely optimising agents.

Bearing this context in mind, the concept of habits, as defined and developed in this study, is essential in analysing the determinants of energy consumption. Indeed, this concept sheds an insightful light on the puzzling question of why energy consumption keeps rising even though there is an evident increase of awareness and concern about energy-related environmental issues such as climate change. Indeed, if we subscribe to the idea that energy-consuming behaviours are often guided by habits and that deeply ingrained habits can become “counter-intentional”, it then follows that people may often display “locked-in” practices in their daily energy consumption behaviour. This hypothesis has been assessed in our empirical analysis whose results show how the presence of strong energy-consuming habitual practices can reduce the effectiveness of economic incentives such as energy subsidies. One additional delicate factor that appears crucial for our purpose is that habits are not fully conscious forms of behaviours. This makes that individuals do not really see habits as a problem given that it is viewed as easily changed.

In sum, based on our evolutionary account of the situation, it follows that, to be more efficient, climate policies would have to both shift the incumbent carbon-based socio-technical systems (for it to shape decisions towards a reduction of greenhouse gas emissions) and also deconstruct habits that this same socio-technical has forged with time (as increased environmental awareness and intentions formulated accordingly are not sufficient in the presence of strong habits).

Accordingly, decision-makers should design measures (e.g. commitment strategies, niche management, etc.) that, as explained in this research, specifically target those change-resisting factors and their key features. This is essential as these factors tend to reduce the efficiency of traditional instruments. Micro-level interventions are thus needed as much as macro-level ones. For instance, it is often the case that external improvements of energy efficiency do not lead to lower energy consumption due to the rebound effect arising from unchanged energy-consuming habits. Bearing this in mind and building on the insights from the evolutionary approach, policy-makers should go beyond the mere subsidisation of technologies. They should instead create conditions enabling the use of the multi-layered, cumulative and self-reinforcing character of economic change highlighted by evolutionary analyses. This means supporting both social and physical technologies with the aim of influencing the selection environment so that only the low-carbon technologies and practices will survive.

Mentioned references:

David, P. A. (1985), Clio and the economics of QWERTY, American Economic Review 75/2: 332–337.

IPCC, 2007, ‘Climate Change 2007: The Physical Science Basis’, Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change [Solomon, S. D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M. Tignor and H.L. Miller (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 996 pp.

Stern, N. 2006, ‘Stern Review: The economics of Climate Change’, Report to the UK Prime Minister and Chancellor, London, 575 p. (www.sternreview.org.uk)

van den Bergh, J.C.J.M. 2007, ‘Evolutionary thinking in environmental economics’, Journal of Evolutionary Economics 17(5): 521-549.

Doctorat en Sciences économiques et de gestion
info:eu-repo/semantics/nonPublished

Collaborative studies between Quaternary scientists and archaeologists increasingly provide new and informative discussions about the nature and timing of cultural change and links with variation in the natural world (particularly climate). In the Eastern Mediterranean region, connecting the human past with palaeoclimate is an important research theme but the complex interactions between them are still poorly understood and past climate records have often been collected from regions distant from the human record. The thesis aims to derive a record of past climatic and environmental changes from lake sediment cores and synthesise this with archaeological data in order to reconstruct human-climate interactions at the regional scale. Annually laminated sediment data collected from Nar Gölϋ crater-lake and archaeological archives from the same region, Cappadocia (Turkey) allow problems of chronological uncertainty between records of the human past and palaeoclimatic archives, and spatially variable datasets to be addressed. New sediment cores collected from Nar Lake in 2010 cover the last ~14000 years based on varve counting and climate-stratigraphic correlation. The changing chemical composition of these sediments has been obtained using high-resolution Itrax XRF core scanning, mainly at 200μm resolution over 21.6m. Temporal differences in Ca and Sr are interpreted as a record of regional moisture levels, while Ti and Fe are elemental proxies that detail changes in catchment in-wash. These and other sedimentary data (e.g. total carbon analysis) document lake evolution from a predominately stable and moist early Holocene climate dominated by high authigenic Ca precipitation to a drier and less stable IV late Holocene dominated by increased authigenic Sr and Mg (and higher lake salinity levels). The most arid climatic conditions occurred during Bronze and early Iron Age times, but frequent and intense centennial-scale climatic shifts between wet and dry are also evidenced during the last 2600 years from Ca/Sr data. Peaks in Fe and Ti, along with Si, K and Rb indicate two distinct phases of increased sediment influx into Nar Lake, namely ~9200 to ~8000 yr. BP (ceramic Neolithic) and again – more importantly – during the last 2600 years (Iron Age and later). These appear to be related primarily to increased human impact on vegetation and soils in the lake-catchment, but volcanic activity and intense rainfall events and/or water deficits may also have played a role. To determine the degree to which climatic variability and cultural change are interlinked, the geochemical record from Nar Lake is correlated against long-term settlement histories which have been derived from systematic archaeological site survey and excavation data from Cappadocia. One of the key outcomes of the project is an examination of periods of climatic stability and instability which are identified by amplitudinal changes from the mean state using correlation of coefficient statistics on the Nar Lake geochemical record. This information about the predictability of climate has been coupled to data in settlement density and location within the resiliency model framework of Holling and Gunderson (2002). Together these data suggest that a series of four long-term adaptive cycles (Neolithic, Chalcolithic-Bronze Age, Iron Age-Classical, Byzantine-Ottoman) characterise the dynamic inter-play between people, climate and their environment. In each adaptive cycle, environmental change contributed (both positively and negatively) to community resilience, although at no point during the Holocene is climatic variability seen as the sole driver of societal change. There were times such as the post-Roman Dark Age (1300 to 1100 yr. B.P.) when increased climatic variability and environmental degradation may have heightened social vulnerability.

4 pp.
Southwest forests are complex systems that are influenced by climate variability. Wildfires naturally occur in these forests and woodlands, but with an increasing population, land management decisions are becoming more difficult. This publication is a result of discussions from the "Workshop on Climate Variability and Ecosystem Impacts" that was sponsored by UA Cooperative Extension in February 2005. It provides a summary of the current situation, a summary of climate change science for land management, and a brief description of suggested future research in climate science as it relates to forests and woodlands.

Climate change is an important contributor to the modification of many bumblebee species’ range boundaries. It was linked to widespread decline at the southern edge of their distribution and to their inability to colonize new areas at the northern edge. Additionally, bumblebee decline is aggravated by other anthropogenic threats like land use change, agricultural practices and pathogen spillover. Predicted consequences are numerous, and could lead to severe economic and ecological impacts on human populations. A species-specific assessment of potential climate change impacts on North American bumblebees, based on the most recent global change scenarios as used in the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC), was done for the first time. Using a massive dataset of georeferenced bumblebee observations and general circulation models, a series of species distribution models explore the impact of different climate change scenarios on climatically suitable areas of 30 bumblebee species. Northward range shifts occur in most bumblebee species’ projected climatic niches, revealing potential hotspots – places projected to be climatically suitable to multiple species – under future climate scenarios. Areas where species are likely to be lost in the absence of intervention are substantial, particularly in eastern parts of the continent. Models showed significant contractions of current ranges even under the very optimistic scenario in which all species disperse at 10 km/year. Results indicate that managed relocation as well as habitat management should be considered as a conservation strategy for some species. This research serves as a foundation for broader discussion and research in a nascent research area. It may assist in establishing localities where first conservation efforts could be directed for vulnerable bumblebee species.

There is much evidence to indicate that the climate is changing. The aims of this study were to develop meadow-like communities of Continental, Mediterranean and Temperate grassland species as a new approach to designing sustainable urban landscapes under different climate change scenarios. To achieve this aim, a community of thirty-six species from Marine, Mediterranean and Continental temperate climates were chosen to represent a gradient from well-fitted to poorly-fitted to the current British climate. The species were chosen to share similar morphological characteristics, in terms of canopy size, texture and structure. They were also chosen to be attractive in terms of colourful flowers, from spring to autumn, which provides a strong design impact. Three series of the experiment were conducted to investigate the effects of different climate scenarios on the fitness and growth performance of native and non-native species in meadow-like communities. The plant species seedlings were grown in situ at Sheffield Botanical Gardens with three watering regime rates (50% increase in precipitation, 50% decrease in precipitation and ambient), two different temperature treatments (Ambient and Ambient plus 30C), two levels of CO2 concentration (Ambient and Ambient +450PPM) in the presence or absence of molluscs. The results indicate that water availability; CO2 concentration and temperature are three important factors to choose plant species for greenspace according to the future climate change scenarios. Although each of the environmental factors has specific effects on species fitness and adjustment, their interaction is more important. At the Ambient level of CO2, the intermediate-fitted group (Mediterranean climate species) shows the highest biomass production in future climate scenarios. The poorly-fitted species cannot tolerate high levels of moisture, when the moisture level reaches Ambient over 50% of the plants in this group will show negligible growth, but increasing temperature can decrease this effect excess water in different species at different levels. Increasing CO2 from the ambient level to 900PPM enhanced the biomass productivity in all groups. The continental temperate grassland species (poorly fitted species) at CO2:900PPM, Temperature: Ambient, Moisture: Ambient and the Ambient +50% condition, showed similar biomass productivity to Mediterranean climate species. Overall, a designed plant community of species from Marine and Mediterranean climates will present the best-fitted species to design naturalistic urban landscapes according the 2050 UK climate change scenarios. Mollusc grazing was affected by different climate scenarios (from dry and warm to wet and hot). Slugs showed different behaviours in dry, wet, warm and ambient temperature in terms of plant selection for feeding. There was no significant difference in biodiversity support between native and non-native species regarding mollusc grazing.

Agriculture is one of the most important human activities providing food and more agricultural goods for seven billion people around the world and is of special importance in sub-Saharan Africa. The majority of people depends on the agricultural sector for their livelihoods and will suffer from negative climate change impacts on agriculture until the middle and end of the 21st century, even more if weak governments, economic crises or violent conflicts endanger the countries’ food security. The impact of temperature increases and changing precipitation patterns on agricultural vegetation motivated this thesis in the first place. Analyzing the potentials of reducing negative climate change impacts by adapting crop management to changing climate is a second objective of the thesis. As a precondition for simulating climate change impacts on agricultural crops with a global crop model first the timing of sowing in the tropics was improved and validated as this is an important factor determining the length and timing of the crops´ development phases, the occurrence of water stress and final crop yield. Crop yields are projected to decline in most regions which is evident from the results of this thesis, but the uncertainties that exist in climate projections and in the efficiency of adaptation options because of political, economical or institutional obstacles have to be considered. The effect of temperature increases and changing precipitation patterns on crop yields can be analyzed separately and varies in space across the continent. Southern Africa is clearly the region most susceptible to climate change, especially to precipitation changes. The Sahel north of 13° N and parts of Eastern Africa with short growing seasons below 120 days and limited wet season precipitation of less than 500 mm are also vulnerable to precipitation changes while in most other part of East and Central Africa, in contrast, the effect of temperature increase on crops overbalances the precipitation effect and is most pronounced in a band stretching from Angola to Ethiopia in the 2060s. The results of this thesis confirm the findings from previous studies on the magnitude of climate change impact on crops in sub-Saharan Africa but beyond that helps to understand the drivers of these changes and the potential of certain management strategies for adaptation in more detail. Crop yield changes depend on the initial growing conditions, on the magnitude of climate change, and on the crop, cropping system and adaptive capacity of African farmers which is only now evident from this comprehensive study for sub-Saharan Africa. Furthermore this study improves the representation of tropical cropping systems in a global crop model and considers the major food crops cultivated in sub-Saharan Africa and climate change impacts throughout the continent.
Landwirtschaft ist eine der wichtigsten menschlichen Aktivitäten, sie stellt Nahrungsmittel und andere landwirtschaftliche Produkte für weltweit 7 Milliarden Menschen zur Verfügung und ist in den Ländern Afrikas südlich der Sahara von besonderer Bedeutung. Die Mehrheit der afrikanischen Bevölkerung bestreitet ihren Lebensunterhalt in der Landwirtschaft und wird von Klimaänderungen stark betroffen sein. Die Doktorarbeit ist durch die Frage motiviert, wie sich von Klimamodellen vorhergesagte Temperaturerhöhungen und sich verändernde Niederschlagsverteilungen auf die landwirtschaftliche Vegetation auswirken werden. Die Forschungsfragen in diesem Kontext beschäftigen sich mit regionalen Unterschieden von Klimaänderungen und ihren Auswirkungen auf die Landwirtschaft und mit möglichen Anpassungsstrategien die mit geringem technischem Aufwand genutzt werden können. In diesem Zusammenhang wird schnell deutlich, dass Daten über die komplexen landwirtschaftlichen Systeme in Afrika südlich der Sahara häufig nur selten vorhanden sind, aus fragwürdigen Quellen stammen oder von schlechter Qualität sind. Die Methoden und Modelle zur Untersuchung der Auswirkungen von Klimaänderungen auf die Landwirtschaft werden zudem ausschließlich in Europa oder Nordamerika entwickelt and häufig in den temperierten Breiten aber seltener in tropischen Gebieten angewendet. Vor allem werden globale, dynamische Vegetationsmodelle in Kombination mit Klimamodellen eingesetzt um Änderungen in der landwirtschaftlichen Produktion auf Grund von Klimaänderungen in der zweiten Hälfte des 21.Jahrhunderts abzuschätzen. Die Ergebnisse der Arbeit zeigen einen mittleren Ertragsrückgang für die wichtigsten landwirtschaftlichen Pflanzen um 6% bis 24% bis 2090 je nach Region, Klimamodell und Anpassungsstrategie. Dieses Ergebnis macht deutlich, dass Landwirte die negativen Folgen von Klimaänderungen abschwächen können, wenn sie die Wahl der Feldfrucht, die Wahl des Anbausystems und den Aussaattermin an geänderte Klimabedingungen anpassen. Die Arbeit stellt methodische Ansätze zur Berechung des Aussaattermins in temperierten und tropischen Gebieten (Kapitel 2) sowie zur Simulation von Mehrfachanbausystemen in den Tropen vor (Kapitel 3). Dabei werden wichtige Parameter für das globale, dynamische Vegetationsmodell LPJmL überprüft und neu berechnet. Es zeigt sich, dass das südliche Afrika und die Sahelregion die am stärksten betroffenen Regionen sind, vor allem aufgrund von Niederschlagsänderungen, weniger aufgrund von Temperaturerhöhungen. In den meisten anderen Teilen, vor allem Zentral- und Ostafrikas bedingen Temperaturerhöhungen Rückgänge der Erträge (Kapitel 4). Diese Arbeit leistet einen wichtigen und umfassenden Beitrag zum Verständnis der Auswirkung von Klimaänderung auf die landwirtschaftliche Vegetation und damit zu einem großen Teil auf die Lebensgrundlage von afrikanischen Landwirten.

Global Circulation Models (GCMs) are used to create projections of possible future climate characteristics under global climate change scenarios. Future local and regional precipitation scenarios can be developed by downscaling synoptic CGM data. Daily 500-mb geopotential heights from the Canadian Centre for Climate Modeling and Analysis's CGCM2 are used to represent future (2020-2050) synoptics and are compared to daily historical (1960-1990) 500-mb geopotential height reanalysis data. The comparisons are made based on manually classified synoptic patterns identified by Changnon et al. (1993.Mon. Weather Rev. 121:633-647). Multiple linear regression models are used to link the historical synoptic pattern frequencies and precipitation amounts for 372 weather stations across western North America,. The station-specific models are then used to forecast future precipitation amounts per weather station based on synoptic pattern frequencies forecast by the CGCM2 climate change forcing scenario. Spatial and temporal variations in precipitation are explored to determine monthly, seasonal and annual trends in climate change impacts on precipitation in western North America. The resulting precipitation scenarios demonstrate a decrease in precipitation from 10 to 30% on an annual basis for much of the south and western regions of the study area. Seasonal forecasts show variations of the same regions with decreases in precipitation and select regions with increases in future precipitation. A major advancement of this analysis was the application of synoptic pattern downscaling to summer precipitation scenarios for western North America.
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A modelling approach focused on snow hydrology was developed and applied to project future changes in spring streamflow volumes in the St. Mary River headwaters basin, Montana. A spatially distributed, physically-based, hydrometeorological and snow mass balance model was refined and used to produce snow water equivalent (SWE) and rainfall surfaces for the study watershed. Snowmelt runoff (SR) and effective rainfall runoff (RR) volumes were compiled for the 1961-2004 historical period. A statistical regression model was developed linking spring streamflow volume (QS) at Babb, Montana to the SR and RR modelled data. The modelling results indicated that SR explained 70% of the variability in QS while RR explained another 9%. The model was applied to climate change scenarios representing the expected range of future change to produce annual QS for the period 2010-2099. Compared to the base period (1961-1990), average QS change ranged from -3% to -12% for the 2020s period. Percent changes increased to between -25% and -32% for the 2050s, and -38% and -55% for the 2080s. Decreases in QS also accompanied substantial advances in the onset of spring snowmelt. Whereas the spring pulse onset on average occurred on April 8 for the base period, it occurred 36 to 50 days earlier during the 2080s. The findings suggest that increasing precipitation will not compensate for the effects of increasing temperature in watershed SWE and associated spring runoff generation. There are implications for stakeholder interests related to ecosystems, the irrigation industry, and recreation.
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Climate change and variability are likely to impact crop productivity. Crop models are widely used for investigating the responses of crop growth and development to climate and weather. However, the spatial and temporal scales of climate model outputs are relatively coarse compared with the usual inputs to dynamic crop models. The general large-area model for annual crops (GLAM) has been developed to simulate groundnut productivity at the spatial scale of global and regional climate models. A wheat version of the model was developed in this study by defining wheat specific parameter sets and by modifying some model processes such as phenology, leaf area growth, extreme high temperature stress and assimilation. This study focused on wheat crops in China. Correlations between observed wheat yield, rainfall and temperature were analysed to understand the response of yield variability to climate variability under the current climate. Climate showed a weak correlation with wheat yield in most areas of China where wheat is grown.

Master of Science
Department of Biological & Agricultural Engineering
Kyle R. Douglas-Mankin
The Great Plains once encompassed 160 million hectares of grassland in the central United States. In the last several decades, conversion of grassland to urban and agricultural production areas has caused significant increases in runoff and erosion. Past attempts to slow this hydrologic system degradation have shown success, but climate change could once again significantly alter the hydrology. The Intergovernmental Panel on Climate Change (IPCC) studies the state of knowledge pertaining to climate change. The IPCC has developed four possible future scenarios (A1, A2, B1 and B2). The output temperature and precipitation data for Northeast Kansas from fifteen A2 General Circulation Models (GCMs) were analyzed in this study. This analysis showed that future temperature increases are consistent among the GCMs. On the other hand, precipitation projections varied greatly among GCMs both on annual and monthly scales. It is clear that the results of a hydrologic study will vary depending on which GCM is used to generate future climate data. To overcome this difficulty, a way to take all GCMs into account in a hydrologic analysis is needed. Separate methods were used to develop three groups of scenarios from the output of fifteen A2 GCMs. Using a stochastic weather generator, WINDS, monthly adjustments for future temperature and precipitation were applied to actual statistics from the 1961 – 1990 to generate 105 years of data for each climate scenario. The SWAT model was used to simulate watershed processes for each scenario. The streamflow output was analyzed with the Indicators of Hydrologic Alteration program, which calculated multiple hydrologic indices that were then compared back to a baseline scenario. This analysis showed that large changes in projected annual precipitation caused significant hydrologic alteration. Similar alterations were obtained using scenarios with minimal annual precipitation change. This was accomplished with seasonal shifts in precipitation, or by significantly increasing annual temperature. One scenario showing an increase in spring precipitation accompanied by a decrease in summer precipitation caused an increase in both flood and drought events for the study area. The results of this study show that climate change has the potential to alter hydrologic regimes in Northeast Kansas.

Background: Climate change and the consequences of global warming is probably one of the greatest issues of our time. Among other concerns, global warming is thought to have a great impact on hydrology worldwide. When the atmosphere warms up, river runoff patterns are altered. Nevertheless these future changes are assumed to increase the hydropower potential in some countries. In the public debate it is often referred to a nine year old investigation claiming an increase of 15-20 % in Swedish energy production from hydropower due to the river runoff increase. On the other hand recent research is hinting that the effect of global warming might be masked by climate variability in the nearest future. This study seeks to investigate whether or not the hydropower-intensive company Fortum will benefit from increased future hydropower potential due to climate change. Methods: Using historical data, the impacts of global warming on the future potential power production in different types of hydropower plants are estimated by the statistical approach of probability density functions. Moreover spectral analysis is used to investigate the impacts of climate variability in various Swedish watersheds. The study investigates both the nearest future, represented by the years 2021-2050, and the end of the century, represented by the years 2069-2098. Results: The future hydropower production is shown to be strongly dependent on the geographical location of a power plant and of the specific power plant type. Although all Swedish rivers where Fortum operates is given more river runoff in the future, some hydropower plants might  suffer from lower hydropower potential due to increased runoff variability. However all reservoir-type power plants in the study, with ability to store water, are calculated to benefit from increased river runoff. Only the run-of-river type power plants, operating with unregulated river flow, are not yet proven to benefit from a changing climate. When considering both specific river and type of power plant, this study indicates that the hydropower potential in the rivers where Fortum operates is expected to increase with 4-15 % towards the end of the century. The one exception is the unregulated river Västerdalälven where this study indicates a possibility of decreased hydropower potential due to climate change. The results of the spectral analysis indicates that up to 30 % of the coefficient of variation in the  monthly mean runoff data is explained by low-frequent periodic fluctuations due to natural climate variability, linked to somewhat predictable climate indices. Conclusion: Natural climate variability is likely to be the dominating factor in the nearest future, at least in regulated rivers. Although there are uncertainties about the future potential power production in the run-of-river type power plants, one cannot deny that most of the Swedish rivers where the major hydropower companies operate are strongly regulated. Adding the fact that river runoff will increase as a consequence of global warming, Fortum is likely to gain from an increased hydropower potential. However, this present study highlights the inaccuracies in using the out-of-date estimation of 15-20 % hydropower-potential increase as a forecast of future potential power production in all Fortum-operated hydropower plants.

This thesis aims to assess the effects of climate change mediated through the watersheds of global dams on water resources delivered to those dams. Dams and reservoirs play an important role in social and economic development contributing water for 12-16% of global food production and providing around 20% of the world's energy supply through hydropower. The first part of this research has been dedicated to the further development of the first global geo-referenced database of dams (KCL GOOD2) that allows for modelling the impacts of land use and climate changes on water supplies. More than 36,000 dams were identified in a collaborative effort using an open source database (GEOWIKI) and Google Earth. This database was then used to extract all individual dam watersheds. These watersheds combined make up around 18% of global land mass which means that impacts of climate change can have profound impacts on the water resources delivered to dams. By combining the calculated watersheds of dams with climate model projections from the IPCC AR4, changes in the water balance in the catchments of these dams were calculated and changes in reservoir water level were estimated for a range of large dams. The AguaAndes/WaterWorld spatial hydrological model using a multi-GCM scenario was then applied to three case study dams in different climate regions around the world to evaluate directional changes in water and sediment supply. Sensitivity to climate and land cover changes of the basins containing the dams was assessed by running the model for a range of scenarios. The final part of this thesis describes the application of the AguaAndes/WaterWorld model to the Santa basin in Peru to assess the impacts of climate change on a small hydroelectric plant using several multi-GCM scenarios to address uncertainty in the projections.

As global mean temperature continues to rise steadily, agricultural systems are projected to face unprecedented challenges to cope with climate change. However, understanding of climate change impacts on global crop yield, and of farmers' adaptive capacity, remains incomplete as previous global assessments: (1) inadequately evaluated the role of extreme weather events; (2) focused on a small subset of the full range of climate change predictions; (3) overlooked uncertainties related to the choice of crop modelling approach and; (4) simpli�ed the representation of farming adaptation strategies. This research aimed to assess climate change impacts on global crop yield that accounts for the knowledge gaps listed above, based on the further development and application of the global crop model PEGASUS. Four main research topics are presented. First, I investigated the roles of extreme heat stress at anthesis on crop yield and uncertainties related to the use of seventy-two climate change scenarios. I showed large disparities in impacts across regions as extreme temperatures adversely a�ects major areas of crop production and lower income countries, the latter appear likely to face larger reduction in crop yields. Second, I coordinated the �rst global gridded crop model intercomparison study, comparing simulations of crop yield and water use under climate change. I found modelled global average crop water productivity increases by up to 17�20.3% when including carbon fertilisation e�ects, but decreases to {28�13.9% when excluding them; and identi�ed fundamental uncertainties and gaps in our understanding of crop response to elevated carbon dioxide. Third, to link climate impacts with adaptation, I introduced the recently developed concept of representative agricultural pathways and examined their potential use in models to explore farming adaptation options within biophysical and socio-economic constraints. Finally, I explored tradeo�s between increasing nitrogen fertiliser use to close the global maize yield gap and the resulting nitrous oxide emissions. I found global maize production increases by 62% based on current harvested area using intensive rates of nitrogen fertiliser. This raises the share of nitrous oxide emissions associated with maize production from 20 to 32% of global cereal related emissions. Finally, these results demonstrated that in some regions increasing nitrogen fertiliser application, without addressing other limiting factors such as soil nutrient imbalance and water scarcity, could raise nitrous oxide emissions without enhancing crop yield.

El primer estudio de esta tesis doctoral demostró que tanto las temperaturas ambientales altas como las bajas y las olas de calor son factores de riesgo de mortalidad por todas las causas en la India, y el riesgo de mortalidad aumenta de manera más pronunciada a temperaturas más altas. El segundo y tercer estudio evaluaron algunos de los beneficios colaterales para la salud relacionados con la contaminación del aire y las compensaciones de la mitigación del cambio climático en la India. Los hallazgos sugirieron que la reducción proyectada de la contaminación del aire ambiental bajo los objetivos del Acuerdo de París puede alargar la esperanza de vida al nacer, reducir la mortalidad prematura y el número de niños con retraso en el crecimiento en la India para 2050 en comparación con los negocios habituales. Sin embargo, los costos de combustible más altos en virtud de los objetivos del Acuerdo de París pueden conducir a una mayor contaminación del aire en los hogares, compensando así por completo los beneficios para el crecimiento lineal infantil de una mejor calidad del aire ambiental. Complementar las medidas de mitigación con el control de la calidad del aire al final de la tubería y las políticas para respaldar el acceso a una cocina limpia puede maximizar los beneficios colaterales para la salud y reducir las compensaciones de mitigación, especialmente entre los más desfavorecidos.
The first study in this PhD thesis demonstrated that both high and low ambient temperatures and heatwaves are risk factors for all-cause mortality in India, with mortality risk increasing more steeply at higher temperatures. The second and third study assessed some of the air pollution related health co-benefits and trade-offs from climate change mitigation in India. Findings suggested that projected reduction of ambient air pollution under the Paris Agreement targets can lengthen life expectancy at birth, reduce premature mortality and the number of stunted children in India by 2050 compared to the business-as-usual. However, higher fuel costs under Paris Agreement targets can lead to higher household air pollution, thus completely offsetting the benefits for child linear growth from improved ambient air quality. Complementing mitigation measures with end-of-pipe air quality control and policies to support access to clean cooking can maximise health co-benefits and reduce mitigation trade-offs, especially among the most disadvantaged.

Climate change and variability are predicted to threaten agricultural production in Southern Africa. For example, Zambia's agriculture remains vulnerable to climate change and variability due to the small-scale farmers' dependence on rain-fed agriculture. Some studies in Zambia have shown the quantitative negative impacts of climate variability on agriculture; however, there is limited knowledge on how farmers perceive the impacts and adapt their agricultural systems. To fill in the knowledge gap mentioned above, the aim of the present study was to evaluate farmers' observations of climate variability impacts and their responses. The study then evaluates the integration of farmers' climate variability observations and adaptation strategies into local district plans. Such integration is deemed critical to ensure agricultural strategies promoted by extension officers are locally relevant and are adopted by the farmers. The study is based on semi-structured interviews and literature review. Thirty-one (31) farmers from Mwembeshi, Chilanga District, Zambia, participated in the study. The findings of the survey indicate that farmers in Mwembeshi are aware of their vulnerability to climate variability impacts. As a result of the observed impacts, they have developed several adaptation strategies. Through this study, extension agents were also interviewed in order find out what adaptation strategies are promoted to the farmers. The findings of the research indicate agricultural extension agents follow national agricultural adaptation strategies (top-down approach). As a result, local agricultural development plans would not specifically integrate/respond to climate variations impacts observed by the farmers. In order to engage local farmer impacts of the climate variability and their adaptation strategies into the local plans, the research suggests a more flexible (or bottom-up) approach to local development planning. Such an approach would allow the integration of local farmer observations of climate variability and their adaptation strategies into district plans. The study also found that extension agents have limited knowledge of climate variability and change, which negatively affects knowledge transfer to farmers on the subject. Therefore, training the extension officers in the subject would most likely increase farmers' knowledge on climate variability and adaptation decision.