Hypotheses about the causes of the growth and decline of the Chacoan regional interaction system in the southwestern United States between A.D. 900 and 1200 are evaluated against tree-ring evidence and the results of an empirical model (PRECON) that computes the statistical relationships between climate and ring-width indices during the 20th century and applies the results to hypothesized precipitation or temperature changes. The statistical responses of 23 indexed conifer ring-width chronologies from New Mexico and Colorado to variations in monthly temperature and precipitation were calculated. Simulated decreases in prior autumn-winter precipitation markedly reduced ring widths, while decreased current summer precipitation was less effective, sometimes reducing ring width or having little effect. Decreased prior winter temperature slightly reduced ring width, while decreased growing season temperature usually increased or did not effect ring widths. Evaluated in terms of these results, the Chaco Canyon area tree-ring record (1) indicates that favorable climatic conditions in the 10th, 11th, and early 12th centuries fostered the growth of the Chacoan system, (2) shows that dry autumn-winter and summer conditions in the middle 1100s contributed to the downfall of the system, (3) does not support the proposition that centuries-long climatic fluctuations evident in southwestern Colorado affected Chaco Canyon, (4) does not support the idea of shifts from summer-to winter-dominant precipitation regimes, and (5) contributes little to assessing the role of anthropogenic environmental change in the collapse of the Chacoan system.

A growing human population and demands for food, freshwater and energy are causing extensive changes in the water and biogeochemical cycles of river catchments around the world. Addressing and investigating such changes is particularly important for transboundary river catchments, where they impose additional risk to a region’s stability. This thesis investigates and develops data-driven methodologies for detecting hydro-climatic and nutrient load changes and their drivers with limited available data and on different catchment scales. As a specific case study, we analyze the Sava River Catchment (SRC) and compare its results with other world regions. A past–present to future evaluation of hydro-climatic data is done on the basis of a water balance approach including analysis of historic developments of land use and hydropower development data and projections of the Coupled Model Intercomparison Project, Phase 5 (CMIP5) output. Using observed water discharge and nutrient concentration data, we propose a novel conceptual model for estimating and spatially resolving total nitrogen (TN) and total phosphorus (TP) input and delivery-retention properties for a river catchment and its nested subcatchments, as well as detection of nutrient hotspots. The thesis identifies hydroclimatic change signals of hydropower-related drivers and finds consistency with other world regions. The proposed nutrient screening methodology provides a good distinction between human-related nutrient inputs and landscape-related transport influences on nutrient loading at subcatchment to catchment scale. A cross-regional comparison of the SRC data with the Baltic region shows similarity between nutrient-relevant indicators and driving socio-economic and hydro-climatic conditions. The study highlights a number of complexities with regard to CMIP5 model representation of water fluxes. The large intermodel range of CMIP5 future projections of fluxes calls for caution when using individual model results for assessing ongoing and future water and nutrient changes. / <p>QC 20170516</p> / VR 2009-3221 / FORMAS 2014-43

Les fluctuations climatiques Quaternaires (<2.5 Ma) offrent un contexte approprié à l’étude de l’impact du changement climatique actuel sur la biodiversité. La dernière glaciation, dont le maximum glaciaire s'est terminé il y a environ 19 000 ans, a ainsi largement participé à la distribution des espèces actuelles. Les derniers milliers d'années constituent donc une période propice à l'étude de la mise en place et du maintien de la biodiversité.L'objectif de ma thèse a été de mieux comprendre comment une espèce de rongeur forestier apparue il y a environ 2 Ma, le campagnol roussâtre (Myodes glareolus), a répondu à ces cycles du Quaternaire. Mon étude s’est basée sur une approche morphométrique de plusieurs caractères impliqués dans la mastication (mandibule et molaires), visant à quantifier la différenciation de forme associée à l’influence de différents facteurs.Des résultats contrastés ont été obtenus selon le caractère considéré, la mandibule montrant une importante variabilité liée aux variations de la structure d’âge des populations. Au contraire, les molaires ont pu être utilisées comme marqueur de la structuration biogéographique du campagnol roussâtre.L'étude dans l'actuel des variations de taille et de forme des molaires et mandibules du campagnol roussâtre Myodes glareolus a nécessité l'intégration de thématiques variées touchant au patrimoine génétique des organismes, à leur développement, aux traits d'histoire de vie, à l'environnement, etc. Ceci a permis de mieux appréhender la complexité des processus conduisant à la grande diversité des patrons de forme observés chez le campagnol roussâtre. / The climatic fluctuations of the Quaternary (<2.5 Ma) provide an appropriate background to the study of the influence of the actual climatic change on the biodiversity. For example, the last glaciation, including the Last Glacial Maximum (~19000 yrs), shaped the geographic distribution observed on actual species.The aim of my thesis was to better understand how a forest-related species of rodent, the bank vole (Myodes glareolus), was affected by the Quaternary cycles. In this way, I used a morphometric approach of diverse characters involved in the mastication process (mandible and molars) to quantify the shape differentiation related to the influence of several factors.Contrasted results were observed, the mandible being widely influenced by the age structure of the studied populations. In contrary, molars can be used as relevant markers of the biogeographic structuration of the bank vole.The study on the size and shape variations of actual specimens needed the integration of various fields of research, dealing with the genetic heritage of the organisms, their development, the environment etc.It allowed a better comprehension of the complexity of the processes leading to a wide diversity of shape patterns within the bank vole.

A thesis submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Doctor of Philosophy The support of the Global Change and Sustainability Research Institute (GCSRI) towards this research is hereby acknowledged. Opinions expressed and conclusions arrived at, are those of the author and are not necessarily to be attributed to the GCSRI. February 2017 in Johannesburg, South Africa / Global change, specifically land cover change and climate change, are recognised as the leading drivers of biodiversity loss worldwide. Habitat loss has resulted in a loss of biodiversity and led to significant declines in species populations. Climate change is altering species distributions, ecosystem composition and phenology. Conservation planning is required to offset these dynamic threats to species persistence into the future. Plants form the basis of trophic structure and functioning and may not be able to track changing environmental conditions as well as mobile species. They thus represent an essential starting point for understanding climate change and habitat loss impacts. The patterns and processes which generate and maintain floristic diversity must be explored before global change impacts on these communities can be assessed and planned for at a landscape scale. This thesis investigates the environmental variables structuring indigenous plant community composition, pattern and turnover in grassland and savanna systems in KwaZulu-Natal. The threats posed by land cover change and climate change are explored and a coarse-grained landscape connectivity map developed to impart maximum resilience in order to maintain floristic diversity in the era of anthropogenically induced global change. The environmental variables correlated to floristic pattern and turnover were temperature, soil fertility and precipitation variables. The orientation of the temperature gradient conflicts with the soil fertility gradient, hence species with particular soil requirements will be hampered in their efforts to track the temperature gradient. The gradients were non-linear with turnover highest on dystrophic soils in warm and drier summer regions. The major drivers of land cover change were cropped agriculture, timber plantations (agroforestry), rural and urban development, dams and mines. The drivers of change differed according to land tenure type. The average rate of habitat loss in the province over an 18 year period was 1.2% per annum, levels which are considered unsustainable. A target level of 50% of natural habitat remaining is recommended. Environmental domains were identified using the environmental correlates of plant community composition. These were used to investigate climate change impacts using a collection of downscaled climate models. Conditions suiting savanna species are set to increase at the expense of conditions suiting grassland species raising significant challenges for the conservation of grasslands. Indices of habitat intactness and climatic stability were used to develop a vulnerability framework to guide conservation actions to mitigate global change impacts on floristic diversity. Building on the insights gained from the study, a connectivity map linking protected areas was developed, that if implemented, will maximise the opportunity to maintain floristic diversity into the future. The spatial location of the corridors was prioritised based on broad scale climatic refugia, high turnover areas and important plant areas for endemic and threatened species. The corridors were aligned along the major climatic gradients driving floristic pattern. The corridors represent the most natural and cost-effective way for species to adapt to climate change and persist in the landscape. This thesis provides new insights into two global threats facing plant communities in KwaZulu-Natal and provides a suite of products that inform dynamic conservation planning and directs appropriate conservation action. The results may be used to inform policy and legislation. / MT2017

Three major teleconnections, Atlantic Multidecadal Oscillation (AMO), North Atlantic Oscillation (NAO), and the Pacific Decadal Oscillation (PDO), in warm and cool phases, effect precipitation in Florida. The effects of the oscillation phases on the precipitation characteristics are analyzed by using long-term daily precipitation data, on different temporal (annual, monthly, and daily) and spatial scales, utilizing numerous indices, and techniques. Long-term extreme precipitation data for 9 different durations is used to examine the effects of the oscillation phases on the rainfall extremes, by employing different parametric and non-parametric statistical tests, along with Depth-Duration- Frequency analysis. Results show that Florida will experience higher rainfall when AMO is in the warm phase, except in the panhandle and south Florida, while PDO cool phase is positively correlated with precipitation, except for the southern part of the peninsula. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2013.

<p>One of the distinguishing features of successful societies is the ability to adapt to change, both</p><p>social but also natural changes like climate change. Climate change is a complex, dynamic,</p><p>non-linear process with a great deal of uncertainty concerning the time perspective, risks and</p><p>consequences. A combination of factors like climate change, geographical vulnerability, a</p><p>densely populated and highly built up coast line along with factors like deficient handling of</p><p>surface runoff and a large usage of ground water leads to an increasingly vulnerable society. It</p><p>also puts a greater pressure on the society to have preventive measures in place.</p><p>The number of actors working with preparing society to the expected impacts of climate</p><p>change and variability is increasing. However more than half of Sweden’s municipalities do</p><p>not consider changing climatic conditions when planning, and many times even allow the</p><p>construction of new living areas in known climatically vulnerable areas. Certain geographical</p><p>areas in Sweden are characterized by environmental problems which enhance the predicted</p><p>effects of climate change. The coast of Scania (Skåne) is one such area, where people for a</p><p>long time have had to adjust to conditions like coastal erosion, recurring high tides, low lying</p><p>areas and sinking land.</p><p>The following study elaborates the politics of adaptive capacity. It is based on a comparative</p><p>case study of two different policy processes regarding adjustments to climatic conditions in</p><p>the coastal municipalities of Vellinge and Lomma in south-western Scania. In other words,</p><p>this study explores the underlying factors that can explain what drives anticipatory measures</p><p>to strengthen the ability and possibility to handle effects related to climate change. The</p><p>theoretical framework consists of theories regarding policy changes in social ecological</p><p>systems, and adaptation to climate. Structural actor based perspective, as well as system</p><p>oriented and process oriented have been applied.</p><p>The results are based on 14 interviews with key politicians, officials and stakeholders from</p><p>non-governmental organizations. The study is also based on reports, a citizen’s survey from</p><p>Statistics Sweden (SCB), newspaper articles, municipal documents, web sites and literature.</p><p>The results show that the municipality of Vellinge implemented adaptation strategies years</p><p>before Lomma municipality. Policy change was triggered by observed vulnerabilities in</p><p>ecological systems which affected the social systems. It resulted in an intense debate (a</p><p>window of opportunity), which in turn opened a policy window.</p><p>The driving forces in policy process are central actors and shadow networks with access to</p><p>knowledge. The results show that knowledge and understanding of ecological systems is</p><p>essential for policy changes in climate adaptations. Research is needed, but research by itself</p><p>will not be sufficient, research and knowledge must be transferred to decision-makers.</p><p>Knowledge transferring is even important for officials and public. That means that an</p><p>understanding of ecological systems is necessary for forming attitudes and for planning a</p><p>society with the ability to meet climate change and the insecurities which are connected with</p><p>it.</p>

Diss. (sammanfattning) Umeå : Sveriges lantbruksuniversitet, 2009. / Härtill 4 uppsatser.

Diss. (sammanfattning) Umeå : Sveriges lantbruksuniversitet, 2010. / Härtill 4 uppsatser.

Master's thesis. / Format: PDF. Bibl.

Unchecked anthropogenic climate change has the potential to destroy human lives and wealth on an unprecedented scale. This dissertation analyzes from an economic perspective various public policy options to correct the market failures caused by climate change. The widespread adoption of environmentally friendly consumer products can reduce the impacts of climate change. The first chapter analyzes various methods of encouraging the market performance of these products. I build a model of observational learning in which a "green" consumer good enters a market to challenge an established "dirty" product. Among other results, I provide conditions for when financial incentives or informational campaigns should be more effective at encouraging the market performance of green products. I also provide a discussion and an empirical analysis of the performance of compact fluorescent light bulbs in the U.S. residential market, and compare the findings to the predictions of the theoretical model. The second chapter provides a critic of the macroeconomic models economists have used to determine optimal climate change abatement policies. I build a model that can incorporate more realistic ranges of uncertainty for both the occurrence of catastrophic events and societal risk aversion than economists have used in the past. Numerical simulations are then used to calculate a range of risk premiums, the magnitude of which display that previous calculations of optimal carbon dioxide taxes are too imprecise to support any particular policy recommendation. Government-backed energy-efficiency programs have become popular as components of local and national strategies to combat climate change. The effectiveness of such policies hinges on whether they provide the appropriate incentives to both energy consumers and program implementers. The third chapter analyzes evaluations of California's energy-efficiency programs to assess their effectiveness at improving our understanding of the programs' performance and providing a check on utility incentives to overstate energy savings. We find, among other results, that evaluations are useful tools to achieve both of these goals because the programs largely did not meet their energy-savings projections, and the utility savings estimates are systematically higher than the third-party savings estimates of the evaluations. / text