Linkages between Atmospheric Circulation, Weather, Climate, Land Cover and Social Dynamics of the Tibetan Plateau

The Tibetan Plateau (TP) is an important landmass that plays a significant role in both regional and global climates. In recent decades, the TP has undergone significant changes due to climate and human activities. Since the 1980s anthropogenic activities, such as the stocking of livestock, land cover change, permafrost degradation, urbanization, highway construction, deforestation and desertification, and unsustainable land management practices, have greatly increased over the TP. As a result, grasslands have undergone rapid degradation and have altered the land surface which in turn has altered the exchange of heat and moisture properties between land and the atmosphere. But gaps still exist in our knowledge of land-atmosphere interactions in the TP and their impacts on weather and climate around the TP, making it difficult to understand the complete energy and water cycles over the region. Moreover, human, and ecological systems are interlinked, and the drivers of change include biophysical, economic, political, social, and cultural elements that operate at different temporal and spatial scales. Current studies do not holistically reflect the complex social-ecological dynamics of the Tibetan Plateau. To increase our understanding of this coupled human-natural system, there is a need for an integrated approach to rendering visible the deep interconnections between the biophysical and social systems of the TP. There is a need for an integrative framework to study the impacts of sedentary and individualized production systems on the health and livelihoods of local communities in the context of land degradation and climate change. To do so, there is a need to understand better the spatial variability and landscape patterns in grassland degradation across the TP. Therefore, the main goal of this dissertation is to contribute to our understanding of the changes over the land surface and how these changes impact the plateau\u27s weather, climate, and social dynamics. This dissertation is structured as three interrelated manuscripts, which each explore specific research questions relating to this larger goal. These manuscripts constitute the three primary papers of this dissertation. The first paper documents the significant association of surface energy flux with vegetation cover, as measured by satellite based AVHRR GIMMS3g normalized difference vegetation index (NDVI) data, during the early growing season of May in the western region of the Tibetan Plateau. In addition, a 1°K increase in the temperature at the 500 hPa level was observed. Based on the identified positive effects of vegetation on the temperature associated with decreased NDVI in the western region of the Tibetan Plateau, I propose a positive energy process for land-atmosphere associations. In the second paper, an increase in Landsat-derived NDVI, i.e., a greening, is identified within the TP, especially during 1990 to 2018 and 2000 to 2018 time periods. Larger median growing season NDVI change values were observed for the Southeast Tibet shrublands and meadows and Tibetan Plateau Alpine Shrublands and Meadows grassland regions, in comparison to the other three regions studied. Land degradation is prominent in the lower and intermediate hillslope positions in comparison to the higher relative topographic positions, and change is more pronounced in the eastern Southeast Tibet shrublands and meadows and Tibetan Plateau Alpine Shrublands and Meadows grasslands. Geomorphons were found to be an effective spatial unit for analysis of hillslope change patterns. Through the extensive literature review presented in third paper, this dissertation recommends using critical physical geography (CPG) to study environmental and social issues in the TP. The conceptual model proposed provides a framework for analysis of the dominant controls, feedback, and interactions between natural, human, socioeconomic, and governance activities, allowing researchers to untangle climate change, land degradation, and vulnerability in the Tibetan Plateau. CPG will further help improve our understanding of the exposure of local people to climate and socio-economic and political change and help policy makers devise appropriate strategies to combat future grassland degradation and to improve the lives and strengthen livelihoods of the inhabitants of the TP

The EU, climate change and geopolitics of the Arctic: Great power strategies and European response

Due to its unique characteristics such as strategic location and appearance, the Arctic is a natural area of great importance for the Earth and its biosphere. Because of climate change, it is increasingly warmer, and in the summer months almost ice-free. This presents big threats for flora, fauna, and mankind. At the same time, these changes provide great opportunities and development potential in terms of new sea trade routes, unexploited raw materials, strategic security advantages. The goal of this thesis is to find out which Arctic strategies the EU, USA, Russia, and China have adopted to deal with the changes in the Arctic. What are their main interests and goals? Is there cause to fear an open conflict or not? Furthermore, it provides an analysis of how the EU is preparing for the changing Arctic. The basic assumption of this thesis is rooted in political Realism and the associated geostrategic variety of Geopolitics. It contains a qualitative analysis, primarily critically analyzing existing literature, but also some primary published sources. The thesis concludes that the EU is already an Arctic actor, sharing partially similar goals for the Arctic as China, with a focus on the region’s economic development. Whereas Russia and the USA give, alongside the economic development, a more prominent role to defense and security matters. However, currently, there is no cause to fear an open armed conflict.Devido às suas características únicas, tais como localização estratégica e aparência, o Árctico é uma área natural de enorme importância para a Terra, e para a sua biosfera. Devido às alterações climáticas, é uma região cada vez mais quente, e nos meses de Verão já quase sem gelo. Isto comporta grandes ameaças para a flora, a fauna e a humanidade. Ao mesmo tempo, estas mudanças criam grandes oportunidades e potencial de desenvolvimento em termos de: novas rotas comerciais marítimas, matérias-primas não exploradas, vantagens estratégicas em termos de segurança. O objectivo desta tese é identificar as estratégias que a UE, EUA, Rússia e China adoptaram para lidar com as mudanças no Árctico. Quais são os seus principais interesses e objectivos? Há ou não motivos para recear um conflito aberto? Além disso, apresenta uma análise de como a UE se está preparando para a mudança em curso no Árctico. A abordagem desta tese está enraizado no Realismo político e na variedade geoestratégica da Geopolítica a ele associada. Contém uma análise qualitativa, analisando principalmente de forma crítica a literatura existente, bem como algumas fontes primárias publicadas. Esta análise documenta conclui que a UE já é um actor do Árctico, partilhando uma abordagem parcialmente semelhantes para o Árctico à da China, com enfoque no desenvolvimento económico destas regiões. Enquanto que a Rússia e os EUA adoptam, a par da aposta no desenvolvimento económico, uma abordagem mais centrada em matérias de defesa e segurança. No entanto, actualmente não há motivo para recear um conflito armado aberto na região

The Socioeconomic and Ecological Drivers of Avian Influenza Risks in China and at the International Level

abstract: Avian influenzas are zoonoses, or pathogens borne by wildlife and livestock that can also infect people. In recent decades, and especially since the emergence of highly pathogenic avian influenza (HPAI) H5N1 in 1996, these diseases have become a significant threat to animal and public health across the world. HPAI H5N1 has caused severe damage to poultry populations, killing, or prompting the culling of, millions of birds in Asia, Africa, and Europe. It has also infected hundreds of people, with a mortality rate of approximately 50%. This dissertation focuses on the ecological and socioeconomic drivers of avian influenza risk, particularly in China, the most populous country to be infected. Among the most significant ecological risk factors are landscapes that serve as “mixing zones” for wild waterfowl and poultry, such as rice paddy, and nearby lakes and wetlands that are important breeding and wintering habitats for wild birds. Poultry outbreaks often involve cross infections between wild and domesticated birds. At the international level, trade in live poultry can spread the disease, especially if the imports are from countries not party to trade agreements with well-developed biosecurity standards. However, these risks can be mitigated in a number of ways. Protected habitats, such as Ramsar wetlands, can segregate wild bird and poultry populations, thereby lowering the chance of interspecies transmission. The industrialization of poultry production, while not without ethical and public health problems, can also be risk-reducing by causing wild-domestic segregation and allowing for the more efficient application of surveillance, vaccination, and other biosecurity measures. Disease surveillance is effective at preventing the spread of avian influenza, including across international borders. Economic modernization in general, as reflected in rising per-capita GDP, appears to mitigate avian influenza risks at both the national and sub-national levels. Poultry vaccination has been effective in many cases, but is an incomplete solution because of the practical difficulties of sustained and widespread implementation. The other popular approach to avian influenza control is culling, which can be highly expensive and raise ethical concerns about large-scale animal slaughter. Therefore, it is more economically efficient, and may even be more ethical, to target the socio-ecological drivers of avian influenza risks, including by implementing the policies discussed here.Dissertation/ThesisDoctoral Dissertation Biology 201

Soil erosion and sediment yield in the upper Yangtze, China

Soil erosion and sedimentation are key environmental problems in the Upper Yangtze because of the ongoing Three Gorges Project (TGP), the largest hydro-power project in the world. There is growing concern about the rapid increase of soil erosion over the last few decades and its consequence for potential sedimentation in the reservoir. The study aims to examine controls on the spatial and temporal distributions of sediment transfer within the Upper Yangtze and the hydrological consequences of land use changes, using varied approaches at different catchment scales. First, soil erosion and sedimentation are examined using the radionuclide Cs-137 as a tracer within a small reservoir catchment in the Three Gorges Area. The results indicates that soil erosion on sloping arable land and the rates of reservoir sedimentation have been severe during the past 40 years, mainly due to cultivation on steep slopes. Changes in reservoir sedimentation rates are mainly attributed to land use changes. The suitability of the Cs-137 techniques for investigating soil erosion and sedimentation in intensely cultivated subtropical environments is also considered. The use of the technique for erosion investigation may have limitations due to the abundance of coarse soil textures, uncertainty about fallout deposition rates and the high incidence of human disturbance, but the technique shows promising perspectives for sedimentation investigation since a few dating horizons might be identified. Second, sediment and runoff measurement data for around 30 years from over 250 hydrological stations within the Upper Yangtze have been examined within a GIS framework. The dataset has been integrated with catchment characteristics derived from a variety of environmental datasets and manipulated with Arc/Info GIS. The analysis of the sediment load data has permitted identification of the most important locations of sediment sources, the shifting pattern of source areas in relation to land use change and sub-catchments exhibiting trending sediment yields corrected for hydrological variability. The study demonstrates the importance of scale dependency of sediment yield in both the identification of temporal change and the modelling of relationships between sediment yield and environmental variables, suggesting that the treatment of the scale problem is crucial for temporal-spatial studies of sediment yield

Soil contamination in China : studies on the status, priorities, policies, management and risk assessment

As China is trying to balance economic development, environmental safety and human health, the Government has released strategic plans and legislation for soil contamination management. Aspects of the quality of China’s soils and management of soil contamination in China are addressed in this thesis. Soil environmental quality standards and science-based risk assessment of contaminants in soils are evaluated. China and the UK use different risk-based approaches to derive soil screening or guideline values (SSVs; SGVs) for contaminants. The approaches are compared and values derived for 6 illustrative contaminants. China’s SSVs are derived using an approach developed in the US as follows: for carcinogens, acceptable level of risk (ACR) is set at 10-6 and the SSVs calculated as 10-6 divided by the soil exposure and toxicity data; for non-carcinogens, the hazard quotient is 1 and the SSV is calculated as 1 divided by the soil exposure and toxicity data. The UK’s SGVs are calculated by the CLEA model, for which the Average Daily Exposure (ADE) from soil sources by a specific exposure route equals the health criteria values (HCVs) for that route, whether for carcinogens or a non-carcinogens. The UK’s CLEA model is also used here to derive SSVs with Chinese input parameters. China’s SSVs, the UK’s SGVs and values for Chinese conditions derived using the UK approach were as follows (mg/kg): As, <1, 35, 20; Cd, 20, 18, 11; Cr (VI), <1, 14, 29; benzene, 1, 1, 2; toluene, 1200, 3005, 3800; ethyl-benzene, 7, 930, 1200. The difference in toxicity assessment and risk characterization for carcinogens results in the biggest difference in SSVs between the 2 countries. However, for non-carcinogenic substances, the difference of SSVs calculation method and SSVs is small. In the future, China can use the UK method to strengthen its toxicity assessment and risk characterization for carcinogenic substances. Data was made available for this thesis from an extensive field and analytical campaign of human exposure to heavy metals in China. This was used to calculate the relative contributions of exposure to As, Cd, Cr, Hg and Pb from environmental media (air, water, soils) via the inhalation, drinking and the diet for different regions of China. Dietary exposure dominated, contributing ~90-97% of the total exposure for these elements. Exposure differences were observed with gender, age and region. This survey information can be used to derive exposures from soil-borne sources. Soil organic matter (SOM) and pH are critical soil properties strongly linked to carbon storage, nutrient cycling and crop productivity, but there is a lack of information on changes in these soil properties over time for China. This study used data from Chinese soil surveys to examine changes in soil pH and SOM across different land uses (dry farmland, paddy fields, grassland, woodland, unused land), with surface soil (0-20 cm) collected in the periods 1985-90 (Survey 1; 890 samples) and 2006-10 (Survey 2; 5005 samples) from two contrasting areas. In the southern part of China, the mean pH of paddy soils fell over the two decades between surveys - from pH 5.81 to 5.19 (p<0.001), while dry farmlands in the northern sampling area fell slightly (from pH 8.15 to 7.82; p<0.001). The mean SOM content of dry farmland soil rose in both areas and the mean SOM of paddy fields in the southern area also rose (all p<0.001). Woodland soil pH in the south increased from 4.71 to 5.29 (p<0.001) but no significant difference was measured in the woodlands of the northern area, although the trend increased. The SOM content of woodland top soils rose in the northern (p=0.003) and southern (p<0.001) study areas. The implications and potential causes of these changes are discussed and suggestions made as to how large-scale soil sampling campaigns can be designed to monitor for changes and potential controlling factors. Because of rapid urbanization in China, the demand for land for urban development is increasing. To upgrade and modernize, China has also moved many major industries and factories from urban centres to less populated areas. With the high economic value of urban land, the transformation and utilization of the brownfield areas left behind has become important economically and socially. Strong scientific, regulatory and decision-making frameworks are needed, to ensure practical, careful and wise use of central and local Government resources, to manage the re-use and regeneration of these brownfield sites. The final chapter provides a thorough review of the background, context, regulations, policies and management procedures to develop and utilize brownfields in developed countries such as the US and UK, and identifies some of the priorities for brownfield governance and redevelopment in China. It is proposed: to establish a monitoring body, to identify shared responsibilities and inputs of various stakeholders, to establish brownfield databases, and to set up a remediation advisory system with technology support as future priorities of brownfield management. Recommendations are made for future research, to support China’s strategic management of soil resources

Sediment deposition and preservation in Aeolian Systems: A comparison of contemporary and ancient ergs

Ancient and contemporary aeolian systems have been subject of important conceptual advances in recent years, however, a disconnect exists between the complexities inherent at the depositional surface and subsequent controls on preservation. At the fundamental level, the depositional environment consists of dune-fields, and the rock record is a stratigraphic architecture consisting of cross-strata and bounding surfaces. Vast outcrops of ancient aeolian strata display huge amounts of temporal variation manifest through dune-field evolution while the sedimentary record of contemporary ergs remain largely unknown. In order to bridge these gaps this research utilises a range of digitally based systems and techniques to analyse spatial data in order to unravel contemporary and ancient system evolutions. The study utilised the Wahiba Sand Sea of Oman and the Jurassic Navajo Sandstone of western USA as contemporary and ancient analogues respectively. Analysis of high to medium-resolution satellite and geophysical datasets demonstrate that antecedent topography has been a dominating allogenic boundary condition during the formation and growth of large linear bedforms in the Wahiba Erg. There appears to be a hierarchy of autogenic processes influenced by antecedent topography that imparts a uniqueness to the emergent dune-field pattern. The production of large-scale virtual outcrop models permitted broad spatial analysis of three sites across the Navajo Sandstone which represent marginal through central erg settings. Results show unique allogenic controls relating to system architectures at each outcrop, some of which provide validations to hypotheses made from observations within the contemporary analogue. The research demonstrates that in extracting signals of allogenic boundary conditions within which autogenic system processes evolved is the basis for the interpretation of geomorphic landforms and their stratigraphic record. The analogues represent a point on a spectrum of preservations styles recently detected in aeolian systems and provide additional examples with which to advance our knowledge