School of Geography - Theses

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    Analysing climate-forced urbanisation in Mongolia
    Barbary, Angus E. ( 2019)
    By 2030, two thirds of humanity is likely to live in urban areas. In many nations such as Mongolia, rapid urbanisation can be associated with development challenges where many people live with limited access to adequate urban infrastructure and services. There are many drivers of urbanisation in Mongolia. One of these drivers is thought to be a cold-climate disaster (dzud), that causes mass livestock fatality and consequent rural-urban migration, when nomadic herders are thought to seek alternative opportunities in urban centres such as the overcrowded capital city, Ulaanbaatar. As a result the city’s urban footprint is thought to spatially expand. The dynamics of this coupled human-physical system are not well understood. This project used mixed-methods, conducting qualitative and quantitative analyses of urban expansion in Ulaanbaatar. It used supervised classification on a 30-year time series of satellite images to measure the rate of change in urban areas from 1989-2019. To gather an understanding of the context of this phenomenon the spatial findings were compared with the opinions expressed in 26 semi-structured interviews with urban management experts in Mongolia to analyse the potential relationship between dzud and the rate of urban expansion. The findings may carry implications for the management of urbanisation in Mongolia, while enhancing our understanding of human-environment relations more broadly.
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    Speleothem-based explorations of millennial-scale climate change in southern Australasia
    Gordon, Jay ( 2018)
    Understanding the way Earth responds to rapid climate change is critical for understanding future climate scenarios. The best natural examples of rapid climate change are found in millennial-scale climate events recorded in Greenland ice cores over the Last Glacial Period (120-12 ka). These occur concurrently with similarly-paced, gradual warming events recorded in Antarctic ice cores. Understandings of the transition between Greenland-like and Antarctic-like millennial-scale climate events are limited by a lack of appropriate records from the southern mid-latitudes. However, calcite cave formations (speleothems) have the potential to record high-resolution millennial-scale climate change in this region. This study looks at three southern mid-latitude cave sites, develops or improves palaeoclimate reconstructions from each, compares these to external records of millennial-scale climate change, and assesses the suitability of each site for future millennial-scale palaeoclimate reconstructions. Palaeoclimate reconstructions were produced based on U-Th dating, stable isotope analysis and trace element analysis techniques. The first ever high-resolution palaeoclimate record from Naracoorte, Australia from the Last Glacial Period was produced, which suggested that millennial-scale climate change here was influenced by changes in the activity of the southern westerlies. The first ever palaeoclimate record from Wombeyan, Australia was produced, which suggested that millennial-scale climate change here was confounded by both tropical and mid-latitude climate effects. An existing palaeoclimate record from Nettlebed was improved upon and reinterpreted, which supported previous findings that millennial-scale climate in Nettlebed is influenced by the intensity of the southern westerlies. Naracoorte and Nettlebed demonstrated good potential for future millennial-scale palaeoclimate reconstructions, although Naracoorte is limited by a lack of speleothem samples from the Last Glacial Period. Wombeyan demonstrated poor potential for future millennial-scale palaeoclimate reconstructions due to its confounded climate signature, and high U-Th age uncertainties due to low speleothem uranium concentrations. These findings have implications for the future study of millennial-scale climate change, by presenting brand new millennial-scale palaeoclimate reconstructions and demonstrating how future millennial-scale palaeoclimate reconstructions can be developed from a critically under-sampled region.