• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 9
  • 2
  • Tagged with
  • 15
  • 15
  • 5
  • 4
  • 3
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 1
  • 1
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Choosing a dangerous limit for climate change : an investigation into how the decision making process is constructed in public discourses

Shaw, Christopher James January 2011 (has links)
International climate change policy is predicated on the claim that climate change is a phenomenon with a single, global dangerous limit of two degrees of warming above the pre-industrial average. However, climate science does not provide sufficient empirical evidence to determine such an exact limit. In addition, a single limit incorrectly assumes that social and physical vulnerabilities to climate change are uniformly distributed in space and time. Public commentaries play an important role in shaping public engagement with an abstract concept such as climate change. This research project examines how public discourses construct the dangerous limits to climate change decision making process. My analysis draws on elite theory to argue that the two degree limit is a discourse which constructs climate change as a problem solvable within existing value systems and patterns of social activity. A comparison of primary and secondary data drawn from diverse sources is used to chart the key historical, social and cultural elements present in the construction and reproduction of the two degree dangerous limit discourse. The historical dimension of my analysis shows that public commentaries have ‘black boxed' the genesis of the two degree dangerous limit idea. I demonstrate how claims of a consensus amongst elite policy and science actors are central to developing a dangerous limit ideology amongst influential public audiences. The two degree discourse elevates the idea of a single dangerous limit to the status of fact, and in so doing marginalises egalitarian and ecological perspectives. I conclude that the two degree limit is a construct which makes possible an international environmental regime safe for the interests of elite actors.
12

Late Quaternary Climatic Geomorphology, Volcanism, and Geoarchaeology of Carrizo Wash, Little Colorado River Headwaters, USA

Onken, Jill January 2015 (has links)
Isolating the climatic mechanisms driving Holocene geomorphic change and deciphering the role of landscape change in prehistoric cultural processes both require well-dated and relatively continuous alluvial chronologies. This study presents a centennial-scale, latest Pleistocene and Holocene chronology based on alluvial fan, floodplain, groundwater-discharge, and volcanic deposits for the Carrizo Wash watershed, a Little Colorado River headwater drainage on the southeastern Colorado Plateau. More than 200 radiocarbon dates provide chronometric control. The age of Zuni Salt Lake volcanic eruptions was re-evaluated using radiocarbon and luminescence dating. Two eruptive phases ~13.3 ka and ~11.8 ka suggest closely spaced, monogenetic events. These terminal Pleistocene ages for the eruptions are significantly younger and substantially more precise than previous argon method ages. Sediment exposed in modern arroyos is dominated by middle Holocene (~7.1–4.9 ka) alluvium in valley contexts, whereas piedmont alluvium dates primarily to the late Holocene (~4.3–2.7 ka). Extensive prehistoric channel entrenchment occurred ~4.9 and 0.8 ka. Localized incision occurred ~1.9 and 1.2 ka, and possibly ~7.5 and 2.7 ka. Extended drought typically preceded arroyo cutting, and entrenchment was associated with increased climate variability, major shifts in precipitation amount or seasonality, and reduced flooding. Accelerated valley and piedmont aggradation appears related to increased flooding and runoff associated with reduced vegetation cover during periods of low effective moisture resulting from enhanced North American Monsoon circulation and weak ENSO conditions. Conversely, slow or stalled deposition appears connected to reduced flooding and runoff fostered by denser vegetation during times of increased effective moisture caused by enhanced El Niños and increased winter precipitation. Ground-water discharge deposits at Cienega Amarilla indicate that spring discharge was greatest and water tables most elevated ~2.3–1.6 ka. Spring discharge appears to reflect variations in El Niño frequency and intensity and the resultant variations in winter precipitation. Study results suggest that predicted increased drought and enhanced or delayed monsoons associated with modern climate change could initiate accelerated erosion of upland areas and increased flooding in southern Colorado Plateau headwater tributaries. Archaeological implications include temporal biases associated with surface site distributions and changing viability of floodwater and water-table farming over time.
13

Morphological impacts of Hurricane Katrina on Petit Bois Island, Mississippi

Oravetz, Jonathan Randal. January 2008 (has links)
Thesis (M.S.)--University of West Florida, 2008. / Title from title page of source document. Document formatted into pages; contains 57 pages. Includes bibliographical references.
14

Towards defining the extent of climatic influence on alluvial fan sedimentation in semi-arid Sonoran and Mojave Deserts, southern California, USA and Baja California, northern Mexico

Kent, Emiko J. 26 September 2011 (has links)
No description available.
15

Periglacial features in the vicinity of Tiffindell Ski Resort, North East Cape Drakensberg, South Africa, and their implications for the development of the resort

Kück, Karen Melody January 1997 (has links)
This thesis provides a description of the periglacial environment and features in the vicinity of Tiffindell Ski resort, on the slopes of Ben MacDhui (3001.2m.), the highest point of the East Cape Drakensberg, South Africa. Active and inactive periglacial features were located, mapped and described. Of particular interest were periglaciar slope deposits including gelifluction turf-banked lobes and stone lobes, and cryoturbation features including polygons and thufur. Local environmental factors, such as aspect, moisture, topography, soil texture and depth of freezing, appear to act as important controls on the spatial distribution of the periglacial features. Identification and quantification of periglacial processes in the regolith was investigated using temperature and soil moisture sensors coupled to dataloggers. Research was undertaken over a 16 month period from June 1995 to September 1996 so that comparisons between the winter conditions of 1995 and 1996 could be drawn. The Tiffindell area was observed to be characterised in the winter months by 'diurnal freezethaw days', as well as by 'ice days', 1996 experiencing colder temperatures than 1995. With more than 78% of the days from May to September 1996 being 'ice days', and simultaneously experiencing high soil moisture contents, freezing penetration to a depth of greater than 0.2m was observed to occur in the Tiffindell area, causing frost heave and gelifluction. The summer thaw of ice lenses that developed in the cold winter months caused surface movement downslope of gelifluction lobes of up to 39mm over an 18 month period, although movement declined rapidly with depth and was essentially restricted to the uppermost 130mm of the regolith. Other features such as sorted and non-sorted polygons and thufur were identified and found to be active under the present climatic conditions and depth of frost penetration at Tiffindell. Stone lobes were identified on the south and southeast-facing slopes at Tiffindell, but are apparently inactive under present climatic conditions. Their existence suggests the presence of severe seasonal frost in the past. The implications of the air and ground surface temperatures, and of seasonal frost penetration for the development of Tiffindell Ski resort were considered, and suggestions regarding their economic significance are presented.

Page generated in 0.0928 seconds