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  • 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.
101

Fossilizing democracy: the twin energy crises and the challenge to liberal democracy.

Anderson, Blake 17 December 2010 (has links)
This paper offers a critical framework for understanding how liberal democracies will be tested and constrained by the twin energy crises of climate change and energy scarcity. The analysis is developed in three distinct phases: the first phase pursues a critical understanding of the contemporary liberal democratic state as it relates to the fossil fuel dependent capitalist economy. I argue that the state’s dependence on economic growth prevents it from confronting the structural nature of the twin energy crises. In phase two I shift focus, engaging with the historically significant relationship between liberal democracy and market-capitalism. This argument is developed by exploring (1) the historical connection between democracy, liberalism and capitalism; (2) the permanent and dynamic tension that arises from these mutually dependent, yet conflicting ideologies and (3) the crucial role fossil energy has played, and continues to play, in masking and displacing the sources and the consequences of this tension. Finally, in phase three, I explore the divergent interests of the liberal and democratic traditions, suggesting this generates points of tension within liberal democracy that may be exacerbated as the twin crises worsens. I conclude by arguing that it is only through understanding how the twin energy crises will test and constrain liberal democracy that we will be able to defend, strengthen and deepen its core values.
102

Assessing students' learning about climate change under two different conditions

Porter, Dianna 11 February 2011 (has links)
This research followed students from three different British Columbia, Grade six classes through two-weeks of instruction on climate change. Pre, post, and follow-up surveys were used to determine the differences in knowledge retention between the students that received, through their science teacher, instruction from a unit and students who received equivalent content instruction from outside presenters. The teacher participant also completed a survey on her experience with the lessons plans. Students’ results on the post and follow-up surveys were compared to a control group’s results. The teacher-based approach to learning about climate change resulted in higher knowledge gain although no difference was found between the groups’ rate of knowledge decline thereafter. The teacher’s feedback corresponded to the result of the analyses by theme, showing that the highest gains in knowledge were for the carbon cycle and the human impacts topic, followed by understanding the difference between climate and weather. The students and teacher alike appeared to struggle with the topic of global warming and the greenhouse effect.
103

Investigation of the California Undercurrent off the west coast of Vancouver Island

Krassovski, Maxim 14 August 2008 (has links)
Current meter records from a long term mooring site on the continental slope off the west coast of Vancouver Island, British Columbia, Canada are used to investigate the scales of variability of the subsurface California Undercurrent and its relation to possible driving mechanisms. Observed along the west coast of North America from Baja California to Vancouver Island, the California Undercurrent is part of the California Current System, a typical basin-scale eastern boundary circulation system. Of the four instruments at nominal depths of 35, 100, 175, and 400 m, the upper two show seasonally reversing flow, while the 175 m instrument registers a year-round poleward flow. The deepest current meter, located approximately 100 m above the bottom, reflects the influence of a nearby submarine canyon. The flow at 100 and 175 m depths, as well as the water properties sampled in the region with CTD casts, are characteristic of the temporal and spatial variability of the California Undercurrent over the continental slope off central and southern Vancouver Island. The correlation of the 175 m flow with local atmospheric forcing (wind stress) in the low-frequency band (periods of months) is higher than with ocean-wide climatic indices, suggesting that regional processes play a key role in the forcing of the subsurface flow.
104

Nonnormal perturbation growth and optimal excitation of the thermohaline circulation using a 2D zonally averaged ocean model

Alexander, Julie 10 November 2008 (has links)
Generalized linear stability theory is used to calculate the optimal initial conditions that result in transient amplification of the thermohaline circulation (THC) in a zonally-averaged single basin ocean model. The eigenmodes of the tangent linear model verify that the system is asymptotically stable but the nonnormality of the system permits the growth of perturbations for a finite period through the interference of nonorthogonal eigenmodes. It is found that the maximum amplification of the THC anomalies occurs after 6 years with both the thermally driven and salinity driven components playing major roles in the amplification process. The transient amplification of THC anomalies is due to the constructive and destructive interference of a large number of eigenmodes and the evolution over time is determined by how the interference pattern evolves. It is found that five of the most highly nonnormal eigenmodes are critical to the initial cancellation of the salinity and temperature contributions to the THC while 11 oscillating modes with decay timescales ranging from 2 to 6 years are the major contributors at the time of maximum amplification. This analysis demonstrates that the different dynamics of salinity and temperature anomalies allows the dramatic growth of perturbations to the THC on relatively short (interannual to decadal) timescales. In addition the ideas of generalized stability theory are used to calculate the stochastic optimals which are the spatial patterns of stochastic forcing that are most efficient at generating variance growth in the THC. It is found that the optimal stochastic forcing occurs at high latitudes and induces low-frequency THC variability by exciting the salinity-dominated modes of the THC. The first stochastic optimal is found to have its largest projection on the same five highly nonnormal eigenmodes found to be critical to the structure of the optimal initial conditions. The model’s response to stochastic forcing is not controlled by the least damped eigenmodes of the tangent linear model but rather by the linear interference of these highly nonnormal eigenmodes. The process of pseudoresonance suggests that the nonnormal eigenmodes are excited and sustained by stochastically induced perturbations which in turn lead to maximum THC variance. Finally, it was shown that the addition of wind stress did not have a large impact on the nonnormal dynamics of the linearised system. Adding wind allowed the value of the vertical diffusivity to be reduced to achieve the same maximum linearised THC amplitude as was used in the case with no wind stress.
105

A dendroclimatic investigation of moisture variability and drought in the Greater Victoria Water Supply Area, Vancouver Island, British Columbia.

Jarrett, Patricia 21 April 2008 (has links)
A 616-year Douglas-fir (Pseudotsuga menziesii) chronology was developed to examine the history of drought and moisture variability in the Sooke Watershed, near Victoria, British Columbia. Ring-width chronologies were compared to historical precipitation, air temperature and drought variables (Palmer Drought Severity Index (PDSI) and Standardized Precipitation Index (SPI)) to determine the climate/radial-growth response to moisture stress on the sampled stands. Correlations between the ring-width chronologies and climate variables revealed that May to July precipitation, May-June SPI and July PDSI were significant limiting factors to radial-width growth. A transfer function was established for each of these variables to create a proxy climate reconstruction of drought in the watershed. The summer precipitation model provided the most accurate representation of past moisture variability (R2 = 0.20) and reveals substantial variation in precipitation over the past six centuries. Evidence from the periodicity of the tree-ring record to suggest that some modes of atmospheric circulation are influencing precipitation supply to the watershed.
106

Regional hyrdrologic controls on acid-sensitivity of lakes in boreal Canada : an isotopic perspective

Bennett, Katrina 24 September 2009 (has links)
This study applied the use of a stable isotope mass-balance model to calculate water throughflow, residency and water-yield and to assess acid-sensitivity for 50 lakes in the Athabasca Oil Sands region of northeastern Alberta. The research project was aimed at improving existing regional hydrologic estimates, based on coarse-scale runoff values derived from river gauging stations. Regional isotopic variations measured for components of the water cycle indicated a wide range of hydrologic conditions prevail, from throughflow, high water-yield lakes (186 mm.yr-1) to evaporative, low water-yield systems (23 mm•yr-1). Notably, hydrology is shown to be a controlling factor on acid-sensitivity and may be altering acid-sensitivity via such processes as water flow through peatland dominated catchments or convergence with acidic neutralizing soils, geology or ground waters. At the throughflow end of the hydrologic spectrum at low levels of isotopic enrichment, isotopes in precipitation were sensitive up to 30%. Relative humidity, on the other hand, is sensitive at high levels of enrichment at the evaporative end of the scale on the order of 25%. This application, in conjunction with landscape and chemical analysis, highlighted the over-riding hydrologic processes occurring at lowland and upland systems of the Boreal Plain that may lead to increased acid-sensitivity or buffering capacity. This thesis documents the first ever demonstration of an isotope mass-balance model to estimate water-yields and subsequently assess critical acid loadings in North America. The results of this research project will allow for improved predictive ability and management of acid-sensitive aquatic ecosystems within future planning frameworks.
107

Sea level change and archaeological site locations on the Dundas Island Archipelago of north coastal British Columbia

McLaren, Duncan 01 May 2008 (has links)
Coastal archaeological sites dating to the late Pleistocene and early Holocene are rare on the northwest coast of North America, as they are in many regions of the world, due to changing environmental factors, in particular glacial isostasy and eustasy, resulting in low visibility and survival of archaeological deposits. This dissertation outlines methods and results used to locate late Pleistocene and early Holocene archaeological sites on the Dundas Island Archipelago on the Northwest Coast culture area of British Columbia, Coast Tsimshian Territory, where archaeological sites older than 5,000 years BP are not known. Part of the reason for this is that masses of glacial ice accumulated on the Cordilleran Mountains of North America during the last glacial maximum, which depressed mainland coastal regions isostatically in relation to sea levels. As a result of lateral displacement of subcrustal material, areas to the west of the Cordillera bulged and landforms were raised relative to the sea. With deglaciation, the depressed crust began to rebound and the forebulge subsided resulting in rapidly dropping sea levels along the mainland to the east and rapidly rising sea levels along outer coastal islands to the west. These processes occurred in concert with sea levels that began rising eustatically following the last glacial maximum. Between the inner and outer coasts lies the Dundas Island Archipelago. This research project hypothesized that the study area was close to a sea level hinge lying between these two regions with very different sea level histories. With less significant shoreline movement, it was further anticipated that shoreline situated archaeological sites dating to the late Pleistocene and early Holocene might be found in close proximity, although slightly higher than the present day shoreline. This dissertation addresses the following question: Where are late Pleistocene and early Holocene archaeological sites situated on the Dundas Island Archipelago? To address this question, this dissertation details the methods and results used to determine a sea-level and vegetation history for the Dundas Island Archipelago and the archaeological prospection that was undertaken along relict shorelines. Pollen analysis of sediments from a lake core identified a sequence of six vegetation zones beginning before 12,385 BP. Based on diatom identification of cores from four lake basins, combined with supporting indicators, a sea level curve for the Dundas Islands was constructed showing a slow regression of shorelines from 13 m above the barnacle line to present day elevations over the last 12,000 years BP. Drawing upon these palaeo-environmental data, areas were selected for archaeological survey and prospection. Field testing of these selected areas resulted in the identification of five archaeological sites dating to the early Holocene. These are the first archaeological sites dating older than 5,000 years BP that have been found and dated in Coast Tsimshian Territory. The elevations and radiocarbon dates on all archaeological deposits are consistent with the sea level curve based on palaeo-environmental data points. Overall, this dissertation draws upon palaeo-environmental methods and results for the purpose of identifying and interpreting archaeological sites situated on raised marine landforms.
108

Spatial and temporal patterns and hydroclimatic controls of river ice break-up in the Mackenzie Delta, NWT

Goulding, Holly Lynn 11 December 2008 (has links)
Concern has been expressed regarding the impacts of climate change on the hydroecology of the Mackenzie Delta, thus identifying a need for better understanding of the ice break-up regime. Archived records at hydrometric stations in the delta for the period 1974 to 2006, supplemented with observations and remotely sensed imagery, are used to assemble a break-up chronology and examine spatial and temporal patterns of break-up flooding. Hydroclimatic controls on break-up are assessed by statistical, qualitative, and trend analysis of upstream discharge and downstream ice characteristics. For the most severe break-up flooding, two event types are identified: ice-driven events, with high backwater and high peak levels in the southern, eastern and western delta, and discharge-driven events, with high levels in the mid and outer delta and along Middle Channel. Break-up initiation during ice (discharge) events occurs earlier (later) than the delta average. Severity of break-up water levels is most influenced by upstream discharge, while timing is related to ice conditions and spring hydrograph rise. Rapid upstream melt and lower intensity melt in the delta prior to break-up characterize the most severe events. Trend analysis reveals a tendency toward earlier break-up, a longer prebreak-up melt interval, and a lower magnitude of hydroclimatic controls.
109

A dendroclimatic investigation in the northern Canadian Rocky Mountains, British Columbia

Flower, Aquila 30 April 2009 (has links)
Subalpine fir (Abies lasiocarpa [Hooker] Nuttall) and white spruce (Picea glauca [Moench] Voss) trees were sampled in an old growth forest in the northern Canadian Rocky Mountains. Dendroclimatological methods were used to analyse the relationship between annual radial-growth and climatic variability. The white spruce ring-width chronology showed stronger sensitivity to climatic variability than the subalpine fir chronology. Both chronologies were positively correlated with growing season mean and minimum temperature. Additionally, the white spruce chronology was correlated with summer maximum temperature, late spring minimum temperature, and diurnal temperature range during the growing season. The subalpine fir ring-width chronology was also correlated with maximum and minimum temperature and diurnal temperature range during the during the previous winter and with the Pacific Decadal Oscillation during each month from December to June. Analysis of the climate-growth responses of individual trees revealed a higher level of intraspecies variability in subalpine fir than in white spruce. The white spruce chronology was selected for use in creating a proxy climate record based on its greater length and stronger sensitivity to climatic variability. Dendroclimatological methods were used to create a regional proxy record of June-July mean temperature extending back to 1772. This reconstruction exhibits a shared pattern of low-frequency variability with other dendroclimatic reconstructions from western Canada and shows no evidence of the recent reduction in sensitivity to climatic variability that is apparent in many other northern spruce chronologies. This study represents the first detailed dendroclimatic analysis undertaken in northern interior British Columbia. This work has elucidated the complex interactions between climate and the radial growth of alpine conifers in the northern Canadian Rocky Mountains. The climate reconstruction presented here fills in one of the remaining spatial gaps in the coverage of annually resolved climate reconstructions in western North America.
110

Spatial and temporal variations of river-ice break-up, Mackenzie River Basin, Canada

De Rham, Laurent Paul 26 August 2009 (has links)
Hydrological data extracted directly from Water Survey of Canada archives covering the 1913-2002 time period is used to assess river ice break-up in the Mackenzie River basin. A return-period analysis indicates that 13 (14) of 28 sites in the basin are dominated by peak water-levels occurring during the spring break-up (open-water) period. One location has a mixed signal. A map of flooding regimes is discussed in terms of physical, hydrological and climatic controls. Annual break-up is found to progress from south to north, over a period representing ~¼ of the year. Average annual duration is ~8 weeks. The at site break-up period, recognized as the most dynamic time of the year on cold-regions river systems is found to last from 4 days to 4 weeks. Break-up timing (1966-1995) is found to be occurring earlier in the western portions of the basin (~3 days/decade), concurrent with late 20th century warming.

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