<p> This thesis estimates the impacts of rooftop photovoltaic (PV) capacity on electricity generation and CO2 emissions in America's Pacific Northwest. The region's demand for electricity is increasing at the same time that it is attempting to reduce its greenhouse gas emissions. The electricity generated by rooftop PV capacity is expected to displace electricity from fossil fueled electricity generators and reduce CO2 emissions, but when and how much? And how can this region maximize and focus the impacts of additional rooftop PV capacity on CO2 emissions? To answer these questions, an hourly urban rooftop PV generation profile for 2009 was created from estimates of regional rooftop PV capacity and solar resource data. That profile was compared with the region's hourly fossil fuel generation profile for 2009 to determine how much urban rooftop PV generation reduced annual fossil fuel electricity generation and CO2 emissions. Those reductions were then projected for a range of additional multiples of rooftop PV capacity. The conclusions indicate that additional rooftop PV capacity in the region primarily displaces electricity from natural gas generators, and shows that the timing of rooftop PV generation corresponds with the use of fossil fuel generators. Each additional Wp/ capita of rooftop PV capacity reduces CO2 emissions by 9,600 to 7,300 tons/ year. The final discussion proposes some methods to maximize and focus rooftop PV impacts on CO2 emissions, and also suggests some questions for further research.</p>

The boreal forest region of Canada is climatically sensitive and may be impacted by anthropogenic-induced climatic changes. The results of this multi-proxy paleolimnological study contribute detailed information on changes to the boreal forest in northwestern (NW) Ontario, showing unequivocal changes in lake and forest structure due to climate during the warmer mid-Holocene. This study uses diatoms, pollen, and charcoal reconstructions to better understand the timing and extent of climate-related changes in Lake 239, Experimental Lakes Area (ELA), in NW Ontario throughout the Holocene with an emphasis on the warmer mid-Holocene. Diatom analysis revealed changes in water quality based on analysis of species assemblages and quantitative inferences of total phosphorus from a deep central core. Lake levels at least 8-m lower than today were inferred from a near-shore core and were concurrent with an increase in nutrient-rich diatom assemblages, an increase in diatom accumulation, and a decrease in chrysophytes relative to diatoms in the central core. A concurrent increase in pollen such as Cupressaceae and Ambrosia indicate more open boreal forest between ~4500-8000 cal yr BP. Pollen-based inferences of temperature suggest an increase on average of 1-2°C warmer than today with winter temperatures up to 4°C warmer. The pollen inferences also suggest enhanced precipitation, but with increased evaporation/evapotranspiration resulting in reduced moisture availability overall. A transect of cores surrounding ELA was synthesized using pollen-based reconstructions of temperature and precipitation to assess regional changes. All sites show shifts in pollen assemblages indicating a warmer mid-Holocene; prairie sites to the west show mid-Holocene decreases in precipitation relative to today, whereas sites near or east of ELA show consistent increases in precipitation, but with enhanced evaporation. Charcoal analysis shows an increase in charcoal accumulation during the mid-Holocene warm period compared to the early and late Holocene, suggesting a more active fire regime. Fire return intervals based on type-M charcoal show a pronounced decrease during the early-to-mid Holocene period and a corresponding increase in fire frequency, whereas fire frequency derived from total charcoal was virtually unchanged over the Holocene. This study helps fill a knowledge gap in NW Ontario noted by several large regional assessments. / Thesis (Ph.D, Biology) -- Queen's University, 2010-07-15 09:54:18.653

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<p> Sub-surface motivations of individuals to engage in planning for climate change adaptation and response are influenced by a combination of orthodox factors such as their community's physical and social demographics, and an array of supplementary factors such their community's epistemology, direct experiences, hyperbolic discounting, media, and outreach initiatives. In turn, public demand for initiatives and a community's ability to facilitate an institutional supply of initiatives shapes the surface motivations of decision-makers that direct the development, implementation, and diffusion of initiatives. This paper investigates the relationship between influential factors and motivations for climate change planning by examining the climate change planning process of Aspen and Boulder in Colorado. Research results indicate that the motivations for climate change planning and subsequent initiatives vary because of differences in a community's orthodox and supplementary factors.</p>

<p> This study primarily focuses on sea ice variability in the Bering Sea, and its thermodynamic and dynamic controls. </p><p> First, the seasonal cycle of sea ice variability in the Bering Sea is studied using a global fine-resolution (1/10-degree) fully-coupled ocean and sea ice model forced with reanalysis atmospheric forcing for 1980-1989. The ocean/sea-ice model consists of the Los Alamos National Laboratory Parallel Ocean Program (POP) and the Los Alamos Sea Ice Model (CICE). The modeled seasonal mean sea ice concentration strongly resembles satellite-derived observations. During winter, which dominates the annual mean, model sea ice is mainly formed in the northern Bering Sea, with the maximum ice growth rate occurring along the coast, due to cold air from northerly winds and ice motion away from the coast. South of St. Lawrence Island, winds drive sea ice to drift southwestward from the north to the southwestern ice covered region. Along the ice edge in the western Bering, ice is melted by warm ocean water, which is carried by the Bering Slope Current flowing to the northwest, resulting in the S-shaped asymmetric pattern seen in the ice edge. </p><p> Second, the year-to-year variability of sea ice in the Bering Sea for 1980-1989 is addressed. While thermodynamic processes dominate the variations in ice volume change in the Bering Sea on the large scale, dynamic processes are important locally near ice margins (both oceanic and land), where local dynamic and thermodynamic ice volume changes have opposite signs with large and similar amplitudes. The thermodynamic ice volume change is dominated by ice-air surface heat flux, which in turn is dominated by sensible heat flux, except near the southern ice edge where it is largely controlled by ocean-ice heat flux. This indicates that surface air temperature, which is specified from observations, strongly controls the ice volume tendency. Ice motion is generally consistent with winds driving the flow, except near certain straits in the north where ice motion largely follows ocean currents. </p><p> This study also addresses Greenland supraglacial lakes on top of ice and ice-dammed lakes adjacent to glaciers. Those surface lakes have been observed to fill and drain periodically, affecting the ice motion over land. This study provides observational constraints on the volume of water contained in and drained from the lakes, based on the repeat laser altimetry. </p>

The objective of this research was to determine the impact of climate change on the Churchill River basin and perform analysis on uncertainty related to this impact. Three hydrological models were used to determine this impact and were calibrated to approximately equivalent levels of efficiency. These include WATFLOODTM, a semi-physically based, distributed model; HBV-EC, a semidistributed, conceptual model; and HMETS, a lumped, conceptual model. These models achieved Nash-Sutcliffe calibration values ranging from 0.51 to 0.71. Climate change simulations indicated that the average of simulations predict a small increase in flow for the 2050s and a slight decrease for the 2080s. Each hydrological model predicted earlier freshets and a shift in timing of low flow events. Uncertainty analysis indicated that the chief contributor of uncertainty was the selection of GCM followed by hydrological model with less significant sources of uncertainty being parameterization of the hydrological model and selection of emissions scenario.

<p>The destruction of the ozone layer, concomitant with a projected enhancement in ocean stratification, will increase the dosage of ultraviolet radiation (UVR), as well as sea surface temperature and incident light level. The diatom <i> Fragilariopsis cylindrus</i> and other Antarctic phytoplankton will therefore be exposed to, and require protection from, increasing levels of damaging UVR, under elevated temperatures and light conditions. It has been hypothesized that phytoplankton utilize photoprotective pigments and the production of mycosporine-like amino acids as strategies against UVB-induced production of reactive oxygen species (ROS). The goal of this research was to investigate photoprotective mechanisms employed by <i>F. cylindrus</i>, following exposure to enhanced UVB. Interactive effects of temperature and light level were explored, as cultures were subjected to temperatures of 0&deg;C or 4&deg;C and light levels of 15 &micro;E m^&minus;2 s^&minus;1 or 100 &micro;E m^&minus;2 s^&minus;1, in order to approximate current and future Southern Ocean stratification conditions. Growth rate and photosynthesis significantly declined by 40&ndash;80% and 50-90%, respectively, following exposure to high UVB relative to control conditions. This decline in physiological health was accompanied by a 50&ndash;300% increase in photoprotective mechanisms. Exposure to high UVB under current climate conditions resulted in the least amount of photodamage and photoprotection. Conversely, elevated light level resulted in the greatest decrease in growth and photosynthesis, accompanied with the greatest increase in photoprotection when exposed to high UVB. Under both light levels, the elevated temperature appeared to mitigate damage caused by high UVB exposure. The results of this study shed light on the mechanisms utilized by <i>F. cylindrus</i> in response to oxidative stress induced by UVB, and how these mechanisms may be expected to change under future ocean stratification conditions. </p>

Climate change research is undergoing a monumental shift, from an almost exclusive focus on mitigation, and the reduction of greenhouse gases, to adaptation, and identifying the ways in which nations, communities and sectors might best respond to the reality of a changing climate. Vulnerability assessments are now being employed to identify the conditions to which socio ecological systems are exposed-sensitive and their capacity to adapt. Work has been conducted across a range of geographical locations and systems as diverse as healthcare and mining. There are however, few examples of analyses incorporating an assessment of the multiple climatic and non-climatic stressors to which agricultural producers are exposed. This thesis examines farm-level vulnerability to climate change of agricultural producers from the Eastern Bay of Plenty, New Zealand. The study area has a diverse agricultural economy, founded upon pastoral farming (dairy and drystock) and kiwifruit. This dependence on agricultural production, and the likely influence of expected changes in climatic conditions in the future provided a unique setting in which to develop a place-based case study exploring vulnerability to future climatic variability and change. Using a mixed methods approach, including semi-structured interviews and temporal analogues, a conceptual framework of farm-level vulnerability was developed and applied. The application of the framework was conducted through an empirical study that relied on engagement with and insights from producers who identified current exposure-sensitivity and adaptive capacity. It is shown that pastoral farmers and kiwifruit growers are exposed-sensitive to a range of climatic and non-climatic conditions that affect production, yields and farm income and returns. It demonstrates that producers have in turn, developed a range of short- and long-term adaptive strategies in order to better manage climatic conditions. It shows that these responses are varied, and are not made in response to climatic conditions alone, illustrating the need to consider other, multiple stimuli. An assessment of future vulnerability is presented, based on the empirical work and the identification of those drivers of vulnerability that are likely to be of concern and that will shape the capacity of farmers and growers to respond to climatic variability and change. The thesis as a whole not only provides a place-based case study on the vulnerability of farmers and kiwifruit growers in eastern New Zealand, but also demonstrates the need to engage with producers in order to develop an understanding of the complex ways in which climatic conditions interact with non-climatic stimuli beyond the farm-gate to influence vulnerability to climatic variability and change, both now and in the future.