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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.
141

The late Quaternary environmental history of the Lake Heron basin, Mid Canterbury, New Zealand

Pugh, Jeremy Mark January 2008 (has links)
The Lake Heron basin is an intermontane basin located approximately 30 kms west of Mount Hutt. Sediments within the basin are derived from a glacier that passed through the Lake Stream Valley from the upper Rakaia Valley. The lack of major drainage in the south part of the basin has increased the preservation potential of glacial phenomena. The area provides opportunities for detailed glacial geomorphology, sedimentology and micropaleontogical work, from which a very high-resolution study on climate change spanning the Last Glacial Maximum (LGM) through to the present was able to be reconstructed. The geomorphology reveals a complex glacial history spanning multiple glaciations. The Pyramid and Dogs Hill Advance are undated but possibly relate to the Waimaungan and Waimean glaciations. The Emily Formation (EM), previously thought to be MIS 4 (Mabin, 1984), was dated using Be10 to c. 25 ka B.P. The EM was largest advance of the Last Glacial Maximum (LGM). Ice during the LGM was at least 150m thicker than previously thought, as indicated by relatively young ages of high elevation moraines. Numerous moraine ridges and kame terraces show a continuous recession from LGM limits, and, supported by decreasing Be10 ages for other LGM moraines, it seems ice retreat was punctuated by minor glacial readvances and still-stands. These may be associated with decadal-scale climate variations, such as the PDO or early ENSO-like systems. There are relatively little sedimentological exposures in the area other than those on the shores of Lake Heron. The sediment at this location demonstrates the nature of glacial and paraglacial sedimentation during the later stages of ice retreat. They show that ice fronts oscillated across several hundred metres before retreating into Lake Heron proper. Vegetation change at Staces Tarn (1200m asl) indicates climate amelioration in the early Holocene. The late glacial vegetation cover of herb and small shrubs was replaced by a low, montane forest about 7,000 yrs B.P, approximately at the time of the regional thermal maxima. From 7,000 and 1,400 yrs B.P, temperatures slowly declined, and grasses slowly moved back onto the site, although the montane forest was still the dominant vegetation. Fires were frequent in the area extending back at least 6,000 years B.P. The largest fire, about 5,300 yrs B.P, caused major forest disruption. But full recovered occurred within about 500 years. Beech forest appears at the site about 3,300 yrs B.P and becomes the dominant forest cover about 1,400 yrs B.P. Cooler, cloudier winters and disturbance by fire promoted the expansion of beech forest at the expense of the previous low, montane forest. Both the increased frequency of fire events and late Holocene beech spread may be linked to ENSO-related variations in rainfall. The youngest zone is characterised by both a dramatic decline in beech forest and an increase in grasses, possibly representing human activity in the area.
142

Climate Change and Agricultural Policy Effects on Water Use in Agricultural Production: A Positive Mathematical Programming Approach

Hale, Andy January 2011 (has links)
Agricultural production is affected by a range of policy and climatic variables. This research explored the impacts of cap and trade, climate change and agricultural policy scenarios on water resource use and allocation in agricultural production. The research is organized into three separate studies, one for each set of scenarios.The first study focused on cap and trade policy for controlling greenhouse gas emissions, combining cost of production estimates with output price projections to determine the overall economic impact of cap and trade legislation, as well as its impact on agricultural water consumption. Price projections that included carbon offsets were higher than projections that did not, due to land being taken out of production and prices being bid up. HR2454 will increase production costs, particularly energy intensive inputs. Output prices increase as producers reduce production in response to cost increases. If agricultural offsets are allowed, output prices will be bid up further. Offsets allow producers to receive payments for cutting emissions. Producers benefit due to indirect price effects. Since water is quantity limited, total water use is unchanged.The next study looked at the physical impacts of climate change on production, particularly rising temperatures and carbon dioxide concentrations. By analyzing the anticipated yield effects, it was found that overall net incomes would decrease and the water constraint would remain binding - meaning total water use is unchanged.The third paper analyzed the effects of agricultural policy on land and water resource allocation. Cotton is directly subsidized. Corn and grain sorghum are subsidized indirectly through ethanol subsidies. Sugar cane prices are artificially high due to tariff rate quotas on sugar imports. Removal of any of these interventions decreased net profits to producers, but water use remains unchanged. Removing all farm programs significantly decreases acres under cultivation, and reduces water use below the water constraint. It comes at a great cost to producers however, given the small amount of water saved.
143

Testing hypotheses related to changes in abundance and distribution of warm-temperate invertebrates on rocky shores along the South coast of England

Herbert, Roger J. H. January 2001 (has links)
No description available.
144

Fossil energy and the environment

Hatamian, Abdol Hamid January 1996 (has links)
No description available.
145

Changing role in a changing climate : can the Bretton Woods Institutional play a new role in promoting sustainable development?

Shih, Wen-Chen January 1999 (has links)
No description available.
146

An investigation of the pattern scaling technique for describing future climates

Mitchell, Timothy D. January 2001 (has links)
No description available.
147

Elevated carbon dioxide and gas exchange in groundnut and sorghum

Singleton-Jones, Paul January 1998 (has links)
No description available.
148

Satellite measurements of surface temperatures

Jung, Fan January 1992 (has links)
No description available.
149

An investigation into the impact of environmental change upon the vegetation of Widdybank Fell, Upper Teesdale

Lewthwaite, Katherine Jane January 1999 (has links)
Widdybank Fell is located in the Upper Teesdale National Nature Reserve in the Northern Pennines. It is internationally renowned for its unique late-glacial relict assemblage of plant species, particularly those on the "sugar limestone” outcrops. Cow Green Reservoir was constructed in the early 1970s and flooded the lower western slopes of Widdybank Fell. At the time there was concern amongst ecologists that the reservoir might alter the local climate and have adverse effects on the remaining vegetation. A comprehensive vegetation survey of Widdybank Fell was carried out by Jones (1973). Aspects of this survey were repeated as part of the present study. There have been significant changes in the composition of some of the plant communities since the 1970s. These changes include a considerable loss of bryophyte diversity and lichen abundance. Overall there has been a decline in "stress tolerant" species, and a loss of calcicole species on the calcareous grasslands. Few of the nationally rare plant species have changed in abundance. Using data from the meteorological stations at Widdybank Fell and from nearby Moor House, it has been demonstrated that the presence of Cow Green Reservoir has resulted in significant changes in the local climate. These changes are consistent with those expected by a classic "lake effect" and include the all year round moderation of minima (e.g. resulting in a reduction in the number of ground frosts). The reservoir has also produced cooler mean air temperatures in spring and warmer mean temperatures in autumn. Despite the observed local climate impact of Cow Green Reservoir it seems most likely that other factors have been responsible for the observed vegetation changes. Acid deposition has probably caused the loss of calcicoles on the calcareous grasslands, and atmospheric nitrogen deposition could explain the loss of bryophyte diversity and lichen abundance.
150

Development of My Footprint Calculator

Mummidisetti, Karthik 01 January 2017 (has links)
The Environmental footprint is a very powerful tool that helps an individual to understand how their everyday activities are impacting environmental surroundings. Data shows that global climate change, which is a growing concern for nations all over the world, is already affecting humankind, plants and animals through raising ocean levels, droughts & desertification and changing weather patterns. In addition to a wide range of policy measures implemented by national and state governments, it is necessary for individuals to understand the impact that their lifestyle may have on their personal environmental footprint, and thus over the global climate change. “My Footprint Calculator” (myfootprintcalculator.com) has been designed to be one the simplest, yet comprehensive, web tools to help individuals calculate and understand their personal environmental impact. “My Footprint Calculator” is a website that queries users about their everyday habits and activities and calculates their personal impact on the environment. This website was re-designed to help users determine their environmental impact in various aspects of their lives ranging from transportation and recycling habits to water and energy usage with the addition of new features that will allow users to share their experiences and their best practices with other users interested in reducing their personal Environmental footprint. The collected data is stored in the database and a future goal of this work plans to analyze the collected data from all users (anonymously) for developing relevant trends and statistics.

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