Coupled climate and sea ice variability in the Arctic was investigated using a combination of modern, historical and proxy observations. In the Canadian Arctic, operational sea ice charts were homogenized into a spatially and temporally consistent gridded dataset. A complete climatic analysis of this dataset revealed the presence of dominant modes of sea ice variability related to driving climate patterns and atmospheric circulation indices such as the North Atlantic Oscillation (NAO) and El Nino Southern Oscillation (ENSO). On a hemispheric scale, the late-summer ice cover extent is decreasing at a much faster rate than the maximum winter ice cover. The disappearing perennial ice is partly replaced by seasonal ice, the areal extent of which has increased steadily over the last century. The enhanced seasonal sea ice freeze-thaw cycle is predicted to increase the salinity of surface waters over continental shelves, thereby enhancing haline convection and ventilation of the deeper Arctic Ocean. Coupled sea ice and climate proxies for the North Baffin Bay region were developed from an existing ice core from Devon Ice Cap and a new ice core from the Prince-of-Wales (POW) Icefield on Ellesmere Island. A sea-salt concentration record from the Devon ice core was found to relate with sea ice concentration in nearby Baffin Bay. The record was used to study past sea ice conditions in Baffin Bay over the last 200 years in relation with temperature proxies (melt %, delta18O). Sea ice extent variations in northern Baffin Bay appear to be mostly dynamically driven, with sea ice decreasing when Nares Strait becomes congested with ice from the Arctic Ocean, and northerly winds advect ice from Baffin Bay southward. A new high-resolution melt record was developed using digital image analysis of the POW ice core. The record was used to show that melting affects the solid conductivity signal of the core, which compromises dating by seasonal layer counting, and hinders the identification of acidic volcanic horizons. The POW melt record, a proxy for summer warmth, was shown to be site-specific, which may be explained by the close presence of the North Open Water polynya and the peculiar position of the ice cap which rests on the shifting boundary between the maritime climate of Baffin Bay and the drier, colder climate of the high Arctic. The long-term, natural variability of late-summer Arctic sea ice was reconstructed from a network of 68 climate proxies from the circum-Arctic region. The proxy network contains both a temperature and a sea ice signal. Past sea ice extent was reconstructed using multivariate statistical calibration of the network against historical sea ice observations over the last century. The record shows that the decline in sea ice extent of the last two decades is anomalous in the context of the last 900 years. Non-linear processes are responsible for much of the variability in ice extent over the past millennium, and the same processes may be enhancing the greenhouse gas-induced decrease in ice extent currently observed.

The establishment of an accurate global carbon budget and the consequent ability to understand and predict future environmental change is dependent on knowing the strength of terrestrial sinks and sources of carbon. Regenerating tropical forests are one of the major terrestrial carbon sinks as they are found growing quickly and are sequestering carbon from the atmosphere. Total forest biomass (which includes above and below ground living mass of plants and litter) is a measure of terrestrial vegetation carbon content. It follows that to determine the strength of terrestrial carbon sinks we require information on the location, extent, biomass and biomass change of regenerating tropical forests. Near-constant cloud cover over the tropics and an insensitivity to biomass change at relatively low levels of biomass has limited the use of optical imagery but not Synthetic Aperture Radar (SAR) imagery for the provision of such information. The biophysical properties of regenerating tropical forests are related to the temporal, spatial, spectral and polarisation characteristics of SAR backscatter (a°) and this formed the framework for this thesis. The objectives were to (i) detect biomass accumulation using the temporal characteristics of 0°, (ii) use the spatial characteristics of a° (texture) to increase the strength of the a7biomass relationship and (ill) use the spectral and polarisation characteristics of 0° to classify a surrogate for biomass in regenerating tropical forests (optical Landsat TM data were also included to widen the spectral analysis). Although no biomass change was detectable using temporal 0°, a seasonal pattern in 0° for young regenerating forest was detected, as a result of changing water content in both vegetation and soil. The influence of recent rainfall was confirmed to be an important source of variation in a°, suggesting the use of SAR data from the dry season only. Using simulated data, seven texture measures showed potential for strengthening the a7biomass relationship. However, when applied to real SAR data only GLCM (Grey Level Co-occurrence Matrix) derived contrast strengthened the a7biomass relationship. The addition of GLCM-derived contrast to a° potentially increases the accuracy of biomass estimation and mapping. Neural networks can be used for the classification of land cover in tropical forest regions. Classification accuracy of around 80% was achieved using combined multiwavelength and multipolarisation SAR and Landsat TM bands for 4 land cover classes (pasture, mature forest, 0-5 years old regenerating forests and 6-18 years old regenerating forest). These results demonstrated that multiwavelength and multipolarisation SAR data could provide information on the location, and extent of regenerating tropical forests. However an increase in the accuracy of biomass estimation relies on the optimal use of additional information that resides within the spatial, spectral and polarisation domains of SAR data.

The rural landscape surrounding the bigger cities are becoming increasingly fragmented due to pressures from urbanization and higher demands on conflicting usages of available buildable land. This has resulted in the natural and cultural landscapes in peri-urban areas being threatened. One usage of this land by equine sport is expanding where the horses need access to land and nature. A great majority of the horses in Sweden are kept in peri-urban areas, but horse keeping is also a factor that increases the risk for land use conflicts. The aim of this study is to better understand the role of horse keeping in the peri-urban landscape, by investigating these activities through the lens of ecosystem services. This study looked into the challenges and potential of horse keeping in physical planning, and how it is currently included by the local government of Österåker municipality in Stockholm county. This was achieved as a qualitative case study, consisting of interviews with local horse keepers, a web based survey for municipal residents and an analysis of available local government planning policies, reports and strategic documents. Horse keeping was found to be primarily associated with cultural ecosystem services, by its contribution to the equine sport sector and the preservation of the rural cultural and natural landscape with high recreational values. By preserving farmland and grazing pastures for horses, horse keeping can also be linked to supporting, regulating and provisioning ecosystem services. In addition, horse keeping in peri-urban areas was found to end in the periphery of the local physical planning. However, there is a need to integrate a long-term strategy and holistic perspective to achieve the full potential of the horse keeping, considering the contribution to the ecosystem services. There is a need for a more creative planning if horses should reach the potential as a resource and a planning tool for a sustainable development in the dynamic peri-urban landscape.

Loess is a very fine aeolian sediment that can be used as a proxy for stadial and interstadial glacialperiods. To understand how Earth’s climate have changed and what effects that change have had on theplanet and life on it we can use climate archives. The composition of loess and soil often contains asmall amount of magnetic minerals which can be used for identifying warmer and colder periods. Theclimate is recorded in the soil as it is deposited and climate changes. By examining loess as a climatearchive, we can increase our understanding of past climate, with this increased understanding inferencesabout changes to future climate and climate changes can be made. The aim of this study has thereforebeen to understand the depositional environment of the loess sequences on Portlet, Jersey in the EnglishChannel. This was done by examining the magnetic susceptibility of 173 samples taken from the unitsin the sequency of Portelet and interpreting the variations of magnetic susceptibility in them. Thelocation of Portelet on the edge of the glacial maximum and next to the Atlantic Ocean makes it aninteresting study area in connection to climate change. The magnetic susceptibility measurements showa variation in warmer and colder periods during the deposition of the sediments in the sequency and theunits vary in the type of enhancement model that can be applied to them. The study provides a clearerpicture of the depositional environment during the stadial and interstadial during the late Quaternary.

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No description available.

No description available.

An abstract is not provided. / Thesis / Bachelor of Arts (BA)

A Geography 4C6 research paper / N/A / Thesis / Bachelor of Arts (BA)

Climate change is predicted to have a big impact on wetland ecosystems, specifically in northern latitudes. Wetlands are important for different species and provide different ecosystem services. This literature study investigated what effects climate change has on boreal wetlands species composition and greenhouse gas (GHG) fluxes, and how this can in turn enhance global warming. Thirteen studies were used to construct a causal loop diagram (CLD). The result indicates that less CO2 will be accumulated together with increases in CO2 emissions, reduced CH4 emissions and species composition will change towards more woody plants. There could be correlations between the changes in species and less accumulated carbon, and the GHG emissions from boreal wetlands can enhance global warming. According to this literature review, there is still a lot of research needed about wetlands in the boreal zone and how they are affected by climate change.