Syftet med undersökningen var att undersöka landskapsförändring och skogsutveckling under de senaste århundraden kring Skrylle naturreservat som är beläget mellan Södra Sandby och Dalby i Lunds kommun. Hur det har sett ut, vad har förändrats samt varför, är frågor som behandlas i undersökningen. Resultatet framställdes med hjälp av äldre historiska kartor samt flygbilder med komplettering av skriftligt källmaterial.  Resultatet visar att största förändringen skedde mellan 1700- och 1800-talet då markanvändningen förändrades helt, från att gå från lövskog till öppen mark. En del förändringar av skogstyp skedde under 1900-talet då gran planterades i området. Den totala skogsarealen är mindre idag än vad det har varit som mest förr. Mycket av förändringarna beror på människans behov och intresse men även en del naturkatastrofer har påverkat skogsutvecklingen.

Rapid warming in northern latitudes will lead to permafrost thaw and subsequent carbon remobilisa­tion and release to the atmosphere. To incorporate the permafrost carbon climate feedback in globalEarth System Models, it is of importance to know the carbon stored in the circum­Arctic permafrostregion as accurate and precise as possible. Whereas soil, Yedoma and delta carbon stocks are alreadyquantified, deep carbon stocks for vast areas of the current permafrost region are still unaccountedfor. The aim of this Master thesis project is to estimate the deep carbon stock (>3m) for Quaternarydeposits outside the known reservoirs. Therefore, 363 boreholes and exposures were compiled fromthe scientific literature. 244 sites provide profile descriptions (depositional environment, depth andthickness) and another 119 sites contain data to calculate carbon densities (ground ice content, coarsefraction (>1cm and/or >2mm), bulk density and total organic carbon). Data gaps were filled usinglocal, regional and global average facies values from the compiled dataset. For spatial upscaling,key regions are defined using the permafrost zone, overburden thickness and ice content. The fielddata compiled here shows disagreements with the Circum­Arctic Map of Permafrost and Ground­Iceconditions (Brown et al. 2002), which should be updated especially in thin and ice­poor regions. Atotal C stock of 1698 ±255 PgC is estimated for 3­25m in Quaternary deposits of the circum­Arcitcpermafrost region, next to the Yedoma domain (327 ­ 466 PgC, Strauss et al. 2017) and deltas (41 ­151 PgC, Hugelius et al. 2014). About 70% of the carbon is stored within 3­10m (1200 ±238 PgC).Due to a publication bias towards thick and organic­rich sediments in the literature, C stocks calcualtedhere might be overestimated. Additional to the Yedoma domain, 309 ±99 PgC are stored in ice­richdeposits of the continuous permafrost zone, a regions especially prone to thermokarst and deep carbonremobilisation. Thermokarst, thermo­fluvial erosion along rivers and coasts as well as carbon releasethrough inland water systems presents possible release mechanisms for stored carbon. The permafrostcarbon estimate determined here doubles the known carbon reservoir in the permafrost region and em­phasises the importance for possible deep carbon release with future permafrost thawing.

A consequence of climate change is rising global sea levels, predicted to bring increased socio-economic and environmental impacts to coastal communities. The Greenland Ice Sheet has become a prominent contributor to rising sea levels, a consequence of the Arctic warming at twice the rate of the global average. Mass loss from the ice sheet is separated between changes in surface mass balance and ice discharge at marine terminating outlet glaciers, with the later dominating mass loss over the past fifty years. While advances in ice sheet modelling have provided greater clarity on Greenland’s future mass loss, there remains inefficiencies in modelling the response of outlet glaciers in Greenland’s fjords. This thesis aims to provide greater insight into behaviour of Kangerlussuaq Glacier, SE Greenland, by employing a 2D flowline model to understand the processes governing ice dynamics and to explore how the glacier may respond to a warming climate. Results indicate that the presence of a winter ice mélange is the principle dictator of Kangerlussuaq Glacier’s behaviour and likely protects against further retreat towards a reverse sloped section of bedrock. However, if such a retreat does materialise, then large overdeepenings in Kangerlussuaq Fjord raise the spectre of uncontrollable retreat and excessive mass loss.

Orientador: Fabiano Tomazini da Conceição / Resumo: As taxas de denudação de longo prazo são reconhecidamente um parâmetro importante na caracterização e na compreensão da evolução geomorfológica dos continentes, de maneira que todos os métodos cabíveis devem ser empregados em sua avaliação, inserindo-se nesse contexto os métodos geocronológicos 40Ar/39Ar e (U-Th)/He. A presença de relevos residuais da Superfície Sul-Americana, com coberturas detrito-lateriticas ricas em minerais supergênicos, torna a região de Caldas Novas – Rio Quente/GO ideal para a realização de estudos dessa natureza. Nesse contexto, o objetivo deste estudo consistiu em caracterizar a evolução do relevo da referida região, bem como obter informações sobre a história de intemperismo, paleoclima e denudação dessa região brasileira durante o Cenozoico. Para tanto, além dos métodos geocronológicos supracitados, foram aplicadas técnicas microanalíticas nos minerais amostrados, além de modelagem espacial da área de estudo em ambiente SIG. Datados através do método (U-Th)/He, as goethitas apresentaram idades entre 55,34±5,5 e 0,13±0,01 Ma, indicando a existência de períodos de intemperismo químico intenso no transição entre o Paleoceno e Eoceno, no decorrer do Eoceno e na transição entre o Oligoceno e o Mioceno, bem como no decorrer do Pleistoceno. O conjunto de dados geocronológicos indicou a relação direta entre a precipitação dos minerais analisados e os ótimos climáticos do Cenozoico. Atribuídas às goethitas amostradas no topo da Serra de Caldas, as idades m... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The long term denudation rates are recognized as an important parameter in the study of continental geomorphological evolution and all applicable methods should be employed in this assessment, including 40Ar/39Ar and (U-Th)/He. The presence of residual reliefs of South American Surface, covered by iron duricrusts, makes the Caldas Novas – Rio Quente/GO an ideal region for conducting these studies. In this context, the main aim of this study was to characterize the relief evolution of the study area, as well to obtain information on the history of weathering, paleoclimate and denudation of this Brazilian region during the Cenozoic. Therefore, in addition to geochronological methods, microanalytical techniques were applied to the sampled minerals, as well as spatial modeling of the study area in a GIS environment. Dated by the (U-Th)/He method, Fe oxides were aged between 55,34±5,5 and 0,13±0,01 Myr, indicating the existence of periods of intense chemical weathering in the transition between the Paleocene and the Eocene, during the Eocene and between Oligocene and Miocene, as well as in during the Pleistocene. Thus, the set of geochronological data indicated the direct relationship between the precipitation of minerals and the optimal climates of the Cenozoic. Assigned to the Goethites sampled at the top of Serra de Caldas, the oldest ages obtained for the South American Surface in the study area were 55,34±5,5 Myr. From these ages, the long-term denudation rates established fo... (Complete abstract click electronic access below) / Doutor

Antropogen inverkan på växthuseffekten är en bidragande faktor i den globala uppvärmningen, som i sin tur kommer att förstärka värmeböljor och den urbana värmeöeffekten. Kombinationen av dessa fenomen kan ha förödande konsekvenser. Höga temperaturer medför en minskad komfort för städers invånare och risken för värmerelaterad sjukdom och dödlighet ökar. Geoengineering som höjer det urbana albedot är en möjlig metod för att motverka allt mer intensiva värmeböljor, vilket i denna studie appliceras på Uppsala stad i form av vita tak. Den totala arean av mörka tak i Uppsala uppgår till 2,8 · 106 m2, vilket utgör mer än en tredjedel av Uppsalas totala takyta. Denna studie visar att implementeringen av vit plåt på mörka tak kan öka takets albedo med 0,42 vilket innebär att det finns en stor potential att öka det urbana albedot i Uppsala. Tidigare forskning tyder på ett samband mellan en ökning av det urbana albedot och en minskad medeltemperatur i städer. Det är därför rimligt att anta att en storskalig implementering av denna typ av geoengineering i Uppsala skulle kunna lindra effekterna av framtida värmeböljor.

Spridning av invasiva arter medför stora konsekvenser för den biologiska mångfalden, människors hälsa och ekonomi. Jättelokan är en av de vanligt förekommande invasiva arterna som finns i Sverige. Det finns omfattande kunskaper om jättelokans biologiska egenskaper, spridning och påverkan på biologiska mångfalden och människor. Syftet med den här uppsatsen är att identifiera de potentiella riskområdena i Kristianstads kommun som bör prioriteras för bekämpning av jättelokan. Variablerna som har undersökts för att besvara uppsatsens syfte är följande: befolkningstäthet, markanvändning, jordarter och närhet till väg och vatten. Dataprogrammet ArcGIS har använts för att behandla och presentera geografisk data. Undersökningen har visat att det är främst kommunens västra och centrala delar som är mest utsatta för spridning. Dessa områden bör lyftas fram för bekämpning med tanke på hälsorisker som jättelokan kan orsaka. Studien indikerar på en positiv trend mellan förekomsten av jättelokan och befolkningstäthet. Mark som används för fruktodling och öppen mark framhävs som de mest invaderade områdena med hög spridning. Högre spridning uppmärksammas i jordarterna svämsediment sand och grusig morän. Studien spårar en positiv trend mellan förekomsten av jättelokan och närheten till trafikleder och vattendrag. Resultaten av undersökningen kan användas för att prioritera områdena för riktade bekämpningsåtgärder.

Geography has been a central element in shaping conflict through the ages, and is especially important in determining which states fight, why they fight, when they fight, and more importantly, where they fight. Despite this, conflict literature has primarily focused on human geography while largely ignoring the geospatial context of ‘where' conflict occurs, or crucially, doesn't occur. Territorial disputes are highly salient issues that quite often result in militarized disputes. Terrain has been key to mitigating conflict even in the face of major variance in state capability and power projection. In this study I investigate how terrain characteristics interact with power projection, opportunity, and willingness and the impact this has across territorial disputes. Exploring terrain's interaction with these concepts and its effect among different types of conflict furthers our understanding of the questions listed above.

Leaves in forests assimilate carbon from the atmosphere and woody components store the net production of that assimilation. Separate structure measurements of leaves and woody components advance the monitoring and modeling of forest ecosystem functions. This dissertation provides a method to determine, for the first time, the 3-D spatial arrangement and the amount of leafy and woody materials separately in a forest by classification of lidar returns from a new, innovative, lidar scanner, the Dual-Wavelength Echidna® Lidar (DWEL). The DWEL uses two lasers pulsing simultaneously and coaxially at near-infrared (1064 nm) and shortwave-infrared (1548 nm) wavelengths to locate scattering targets in 3-D space, associated with their reflectance at the two wavelengths. The instrument produces 3-D bispectral "clouds" of scattering points that reveal new details of forest structure and open doors to three-dimensional mapping of biophysical and biochemical properties of forests. The three parts of this dissertation concern calibration of bispectral lidar returns; retrieval of height profiles of leafy and woody materials within a forest canopy; and virtual reconstruction of forest trees from multiple scans to estimate their aboveground woody biomass. The test area was a midlatitude forest stand within the Harvard Forest, Petersham, Massachusetts, scanned at five locations in a 1-ha site in leaf-off and leaf-on conditions in 2014. The model for radiometric calibration assigned accurate values of spectral apparent reflectance, a range-independent and instrument-independent property, to scattering points derived from the scans. The classification of leafy and woody points, using both spectral and spatial context information, achieved an overall accuracy of 79±1% and 75±2% for leaf-off and leaf-on scans, respectively. Between-scan variation in leaf profiles was larger than wood profiles in leaf-off seasons but relatively similar to wood profiles in leaf-on seasons, reflecting the changing spatial heterogeneity within the stand over seasons. A 3-D structure-fitting algorithm estimated wood volume by modeling stems and branches from point clouds of five individual trees with cylinders. The algorithm showed the least variance for leaf-off, woody-points-only data, validating the value of separating leafy and woody points to the direct biomass estimates through the structure modeling of individual trees.

Northern Iceland is a place of great interest for climatic studies. The land was fairly untouched by human activity until the Landnám period (870-930 AD), when humans first started to colonize the island. The study site is situated in the valley of Hjaltadalur close to the village Hólar, which after the settlement of humans became the religious and culture center of northern Iceland. Peat sediment cores were drilled to gain knowledge of the climatic fluctuations and environmental development in the area. Peat is a perfect archive of climatic and environmental changes due to its ability to preserve material like pollen, tephra and insect fossils which can be identified and analyzed to gain a better understanding of the past climate. Out of four possible drilling sites in the valley of Hjaltadalur, northern Iceland, Viðvik peat land was chosen for climatic analyses. Pollen, loss on ignition, tephra and radiocarbon dating analyses were performed on the peat material and samples for future macrofossil analyses were collected. The analyses provided useful information and insights into temperature fluctuations during the late Holocene, which could be correlated with other palaeoclimate research made in the past decades in the northern regions of Iceland. The pollen diagrams presented in this thesis show a transition from a warm and dry forestlike landscape to a cooler, more humid, open landscape during the last 5000 years. This visible transition, which contributed to a reduction of the birch population, started before the european settlement and thus implies that humans were not solely responsible for the birch decline in Iceland after the Landnám period (870-930 AD).

Understanding the formation mechanics of glacial crevasses is crucial in a variety of glacial applications. Besides being a serious safety hazard during field campaigns, crevasses influence calving rates, mass balance, and the hydrological network of glaciers. Therefore, knowledge about their spatial distribution and potential development zones is highly beneficial. In this project, spatial distribution of surface crevasses on the Svalbard archipelago is investigated using a simple crevasse depth model, so called Nye’s zero-stress model, and a set of surface ice velocity data. The model is run for various ice temperatures as it is one of the parameters affecting crevasse development. The crevasse occurrences are also mapped and digitised manually using high resolution remote-sensed images. A special emphasis is put on the Lomonosovfonna ice cap, central Spitsbergen, where the crevasse distribution is studied in detail. The results indicate the greatest density of crevasses in regions of high ice surface velocity and concurrently high strain rates. These areas encompass mainly fast-flowing outlet valley glaciers, while the more stagnant ice caps and ice fields are characterised by little to no crevassing except for their margins. The modelled spatial distribution is concurrent with the observations, particularly for certain ice temperatures, highlighting the importance of accurate ice temperature measurements in modelling and a need of separation of the accumulation and ablation zones. Overall, the Nye’s zero-stress model yields accurate results and proves to be a suitable tool for the task. With room for fine-tuning, it is a promising tool that is easy to incorporate in other models.