This dissertation investigates the emergence and evolution of United States' national interests in the Arctic region, as well as examines the factors that influence how the U.S. engages in cooperative endeavors in the region with other Arctic states. Though geographically located on the periphery of broader global politics, the region nevertheless is geopolitically situated at the convergence of three continents—North America, Asia, and Europe—in an area historically significant to, but often underappreciated by, the U.S. Government. Two research questions frame this study. The primary research question asks: How have U.S. national interests in the Arctic region evolved over time, and what factors help explain the evolution of U.S. engagement in the region? U.S. perceptions of the region's geopolitical significance gives rise to a subsidiary question: To what degree has the U.S viewed the Arctic region as a zone of competition or a zone of cooperation? Drawing on a range of archival sources, academic literature, historical and contemporary U.S. Government documents—including several declassified documents, as well as personal interviews of key Arctic experts, this study analyzes the development of U.S. interests in the Arctic over four distinct time periods, collectively spanning over a hundred years. These time periods are pre-World War I to the end of World War II (1906-1945); the first half of the four-decade-long Cold War (1945-1967); the second half of the Cold War (1968-1989); and the post-Cold War period (1990-2017). The study produces three major findings. First, U.S. overall interest in the Arctic region increased and decreased in conjunction with how the U.S. perceived the region's overall geopolitical significance. This waxing and waning of U.S. involvement in the polar north generally aligned with the U.S. viewing the Arctic as either a zone of insignificance, competition, or cooperation at different phases over the study's time period. The study's second major finding is that U.S. security interests in the Arctic singularly dominated and shaped America's overall set of national interests that emerged in the region, particularly since World War II. While constituting a number of issues, the most important U.S. security interest in the Arctic has been ensuring freedom of navigation in and through the Arctic. The region's overwhelming maritime composition, along with freedom of navigation's centrality to America's broader global power and interests, ensures the security-driven focus of America's overall Arctic national interests. The final key finding reveals that U.S. Arctic cooperative engagement is conditional. Geopolitical perceptions of the Arctic as either a zone of competition or a zone of cooperation conditions America's willingness to engage with other Arctic states in the region. Since the end of the Cold War and the ensuing period of circumpolar cooperation, U.S. participation in Arctic cooperative arrangements has been conditioned on how much it perceives such arrangements intrude on U.S. autonomy and freedom to act in and through the region. / Doctor of Philosophy / The Arctic is a vast and sparsely populated region that historically has been viewed geographically and geopolitically peripheral to the rest of the world. The United States has not always considered the region important, even though it has territory there. This study asks two questions. First: How have U.S. national interests in the Arctic region evolved over time, and what factors help explain the evolution of U.S. engagement in the region? Second: To what degree has the U.S viewed the Arctic region as a zone of competition or a zone of cooperation? Three major findings emerge from this study, which covers the early 20th century to the second decade of the 21st century—more than a hundred years. First, the evolution of U.S. interests in the Arctic region have waxed and waned in concert with how important the U.S. perceives the region. Second, America's security interests in the Arctic region dominate and drive its overall approach to the region. Finally, U.S.'s willingness to cooperatively engage with other Arctic states in the region depends on how the U.S. believes such engagements effect its ability to act in and through the Arctic region. The Arctic region is becoming more geopolitically important than at any time since at least the Cold War. Rapid global warming could potentially make the region's historically inaccessible shipping routes and vast natural resources accessible by 2050. With Russia already the largest Arctic presence, and China's increased focus on the Arctic, the region could become a space for strategic competition that could threaten U.S. national interests. This study provides the policy community the background and context to navigate the geopolitical challenges and opportunities being unleashed in the Arctic region.

the work that follows is a study in material and the nature of its construction. i chose a site that was rich in tradition of building, but chose to not mimic tradition. the arctic circle of norway has a tradition of stone and wood construction. the remote qualities of the site lead me to choose a house, of local stone and wood. the extreme conditions of the environment posed the challenges in design and construction. i did not test the limits of the stone, but let the stone do what is natural to it. i chose not to force the stone to be anything other than itself, and working with these natural tendencies to make the decisions of construction. / Master of Architecture

There are currently growing geopolitical tensions within the Arctic region. Furthermore, climate change is quickly providing easier access to the Arctic region and its natural resources, strategic positioning, and unclaimed territory. Simultaneously, the EC and EU Arctic states are pushing public discourse with an incorporated distaste for the growing geopolitical tensions and increasing interest by certain states. However, there is a lack of academic literature applying a poststructuralist approach to the construction of these security threats within this topic. Therefore, the thesis will incorporate several theoretical tools by prominent poststructuralists such as Michel Foucault and Jacques Derrida, including identity, deconstruction, and power/knowledge for the analysis.  Moreover, the chosen methodological approach for the analysis is a predicate analysis. The predicate analysis aided the thesis in successfully approaching the research question, by exploring how the EC and EU Arctic states have constructed Russia as a security threat through their public Arctic discourse. Thus, the findings concluded that the EC and EU Arctic states do construct Russia as a security threat within their public discourse through the chosen theoretical tools.

Previous research indicates that future reductions in Arctic sea ice cover (SIC) could alter storm tracks and precipitation patterns in western North America and negatively impact water resources in the American southwest. Other research suggests that multiple periods of increased precipitation and/or cooler temperatures in the American southwest during the Little Ice Age (LIA) were due to strong El Niño events; historical records also describe expanded Arctic SIC at this time. We use 16th-19th century Arctic SIC records from the ACSYS Historical Ice Chart Archive as a basis for expanding Arctic SIC from 1870 HadISST data to theoretical LIA extents. Then, in a suite of sensitivity studies, we investigate the relative influences of and interactions between El Niño-Southern Oscillation (ENSO) related sea surface temperature (SST) variation and varying Arctic SIC in controlling storm tracks, precipitation patterns, and overall climate conditions in the American southwest. We find that tropical Pacific SSTs greatly influence climate system response to variability in Arctic SIC, with ENSO-Neutral SSTs permitting the greatest response. Additionally, the degree of expansion and symmetry of Arctic SIC also influence precipitation regime response. These findings suggest that the climate response to future Arctic SIC retreat may not only be highly dependent on the spatial patterns and extent of SIC reductions, but also upon ENSO variability, such that El Nino events may reduce the potential climate impact of ice reductions as compared to Neutral or La Nina events. / Master of Science

Aerosols change the Earth's energy balance. Black carbon (BC) aerosols are a product of incomplete combustion of fossil fuels and biomass burning and cause a net warming through aerosol radiation interactions (ari) and aerosol cloud interactions (aci). BC aerosols have potentially strong implications on the Arctic climate, yet the net global climate effect of BC is very uncertain. Best estimates assume a net warming effect, roughly half to that of CO2. However, the time scales during which CO2 emissions affect the global climate are on the order of hundreds of years, while BC is a short-lived climate pollutant (SLCP) with atmospheric life times of days to weeks. Climate models or atmospheric transport models struggle to emulate the seasonality and amplitude of BC concentrations in the Arctic, which are low in summer and high in winter/spring during the so called Arctic haze season. The high uncertainties regarding BC's climate impact are not only related to ari and aci, but also due to model parameterizations of BC lifetime and transport, and the highly uncertain estimates of global and regional BC emissions. Given the high uncertainties in technology-based emission inventories (EI), there is a need for an observation-based assessment of sources of BC in the atmosphere. We study short-term and long-term observations of elemental carbon (EC), the mass-based analog of optically-defined BC. EC aerosol concentrations and carbon-isotope-based (δ13C and ∆14C) sources were constrained (top-down) for three Arctic receptor sites in Abisko (northern Sweden), Tiksi (East Siberian Russia), and Zeppelin (on Svalbard, Norway). The radiocarbon (∆14C) signature allows to draw conclusion on the EC sources (fossil fuels vs. biomass burning) with high accuracy (&lt;5% variation). Stable carbon isotopic fingerprints (δ13C) give qualitative information of the consumed fuel type, i.e. coal, C3-plants (wood), liquid fossil fuels (diesel) or gas flaring (methane and non-methane hydrocarbons). These fingerprints can be used in conjunction with Bayesian statistics, to estimate quantitative source contributions of the sources. Finally, our observations were compared to predictions from a state of the art atmospheric transport model (coupled to BC emissions), conducted by our collaborators at NILU (Norwegian Institute for Air Research). Observed BC concentrations showed a high seasonality throughout the year, with elevated concentrations in the winter, at all sites. The highest concentrations were measured on Svalbard during a short campaign (Jan-Mar 2009) focusing on BC pollution events. Long-term observations showed that Svalbard (2013) had overall the lowest annual BC concentrations, followed by Abisko (2012) and Tiksi (2013). Isotope constraints on BC combustion sources exhibited a high seasonality and big amplitude all across the Eurasian Arctic. Uniform seasonal trends were observed in all three year-round studies, showing fractions of biomass burning of 60-70% in summer and 10-40% in winter. Europe was the major source region (&gt;80%) for BC emissions arriving at Abisko and the main sources were liquid fossil fuels and biomass burning (wood). The model agreed very well with the Abisko observations, showing good model skill and relatively well constrained sources in the European regions of the EI. However, for the Svalbard and East Siberian Arctic observatories the model-observation agreement was not as good. Here, Russia, Europe and China were the major contributors to the mostly liquid fossil and biomass burning BC emissions. This showed that the EI still needs to be improved, especially in regions where emissions are high but observations are scarce (low ratio of observations to emitted pollutant quantity). Strategies for BC mitigation in the (Eurasian) Arctic are probably most efficient, if fossil fuel (diesel) emissions are tackled during winter and spring periods, all across Eurasia. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Manuscript. Paper 3: Manuscript.</p>

Marine diatoms are the dominant primary producers in coastal and shelf regions, and contribute to about 20% of the annual photosynthesis on Earth. Diatoms also exert a major control on the marine silicon (Si) cycle through the formation of biogenic silica (bSiO2). Continental shelves account for half of the total marine area in the Arctic, yet our knowledge of the cycling of Si for this critically climate-impacted region is limited. The overall objective of this thesis was to improve our understanding of marine bSiO2 dynamics and Si cycling in marine Arctic and Subarctic ecosystems using novel techniques. Phytoplankton and nutrient observations, including dissolved and particulate silica concentrations, are presented from a period of ten years within five biological ‘hotspots’ in the Bering and Chukchi Seas. The first measurements of bSiO2 production and dissolution rates are also presented from a period of four years at the same sites. Results from this work show that (i) although interannual variability is high, diatoms are responsible for most of the high primary productivity in the Bering and Chukchi Seas, (ii) bSiO2 is primarily re-dissolved within the euphotic zone rather than exported, and (iii) phytoplankton phenology and marine Si cycling are affected by short-term climatic changes in this region. We also present the first measurements of bSiO2 production rates along a transect from the Canadian Arctic Archipelago (CAA), through Baffin Bay and into the Labrador Sea. We show that diatoms are both abundant and productive throughout these regions in summer, despite widespread Si limitation in the low-nutrient surface waters. Finally, we also investigated the natural variations in the Si isotopic composition of silicic acid (30Si(OH)4). On a transect through the Bering and Chukchi Seas, Canada Basin and CAA, and finally to Baffin Bay and the Labrador Sea, we found that δ30Si(OH)4 signals reflect water mass composition, the dissolution of bSiO2 throughout the water column, and the biological utilization of Si in surface waters. Ultimately, this work provides insight into the processes controlling marine Si cycling within the Arctic and its links to the global marine Si cycle and other biogeochemical cycles. / Graduate / 2020-03-13

The Arctic has long been considered to be a pristine environment, far from population centers and pollution sources. The detection of synthetic organochlorine compounds in various elements of the Arctic food web has confirmed the global dispersion of pollutants, particularly of persistent compounds such as organochlorines and heavy metals. Levels of heavy metals, although elevated, appear to be naturally so throughout much of the Arctic. Arctic pollution is both a humanitarian and ecological concern. Many arctic coastal communities depend heavily on marine mammal fat for sustenance, and are therefore potentially exposed to high levels of organochlorines and some metals. From an ecological perspective, the structure of arctic food webs, the importance of lipid mobilization for winter survival, and the adaptive physiologies of arctic organisms may result in an enhanced response to contaminant exposure. This thesis assesses the exposure and effect of organochlorine and heavy metal exposure in inland freshwater ecosystems of Arctic Alaska, and evaluates the physiological response of arctic grayling to experimental polychlorinated biphenyl (PCB) exposure. / Graduation date: 1995

No description available.

The sea ice extent change and variability of the Canadian Arctic Archipelago (CAA) are quite different compared to the Arctic as a whole due to its unique geographic settings. In this thesis, the sea ice retreat processes, the connection with other Arctic regions, and the linkages to the surface radiation flux in the CAA are examined. The sea ice retreat processes in the CAA follow a four-phase process: a slow ice melt phase that usually lasts until early June (phase 1); a quick melt phase with large daily sea ice extent change which lasts close to half-a-month (phase 2); a slow melt phase that looks like slow sea ice melt or even a small ice increase that lasts another half-a-month (phase 3); and a steady ice decrease phase (phase 4). With the help of Moderate-Resolution Imaging Spectroradiometer (MODIS) data, it is identified that the quick melt in phase 2 is actually melt ponding, with melt ponds being falsely identified as open water by passive microwave. A simplified data assimilation method is then developed to improve the passive microwave sea ice concentration estimation by fusion with MODIS ice surface temperature data. The ice concentration from the analysis is found to improve the original passive microwave sea ice concentration estimation, with the largest improvements during sea ice melt. The sea ice retreat patterns in the CAA region are correlated with the sea ice retreat patterns in other regions of the Arctic. A decision tree classifier is designed to segment the sea ice retreat patterns in the CAA into several classes and classification maps are generated. These maps are effective in identifying the geographic locations that have large changes in the sea ice retreat patterns through the years. The daily progressions of the surface radiation components are described in detail. Due to the lack of multiple reflection, the percentage of shortwave radiation at the top of atmosphere that reaches the surface is influenced by the form of melt ponds over ice surface. The roles that each surface radiation component plays in forcing sea ice retreat are different in different years.

No description available.