Este trabalho teve como objetivo analisar os possíveis efeitos de um aumento do nível do mar no padrão de correntes no Sistema Estuarino de Santos (SP), através do uso do modelo hidrodinâmico do Delft3D-FLOW, considerando diferentes taxas de aumento de acordo com o quinto relatório do Intergovernmental Panel on Climate Change (AR5). Os resultados indicam alteração na velocidade da corrente ao longo do domínio implementado, mais evidente durante a sizígia. Observa-se um aumento da magnitude da corrente em praticamente todo o Canal de São Vicente e redução da magnitude nos canais do Porto de Santos, canal de Bertioga e na região interna do Estuário de Santos. Os resultados do modelo numérico foram comparados com diversos dados coletados na região de estudo e verificou-se a correta representação dos padrões de circulação da área. Este estudo comprovou a importância de utilizarmos resultados de um modelo de maior escala (HYCOM) como forçantes, através da condição de fronteira denominada Riemann, permitindo que o modelo represente fenômenos de baixa frequência, que geram circulações e variações do nível do mar com a mesma ordem de grandeza dos efeitos da maré astronômica na área de estudo. / This study aimed to analyze the possible effects of a sea level rise in Sistema Estuarino de Santos (SP) circulation pattern, through the use of Delft3D-FLOW Hydrodynamic Model considering different elevation rates according to Intergovernmental Panel on Climate Change fifth report (AR5). The results indicate change in the current\'s magnitude, being more evident during the spring tide. There is an increase in the velocity practically all over São Vicente Channel and the reduction of magnitude in the Porto de Santos and Bertioga channels and in the inner region of the estuary. The numerical model results were compared with several measured data and it was verified that the model correctly representats the circulation patterns of the area. This study proved the importance of using results of a larger scale model (HYCOM), forced through a boundary condition called Riemann, allowing the model to represent low frequency phenomena, which generate sea level variations with the same order of magnitude of the effects of the astronomical tide in the study area.

Semi-natural grasslands with traditional management are known to be very species-rich, with many plant species strongly associated with the habitat. The last century’s decline of semi-natural grasslands, as a result of land use change and abandonment, has made the remaining semi-natural grassland a high concern for conservation. Since management can be costly and the available resources often are limited, it is important to use the most beneficial management method for preserving and enhancing the biodiversity. One semi-natural grassland type of certain interest around the Baltic region are coastal grasslands. In this study, I investigated vascular plant species occurrence in ten managed coastal grasslands located in the Stockholm archipelago. The effect of recent land-uplift and future sea level rise on the ten coastal grasslands were analyzed as well. A major part of all ten grasslands had been subjected to the process of isostatic land-uplift the past 100 years. Five of the grasslands were currently managed by grazing and the other five were managed by traditional mowing. There was no significant difference in alpha and gamma diversity between the two management types. Though, higher biodiversity values, such as more different species found in total, higher amount of species typically linked to meadows and pastures, less succession species and more red-listed species, were found in the traditionally mowed grasslands. Furthermore, a sea level rise with 40 cm the next 100 years in the region would lead to loss of plant species diversity in the investigated coastal grasslands. One major concern is the limited areas upwards on the coastal grasslands for species to migrate to in the future, which is expected to primarily affect species associated with meadows and pastures. The study highlights the importance of open and managed grassland areas further up the coastal grasslands for local species to migrate to, if the sea level would rise as predicted by future climate scenarios. Albeit weak the results of this study indicate that traditional mowing generates higher biodiversity values compared to grazing, hence it should be the preferred management method in coastal grasslands in the Stockholm archipelago.

Le milieu littoral des espaces insulaires ultra-marins intertropicaux français est doublement impacté par les aléas hydro-climatiques et sismiques naturels, et par les actions anthropiques déstabilisatrices locales ou globales. Le mémoire traite spécifiquement des cas de Wallis & Futuna et de Lifou (archipel des Loyauté) dans le Pacifique sud et de Mayotte dans l’océan Indien. Il aborde, sous une approche pluridisciplinaire, les différentes facettes du potentiel d’adaptation des populations locales aux variations du niveau marin de différents ordres : ponctuel (associés aux vagues de tempêtes et de tsunami) et global (avec la transgression liée au réchauffement climatique mis en évidence par la communauté scientifique). La montée des eaux, qui semble inéluctable à moyen terme, et les risques hydro-climatiques et sismiques (tsunamis) actuels impliquent que les sociétés devront, dans un futur plus ou moins proche, ajuster leur vision des modes d’occupation de l’espace et tout particulièrement celle du domaine littoral sur lequel vit l’essentiel des populations des îles étudiées. Le croisement des différentes approches disciplinaires abordées dans le mémoire permet de proposer des méthodes et des outils novateurs en vue d’une optimisation des stratégies d’adaptation à la montée des eaux. / The coastal environment of French overseas territories is both affected by the hydroclimatic and natural seismic hazards, and local or global destabilizing anthropogenic actions. This PhD deals specifically with cases of Wallis and Futuna and Lifou (Loyalty Islands) in the South Pacific, and Mayotte in the Indian Ocean. In a multidisciplinary approach, it gets onto the different facets of the adaptation potential of local societies when it comes to changes at sea level: occasional (associated with storm waves and tsunami) and global (with sea level rise related to global warming). The sea level rise, that seems inevitable in the medium term, hydro-climatic and seismic (tsunami) risks, means that local societies will probably adjust and organize their territories in a different way, especially coastal area (the most occupied space at the island scale). The different disciplinary approaches crossing can offer innovative tools and methods for optimizing the sea level rise adaptation strategies.

Satellite imagery and volume-area scaling are used to asses the glacier area and ice volume of Iceland from the Little Ice Age maximum to present day, obtaining a final result in sea level rise between 1890 - 2015. The Little Ice Age was a time of regional cooling, with glaciers reaching their maximum extent (~1890 for Iceland) with warming and glacier retreat after this period ended. Ice volume estimates are important to know due to their relevance in potential sea level rise calculations. Understanding both of these estimations for Iceland connects the impact a changing climate has on regional and global scales. Different scaling parameters used in the volume-area scaling approach to determine ice volume and ultimately sea level equivalents highlight the range of estimates acquired and point out the need in choosing appropriate values based on glacier region. A comparison to using mass balance measurements for volume estimates is also noted, showing differences in ice volume loss over past and present time periods. The Icelandic glacier area for present day is an updated value from previous studies at 10,803 ± 83 km2 and a first ever reported Icelandic Little Ice Age maximum glacier area of 12,201 ± 91 km2. For potential sea level rise, it is found the most reliable estimate from the volume- area scaling assessment is 2.67 mm from the Little Ice Age maximum to present day, with a yearly contribution since 1890 of 0.02 mm. / Satellitbilder och volym-area skalningsmetoden användes för att uppskatta glaciärarea och isvolym på Island från Lilla istiden till nutid, för att få fram hur stor höjningen av havsnivån varit under denna tidsperiod (1890 – 2015). Den lilla istiden var en tid av regional kylning då glaciärer nådde sin maximala utsträckning (~1890 för Island) följt av en snabb reträtt efter att denna period slutade. Uppskattningen av isvolym är viktigt att veta på grund av dess relevans i potentiella beräkningar av höjningen av havsnivån. Att förstå båda dessa uppskattningar för Island är kopplat till den påverkan ett förändrat klimat har på regional och global nivå. De olika skalparametrar som använts i volym-area skalningsmetoden för att bestämma volymen av is, och dess motsvarigheter i havsnivå, gav en rad av olika uppskattningar. Detta pekar på behovet att välja ett lämpligt parametervärde baserat på glaciärregionen. En jämförelse med att använda mätningar av massbalans för volymuppskattningar gjordes också, vilket visar skillnader i isvolymförlust över tidigare och nuvarande tidsperioder. Dagens värde på den isländska glaciärarean är uppdaterat från tidigare studier på 10,803 ± 83 km2 och den första rapporterade maximala isländska glaciärarean från Lilla istiden på 12,201 ± 91 km2. För potentiell höjning av havsnivån, har man funnit att den mest tillförlitlig uppskattning från volym-area skalningsmetoden är 2,67 mm från Lilla istidens maximum till nutid, med ett årligt bidrag sedan 1890 av 0,02 mm. (Översättning Cecilia Bayard.)

Sediment accretion and elevation change in tidal forests, and the corresponding ability of these wetlands to keep pace with sea-level rise (SLR), represent data gaps in our understanding of wetland sustainability. Surface Elevation Tables and marker horizons were installed in three mature tidal forests and a restored tidal marsh, allowing us to measure elevation change, accretion, and subsidence. Additionally, we measured predictor variables to test for their significance in explaining accretion and elevation change rates. Mean accretion at our sites was 11.67 +/- 3.01 mm yr-1 and mean elevation change was -20.22 +/- 8.10 mm yr-1, suggesting subsidence occurring beneath the sites. Processes contributing to accretion and elevation change at our sites may be driven by hydrologic patterns. Comparing our elevation trends with SLR trends suggests that our study sites may not keep pace with SLR. However, we may be observing short-term oscillations that do not indicate true long-term trends.

Awareness of extreme high tide flooding in coastal communities has been increasing in recent years, reflecting growing concern over accelerated sea level rise. As a low-lying, urban coastal community with high value real estate, Miami often tops the rankings of cities worldwide in terms of vulnerability to sea level rise. Understanding perceptions of these changes and how communities are dealing with the impacts reveals much about vulnerability to climate change and the challenges of adaptation. This empirical study uses an innovative mixed-methods approach that combines ethnographic observations of high tide flooding, qualitative interviews and analysis of tidal data to reveal coping strategies used by residents and businesses as well as perceptions of sea level rise and climate change, and to assess the relationship between measurable sea levels and perceptions of flooding. I conduct a case study of Miami Beach’s storm water master planning process which included sea level rise projections, one of the first in the nation to do so, that reveals the different and sometimes competing logics of planners, public officials, activists, residents and business interests with regards to climate change adaptation. By taking a deeply contextual account of hazards and adaptation efforts in a local area I demonstrate how this approach can be effective at shedding light on some of the challenges posed by anthropogenic climate change and accelerated rates of sea level rise. The findings highlight challenges for infrastructure planning in low-lying, urban coastal areas, and for individual risk assessment in the context of rapidly evolving discourse about the threat of sea level rise. Recognition of the trade-offs and limits of incremental adaptation strategies point to transformative approaches, at the same time highlighting equity concerns in adaptation governance and planning. This new impact assessment method contributes to the integration of social and physical science approaches to climate change, resulting in improved understanding of socio-ecological vulnerability to environmental change.

Increasing sea levels and anthropogenic disturbances have caused the world’s coastal vegetation to decline 25-50% in the past 50 years. Future sea level rise (SLR) rates are expected to increase, further threatening coastal habitats. In combination with SLR, the Everglades ecosystem has undergone large-scale drainage and restoration changing Florida’s coastal vegetation. Everglades National Park (ENP) has 21 coastal plant species threatened by SLR. My dissertation focuses on three aspects of coastal plant community change related to SLR and dehydration. 1) I assessed the extent and direction coastal communities—three harboring rare plant species—shifted from 1978 to 2011. I created a classified vegetation map and compared it to a 1978 map. I hypothesized coastal communities transitioned from less salt- and inundation-tolerant to more salt- and inundation-tolerant communities. I found communities shifted as hypothesized, suggesting the site became saltier and wetter. Additionally, all three communities harboring rare plants shrunk in size. 2) I evaluated invading halophyte (salt-tolerant) plant influence on soil salinity via a replacement series greenhouse experiment. I used two halophytes and two glycophytes (non-salt-tolerant) to look at soil salinity over time under 26 and 38‰ groundwater. I hypothesized that halophytes increase soil salinity as compared to glycophytes through continued transpiration during dry, highly saline periods. My results supported halophytic influence on soil salinity; however, not from higher transpiration rates. Osmotic or ionic stress likely decreased glycophytic biomass resulting in less overall plant transpiration. 3) I assessed the best plant life-stage to use for on-the-ground plot-based community change monitoring. I tested the effects of increasing salinity (0, 5, 15, 30, and 45‰) on seed germination and seedling establishment of five coastal species, and compared my results to salinity effects on one-year olds and adults of the same species. I hypothesized that seedling establishment was the most vulnerable life-stage to salt stress. The results supported my hypothesis; seedling establishment is the life-stage best monitored for community change. Additionally, I determined the federally endangered plant Chromolaena frustrata’s salinity tolerance. The species was sensitive to salinity >5‰ at all developmental stages suggesting C. frustrata is highly threatened by SLR.

Bald Cypress (Taxodium distichum (L.) Rich.) is native to freshwater wetlands of Florida. The vitality of cypress within coastal freshwater wetlands is threatened by saltwater intrusion. Biomarkers to detect sub-lethal salinity stress were developed using a controlled greenhouse study. Cypress saplings maintained at elevated salinities of 4 and 8‰ exhibited a decrease in maximum quantum yield (MQY) and an increase in non-photochemical quenching (NPQ). Cypress leaves exhibited an increase in Na+, H2O2, and free proline content compared to plants maintained in freshwater. These biomarkers were used to detect salinity stress within a population of cypress associated with the lower St. Johns River where saltwater intrusion is occurring. Cypress in a basin swamp exhibited signs of salinity stress with low MQY and elevated NPQ values compared to Cypress at other sites. Cypress leaves at the basin swamp also had the highest Na+, lipid peroxidation, and proline content compared to plants at other sites. Detached Cypress leaf experiments were conducted to explore the mechanisms of salt tolerance. Detached cypress leaves were first exposed to elevated NaCl concentrations for 24, 48, or 72 hours. Elevated salinity caused a decrease in leaf transpiration for all times tested. Total peroxidase activity exhibited an increase in response to salt stress after 48 hours. Enhanced peroxidase activity was found to be associated with the induction of a ~37 kDa peroxidase isoform. Treatment of leaves with clofibrate caused an increase in activity of the ~37 kDa peroxidase. Pre-treatment of leaves with brefeldin A (BFA) blocked the induction of the ~37 kDa peroxidase associated with salt stress. Pre-treatment of Cypress leaves with diphenyliodonium (DPI) blocked the decrease in transpiration associated with salt stress, suggesting that H2O2 is enzymatically produced within the stomata in response to salt stress

Uppvärmningen av klimatet resulterar i att havsnivån stiger globalt. Detta riskerar att få omfattande sociala, ekonomiska och ekologiska konsekvenser, i synnerhet för områden som angränsar mot kusten. I Sverige har kommunerna planmonopol och förväntas ta ett stort ansvar för klimatanpassning. I Stockholm antas havet stiga cirka 0,5 meter till år 2100 och det kommer troligtvis att fortsätta stiga efter det. Denna studie bygger främst på intervjuer i syftet att utreda huruvida det råder konsensus mellan stadens planerare och politikerna i Stockholms stad gällande hur hantering av en förhöjd havsnivå bör ske. Frågan är relativt ny och i ett spekulativt stadium vilket gör att det är svårt att se tydliga skiljelinjer. Samtliga personer som ingått i denna studie är dock överens om att problematiken kring ett stigande hav är en viktig fråga i behov av mer djupgående utredningar. Även att det i slutänden kommer att bli en samhällsekonomisk analys som blir avgörande för vad, när och hur något ska genomföras. / The warming of the climate will result in rising sea levels globally. This is likely to result in widespread social, economic and environmental consequences, especially for areas adjacent to the coast. In Sweden the municipalities have a monopoly for planning and the municipalities are expected to take a substantial responsibility for the city’s adaptation to the new sea levels. In Stockholm, the expected sea level rise is approximately 0.5 meters until 2100 and the sea is expected to continue to rise after 2100. This study is based on interviews with the purpose to investigate whether there is consensus between the city planners and the politicians in the City of Stockholm in how the management of the rising sea levels should be handled. The question is relatively new and rather in a speculative stage which makes it difficult to see clear dividing lines. However all interviewees in this study agreed that the problem of rising sea levels is an important issue that is in need of more in-depth investigation. Although it will ultimately become an economic analysis that will determine what, when, and how something should be implemented.

The Antarctic ice sheet is increasingly contributing to sea-level rise because of accelerated mass losses at its floating extensions -- its ice shelves. By floating while remaining attached to the grounded ice sheet, ice shelves buttress (i.e. restrain) the inland ice in such a way that ice-shelf losses lead to accelerated ice discharge in the ocean. This thesis investigates the stability of Antarctic ice shelves -- so crucial for the stability of the entire ice sheet -- using the Roi Baudouin Ice Shelf (RBIS), Dronning Maud Land, East Antarctica, as a case study. The RBIS has remained relatively stable over the last millennia and presents various kilometre-scale features (pinning point, ice-shelf channels and englacial lakes) with potential impact on its present and future stability.We first derive a horizontal velocity field, combining interferometry and speckle tracking with Synthetic Aperture Radar images from ERS 1/2 and ALOS-PALSAR, respectively. The resulting velocities and associated shear-strain rates represent the most detailed fields, currently available for the RBIS and clearly resolve small-scale features of the RBIS: significant slow-down and shearing are observed upstream of a small pinning point and ice converges at ice-shelf channels. We then combine our flow field with high-resolution elevations from TanDEM-X to infer the Basal Mass Balance (BMB) of the RBIS. This method relies on mass conservation in a Lagrangian frame and enables us to finely detect spatial variability in the BMB. We show that the BMB of the RBIS varies substantially on sub-kilometre scales. Our technique is promising and could easily be applied more widely.Additionally, the flow field is used to investigate how considering/ignoring small pinning points in observations (geometry and velocities) impacts data initialisation of poorly known parameters (e.g. basal friction, ice viscosity) and subsequent ice-sheet modelling with BISICLES. We find that overlooking the pinning point in the bathymetry leads to erroneous ice-shelf properties whereas accurately capturing the pinning point in velocities is of secondary importance. Finally, before concluding the thesis, we discuss the stability of the RBIS and its neighbouring ice shelves. Most studies agree that the ice shelf has remained stable over the last decades to millennia and would likely remain so in the absence of external forcing. We however point out to three potential triggers of instabilities: (i) large quantities of surface meltwater are formed in the grounding zone and subsequently stored on the ice shelf, thereby providing fuel for hydrofracturing; (ii) ice-shelf channels are found to significantly incise the ice inland and (iii) a bathymetric trough beneath the RBIS forms a potential gateway for warm water intrusions the ice-shelf cavity, which could destabilise the ice shelf from below. We close with a short essay on the importance of outreach, where we argue that public engagement as a scientist should be considered as being part of science and should be valued for its worth. This chapter gives us the opportunity to present outreach activities undertaken in the frame of this thesis. We conclude that, just like ice shelves control Antarctic ice losses, science communication determines transfers of scientific expertise to public knowledge. / Doctorat en Sciences / info:eu-repo/semantics/nonPublished