scholarly journals Assessing population exposure to coastal flooding due to sea level rise

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Mathew E. Hauer ◽  
Dean Hardy ◽  
Scott A. Kulp ◽  
Valerie Mueller ◽  
David J. Wrathall ◽  
...  

AbstractThe exposure of populations to sea-level rise (SLR) is a leading indicator assessing the impact of future climate change on coastal regions. SLR exposes coastal populations to a spectrum of impacts with broad spatial and temporal heterogeneity, but exposure assessments often narrowly define the spatial zone of flooding. Here we show how choice of zone results in differential exposure estimates across space and time. Further, we apply a spatio-temporal flood-modeling approach that integrates across these spatial zones to assess the annual probability of population exposure. We apply our model to the coastal United States to demonstrate a more robust assessment of population exposure to flooding from SLR in any given year. Our results suggest that more explicit decisions regarding spatial zone (and associated temporal implication) will improve adaptation planning and policies by indicating the relative chance and magnitude of coastal populations to be affected by future SLR.

2020 ◽  
Vol 2 ◽  
Author(s):  
Audrius Sabūnas ◽  
Nobuhito Mori ◽  
Nobuki Fukui ◽  
Takuya Miyashita ◽  
Tomoya Shimura

Projecting the sea level rise (SLR), storm surges, and related inundation in the Pacific Islands due to climate change is important for assessing the impact of climate change on coastal regions as well as the adaptation of the coastal regions. The compounding effects of storm surges and SLR are one of the major causes of flooding and extreme events; however, a quantitative impact assessment that considers the topographical features of the island has not been properly conducted.Therefore, this study projects the impact of storm surge and SLR due to climate change on Viti Levu, which is the biggest and most populous island in Fiji. The impact of SLR on the inundation in coastal areas was simulated using a dynamic model based on the IPCC SROCC scenarios and the 1/100 years return period storm surge implemented based on the RCP8.5 equivalent scenario. The affected inundation area and population due to storm surges and SLRs are discussed based on the compound effects of SLR and storm surge.Although the contribution of SLR to the inundation area was quite significant, the 1/100 year storm surge increased by 10 to 50% of the inundation area. In addition, a narrow and shallow bay with a flat land area had the largest impact of storm surge inundation. Furthermore, the western wind direction had the most severe storm surge inundation and related population exposure due to the topographic and bathymetric characteristics of Viti Levu Island.


2015 ◽  
Vol 19 (2) ◽  
pp. 933-949 ◽  
Author(s):  
S. Holding ◽  
D. M. Allen

Abstract. Freshwater lenses on small islands are vulnerable to many climate change-related stressors, which can act over relatively long time periods, on the order of decades (e.g., sea level rise, changes in recharge), or short time periods, such as days (storm surge overwash). This study evaluates the response of the freshwater lens on a small low-lying island to various stressors. To account for the varying temporal and spatial scales of the stressors, two different density-dependent flow and solute transport codes are used: SEAWAT (saturated) and HydroGeoSphere (unsaturated/saturated). The study site is Andros Island in the Bahamas, which is characteristic of other low-lying carbonate islands in the Caribbean and Pacific regions. In addition to projected sea level rise and reduced recharge under future climate change, Andros Island experienced a storm surge overwash event during Hurricane Francis in 2004, which contaminated the main wellfield. Simulations of reduced recharge result in a greater loss of freshwater lens volume (up to 19%), while sea level rise contributes a lower volume loss (up to 5%) due to the flux-controlled conceptualization of Andros Island, which limits the impact of sea level rise. Reduced recharge and sea level rise were simulated as incremental instantaneous shifts. The lens responds relatively quickly to these stressors, within 0.5 to 3 years, with response time increasing as the magnitude of the stressor increases. Simulations of the storm surge overwash indicate that the freshwater lens recovers over time; however, prompt remedial action can restore the lens to potable concentrations up to 1 month sooner.


Facies ◽  
2021 ◽  
Vol 67 (3) ◽  
Author(s):  
Markus Wilmsen ◽  
Udita Bansal

AbstractCenomanian strata of the Elbtal Group (Saxony, eastern Germany) reflect a major global sea-level rise and contain, in certain intervals, a green authigenic clay mineral in abundance. Based on the integrated study of five new core sections, the environmental background and spatio-temporal patterns of these glauconitic strata are reconstructed and some general preconditions allegedly needed for glaucony formation are critically questioned. XRD analyses of green grains extracted from selected samples confirm their glauconitic mineralogy. Based on field observations as well as on the careful evaluation of litho- and microfacies, 12 glauconitc facies types (GFTs), broadly reflecting a proximal–distal gradient, have been identified, containing granular and matrix glaucony of exclusively intrasequential origin. When observed in stratigraphic succession, GFT-1 to GFT-12 commonly occur superimposed in transgressive cycles starting with the glauconitic basal conglomerates, followed up-section by glauconitic sandstones, sandy glauconitites, fine-grained, bioturbated, argillaceous and/or marly glauconitic sandstones; glauconitic argillaceous marls, glauconitic marlstones, and glauconitic calcareous nodules continue the retrogradational fining-upward trend. The vertical facies succession with upwards decreasing glaucony content demonstrates that the center of production and deposition of glaucony in the Cenomanian of Saxony was the nearshore zone. This time-transgressive glaucony depocenter tracks the regional onlap patterns of the Elbtal Group, shifting southeastwards during the Cenomanian 2nd-order sea-level rise. The substantial development of glaucony in the thick (60 m) uppermost Cenomanian Pennrich Formation, reflecting a tidal, shallow-marine, nearshore siliciclastic depositional system and temporally corresponding to only ~ 400 kyr, shows that glaucony formation occurred under wet, warm-temperate conditions, high accumulation rates and on rather short-term time scales. Our new integrated data thus indicate that environmental factors such as great water depth, cool temperatures, long time scales, and sediment starvation had no impact on early Late Cretaceous glaucony formation in Saxony, suggesting that the determining factors of ancient glaucony may be fundamentally different from recent conditions and revealing certain limitations of the uniformitarian approach.


2021 ◽  
Vol 23 (2-3) ◽  
pp. 115-132
Author(s):  
Łukasz Kułaga

Abstract The increase in sea levels, as a result of climate change in territorial aspect will have a potential impact on two major issues – maritime zones and land territory. The latter goes into the heart of the theory of the state in international law as it requires us to confront the problem of complete and permanent disappearance of a State territory. When studying these processes, one should take into account the fundamental lack of appropriate precedents and analogies in international law, especially in the context of the extinction of the state, which could be used for guidance in this respect. The article analyses sea level rise impact on baselines and agreed maritime boundaries (in particular taking into account fundamental change of circumstances rule). Furthermore, the issue of submergence of the entire territory of a State is discussed taking into account the presumption of statehood, past examples of extinction of states and the importance of recognition in this respect.


2021 ◽  
Author(s):  
Fabien Maussion ◽  
Quentin Lejeune ◽  
Ben Marzeion ◽  
Matthias Mengel ◽  
David Rounce ◽  
...  

<p>Mountain glaciers have a delayed response to climate change and are expected to continue to melt long after greenhouse gas emissions have stopped, with consequences both for sea-level rise and water resources. In this contribution, we use the Open Global Glacier Model (OGGM) to compute global glacier volume and runoff changes until the year 2300 under a suite of stylized greenhouse gas emission characterized by (i) the year at which anthropogenic emissions culminate, (ii) their reduction rates after peak emissions and (iii) whether they lead to a long-term global temperature stabilization or decline. We show that even under scenarios that achieve the Paris Agreement goal of holding global-mean temperature below 2 °C, glacier contribution to sea-level rise will continue well beyond 2100. Because of this delayed response, the year of peak emissions (i.e. the timing of mitigation action) has a stronger influence on mit-term global glacier change than other emission scenario characteristics, while long-term change is dependent on all factors. We also discuss the impact of early climate mitigation on regional glacier change and the consequences for glacier runoff, both short-term (where some basins are expected to experience an increase of glacier runoff) and long-term (where all regions are expecting a net-zero or even negative glacier contribution to total runoff), underlining the importance of mountain glaciers for regional water availability at all timescales.</p>


2021 ◽  
Vol 91 (3) ◽  
pp. 262-295
Author(s):  
BRIAN J. WILLIS ◽  
TAO SUN ◽  
R. BRUCE AINSWORTH

Abstract Process-physics-based, coupled hydrodynamic–morphodynamic delta models are constructed to understand preserved facies heterogeneities that can influence subsurface fluid flow. Two deltaic systems are compared that differ only in the presence of waves: one river dominated and the other strongly influenced by longshore currents. To understand an entire preserved deltaic succession, the growth of multiple laterally adjacent delta lobes is modeled to define delta axial to marginal facies trends through an entire regressive–transgressive depositional succession. The goal is to refine a facies model for symmetrical wave-dominated deltas (where littoral drift diverges from the delta lobe apex). Because many factors change depositional processes on deltas, the description of the river-dominated example is included to provide a direct reference case from which to define the impact of waves on preserved facies patterns. Both systems display strong facies trends from delta axis to margin that continued into inter-deltaic areas. River-dominated delta regression preserved a dendritic branching of compensationally stacked bodies. Transgression, initiated by sea-level rise, backfilled the main channel and deposited levees and splays on the submerging delta top. Wave-dominated deltas developed dual clinoforms: a shoreface clinoform built as littoral drift carried sediment away from the river month and onshore, and a subaqueous delta-front clinoform composed of sediment accumulated below wave base. Although littoral drift in both directions away from the delta axis stabilized the position of the river at the shoreline, distributary-channel avulsions and lateral migration of river flows across the subaqueous delta top produced heterogeneities in both sets of clinoform deposits. Separation of shoreface and subaqueous delta-front clinoforms across a subaqueous delta top eroded to wave base produced a discontinuity in progradational vertical successions that appeared gradual in some locations but abrupt in others. Littoral drift flows away from adjacent deltas converged in inter-deltaic areas, producing shallow water longshore bars cut by wave-return-flow channels with associated terminal mouth bars. Transgression initiated by sea-level rise initially led to vertical aggradation of wave-reworked sheet sands on the subaqueous delta top and then retreating shoreface barrier sands as the subaerial delta top flooded. Pseudo inter-well flow tests responded to local heterogeneities in the preserved deposits. As expected, abandoned channels in the river-dominated case defined shoreline-perpendicular preferential flow paths and wave-dominated delta deposits are more locally homogeneous, but scenarios for development of more pronounced shore-parallel heterogeneity patterns for wave-influenced deltas are discussed. The results highlight the need to consider the dual clinoform nature of wave-dominated delta deposition for facies prediction and subsurface interpretation.


2017 ◽  
Vol 17 (9) ◽  
pp. 1559-1571 ◽  
Author(s):  
Yann Krien ◽  
Bernard Dudon ◽  
Jean Roger ◽  
Gael Arnaud ◽  
Narcisse Zahibo

Abstract. In the Lesser Antilles, coastal inundations from hurricane-induced storm surges pose a great threat to lives, properties and ecosystems. Assessing current and future storm surge hazards with sufficient spatial resolution is of primary interest to help coastal planners and decision makers develop mitigation and adaptation measures. Here, we use wave–current numerical models and statistical methods to investigate worst case scenarios and 100-year surge levels for the case study of Martinique under present climate or considering a potential sea level rise. Results confirm that the wave setup plays a major role in the Lesser Antilles, where the narrow island shelf impedes the piling-up of large amounts of wind-driven water on the shoreline during extreme events. The radiation stress gradients thus contribute significantly to the total surge – up to 100 % in some cases. The nonlinear interactions of sea level rise (SLR) with bathymetry and topography are generally found to be relatively small in Martinique but can reach several tens of centimeters in low-lying areas where the inundation extent is strongly enhanced compared to present conditions. These findings further emphasize the importance of waves for developing operational storm surge warning systems in the Lesser Antilles and encourage caution when using static methods to assess the impact of sea level rise on storm surge hazard.


Author(s):  
Emojong Amai Mercy ◽  
Eliud Garry Michura

This paper discusses the less publicised but far from less significant, an issue of how the international community’s approach to maritime boundary delimitation will be impacted by climate change resulting in sea level rise with coastal lands submerging affecting the international boundaries and impacting on biodiversity and human survival in the future. The climate change effect is already creating pressure on international law regardless of the direction that the law of the sea takes in remedying this dilemma. It is quite apparent that global disputes and conflicts are arising and solutions are needed urgently. The climate change and the consequent global sea level rise are widely touted to submerge islands and coastlines without discrimination. The international community has been relatively slow to react to what could pose an unprecedented threat to human civilisation.  The policies that have been applied have arguably been reactive and not proactive.  In future climate change may develop other by-products which may not be understood at this moment and may require a proactive approach. Further discussion of the merits of the potential paths is ideal in ensuring that appropriate and well thought-out resolutions are negotiated. Regardless of the outcome, the thorough debate is required to ensure the correct decision is made and that the balancing act between fulfilling states' interests and achieving a meaningful result does not become detrimental to the solidity and the enforceability of the outcome. There is a need to establish a comprehensive framework for ocean governance for management and long-term development and sustainability.


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