Potential Sea Level Rise Research Articles

Modeling Investigation of Potential Sea Level Rise Effect on Hydrodynamics and Sediment Transport in Hyères Bay, France

Modeling Investigation of Potential Sea Level Rise Effect on Hydrodynamics and Sediment Transport in Hyères Bay, France

The contribution of coastal land subsidence to potential sea-level rise impact in data-sparse settings: The case of Ghana’s Volta delta

Deltas are highly valuable environmental systems, ensuring various livelihoods through their ecosystem services. However, human impact and climate change stressors are impacting deltas immensely. Consequently, many deltas, including Ghana's Volta Delta, are facing increasing risks, especially as hazards are increasing in magnitude and impacting coastal livelihoods. To provide a better understanding of coastal hazards in the Volta Delta, this study assessed the Delta's subsidence regime and its consequences for the potential impact of sea-level rise (SLR). Using the Interferometric Synthetic Aperture Radar (InSAR) technique and Global Navigation Satellite System (GNSS) surveys, vertical land motion (VLM) was documented. Interferograms of Sentinel-1 data from 2016 to 2020 indicated subsiding rates of up to −9.2 mm/yr. By combining local VLM information with recent SLR projections and elevation data, this study updates those projections and provides local assessments of potential Relative SLR (rSLR) impact. According to these locally improved scenarios, up to ∼45 % of the Delta will fall below local sea level by 2100, of which close to 10 % is explained by the integration of local VLM data alone. Depending on the climate change scenarios used, land subsidence will increase the deltaic area at risk by 4.31 % (96.27 km2) to 10.18 % (227.64 km2) and consequently exacerbate its exposure to coastal inundation. To avert the projections, the study recommends robust monitoring regimes; alternative freshwater sources to groundwater; reduced sediment trapping and river obstruction; and the need to stall ongoing oil and gas prospecting and subsequent extraction in the Voltain Basin.

Differences in carbon, nitrogen and phosphorus release of decomposed branch litter due to potential sea level rise

Influences of potential sea level rise on the carbon, nitrogen and phosphorus release of decomposed branch litter (an important component of the total litter production) in mangrove forests have seldom been reported. In the present study, differences in carbon, nitrogen and phosphorus release of decomposed branch litter due to potential sea level rise were analyzed at three sites with different inundation situations, simulating tidal flooding situations with rising sea level of 0, 40 and 80 cm (R0, R40 and R80). Sea level rise significantly decreased mean decomposition rate of branch litter, while dry weight loss rate of branch litter was not significantly changed with rising sea level. Release percentage of carbon, nitrogen and phosphorus in branch litter within 50 weeks of decomposition at site R0 was approximately 35%, 32% and 60%, respectively. Compared with site R0, changes in mean decomposition rate caused by sea level rise resulted in lower release rates of carbon, nitrogen and phosphorus in branch litter at site R40 and site R80. These results suggested that ecological role of nutrient (carbon, nitrogen and phosphorus) release through branch litter decomposition on mangrove forests and adjacent coastal ecosystems should be considered. Sea level rise will reduce the chance of carbon, nitrogen and phosphorus in branch litter to be transferred into adjacent coastal ecosystems through branch litter decomposition.

Applying two methodologies of an integrated coastal vulnerability index (ICVI) to future sea-level rise

Climate change is an issue of concern and is expected to cause various adverse impacts on human societies in the near and long-term future. Sea-level rise, which is caused by global warming and melting continental ice sheets, in combination with the rising global population and evolution of human activities in coastal areas, tends to make coastal societies more prone to coastal hazards. The Gulf of Corinth in Greece with its diverse coastal landforms and tectonic complexity makes the region unique when considering an assessment of coastal vulnerability. In this study we apply an Integrated Coastal Vulnerability Index (ICVI) to a potential sea-level rise for the southern coastline of the Gulf of Corinth (Greece) consisting of physical and socio-economic parameters. Among multiple different methodologies that have been developed over the recent years, we decided to apply two of the mathematical approaches we believe are best suited for the protection of human activities in our study area. The first one, ICVI_1, is based on the Coastal Vulnerability Index (CVI) by Thieler and Hammar-Klose (1999) with variables of equal relative importance, whereas the second one, ICVI_2, uses the Analytic Hierarchic Process (AHP) with the assignment of relative weight values to each parameter. The parameters were identified and ranked into a vulnerability index with a scale from 1 to 5. The results reveal that both approaches depict more or less the same coastal sections of high or very high vulnerability, but differ in the distribution of extreme values. ICVI_1 shows that 18.3% of the total coastline features very high vulnerability (score 5), while ICVI_2 shows 9.1%. The coastal sections with the highest scores of vulnerability are mostly represented in the eastern part of the studied coastline with low-lying regions of gentle slope and concentrated human activity.

The influence of microtopography on soil carbon accumulation and nutrient release from a rewetted coastal peatland

Coastal peatlands have been frequently blocked from the sea and artificially drained for agriculture. With an increasing awareness of ecosystem functions, several of these coastal peatlands have been rewetted through dike removal, allowing seawater flooding. In this study, we investigated a recently rewetted peatland on the Baltic Sea coast with the aim to characterize the prevailing soils/sediments with respect to organic matter accumulation and the potential release of nutrients upon seawater flooding. Eighty disturbed soil samples were collected from two depths at different elevations (–0.90 to 0.97 m compared to sea level) and analyzed for soil organic matter (SOM) content and carbon:nitrogen (C:N) ratio. Additionally, nine undisturbed soil cores were collected from three distinct elevation groups and used in leaching experiments with alternating freshwater and Baltic Sea water. The results demonstrated a moderate to strong spatial dependence of surface elevation, SOM content, and C:N ratio. SOM content and C:N ratio were strongly negatively correlated with elevation, indicating that organic matter mineralization was restricted in low-lying areas. The results also showed that the soils at low elevations release more dissolved organic carbon (DOC) and ammonium (NH4+) than soils at high elevations. For soils at low elevations, higher DOC concentrations were observed when flushing with freshwater, whereas higher NH4+ concentrations were found when flushing with brackish water. Recorded NH4+ concentrations in organic-rich peat reached 14.82 ± 9.25 mg L–1, exceeding Baltic seawater (e.g., 0.03 mg L–1) by two orders of magnitude. A potential sea level rise may increase the export of NH4+ from low-lying and rewetted peat soils to the sea, impacting adjacent marine ecosystems. Overall, in coastal peatlands, geochemical processes (e.g., C and N cycling and release) are closely linked to microtopography and related patterns of organic matter content of the soil and sediments.

Seasonal variability in Antarctic ice shelf velocities forced by sea surface height variations

Abstract. Antarctica's ice shelves resist the flow of grounded ice towards the ocean through “buttressing” arising from their contact with ice rises, rumples, and lateral margins. Ice shelf thinning and retreat reduce buttressing, leading to increased delivery of mass to the ocean that adds to global sea level. Ice shelf response to large annual cycles in atmospheric and oceanic processes provides opportunities to study the dynamics of both ice shelves and the buttressed grounded ice. Here, we explore whether seasonal variability of sea surface height (SSH) can explain observed seasonal variability of ice velocity. We investigate this hypothesis using several time series of ice velocity from the Ross Ice Shelf (RIS), satellite-based estimates of SSH seaward of the RIS front, ocean models of SSH under and near RIS, and a viscous ice sheet model. The observed annual changes in RIS velocity are of the order of 1–10 m a−1 (roughly 1 % of mean flow). The ice sheet model, forced by the observed and modelled range of SSH of about 10 cm, reproduces the observed velocity changes when sufficiently large basal drag changes near the grounding line are parameterised. The model response is dominated by grounding line migration but with a significant contribution from SSH-induced tilt of the ice shelf. We expect that climate-driven changes in the seasonal cycles of winds and upper-ocean summer warming will modify the seasonal response of ice shelves to SSH and that nonlinear responses of the ice sheet will affect the longer trend in ice sheet response and its potential sea-level rise contribution.

Numerical assessment of potential sea level rise impacts on coastal retreat along the Nigerian Mahin mud coast

Numerical assessment of potential sea level rise impacts on coastal retreat along the Nigerian Mahin mud coast

Assessing Public Transportation Vulnerability to Sea Level Rise:A Case Study Application

The potential for sea level rise inundation of critical transportation infrastructure rises as the threat of climate change continues. Inundation of public transportation including railroads and bus routes, specifically those located in low-lying coastal areas, are vulnerable to these impacts. Therefore, identifying vulnerable facilities in order to implement adaptation planning practices is essential to protecting these facilities and avoiding impacts on mobility. This research focuses on the application of the Transit Inundation Modeling Method (TIMM) to a transit network (railways and bus routes) in Philadelphia County, Pennsylvania. TIMM is developed based on the need to identify transit infrastructure systems that are vulnerable to sea level rise using Geographic Information Systems (GIS). Applying TIMM to a real-world transit network provides an example for how transit agencies throughout the nation can begin to identify at-risk links and nodes based on potential sea level rise inundation levels.

Potential sea-level rise effects on the hydrodynamics and transport processes in Hudson–Raritan Estuary, NY–NJ

Potential sea-level rise effects on the hydrodynamics and transport processes in Hudson–Raritan Estuary, NY–NJ

Potential Sea Level Rise Inundation in the Mediterranean: From Susceptibility Assessment to Risk Scenarios for Policy Action

Coastal ecosystems and anthropic activities are prone to be affected by the negative impact of marine-related processes induced by climate change, such as erosion, flooding and permanent inundation. Studies aiming at defining potential risk scenarios represent a valuable tool for the identification of the most suitable coastal adaptation measures. After outlining sea level rise implications at the Mediterranean scale, this paper deals with inundation risk scenarios for the years 2050 and 2100 for the north-eastern sector of the Island of Gozo (Malta), central Mediterranean Sea. The analysis, carried out by applying an index-based procedure, firstly required the evaluation of the susceptibility to inundation of the investigated coastal stretch under different sea level projections. Then, the spatial combination of inundation susceptibility with the exposure and vulnerability of the area allowed identification of the most critical sectors in terms of coastal risk. The results of the analysis showed that, under the worst-case climate scenarios, 5.5% and 8.1% of the investigated coastal sector are prone to very high inundation risk (Class R4) in 2050 and 2100, respectively. In particular, the bays of Ramla and Marsalforn, which are characterized by significant economic and touristic activities, were found to be the sites where the expected impacts of future sea level rise will be higher if no management strategy and adaptation action are taken in the near future.

Reviewing the elements of marine ice cliff instability

Antarctica’s ice sheets are the largest potential sea-level rise contributors, but projections of future sea-level rise yield wide ranges of estimates under different emission scenarios. An important factor in the variability of estimates is marine ice cliff instability (MICI). Inclusion of MICI yields the highest potential sea-level rise cases but also the largest uncertainty due to poor understanding of the factors that control it and the mechanisms of how it happens. Although evidence for MICI has been implied by paleo-ice sheet studies and observations of keel plough mark on sea-floor, recent statistical and modelling studies have suggested a lower magnitude of MICI effect on sea-level rise due to thinning of ice sheets and buttressing forces exerted on potentially failing cliffs. This paper reviews the factors that control MICI with the goal of identifying priorities for modern ice sheet studies to better bound the estimates.

Quantifying the potential future contribution to global mean sea level from the Filchner–Ronne basin, Antarctica

Abstract. The future of the Antarctic Ice Sheet in response to climate warming is one of the largest sources of uncertainty in estimates of future changes in global mean sea level (ΔGMSL). Mass loss is currently concentrated in regions of warm circumpolar deep water, but it is unclear how ice shelves currently surrounded by relatively cold ocean waters will respond to climatic changes in the future. Studies suggest that warm water could flush the Filchner–Ronne (FR) ice shelf cavity during the 21st century, but the inland ice sheet response to a drastic increase in ice shelf melt rates is poorly known. Here, we use an ice flow model and uncertainty quantification approach to project the GMSL contribution of the FR basin under RCP emissions scenarios, and we assess the forward propagation and proportional contribution of uncertainties in model parameters (related to ice dynamics and atmospheric/oceanic forcing) on these projections. Our probabilistic projections, derived from an extensive sample of the parameter space using a surrogate model, reveal that the FR basin is unlikely to contribute positively to sea level rise by the 23rd century. This is primarily due to the mitigating effect of increased accumulation with warming, which is capable of suppressing ice loss associated with ocean-driven increases in sub-shelf melt. Mass gain (negative ΔGMSL) from the FR basin increases with warming, but uncertainties in these projections also become larger. In the highest emission scenario RCP8.5, ΔGMSL is likely to range from −103 to 26 mm, and this large spread can be apportioned predominantly to uncertainties in parameters driving increases in precipitation (30 %) and sub-shelf melting (44 %). There is potential, within the bounds of our input parameter space, for major collapse and retreat of ice streams feeding the FR ice shelf, and a substantial positive contribution to GMSL (up to approx. 300 mm), but we consider such a scenario to be very unlikely. Adopting uncertainty quantification techniques in future studies will help to provide robust estimates of potential sea level rise and further identify target areas for constraining projections.

The Role of Traditional Knowledge in Coastal Adaptation Priorities: The Pamunkey Indian Reservation

Coastal reservations are increasingly vulnerable to hazards exacerbated by climate change. Resources for restoration projects are limited. Storm surge, storms, tidal flooding, and erosion endanger artifacts and limit livelihoods of tribes in coastal Virginia. GIS offers a platform to increase communication between scientists, planners, and indigenous groups. The Pamunkey Indian Tribe engaged in a participatory mapping exercise to assess the role of traditional ecological knowledge (TEK) in coastal management decision-making and its capacity to address flooding. Priorities and strategies were spatially referenced using maps of potential sea level rise for 2040, 2060, and 2080, input into a resilience matrix to identify benchmarks for each phase of disaster resilience building, and contextualized with oral histories. Results highlight increased immediacy to protect housing and heritage sites along the shoreline as well as maintain access to the Reservation. Preferences toward structural solutions guided by and facilitating TEK options were expressed. Additional community capacities, tribal council support, federal assistance, impact assessments, and coordination would facilitate risk reduction project implementation. The screening process integrates TEK with planning and is transferable to neighboring tribes.

Glacier geoengineering to address sea-level rise: A geotechnical approach

It is remarkable that the high-end sea level rise threat over the next few hundred years comes almost entirely from only a handful of ice streams and large glaciers. These occupy a few percent of ice sheets’ coastline. Accordingly, spatially limited interventions at source may provide globally-equitable mitigation from rising seas. Ice streams control draining of ice sheets; glacier retreat or acceleration serves to greatly increase potential sea level rise. While various climatic geoengineering approaches have been considered, serious consideration of geotechnical approaches has been limited – particularly regarding glaciers. This study summarises novel and extant geotechnical techniques for glacier restraint, identifying candidates for further research. These include draining or freezing the bed; altering surface albedo; creating obstacles: retaining snow; stiffening shear margins with ice; blocking warm sea water entry; thickening ice shelves (increasing buttressing, and strengthening fractured shelves against disintegration); as well as using regional climate engineering or local cloud seeding to cool the glacier or add snow. Not all of these ideas are judged reasonable or feasible, and even fewer are likely to be found to be advisable after further consideration. By describing and evaluating the potential and risks of a large menu of responses – even apparently hopeless ones – we can increase the chances of finding one that works in times of need.

Predicted Responses of Beaches, Bays, and Inner-Shelf Sand Supplies to Potential Sea Level Rise (0.5-1.0 m) in Three Small Littoral Subcells in the High-Wave-Energy Northern Oregon Coast, USA

Three small subcells (Nehalem, Tillamook, and Netarts) totaling ~55 km shoreline length in the high-wave energy northern Oregon coast are evaluated for potential beach sand loss from sea level rise (SLR) of 0.5–1.0 m during the next century. The predicted erosion is based on beach sand displacement from the narrow beaches (average ~120 m width) to increased submarine accommodation spaces in the innermost-shelf (to 30 m water depth) and in the subcell estuaries (Tillamook Bay, Netarts Bay, and Nehalem Bay), following predicted near-future SLR. Beach sand sources from local rivers, paleo-shelf deposits, and/or sea cliff retreat are discriminated by distinctive heavy-mineral tracers. Modern beach sands in the study area are derived from river sand (~75 %) and paleo-shelf sand (~25 %). The supplies of paleo-shelf sand to the beaches have largely diminished in late-Holocene time. The river-enriched beach sands have been transported offshore to the inner-shelf (0–50 m water depth) to fill increasing accommodation space in the inner-shelf during latest-Holocene conditions of relative SLR (1.0 m ka-1). To evaluate the beach sand response to future SLR, representative beach profiles (n=17) and intervening beach segment distances were compiled to yield beach sand volumes above mean lower low water (MLLW) or shallower wave-cut platforms ‘bedrock’. Across-shore cross-sectional areas, as averaged for each subcell, are as follows; Cannon Beach (304 m2), Tillamook (683 m2), and Netarts (227 m2). Littoral sand displacements to the adjacent innermost-shelf (to 30 m water depth) and the marine-dominated areas of the three estuaries are based on assumed vertical sand accretion rates of 1.0 m per century and a conservative value of 0.5 m per century. The filling of such submarine accommodation spaces will displace all active-beach sand reserves in all three subcells for either the 1.0 m or 0.5 m thickness accommodation space scenarios. Large beach sand deficits, primarily from the filling of offshore accommodation spaces, could cause further retreat of soft-shorelines, including barrier spit and beach plain/dune deposits, in the Tillamook subcell (150-280 m) and in the southern half of the Netarts subcell (370-770 m). The accommodation space approach used to predict beach sand volume loss from future SLR should have broad applicability in complex littoral systems worldwide.

TURNING 3D DATA SURVEYS OF INTERTIDAL ZONES INTO NEW MODES OF 3D VISUALIZATION, SIMULATION AND SPATIAL INTERFACE EXPERIENCES

Abstract. This paper reports on Intertidal – a collaborative project to demonstrate integrated workflows to 3D spatial data infrastructure (SDI), simulations and geovisual interfaces - as integrated approaches to support the 3D characterization of coastal morphology, intertidal dynamics, potential sea level rise, and mitigation responses to them. Specifically, this project emphasized the potential of emerging 3D data, new analytical visualization methods, and emerging 3D interface technologies as ingredients of emerging and future environmental data science and visualization practice of coastal/intertidal environments.

Modeling of a future scenario of potential sea level rise and consequences to land use in the Cananéia-Iguape Estuarine-Lagoonal Complex (Brazil)

The objective of this study was to develop possible future land use scenarios for the Cananéia-Iguape Estuarine-Lagoonal Complex by the analysis of the land use evolution along 24 years (1986-2010), and to predict scenarios for 2025. In order to predict the scenario of the land use and occupation classes of 2025 a simulation was carried out by means of the Markov chain methods and calibration of the simulation model in the IDRISI Andes program. In the phase prior to this step it was utilized TM sensor scenes (Landsat 5) and supervised classification techniques to simulating the land use and occupation map of 2010 from land use and occupation maps from 1986 and 1999. Then the land use and occupation map of 2010 was utilized inside de Markov chain to simulate the map of 2025. By applying the techniques proposed by Titus and Narayanan, Pfeffer, Ramhstorf and the Intergovernmental Panel on Climate Change (IPCC) model, the vulnerability of the study area was calculated taking into consideration a potential sea level rise in 2025, 2050 and 2100. In the last step of the applied method, land use and occupation classes were assessed, which will possibly be affected by a highest tide event in 2025. It was observed that 80.92% the area flooded during highest tide events in 1999 was composed of dense arboreal vegetation and it is concluded that this expansion of the dense arboreal vegetation area will also occur towards the coastal zone in 2025. We suggest that the local factor for sea level rise in the study area has a strong geological component, so that, instead of a mere sea level rise, an opposite movement is taking place, which is the subsidence of the plain due to modern tectonism.

Impacts of Potential Sea-Level Rise on Tidal Dynamics in Khor Abdullah and Khor Al-Zubair, Northwest of Arabian Gulf

According to recent studies, sea-level rise (SLR) not only increases the coastal flooding probability but also may change the characteristics of tidal systems in coastal waterbodies. To investigate such changes in Khor Abdulla and Khor Al-Zubair, a two-dimensional depth-averaged model was applied. The calibration and validation were performed through the comparison of model results with measurements of water level and flow velocities in particular sites within model domain. SLR scenarios of 0.25, 0.5, 0.75, and 1 m were simulated. The simulation results indicate that the response of the principal tidal constituents was spatially nonuniform and exhibited a nonlinearity with SLR scenarios. However, the M2 amplitude decreases in most locations with SLR, with the most reduction occur in the upper reaches of the study area, while S2 and N2 amplitudes display a slight increase in a most sites along KA and KZ. Similarly, the amplitudes of K1 and O1 experience to a notable decrease in most locations when sea level rises. Additionally, there is a reduction in constituents’ phases with SLR scenarios. The decrement in constituents’ phases indicates that these waves will arrive earlier when sea level rises due to the nature of tidal wave propagation and their dependency on the water depth. Furthermore, the magnitude of the tidal currents also displays a spatially irregular response to SLR with a noticeable shift in the time of peak flood and ebb current velocities in many locations, while the direction of the currents remains unchanged at most sites of the study area.

RELATIVE SEA LEVEL CHANGE ALONG THE BLACK SEA COAST FROM TIDE-GAUGE OBSERVATIONS

Abstract. Potential sea level rise poses a significant threat to low-lying areas. Considering present and future of coastal areas, scientific study of sea level rise is an essential for adapting to sea level extremes. In this study, the relative sea level change in the Black Sea were investigated using data of 12 tide-gauge and 6 GNSS stations. Results generally indicated sea level rise along the Black Sea coast. Only at Bourgas tide-gauge station, a sea level fall was detected. A significant sea level change were not determined at Sinop tide-gauge station. On the other hand, at some stations such as Poti and Sile, ground subsidence contribution to relative sea level changes were observed.

A consensus estimate for the ice thickness distribution of all glaciers on Earth

Knowledge of the ice thickness distribution of the world’s glaciers is a fundamental prerequisite for a range of studies. Projections of future glacier change, estimates of the available freshwater resources or assessments of potential sea-level rise all need glacier ice thickness to be accurately constrained. Previous estimates of global glacier volumes are mostly based on scaling relations between glacier area and volume, and only one study provides global-scale information on the ice thickness distribution of individual glaciers. Here we use an ensemble of up to five models to provide a consensus estimate for the ice thickness distribution of all the about 215,000 glaciers outside the Greenland and Antarctic ice sheets. The models use principles of ice flow dynamics to invert for ice thickness from surface characteristics. We find a total volume of 158 ± 41 × 103 km3, which is equivalent to 0.32 ± 0.08 m of sea-level change when the fraction of ice located below present-day sea level (roughly 15%) is subtracted. Our results indicate that High Mountain Asia hosts about 27% less glacier ice than previously suggested, and imply that the timing by which the region is expected to lose half of its present-day glacier area has to be moved forward by about one decade. The ice volume of glaciers outside the Greenland and Antarctic ice sheets totals about 158,000 km3, with about 27% less ice in High Mountain Asia than thought, according to multiple models that estimate ice thickness from surface characteristics.