Different Scenarios Of Sea Level Rise Research Articles

Effect of alongshore sediment supply gradients on projected shoreline position under sea-level rise (northwestern Portuguese coast)

Shoreline changes are associated with natural and anthropic factors, such as sea-level rise, sediment budget, and beach fills. Shoreline retreat is mainly related to sediment deficit and sea-level rise. Some studies show that by the end of the 21st century some beaches may be lost, with the erosion of sandy beaches becoming predominant across the globe. The main purpose of this work is to model the shoreline evolution for 2050 and 2100 along a sandy coastal stretch in the NW Portugal, considering different scenarios of sea-level rise, to evaluate the influence this parameter and sediment budget have on shoreline displacement, as well as estimate the nourishment volume necessary to hold the shoreline in case of shoreline retreat. For this, we applied the stochastic version of the Random Shoreface Translation Model (RanSTM), in four cross-shore topo-bathymetric profiles, which are representative of alongshore coastal compartments. The overall results indicate that the key drivers in shoreline migration along the coastal stretch are not the same for the different profiles; in areas with a sediment supply deficit, shoreline recession increases, and hence the volume of sand required to hold the shoreline position in those zones is much greater. In contrast, positive sediment budgets can mitigate or reverse the erosion caused by sea-level rise.

Free and open-source software for Geographic Information System on coastal management: A study case of sea-level rise in southern Brazil

This work assesses sea-level rise impact using three different models created on Free and Open-Source Software for Geographic Information System to help coastal managers in the initial stages. The End Point Rate for QGIS (EPR4Q) computes a coastline projection using the End Point Rate method. The Uncertainty Bathtub Model (uBTM) analyses the effects of sea-level rise through the uncertainty of sea-level projections and the vertical error of the Digital Elevation/Terrain Model. The Bruun Rule for Google Earth Engine Model (BRGM) predicts the position of the shoreline with sea-level rise, using topographic and bathymetric data from Unmanned Aerial Vehicles and Coastal Modeling System, respectively. Based on the regional projections of the Special Report on Climate Change and Oceans and Cryosphere of the Intergovernmental Panel on Climate Change, the models were applied to a study case on the coast of Rio Grande do Sul—Brazilunder different scenarios of sea-level rise expected by the end of this century. The results showed a maximum coastal retreat for the year 2100 of -502 m and -1727 m using EPR4Q and BRGM, respectively. The uBTM with Mapbiomas land use showed a maximum of 44.57 km 2 of urban area affected by sea-level flooding. This study highlights the feasibility of conducting coastal management analysis in GIS environment using non-commercial software.

Potential impact of sea level rise on the geomorphology of Kuwait state coastline

Sea level rise (SLR) is one of the most severe risks threatening coastal zones all over the world. In Kuwait, coastal areas accommodate about 90% of the total population and most of the urban area. Thus, SLR is expected to have significant impacts on Kuwaiti coastal areas, which may lead to changes in their ecosystems and the geomorphological units in the coastal area. This paper aims to assess the impacts of SLR on the geomorphology of the Kuwaiti coastline under two different scenarios of SLR: an integrated analysis model involving a variety of methods and a composite vulnerability index integrating five criteria. The results revealed that about 58% of the total coastal area is susceptible to inundation under 1- and 2-m SLR scenario, whereas 8.3% of Kuwaiti coastal areas have moderate to high vulnerability levels. Moreover, it was found that SLR may have significant implications for some Kuwaiti coastal areas including expanding sabkhas areas, shoreline retreat, changing coastal hydrodynamics, and erosion patterns and accelerated weathering process. To avoid such potential impacts, it is essential to develop a national strategy for adaptation to SLR impact and mainstreaming adaptation into development plans.

Increasing pressures, eroding beaches and climate change in Morocco

The coastal zone of Morocco forms one of the main socioeconomic areas of the country. However, intensive coastal development places beaches under significant anthropogenic pressures, aggravated by sea-level rise and storm surges due to climate change. The potential retreat of the beaches can threaten seaside tourism business, which plays a critical role in the local economy. It is therefore important to predict the behavior of the most touristic beaches in Morocco, in response to the future sea-level rise. The estimation of the rate of beach retreat under different scenarios of sea-level rise, at 16 touristic sandy beaches, using an ensemble of five morpho-dynamic models showed that: (i) the narrower the beach, the more it is at risk of erosion and loss in response to SLR; (ii) almost half of the studied beaches would lose more than 50% of their width with 2m SRL scenario. The main shortcomings of current management approaches to coastal erosion are analyzed and recommendations for future beach management within an integrated strategy are suggested.

Linking management planning for coastal wetlands to potential future wave attenuation under a range of relative sea-level rise scenarios.

Understanding changes in wave attenuation by emergent vegetation as wetlands degrade or accrete over time is crucial for incorporation of wetlands into holistic coastal risk management. Linked SLAMM and XBeach models were used to investigate potential future changes in wave attenuation over a 50-year period in a degrading, subtropical wetland and a prograding, temperate wetland. These contrasting systems also have differing management contexts and were contrasted to demonstrate how the linked models can provide management-relevant insights. Morphological development of wetlands for different scenarios of sea-level rise and accretion was simulated with SLAMM and then coupled with different vegetation characteristics to predict the influence on future wave attenuation using XBeach. The geomorphological context, subsidence, and accretion resulted in large predicted reductions in the extent of vegetated land (e.g., wetland) and changes in wave height reduction potential across the wetland. These were exacerbated by increases in sea-level from +0.217 m to +0.386 m over a 50-year period, especially at the lowest accretion rates in the degrading wetland. Mangrove vegetation increased wave attenuation within the degrading, subtropical, saline wetland, while grazing reduced wave attenuation in the temperate, prograding wetland. Coastal management decisions and actions, related to coastal vegetation type and structure, have the potential to change future wave attenuation at a spatial scale relevant to coastal protection planning. Therefore, a coastal management approach that includes disaster risk reduction, biodiversity, and climate change, can be informed by coastal modeling tools, such as those demonstrated here for two contrasting case studies.

Economic Valuation of Sea Level Rise Impacts on Agricultural Sector in Northern Governorates of the Nile Delta

It is widely believed, according to the IPCC (Intergovernmental Panel on Climate Change) projections, that there will be an increase in the global average sea level of 0.18 cm to 0.59 cm through the twenty-first century. The coastal area of the Nile delta is considered to be one of the most vulnerable areas to Sea Level Rise (SLR) in the world. Where, the Nile Delta consists mostly of lowland areas which accommodate a significant proportion of the Egyptian agricultural and economic activities. SLR is expected to have a profound impact on the agricultural areas of the Nile Delta, through either inundation or higher levels and salinity of groundwater. Due to the prevailed vulnerability of the Nile delta and as guidance for decision and policy making, it is necessary to provide estimates of potential economic damage that can result from such SLR. The paper in hand intends to estimate the economic value of the agricultural areas, in the coastal governorates of the Nile Delta, susceptible to inundation due to SLR according to most recent SLR scenarios and to estimate the economic value of potential impacts of rising groundwater table, associated with SLR, on agricultural productivity by the year 2100. The results indicate that about 7.5%, 36.3%, and 44.0% of the total cultivated area of the coastal governorates of the Nile Delta (with a market value of 51.7, 196.6 and 232.6 billion EGP (Egyptian Pound)) will be susceptible to inundation under the different scenarios of SLR. Moreover, it was found that the future accumulative crop yield loss due to increasing groundwater level was estimated, using segmented linear regression, to be as much as 32.3 billion EGP. It is worth mentioning that these estimates do not include indirect impacts of higher levels of groundwater table, which may include loss of jobs and/or earnings, impacts on food supply and food security in the area.

Vulnerability of the Nile Delta coastal areas to inundation by sea level rise

Sea level changes are typically caused by several natural phenomena, including ocean thermal expansion, glacial melt from Greenland and Antarctica. Global average sea level is expected to rise, through the twenty-first century, according to the IPCC projections by between 0.18 and 0.59cm. Such a rise in sea level will significantly impact coastal area of the Nile Delta, consisting generally of lowland and is densely populated areas and accommodates significant proportion of Egypt's economic activities and built-up areas. The Nile Delta has been examined in several previous studies, which worked under various hypothetical sea level rise (SLR) scenarios and provided different estimates of areas susceptible to inundation due to SLR. The paper intends, in this respect, to identify areas, as well as land use/land cover, susceptible to inundation by SLR based upon most recent scenarios of SLR, by the year 2100 using GIS. The results indicate that about 22.49, 42.18, and 49.22% of the total area of coastal governorates of the Nile Delta would be susceptible to inundation under different scenarios of SLR. Also, it was found that 15.56% of the total areas of the Nile Delta that would be vulnerable to inundation due to land subsidence only, even in the absence of any rise in sea level. Moreover, it was found that a considerable proportion of these areas (ranging between 32.32 and 53.66%) are currently either wetland or undeveloped areas. Furthermore, natural and/or man-made structures, such as the banks of the International Coastal Highway, were found to provide unintended protection to some of these areas. This suggests that the inundation impact of SLR on the Nile Delta is less than previously reported.

Application of a barrier island translation model to the millennial-scale evolution of Sand Key, Florida

The evolution of a barrier island and its stratigraphic architecture is investigated with the numerical model BIT (barrier island translation). The model simulates, with simplified equations, the effects of various processes (wind waves, storm surges, sea-level oscillations) on sediment location and characteristics. The presented formulation is able to reproduce both the cross-shore profile and the distribution of sediment facies in time. The model is based on two appropriate simplifying assumptions: (i) the conservation of the total mass of sediments and (ii) the conservation of the equilibrium cross-shore beach profile. Particular attention is devoted to the treatment of sediment reworking by wind waves and barrier overwash, which is induced by extreme events like storms and hurricanes, and causes a relative transport of sediments from the body of the sand barrier to the top of the island and to the back-barrier area. The model is applied to Sand Key, Florida. Model results show a satisfactory reproduction of the geometry and stratigraphy of the inner shelf, with the correct position of every stratigraphic facies within the barrier island. Simulations under different scenarios of sea-level rise during the last 8000 yr indicate that the rate of overwash and lagoonal deposition are critical for the survival of the barrier island under past sea-level oscillations.