Search Results (41)

Storm waves and rising sea levels pose significant threats to low-lying coastal areas, particularly sandy beaches, which are especially vulnerable. The research on the long-time-scale changes in sandy coasts, especially the identification of tipping points in the shoreline-retreat rate, is limited. Vung Tau beach, characterized by its low terrain and rapid tourism-driven economic growth, was selected as a typical study area to quantify the shoreline retreat throughout the 21st century under various sea-level rise (SLR) scenarios, and to identify the existence of tipping points by investigating the projected annual change in shoreline retreat (m/yr). This study employs the Probabilistic Coastline Recession (PCR) model, a physics-based tool specifically designed for long-term coastline change assessments. The results indicate that shoreline retreat accelerates over time, particularly after a tipping point is reached around 2050 in the SSP1-2.6, SSP2-4.5, and SSP5-8.5 scenarios. Under the SSP5-8.5 scenario, the median retreat distance is projected to increase from 19 m in 2050 to 89 m by 2100, nearly a fourfold rise. In comparison, the retreat distances are smaller under the SSP1-2.6 and SSP2-4.5 scenarios, but the same accelerating trend is observed beyond 2050. These findings highlight the growing risks associated with sea-level rise, especially the rapid increase in exceedance probabilities for retreat distances by the end of the century. By 2100, the probability of losing the entire beach at Vung Tau is projected to be 22% under SSP5-8.5. The approach of identifying tipping points based on the PCR model presented here can be applied to other sandy coastal regions, providing critical references for timely planning and the implementation of adaptation measures. Full article

The boundary between land and sea is among the most extensive and extreme ecological barriers on planet Earth. Intertidal organisms living at this junction are subject to potentially lethal conditions related to desiccation, temperature fluctuations, and wave shock. Although difficult to quantify at a global level, rocky coasts account for between a third and three-quarters of all shorelines today. Resistant to coastal erosion, rocky coasts also exhibit adaptations by marine invertebrates and marine algae within intertidal zones that are geographically widespread. Biotic composition is variable depending on the tidal range at any given place and on climatic differences between tropical and more temperate latitudes. Contemporary granite shores having low recession rates with well-established biotic zones are reviewed in three regions: Mount Desert Island in Maine, USA (44° N latitude), Mahé and Praslin islands in Seychelles (4°30′ S Latitude), and Lizard Island off the coast of Queensland, Australia (14°40′ S Latitude). The zonal composition and overall biotic diversity at these locations are compared, as well as the fossilization potential of key biota. Over the Phanerozoic time period during the last 538 million years, the ratio between land and ocean varied as a function of plate tectonics depending on the maximum dispersal or coalescence of continents and on relative changes in global sea level. Fossil biotas from a dozen paleoislands with dominant rocky shores that range from 485 million to 125,000 years in age are reviewed to show diversification through time, taking into account episodic mass extinctions. Relationships between storm tracks and volcanic eruptions that factor into physical disruptions are also considered as means of rapid burial and preservation. Themes related to rocky-shore ecology and paleoecology benefit from the cross-fertilization of ideas by marine biologists and marine paleontologists. It is hoped this review may attract a cohort of new students to these allied fields of study, especially in Asia, Africa, and South America. Full article

The Thermaikos Gulf (TG) is a semi-enclosed, river-influenced, marine system situated in the eastern Mediterranean Sea, sustaining both urban coastal regions and ecologically preserved natural areas. Facing a plethora of environmental and anthropogenic pressures, the TG serves as a critical nexus where human activities intersect with marine ecosystems. The quality and health of the TG’s marine environment are tightly linked to the socioeconomic activities of the coastal communities comprising approximately 1.5 million inhabitants. The main features of the TG’s environmental dynamics and ecological status have been scrutinized by dedicated research endeavors during the last 50 years. This review synthesizes the seminal findings of these investigations, offering an evaluation of their contribution to research, their present collective impact, and their trajectory toward the future. A severe deterioration of the TG’s environmental quality was detected in the 1970s and 1980s when the treatment of urban wastewater was completely absent. A steady trend of recovery was observed after the 1990s; however, so far, the goal of a “good environmental state” mandated by national legislation and European directives has not been achieved. A clear reduction in research was detected after 2010, associated with the recession of the Greek economy, following the “golden period” for research in the TG from the mid-1990s until the late 2000s. The most important research gaps and uncertainties are discussed, while specific targeted recommendations for the improvement of monitoring and understanding of the physical, biochemical, and ecological state of the gulf are provided: (i) increase in permanent observational stations (temporally and spatially); (ii) inclusion of all major environmental parameters; (iii) monitoring of the quantity and quality of all land-originated freshwater discharges; (iv) monitoring and management of important aspects of the marine environment that have received minimal attention in the past (e.g., coastal erosion, plastic pollution); (v) development of accurate prediction tools (e.g., numerical techniques) to support first-level responders and efficient management; (vi) establishment of a supervising public entity that would support the holistic overview and management of the entire TG. These suggestions are directed at overcoming the existing uncertainties in the knowledge of the TG, safeguarding its ecological integrity and its role as a crucial link to marine biodiversity and sustainability in the Mediterranean basin. Full article

The morphoevolution of coastal areas is due to the interactions of multiple continental and marine processes that define a highly dynamic environment. These processes can occur as rapid catastrophic events (e.g., landslides, storms, and coastal land use) or as slower continuous processes (i.e., wave, tidal, and current actions), creating a multi-hazard scenario. Maronti Bay (Ischia Island, Southern Italy) can be classified as a pocket beach that represents an important tourist and environmental area for the island, although it has been historically affected by slope instability, sea cliff recession, and coastal erosion. In this study, the historical morphoevolution of the shoreline was analysed by means of a dataset of aerial photographs and cartographic information available in the literature over a 25-year period. Furthermore, the role of cliff recession and its impact on the beach was also explored, as in recent years, the stability condition of the area was worsened by the occurrence of a remarkable landslide in 2019. The latter was reactivated following a cloudburst on the 26th of November 2022 that affected the whole Island and was analysed with the Dem of Difference technique. It provided an estimate of the mobilised volumes and showed how the erosion and deposition areas were distributed and modified by wave action. The insights from this research can be valuable in developing mitigation strategies and protective measures to safeguard the surrounding environment and ensure the safety of residents and tourists in this multi-hazard environment. Full article

Within the last century, the global sea level has risen between 16 and 21 cm and will likely accelerate into the future. Projections from the Intergovernmental Panel on Climate Change (IPCC) show the global mean sea level (GMSL) rise may increase to up to 1 m (1000 mm) by 2100. The primary cause of the sea level rise can be attributed to climate change through the thermal expansion of seawater and the recession of glaciers from melting. Because of the complexity of the climate and environmental systems, it is very difficult to accurately predict the increase in sea level. The latest estimate of GMSL rise is about 3 mm/year, but as GMSL is a global measure, it may not represent local sea level changes. It is essential to obtain tailored estimates of sea level rise in coastline Florida, as the state is strongly impacted by the global sea level rise. The goal of this study is to model the sea level in coastal Florida using climate factors. Hence, water temperature, water salinity, sea surface height anomalies (SSHA), and El Niño southern oscillation (ENSO) 3.4 index were considered to predict coastal Florida sea level. The sea level changes across coastal Florida were modeled using both multiple regression as a broadly used parametric model and the generalized additive model (GAM), which is a nonparametric method. The local rates and variances of sea surface height anomalies (SSHA) were analyzed and compared to regional and global measurements. The identified optimal model to explain and predict sea level was a GAM with the year, global and regional (adjacent basins) SSHA, local water temperature and salinity, and ENSO as predictors. All predictors including global SSHA, regional SSHA, water temperature, water salinity, ENSO, and the year were identified to have a positive impact on the sea level and can help to explain the variations in the sea level in coastal Florida. Particularly, the global and regional SSHA and the year are important factors to predict sea level changes. Full article

Impervious land expansion is linked to ecosystem fragmentation and degradation, posing threats to nature conservation and multiplying climate change impacts. This is particularly true on the Mediterranean coast, where persistent urbanization is coupled with tourism development, further intensifying coastal erosion, flood risk, heat stress and biodiversity loss, while decreasing carbon sequestration. In this research, high-resolution imperviousness data were analyzed through a geospatial methodology to detect patterns and processes in a heavily burdened Mediterranean coastal area, namely Greece. The methodology was structured on a set of GIS tools, analyzing the distribution of new impervious cover between 2006 and 2018, to evaluate pressures exerted on coastal territories and on the environmental protection network. The results revealed relatively slow rates of impervious land expansion at a nationwide scale, mostly attributed to the economic recession period in Greece. However, certain locations exhibited continuing artificialization of land even within Natura 2000 areas, while future pressures on coastal territories are expected to increase due to the restarting of construction activity and the continuing dynamic of the mass tourism sector. The conclusions imply that controlling for imperviousness is important in order to develop spatial planning policies for climate resilience, which should be decisively enforced in the Mediterranean to prevent a business-as-usual scenario. Full article

Many issues arise from the recession of sea cliffs, including threats to coastal communities and infrastructure. The best proxy to study cliff instability processes is the cliff face evolution. Unfortunately, due to its verticality, this proxy is difficult to observe and measure. This study proposed and compared three remote sensing methods based on structure-from-motion (SfM) photogrammetry or stereorestitution: boat-based SfM photogrammetry with smartphones, unmanned aerial system (UAS) or unmanned aerial vehicle (UAV) photogrammetry with centimetric positioning and Pléiades tri-stereo imagery. An inter-comparison showed that the mean distance between the point clouds produced by the different methods was about 2 m. The satellite approach had the advantage of covering greater distances. The SfM photogrammetry approach from a boat allowed for a better reconstruction of the cliff foot (especially in the case of overhangs). However, over long distances, significant geometric distortions affected the method. The UAS with centimetric positioning offered a good compromise, but flight autonomy limited the extent of the monitored area. SfM photogrammetry from a boat can be used as an initial estimate for risk management services following a localized emergency. For long-term monitoring of the coastline and its evolution, satellite photogrammetry is recommended. Full article

Thailand’s current beach management strategies lack integration across sectors, resulting in conflicts of interest and insufficient consideration of diverse beach uses. The complexity of environmental, socio-economic, and coastal disasters challenge policymakers to describe the conditions of sandy beaches, and the most effective coastal management adaptation measures. This study suggests an integrated approach to evaluate beach conditions by incorporating the Urbanization Index, Conservation Index, and Recreation Index. Furthermore, the assessment of beach conditions will include the Threat Index, which consists of erosion rates and shoreline recession caused by sea level rise. The trends index will prioritize beach conditions for appropriate management actions. The study suggests management strategies that aim to preserve the physical and environmental aspects of the beach, while restoring its functionality for ecosystem services by applying engineering structures with beach nourishment. The main purpose of this study is to develop a beach condition that can be used as a guideline for sandy beach management in Thailand. It provides insights and recommendations to policymakers for enhancing the sustainability and resilience of Thailand’s coastal areas in the face of urbanization and climate change. Full article

Phuket, the study area of this work with 33 sandy beaches, provides about 15% of the nation’s gross domestic product from the tourism industry. Many factors cause shoreline changes affecting beach areas, such as seasonal erosion and rising sea levels. In this study, shoreline position was the key parameter for evaluating shoreline changes. The CoastSat open-source software was selected to analyze the shoreline changes using a publicly available satellite imagery API. The future shoreline recession was projected using the Bruun rule integrated with field observation data and sea level rise scenarios from Coupled Model Intercomparison Project Phase 6 (CMIP6). The result indicated that eight of the study site’s locations were under mild erosion from 2013 to 2021. The average shoreline change varied between −4.10 and 5.47 m/year. The projection of future beach loss due to sea level rise found that 20 beaches and 32 beaches will be lost entirely under SSP1 2.6 and SSP5 8.5, respectively. Beach morphology is influenced by human-induced activities, such as coastal urbanization and the development of structures along the coast. This study discusses the effectiveness of the present coastal protection structure with data from field observations and suggests possible future management strategies. Full article

Regular monitoring is essential for vulnerable coastal locations such as areas of landward retreat. However, for coastal practitioners, surveying is limited by budget, specialist personnel/equipment and weather. In combination structure-from-motion and multi-view stereo (SfM-MVS) has helped to improve accessibility to topographic data acquisition. Pole-mounted cameras with SfM-MVS have gained traction but to guarantee coverage and reconstruction quality, greater understanding of camera position and interaction is required. This study uses a multi-camera array for image acquisition and reviews processing procedures in Agisoft Photoscan (Metashape). The camera rig was deployed at three sites and results were verified against a terrestrial laser scanner (TLS) and independent precision estimates. The multi-camera approach provided effective image acquisition ~11 times faster than the TLS. Reconstruction quality equalled (>92% similarity) the TLS, subject to processing parameters. A change in the image alignment parameter demonstrated a significant influence on deformation, reducing reprojection error by~94%. A lower densification parameter (‘High’) offered results ~4.39% dissimilar from the TLS at 1/8th of the processing time of other parameters. Independent precision estimates were <8.2 mm for x, y and z dimensions. These findings illustrate the potential of multi-camera systems and the influence of processing on point cloud quality and computation time. Full article

In recent decades, the global incidence of dengue has risen sharply, with more than 75% of infected people showing mild or no symptoms. Since the year 2000, dengue in China has spread quickly. At this stage, there is an urgent need to fully understand its transmission intensity and spread in China. Serological data provide reliable evidence for symptomatic and recessive infections. Through a literature search, we included 23 studies that collected age-specific serological dengue data released from 1980 to 2021 in China. Fitting four catalytic models to these data, we distinguished the transmission mechanisms by deviation information criterion and estimated force of infection and basic reproduction number (R₀), important parameters for quantifying transmission intensity. We found that transmission intensity varies over age in most of the study populations, and attenuation of antibody protection is identified in some study populations; the R₀ of dengue in China is between 1.04–2.33. Due to the scarceness of the data, the temporal trend cannot be identified, but data shows that transmission intensity weakened from coastal to inland areas and from southern to northern areas in China if assuming it remained temporally steady during the study period. The results should be useful for the effective control of dengue in China. Full article

The coastal area of Safi between Cap Beddouza and Jorf Lihoudi is dominated by different forms of marine cliffs forming the coastline, with rock formations ranging from Jurassic to Quaternary. The main coastal geological risk is the instabilities of these cliffs due to the falls and collapses of the blocks, as well as landslides. The aim of this paper is to give detailed information on the rate of the cliff summit recession for the last 66 years, obtained by applying the DSAS model, in parallel with the identification of unstable elements, including their different parameters such as size, abundance, activity in time and their effect on the recession of the cliff top, which is fundamental information for the evolution the models of sea cliffs. These phenomena constitute a significant economical, social, and environmental risk. Full article

Small Arctic coastal catchments and coastal lagoon systems are some of the most vulnerable to climate change. Glacial retreat and the development of glacial lakes and drainage systems provide opportunities for hazardous events such as GLOFs. We observe that the stability of lagoons and their associated barriers are controlled by the frequency and magnitude of storms approaching the coasts, access to sediment supplies and resilience to sea-level rise. Based on multidecadal remote sensing data, we were able to identify the rate of glacial recession, the development of glacial lakes, vegetation response to climate change and a GLOF event, and shoreline and lagoon responses to the environmental shifts within the small catchment. Here we present an example of lagoon system evolution where a glacial outburst flood exerted significant control over lagoon drainage and coastal barrier stability. Full article

The notion of resilience has been increasingly adopted in economic geography, concerning how regions resist and recover from all kinds of shocks. Most of the literature on the resilience of coastal areas focuses on biophysical stressors, such as climate change and some environmental factors. In this research, we analyze the regional economic resilience characteristics responding to the Great Financial Crisis in 2008 and its main determinants. We conclude that the coastal areas encountered more recession (or less growth) in the long term, and the secondary industry showed higher resilience than the tertiary industry. The influential factors of regional economic resilience varied across different stages of the crisis, and for the long term, good financial arrangement and governance ability could prompt the regional resilience to the crisis. Finally, some policy implications are proposed which may benefit dealings with major shocks such as economic crises and COVID-19. Full article

Climate change is one of the issues of greatest concern to today’s society. The increase in temperatures has affected sea levels, polar masses and extreme events, among others. There are many scientific studies that analyze the impacts of climate change on coastal communities, but most of them focus on beach erosion and coastal recession. Scientific literature on the effects of climate change on ports and harbors and their adaptation is much less abundant. Ports are essential for the economy and society of their cities, so studying the impact of climate change on them is an urgent need. The Mediterranean and the Spanish Mediterranean coast is one of the areas that will be most affected by climate change in the future. In addition, the Spanish economy depends a lot on its tourism and, thus, on its coastal cities. Therefore, the study of the impact of climate change on Spanish ports and coastal communities is essential. This article presents a review of the studies carried out until now on the effects of climate change on Spanish ports, and it identifies research gaps and weaknesses and suggests new research lines. Full article