Coastal Urbanization Research Articles

Synergy of Remote Sensing and Geospatial Technologies to Advance Sustainable Development Goals for Future Coastal Urbanization and Environmental Challenges in a Riverine Megacity

Riverine coastal megacities, particularly in semi-arid South Asian regions, face escalating environmental challenges due to rapid urbanization and climate change. While previous studies have examined urban growth patterns or environmental impacts independently, there remains a critical gap in understanding the integrated impacts of land use/land cover (LULC) changes on both ecosystem vulnerability and sustainable development achievements. This study addresses this gap through an innovative integration of multitemporal Landsat imagery (5, 7, and 8), SRTM-DEM, historical land use maps, and population data using the MOLUSCE plugin with cellular automata–artificial neural networks (CA-ANN) modelling to monitor LULC changes over three decades (1990–2020) and project future changes for 2025, 2030, and 2035, supporting the Sustainable Development Goals (SDGs) in Karachi, southern Pakistan, one of the world’s most populous megacities. The framework integrates LULC analysis with SDG metrics, achieving an overall accuracy greater than 97%, with user and producer accuracies above 77% and a Kappa coefficient approaching 1, demonstrating a high level of agreement. Results revealed significant urban expansion from 13.4% to 23.7% of the total area between 1990 and 2020, with concurrent reductions in vegetation cover, water bodies, and wetlands. Erosion along the riverbank has caused the Malir River’s area to decrease from 17.19 to 5.07 km2 by 2020, highlighting a key factor contributing to urban flooding during the monsoon season. Flood risk projections indicate that urbanized areas will be most affected, with 66.65% potentially inundated by 2035. This study’s innovative contribution lies in quantifying SDG achievements, showing varied progress: 26% for SDG 9 (Industry, Innovation, and Infrastructure), 18% for SDG 11 (Sustainable Cities and Communities), 13% for SDG 13 (Climate Action), and 16% for SDG 8 (Decent Work and Economic Growth). However, declining vegetation cover and water bodies pose challenges for SDG 15 (Life on Land) and SDG 6 (Clean Water and Sanitation), with 16% and 11%, respectively. This integrated approach provides valuable insights for urban planners, offering a novel framework for adaptive urban planning strategies and advancing sustainable practices in similar stressed megacity regions.

A Short Review of Strategies for Augmenting Organism Recruitment on Coastal Defense Structures

The global demand for coastal urbanization is rising with the increasing population. Alas, living close to the ocean threatens human endeavors with high currents, waves, and increasing storm frequency. Accordingly, the need for more coastal defense structures (CDSs) rises. Structures built from complex units meant to prevent and/or mitigate coastal erosion and floods, additionally providing wave protection or wave attenuation, are constructed on and near natural habitats where they alter local ecosystems. Traditional CDSs mostly fail to harbor diverse and abundant communities. However, this can be changed by eco-friendly methodologies and designs that are being tested and implemented to improve CDSs’ ecological value. Some of these can be implemented during the construction period, while others can fit on existing structures, such as wave breakers and seawalls. Effective methods include augmenting surface rugosity through strategic perforations, integrating artificial panels for increased complexity, implementing soft (naturally based) engineering solutions such as geotextiles, replacing industrial concrete mixtures for CDS construction with “green concrete” and ecologically friendly mixtures, and using alternative, eco-friendly units in CDS erections. In this mini review, we suggest that by integrating sustainable practices into coastal development, we can significantly mitigate the ecological damage caused by traditional CDSs and promote more harmonious relationships between human construction and the marine environment. This shift towards environmentally conscious coastal defenses is essential and a responsibility for ensuring the long-term sustainability of our coastal communities and the health of our oceans. We present current methodologies used on breakwaters worldwide.

Determining Vulnerability Indicators of Buildings for Sea-Level Rise and Floods in Urban Coastal Areas

Projected sea-level rise and floods due to climate change impacts are the hazards threatening urban coastal areas. In the literature on mitigation and adaptation, it is determined that studies in the field of architectural design for the assessment of risks and vulnerabilities to these hazards are not yet at a sufficient level. This study aims to determine the vulnerability indicators of buildings due to architectural design decisions in the urban coastal areas facing the risk of sea-level rise and flood hazards. In this direction, it is argued that the decisions that are taken regarding the building and its environment during the architectural design process can be interpreted as vulnerability indicators in vulnerability assessments of buildings to be made in the context of these hazards. In this context, an indicator-based assessment framework is proposed as a method of examining the vulnerability and climate resilience capacity of design practices in urban coastal areas. The first stage of the research methodology includes the results of a literature review to identify indicators of building vulnerability. In the second stage, these indicators were presented for expert opinions and analyzed with the Delphi method and an assessment framework was created. This assessment framework is designed to serve as a decision-making tool or checklist for decision makers, facilitating the integration of vulnerability indicators into the design, implementation, and retrofitting of buildings in urban coastal areas. Due to its hierarchical, yet flexible, and adaptable structure, it can be used by architects, urban planners, and policy makers in terms of assessing buildings and its environments so that actions for adaptation can be implemented.

Mapping Land Use and Assessing Coastal Urbanization Impacts: A Case Study in Tangier Northern Morocco

Mapping Land Use and Assessing Coastal Urbanization Impacts: A Case Study in Tangier Northern Morocco

Foraging in contrasting oceanographic regions impacts the fatty acid profile of two closely related pelagic seabirds

Coastal urbanisation negatively affects marine ecosystems through habitat degradation and pollution. Cory’s (Calonectris borealis) and Scopoli’s (C. diomedea) shearwaters are closely related species inhabiting the Northeast Atlantic Ocean and the Mediterranean Sea, respectively. This study assesses the fatty acid profile, with the trophic and foraging ecology, of Cory’s and Scopoli’s shearwaters breeding at Berlenga (Atlantic Ocean) and Chafarinas (Mediterranean Sea) Islands. The diet quality of Scopoli’s shearwaters is expected to be generally lower, characterised by reduced levels of ω-3 fatty acids. Additionally, higher concentrations of specific fatty acid trophic markers are anticipated, reflecting the Mediterranean's semi-enclosed environment, low productivity, and pollution challenges. These markers include oleic acid, vaccenic acid, trans fatty acids (indicative of urban and industrial discharges), and odd-chain fatty acids (indicative of bacterial presence). This study supported these predictions, with Scopoli’s shearwaters foraging in the Mediterranean having higher concentrations of oleic and vaccenic acids, odd-chain fatty acids, and trans-palmitoleic acid in their plasma. Yet, concentrations of ω-3 were also higher in Scopoli’s shearwaters. This may result from diverse prey availability and selection, and different habitat exploitation, partially supported by differences in the trophic ecology and foraging patterns of both species; or from an enhanced immunological basal response of Scopoli’s shearwaters to cope with higher anthropogenic pressure in the western Mediterranean Sea. Further studies including specific diet and contaminant analyses are crucial to understand differences in fatty acid profiles of seabirds inhabiting both oceanic basins and the implications of diet quality for seabird populations.

Beyond the Rising Tide: Towards Effective Climate Policy in Coastal Urban Centers

As urban areas expand rapidly, understanding the complex interactions between human migration, climate change impacts, and biodiversity loss is crucial for effective climate policy. However, comprehensive knowledge of the simultaneous interaction of these aspects is still scarce. Thus, this paper proposes the classification of ‘Climate Emergency Coastal Cities’, with the categorization of 43 cities into four levels according to their vulnerability (extreme, very high, high, and critical). Our study contributes to evidence-based climate policy and supports efficient resource allocation and interventions for the most vulnerable coastal cities. Highly anthropogenic megacities were ranked as the most sensitive to climate emergencies (Lagos, Nigeria; Jakarta, Indonesia; Los Angeles and Houston, USA; and Hong Kong and Shenzhen, China). It is noteworthy that in countries from both the Global North and South, the entry of new populations is a critical issue, and represents a threat to urban structures and biodiversity; however, in territories with fragile economies and numerous governance challenges, the required structure is still more challenging. The study concludes that integrated urban planning policies are crucial, considering various perspectives and coordinated actions. Policies should address marginalized urban groups and include migrants, and promote human well-being, ecosystem recovery, and climate mitigation, for effective adaptation.

High-resolution simulation of coastal flooding under extreme storm tides and sea level rise: A case study of Macau

In the face of climate change, coastal cities are challenged with growing risks from rising sea levels and intensified storm surges which could turn urban areas into temporary waterways. To address this, our study developed a high-resolution coastal urban flood model, OUC-CUFM (Ocean University of China – Coastal Urban Flood Model), designed to help municipal governments make precise coastal flood forecasts and reduce potential threats to people and property. This model is based on two-dimensional nonlinear Navier–Stokes shallow water equations, incorporating factors like local acceleration, convection, bottom friction, wind stress, and shallow water effects. Using the finite difference method with upwind spatial discretization and a leapfrog time scheme, it can simulate detailed street-level water flow interactions with buildings. In a case study on Macau, we used a 5-m resolution digital elevation model to simulate storm tide flooding from Typhoons Hato (2017) and Mangkhut (2018), with the former for model calibration and the later for validation. Comparisons between simulated and observed water levels showed that the model accurately captured storm water arrival, overtopping, and flood extent and depth. The model also projected flood changes under sea level rise (SLR) scenarios of 0.5 m (by 2070) and 1.0 m (by 2100) for Typhoon Hato, indicating that such SLRs would significantly increase storm-induced flood depth and extent. This model serves as a valuable tool for street-scale flood risk analysis, hazard mapping, and assessing the impact of coastal defenses, like dyke upgrades or new dyke construction, in densely built coastal cities.

A bright spot of conservation in a Brazilian hotspot of cumulative impacts considering ecosystem quality in a cross-shelf gradient: Perspectives to MPAs network

Coastal regions are the main populated areas in the world and the effectiveness of Marine Protected Areas (MPAs) depends on management, stakeholder engagement, and environmental settings, which differ across land-to-sea gradients. This study describes the patterns of biological diversity and the abiotic environment along a densely inhabited stretch of the Brazilian coastline. We examined sea surface temperature and chlorophyll-a concentrations among urbanized coasts, inshore, and open water zones. Locally, we considered sites under contrasting protection status (partially restrictive MPA, multiple-use MPA, and no protection areas), the impact of sedimentation, the structure of sessile (algae, corals, and other invertebrates) and fish communities (abundance and diversity). Urban coastal sites are dominated by filamentous turfs (∼55 % coverage), exhibit high sedimentation rates (mean ∼180 mg/cm2/day), and low fish diversity (mean below 9 species/60m2). Open water zones have higher benthic and fish diversity. The highest biomass of fishes (mean ∼575 g/m2) as well as native corals (mean ∼13 %) and calcareous algal turf abundance (mean ∼38 %) was observed in the Alcatrazes archipelago, which increased its no-take MPA limits recently. In an unmanaged multiple-use protected Island, reefs were dominated by the invasive sun coral Tubastraea spp. The expansion of this alien coral is a real threat to the regional biodiversity, and its risk should be considered in management practices, which is done in the Alcatrazes archipelago. Our analysis demonstrates that effective management of multiple-use coastal settings may need to include flexible approaches that include land-based management, which can complement MPA tools to protect and conserve biodiversity. Since the region is considered a hotspot of cumulative impacts, ecosystem quality of the Alcatrazes archipelago could be considered substantially better than expected, being a bright spot of conservation. The expansion of its no-take area might help the role of MPAs within a comprehensive global conservation strategy.

Coastal urban flood risk management: Challenges and opportunities − A systematic review

Generational mechanisms and spatio-temporal evolution patterns of coastal urban flood risk involve complex interactions between climate change, sea level rise and human-induced factors, necessitating integrated adaptive flood management strategies to mitigate evolving vulnerabilities. This systematic review offers a thorough assessment of the challenges and strategic opportunities for sustainable adaptation in managing flood risk in coastal urban areas. It integrates emerging innovative technologies and financial solutions to identify promising approaches to implement mitigation strategies and improve coastal urban flood resilience. Enhancing governance and policy frameworks is crucial for the successful implementation of coastal urban flood risk management (CUFRM) plans. An innovative participatory planning framework is developed to promote flood management practices which are socially inclusive and equitable. Funding for green infrastructure and nature-based solutions and the strategic use of public-private partnerships are effective methods for advancing sustainable flood risk management (FRM). The advancements in emerging technologies, such as artificial intelligence (AI), machine learning (ML), deep learning (DL), social media and digital twin technologies, provide dynamic and collaborative platforms for simulating flood scenarios and have potential to significantly improve CUFRM practices. In the end, a cross-country comparison of current practices in Australia, China, the Netherlands, the UK and the USA reveals a diverse range of approaches and valuable insights derived from regional experiences. The review provides a comprehensive analysis for researchers, policymakers and practitioners aiming to improve flood resilience in coastal metropolitan regions by learning from effective UFRM approaches that enhance governance structures, infrastructure resilience and funding mechanisms.

The Assessment of Land Suitability for Urban Expansion and Renewal for Coastal Urban Agglomerations: A Pilot Study of the Guangdong-Hong Kong-Macao Greater Bay Area

Effectively and rationally allocating land resources, while coordinating urban expansion with internal renewal strategies, is crucial for achieving high-quality regional development in coastal urban agglomerations. Land-use suitability assessment (LSA) is a key method for coastal land-use planning, but it is primarily used to delineate ecological redlines or areas for urban expansion, often overlooking the spatial analysis needed for urban renewal. This is particularly critical in coastal urban agglomerations facing land scarcity and ecological fragility. Here, we combined land use and the Analytical Hierarchical Process (to consider stakeholder priorities) in a Minimum cumulative resistance model (MCRM) to determine suitable coastal urban growth and renewal based on a suite of 12 indicators relevant to development intensity and stock space. Application to the Guangdong-Hong Kong-Macao Greater Bay Area (GBA) indicates a dominance of the Ecological Buffer Zone (70.5%), and the available stock space in the GBA comprises only 9.2% of the total area. Our modeling framework tailored different development strategies for different cities: Huizhou and Zhaoqing had space for urban expansion to varying degrees, while other cities were found to be suitable for urban renewal due to low stock space and high development intensity. Our modeling approach, incorporating stakeholder input and objective evaluation of geographic land-use information, can assist planners in improving ecological security while promoting high-quality developments in coastal areas.

Eye of the Beholder: Prevalence of Binge Eating Disorder among Youth in Urban Coastal Karnataka, India

Abstract Introduction: Eating disorders (EDs) are on the rise and can result in medical and psychiatric morbidities in children, adolescents as well as during adulthood. It is crucial to understand the disease burden for its early diagnosis, intervention, and prevention. Our study was thus conducted over 5 months to estimate the prevalence of binge ED (BED) among adolescents and young adults in Mangalore, Karnataka. Materials and Methods: A total of 300 participants between the ages of 15 and 24 years were administered the Questionnaire on Eating and Weight Patterns - 5. Responses were categorized into “possible diagnosis of BED” and “possible diagnosis of bulimia nervosa (BN).” Results: The mean age of the participants was 19.4 ± 3.1 years and their mean body mass index was 22.7 ± 3.9 kg/m2. Among 300 participants, 15 (5.0%) had a possible diagnosis of BN, while 4 (1.3%) had a probable diagnosis of BED, both were found to be more among females than males. Sixty participants reported having loss of control over their food intake, of which only 26 (43.3%) reported being upset about it. However, on multivariate logistic regression, none of the sociodemographic factors were found to be significant in our study. Conclusion: It is essential to encourage healthy eating habits and physical activity at an early age along with the inclusion of screening for EDs in school health programs. Raising awareness among parents and children is crucial in bringing about sustained behavior change.

Coastal urbanization may indirectly positively impact growth of mangrove forests

Coastal urbanization is a key driver of mangrove loss, yet its global impacts on mangroves have yet to be thoroughly understood. Here we present a fine-scale assessment of the hidden impacts of urbanization on mangroves mediated by climate, and the joint effects of urbanization and climate at the global scale. Surprisingly, both urbanization and climate had positive impacts on mangrove growth and carbon stock in some regions, which is different from the general belief of the adverse impacts from previous research. In total, 27.3% of global mangroves received positive impacts from urbanization regarding their extent and carbon stock, among which 59.5% are indirectly mediated by climate. Moreover, mangroves in subtropical/temperate climate zones experienced more indirect positive impacts from urbanization, which enhances local climate conditions for growth by altering temperature, rainfall and sea levels. These findings suggest the feasibility of facilitating mangrove conservation through effective urban planning to achieve coastal sustainability.

Urbanization alters sandy beach scavenging assemblages and dogs suppress ecosystem function

AbstractUrbanization is rapidly transforming coastal landscapes around the world, altering the structure and function of marine, intertidal, and terrestrial ecosystems. In tandem, coastal areas are hotspots for human recreation, leading to shifts in wildlife behavior and activity patterns. Together, urban development and recreational use of wildlife habitats can shape wildlife behavior, abundance, and ecosystem dynamics at different spatial and temporal scales. In this study, we explore the impact of urbanization and human and domestic dog activity on the structure of vertebrate scavenging assemblages and the ecosystem functions they provide in sandy beach ecosystems across 40 km of the central California coast, USA. We surveyed vertebrate scavenging assemblages using baited camera traps on 17 beaches spanning a gradient of coastal urbanization. We found that urbanization extent within small spatial scales (i.e., 1 or 3 km radii of each site) and the rate of beach visitation by domestic dogs or humans were the best additive predictors of assemblage structure. We identified pronounced urbanization‐associated shifts in the composition of vertebrate scavenger guilds but found that the rate of carrion processing was more strongly influenced by domestic dog habitat use and diel period. Scavenging activity was substantially lower on beaches with more domestic dogs, suggesting that dogs interfere with critical scavenging ecosystem functions on sandy beaches. Our results underscore the pervasive and nuanced effects of urbanization and recreation on the dynamics of land–sea connectivity and suggest a need for comprehensive consideration of cross‐ecosystem linkages in ongoing shoreline conservation and development efforts.

Metal Bioaccumulation and Biochemical Responses in Loggerhead Turtles (Caretta caretta) from the Gulf of Gabès (Tunisia)

Caretta caretta (Cheloniidae, Cryptodira) is a species of turtle considered a ‘flagship species’ in the Mediterranean Sea. Unfortunately, the circular marine currents and semi-enclosed configuration of the Mediterranean Sea encourage the accumulation of pollutants (metals, pesticides, etc.) emitted by human activities. Tunisia suffers particularly from coastal urbanisation and industrial development. Metal concentrations (Ag, Al, As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Zn) were measured in distinct tissues (heart, kidney, liver, lung, muscle) of loggerhead turtles stranded in the Gulf of Gabès (Tunisia) to estimate the pollution levels in this emblematic species. High concentrations of arsenic and cadmium were found in marine turtles. Therefore, the differential accumulation of metals was measured in the tissues. For example, the liver appears to be a preferential organ for the accumulation of copper, iron, silver and zinc. In contrast, cobalt and cadmium were more concentrated in the kidneys, while arsenic, chromium and nickel were mainly found in the muscles. Antioxidant enzyme responses (catalase, GPx and SOD) and lipid peroxidation were more expressed in the liver and kidneys than in the muscles.

Geospatial fish consumption patterns and paradigmsin Odisha State, India

The current study investigated the geographic distribution and characteristics of fish consumption in Odisha State, India. The study was conducted across various locations, comprising urban coastal (Puri), rural coastal (Balasore), urban non-coastal (Cuttack) andrural non-coastal (Mayurbhanj) districts in the state. A total of 1440 respondents were selected for assessing the fish consumption patterns across theses diverse locations. According to the consumer profile, 82% of respondents were between the age of 20 and50, with 24% having a college degree. More than 90% of the respondents reported that they consume fish regularly. The results indicated that increased fish availability (62%), accessibility (52%), and affordability (48%) contributed to a rise in fish consumption over time. Over all, distance to the fish access points ranged between 1 to 2 . Catla was the most preferred fish species among consumers, followed by Rohu and other carps. Several barriers to increasing fish consumption were identified based on the perceptions of the respondents, such as erratic availability, lack of preference for fresh fish, wide price variations, limited access and high price. The data were analysed using a range of statistical and econometric methods, including conjoint analysis, preference assessment index and discriminant analysis. Keywords: Coastal, Conjoint analysis, Discriminant analysis, Fish consumption, Non-coastal, Preference assessment index

Stormwater Management in Urban Coastal Areas—A Review

Stormwater management in coastal urban cities, where drainage networks are influenced by marine dynamics and specific soil and altimetry conditions, has specific challenges that need to be addressed to ensure adequate management in such areas, which are also heavily affected by floods. Their location downstream of drainage basins and the interaction of network outfalls with current and tidal variability increases the vulnerability of populations and should therefore be the target of specific studies. This article presents a literature review, where publications that focus on stormwater management in coastal urban areas were identified and analyzed. The main objective was to present the key issues related to drainage in coastal areas, the most relevant challenges, the solutions and strategies that reveal the greater potential for application and the challenges for modeling this type of case. It is intended to provide a grounded basis for new ways of optimizing stormwater drainage in coastal areas and promote a sustainable urban water cycle. This review reveals the necessity to implement a multidisciplinary approach to minimize three main issues: urban flooding, stormwater pollution and groundwater salinization, including the adaptation of existing infrastructures, complementing them with control solutions at source, correct urban planning and the involvement of populations. For an effective management of urban stormwater drainage in coastal areas, this approach must be carried out on a watershed scale, duly supported by reliable decision support tools and monitoring systems.

Remote sensing of 50 years of coastal urbanization and environmental change in the Arabian Gulf: a systematic review

Remote sensing of 50 years of coastal urbanization and environmental change in the Arabian Gulf: a systematic review

Effect of Wet Scavenging on Black Carbon Aerosols over a Coastal Urban Site in India

Effect of Wet Scavenging on Black Carbon Aerosols over a Coastal Urban Site in India

Assessment of Coastal Carbon Storage and Analysis of Its Driving Factors: A Case Study of Jiaozhou Bay, China

Global climate change and coastal urbanization have significantly impacted the health and carbon storage of coastal zone ecosystems. Investigating the spatial and temporal variations in coastal carbon storage is crucial for developing effective strategies for land management and ecological protection. Current methods for evaluating carbon storage are hindered by insufficient accuracy and data acquisition challenges, necessitating solutions to enhance both reliability and precision. This study aims to assess the variations in carbon storage and annual carbon sequestration in the Jiaozhou Bay coastal zone from 1990 to 2020 and to identify the driving factors by integrating the Integrated Valuation of Ecosystem Services and Trade-offs (InVEST) and Carnegie Ames Stanford Approach (CASA) models with remote sensing data and geographic detector methods. The findings suggest that Jiaozhou Bay has experienced a substantial decrease in carbon storage, declining by 17.4% from 1990 to 2020, and annual carbon sequestration, decreasing by 35.5% from 1990 to 2016, but has stabilized recently. Vegetation cover and water bodies play critical roles in regional carbon storage. Furthermore, the dynamics of carbon storage and land use patterns are significantly influenced by socioeconomic factors, including GDP and population density. A comparison of the InVEST and CASA models demonstrates consistency in their carbon storage and annual carbon sequestration assessments. Combining these models in future assessments can enhance the scientific rigor and accuracy of the research, providing more reliable evidence for ecosystem management and policy making.

Inland O3 Production Due to Nitrogen Dioxide Transport Downwind a Coastal Urban Area: A Neural Network Assessment

Inland O3 Production Due to Nitrogen Dioxide Transport Downwind a Coastal Urban Area: A Neural Network Assessment