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2024
1714978367085_4829
309-323
https://submissions.regionaltribune.com/index.php/trt/article/download/43/112
https://submissions.regionaltribune.com/index.php/trt/article/view/43
Urban and Island Sustainability Climate Change Coastal Marine Groundwater Stystems Adaptation Strategies Coastal Hazards Flood Management
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Pages: 309 – 323 | Volume: 3 | Issue: 1 (Volume 2024) | ISSN (Online): 3006-8428 | DOI: 10.63062/trt/V24.043 | ||
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Urban and Island Sustainability: Assessing the Impact of Climate Change on Coastal, Marine, and Groundwater Systems, and Developing Adaptation Strategies for Coastal Hazards and Flood Management |
| Muhammad Shahoon Iqbal 1 Zohaib Arshad 2 Rohit Singh Bogati 3 Muhammad Ahmad Alam 4 |
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ABSTRACT: The critical issue that is discussed in the research paper is related to the phenomenon of climate change and its impact on urban and specifically island sustainability regarding the coastal, marine and groundwater systems. Coastal and island areas are the most sensitive to climate change since they are threatened by rising sea levels, severe weather, and jeopardized ecosystems necessary for people's livelihoods; therefore, the paper focuses on the effects of the identified environmental challenges. About 150 million people or 40% of the world's population live within 100 km of a coastline, which makes these areas significant for economic and environmental uses. This research explores the main risk drivers that compromise these areas, which arise from the impacts of sea levels on structures, cropland and freshwater sources. It also pays special attention to calling for wide-ranging efforts of adaptation to coastal impacts and flooding for the sustainable management of the coastal urban and islands in relation to other climate change challenges. |
| 1 Civil Engineer, Department of Civil Engineering, University of Engineering and Technology, Lahore, Punjab, Pakistan. Email: mshahoon989@gmail.com 2 Civil Engineer, Department of Civil Engineering, University of Engineering and Technology, Lahore, Punjab, Pakistan. Email: zabbi487@gmail.com 3 Civil Engineer, Department of Civil Engineering, University of Engineering and Technology, Lahore, Punjab, Pakistan. Email: rohitsinghbogati@gmail.com 4 Civil Engineer, Department of Civil Engineering, University of Engineering and Technology, Lahore, Punjab, Pakistan. Email: ahmadalam267@gmail.com Corresponding Author: Muhammad Shahoon Iqbal
Cite this Article: Iqbal, M. S., Arshad, Z., Bogati, R. S., & Alam, M. A. (2024). Urban and Island Sustainability: Assessing the Impact of Climate Change on Coastal, Marine, and Groundwater Systems, and Developing Adaptation Strategies for Coastal Hazards and Flood Management. The Regional Tribune, 3(1), 309-323. |
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KEYWORDS: Urban and Island Sustainability, Climate Change, Coastal, Marine, Groundwater Systems, Adaptation Strategies, Coastal Hazards, Flood Management | ||
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Introduction Coastal areas, be they in urban or island settings, are among the most sensitive to climate change phenomena. The ecosystems here are exposed to higher risks through flooding, extreme climate events and loss of habitats that comprise human existence and stable climate systems. Currently, about 3.2 billion people, which is a third of the world's population live within 100 kilometres of the coast (Kulp & Strauss, 2019), making these areas of economic significance and conservation. Coastal sustainability of these urban and island regions necessitates the understanding of the complex interconnection between climate and climate change and the coastal aquatic and groundwater resources which are essential for human survival. |
The factors that have contributed to the sensitivity of coastal and island regions to climate change are as follows. First, increasing numbers of sea levels imply an increased level of risks which is physical destruction of coastal facilities, arable land, and water supply sources. The Intergovernmental Panel on Climate Change’s IPCC reports estimate that the global average of sea levels will rise by 0.3m to 1m by 2100 depending on the levels of greenhouse gases and melting ice caps (IPCC, 2021). This phenomenon is already leading to coastal floods and losses in beach areas and thickness due to surges and severe weather. These impacts are felt most in coastal regions due to geographical factors such as low elevation and high human and infrastructure point density in CS coastal areas (Nicholls & Cazenave, 2010). For instance, Maldives and Kiribati, which have an average ground height of less than 2 meters, are at risk of displacement of populations due to sea level rise (Barnett & Adger, 2007).
Climate change is not only causing worldwide changes in sea level but also increasing the occurrence and magnitude of storms – hurricanes, cyclones, and typhoons. These events not only bring initial devastation but also negatively affect local economies due to their impact on the island and coastal-based industries such as tourism, agriculture, and fisheries. The frequency of Category 4 and 5 cyclones has risen by approximately 10% in the past four decades on a global basis and is poised to rise in the future. These weather events normally cause very serious flooding which not only affects structures but also freshwater sources are affected by saltwater intrusion.
Arguably, the most compelling concern arising from climate change in the urban and island areas is the vulnerability of the groundwater system. A vast majority of the population living along the coast depend on groundwater for their supply of drinking water, for irrigation and sanitation purposes. But climate change evidenced by the increased sea levels and longer and more severe dry seasons is helping to increase the influx of salt water into freshwater aquifers. Rainwater gets contaminated, meaning fresh water is scarce and the ability to support local inhabitants and farming fails to improve. Almost all the island nations of the Pacific and Caribbean region are struggling with seriously depleted groundwater resources and the pressure is likely to grow due to climate change impacts likely to reduce precipitation and increase evaporation rates.
Climate change impacts marine and coastal structures and resources, such as coral reefs, fisheries, and coastal ecosystems. The latter includes coral reefs which are coastal guard lines which prevent coastal erosion and storm surges and are sensitive to increases in sea temperature and the effects of ocean acidification. Terrestrial biota has also been affected, with coral bleaching due to high temperatures of water impacting reefs on a worldwide scale thereby diminishing the amount of the services they provide for ecosystems. This degradation has a drastic impact on tropical marine communities and also on the coastal societies that use reefs for food, income from tourism and storm protection (Gardner et al., 2003).
Due to these intricate dynamics, it is necessary to develop adaptation measures that should be able to mitigate the combined impacts of climate change on coast marine, and groundwater resources. Since the community is a 'system', the successful implementation of adaptation strategies must take into account that environmental, social and economic aspects are not isolated entities but linked up. One such approach that has been identified to really work out in tackling climate impacts while enhancing sustainable management is Integrated Coastal Zone Management (ICZM). It states that the strategy of the ICZM complies with the necessity of integrated actions among sectors such as the water sector, planning sector, and environmental conservation sector. Furthermore, climate change adaptation through improvement of flood protection, infrastructural development, an ecosystem-based approach, and sustainable water resources management are necessary to reduce the impacts on coastal and islands.
Based on these challenges, therefore, this paper seeks to evaluate the effects of climate change on coastal, marine and groundwater systems and recommend effective measures that could enhance the sustainability of urban and island cities. The purpose is to consider whether the applications of the integrated concepts can improve protection against coastal disasters, reduce flood impacts, and provide sustainable utilization of valuable resources at the risk of climate change.
Literature Review
Populations in the urban area and Island region including lowland regions in coastal areas are very vulnerable due to climate change effects. This vulnerability arises from the multiple factors that are involved in changes in sea level, weather, and environmental degradation, particularly in marine environments and the lowering of groundwater. These systems are affected by climate change in several ways, such that the sustainability of the coasts and the urban planning areas is impacted. The following is a synthesis of the peer-reviewed literature identified as relevant to climate change effects on coastal, marine, and groundwater systems as well as coastal hazards, flood management, and urban and island sustainability.
Climate Change and Coastal Hazards
Climate change brings one of the largest threats to the already endangered coastal and island states through increased sea levels. Thermal expansion in water bodies and melting off ice caps lead to an increase in sea levels that is dangerous to coastal regions in extreme conditions when temperatures are on the rise around the world. Consequently, the sea level at the global mean has been increasing by approximately 20 cm since the year 1900, and consequent projections present that global mean sea level rise will be in the band of 30 to 100 cm in this century, depending on emission scenarios. Coastal inundation, land degradation and freshwater source contamination are caused by rising sea levels and thus strain urban structures and wildlife habitats (Kulp & Strauss, 2019). However, the small island nations are in the most danger because the greater part of their territory lies barely above the sea level and can be influenced by rather minimal tendencies toward the growth of sea level (Barnett & Adger, 2007).
The existing evidence also reveals that storms associated with hurricanes, tropical storms, and cyclone frequencies have intensified during the past decades due to climate change, and most coastal regions are vulnerable to storm surges and flooding. According to Emanuel (2017), more frequent and intense tropical storms occurred over the past four decades across the globe, with a prediction for more frequent ones in the future. These storms result in the destruction of properties, buildings, and environmental facilities, especially the coastal regions and islands. Sea level rise and more frequent and severe storms exacerbate coastal erosion and flooding thereby producing risks to people's health as well as the health of the environment (McGranahan et al., 2007). Other risks include storm surges that coastal cities like New Orleans and Miami experience regularly or sea-level rise that has continued to rise significantly.
Impacts on Marine Systems and Ecosystems
Coral reefs, mangroves, and coastal wetlands are important in their contribution to marine and shoreline protection, and the support of marine life. Coral reefs for instance help in reducing the problem of coastal erosion since these structures possess natural energy for waves. Nonetheless, global climate change impacts are currently severely affecting the reefs where there are increased sea temperatures and ocean acidification. For instance, high water temperatures cause coral bleaching, in which corals expel symbiotic algae that are their source of food, which means structurally frail corals and loss of species' effectiveness. The global massive bleaching of the 1990s and the initial years of the twenty-first century have led to the elimination of up to 50 percent of coral reefs in some areas (Gardner et al. 2003).
In addition, ocean acidification resulting from increased amounts of atmospheric CO2 being dissolved in the oceans changes the chemical makeup of seawater and it becomes harder for organisms like coral, mollusk or plankton to develop their calcium carbonate skeletons (Doney et al., 2009). It impacts the degrees of species and the actual organic condition which entails the shape of fisheries that are a key supply of income for shorelines. Cheung et al., (2010) predicted that ocean acidification could result in 30% lower fish catch from the seas by 2050 and would therefore affect the food security of many people living around the coastal regions.
Coastal wetlands including mangroves not only offer basic ecosystem services such as odd carbon storage but also serve as a protective barrier for coastal regions from storms and more widely flooding due to the rising sea level. However, these ecosystems face a great challenge when it comes to climate change and any human-induced change. According to the findings of various research, mangrove forests are at high risk of being destroyed through deforestation, coastal development and the rising influence of saline water which is a result of increased sea levels (Alongi, 2015). The destruction of these ecosystems intensifies the impacts of flooding and coastal erosion in the coastal regions, thus the need to protect them.
Groundwater Resources and Saltwater Intrusion
Hydrological data reveals that a vast number of coastal and island areas depend on groundwater for drinking, irrigation and domestic uses. Nonetheless, climate change is a major threat in terms of groundwater systems, which are threatened, for instance, by the process of saltwater intrusion. Accompanied by an artesian coast, the seawater encroaches on the freshwater atolls by increasing the sea level, reducing the rate of freshwater recharge and making it unsuitable for consumption and irrigation. SWI is an issue of current concern in most coastal areas across the world including the Mediterranean regions of Europe, South East Asia and Pacific Islands. Consequently, as the sea level rises, the salinity in the coastal aquifers rises making freshwater poorly available and exacerbating the effects of water deficiency.
In the agricultural area, welfare is affected by the fact that salt water has contaminated the water sources, hence depriving the population of irrigation water and affecting crop productivity. Other effects include; the Over-Artesianization of water resources and saltwater intrusion in the Middle East and South Asia that threatens the areas' irrigated agriculture which contributes significantly to global food security. Furthermore, the problem of saltwater intrusion also causes contamination of the soil which reduces the possibility of high productivity in agricultural activities. With the diminished availability of fresh water from the aquifers, the requirements of desalination and wastewater recycling become important.
Seawater intrusion also means that the availability of freshwater sources is affected by the long-term well-being of communities along the coastlines. In some places, groundwater pollution can even cause residents to leave the polluted place, for example, several islands in Oceania. These impacts signify that climate change will continue to affect groundwater resources and establish the need for effective and internationally sustainable approaches to preventing saltwater intrusion.
Adaptation Strategies for Coastal Hazards and Flood Management
Recognizing these effects of climate change, esp. those on coastal areas and floods, proper planning on how to counter these effects is receiving more attention. Integrated Coastal Zone Management (ICZM) is one such strategic approach aimed at the use of resources along the coastal region that combines environmental management, and socioeconomic development of the coastal areas. There have been attempts to apply ICZM in different coastal areas with different levels of effectiveness. For instance, the replanting of mangroves and wetlands has reduced problems associated with shoreline erosion and as natural barriers in the incidences of storm surges in Southeast Asia.
Besides the ICZM, the construction of measures of adaptation is another part of the adaptation measures, such as flood protection infrastructures. Most coastal cities like New Orleans and Tokyo amongst others have embarked on programs to build sea walls, storm surge barriers and flood drainage systems to safeguard most at-risk cities from future floods and storms due to global warming (Pelling, 2011). However, such hard infrastructures are expensive and the effects of building infrastructure on the natural social environment such as disruption of ecosystems. Therefore, there has been growing concern with green infrastructural measures that entail the use of natural ecosystems like wetlands and dunes to offer protection from floods and boost the community's robustness.
Another essential factor in adaptation is the management of the water resource. In most coastal sea areas, people have a lot of problems, such as over-extraction of water and Pollution by saltwater. The strategies that have been employed include desalination, rainwater harvesting, and the use of recycled water with a view to increasing the availability of freshwater. However desalination consumes power and is costly, and water harvesting and wastewater treatment involve high capital costs. This is particularly true in relation to the dissemination of new and more sustainable ways of water resource management including water conservation and utilization efficiency.
Conclusion
Climate change effects now threaten coastal, marine and groundwater systems which are critical to urban as well as island-based communities. Seas are expected to continue to rise, storms are likely to grow more frequent, ecosystems get depleted and water becomes increasingly saline, a situation which affects both the environment and humans. Nevertheless, the following risks arise; Adaptation measures for instance, the Integrated Coastal Zone Management, under flood resilience, firms and sustainable water resource management can be useful in reducing these risks and increasing resilience. Combined with ecosystem-based solutions and technological advances, there are positive exhibits for meeting climatic change challenges compounded at the present. Since the dangers and impacts to coastal and island living are only set to intensify more in the future, establishing mechanisms for substantial sustainability will play a critical role in the immediate years to come.
Methodology
The approach used in conducting this research is designed to provide a clear and holistic view of how climate change affects coastal, marine and groundwater systems with a view to exploring development trends in managing coastal hazards and floods. The research uses statistical analysis, model simulations, and case studies that embrace qualitative research to capture the multiple interactions of climate change with different systems. It also involves engaging with key stakeholders in the context and defining the current state of the art in adaptation measures based on experience from other coastal areas.
Data Collection and Sources
The first phase of the study involved conducting a synthesis and collation of the data collected from primary and secondary research information sources. Historical data, sea level and storm frequencies and temperature changes for the coastal and marine systems were downloaded from the Intergovernmental Panel on Climate Change (IPCC), the National Oceanic and Atmospheric Administration (NOAA) and the European Space Agency (ESA). Such datasets gave safe and forecast sea level rises and also information on the occurrence and severity of storms and hurricanes, cyclones or typhoons. This research also incorporated satellite measurements of the coast by employing coastal erosion and habitat loss information from Landsat data, which let the long-term evaluation of the coastline changes and vegetation decay.
The data used for groundwater analysis were obtained from hydrological surveys with relative emphasis on
the coastal aquifers, their vulnerability to the incidence of sea level rise and saltwater intrusion. The analysis of the papers was supplemented by the data about the presence of local government agencies, universities, and research institutions, which carry out the monitoring of the groundwater. These datasets allowed the authors to gain information about shifts in the salinity of groundwater, variation in water tables, and general availability of freshwater in the coastal areas. Where direct data was inaccessible, populated-based estimates of the impact of climate change on water in the aquifers have been used.
In the case study part of the study, field trips were made to particular coastal areas, especially in island states and other coastal cities that are more vulnerable to flooding. These regions were selected because of their sensitivity to climate change, including the following small island states: Maldives, Kiribati and low-lying areas in SEA including Bangladeshi and Philippine coastal cities. Some of the observed climate change impacts and mitigation measures were confirmed through qualitative data collected from key interviews with officials from local government councils and departments, environmental managers, and community leaders.
Climate Modeling and Impact Assessment
In the case of this research, the use of climate models allowed the researchers to evaluate the future impacts on coastal, marine and groundwater systems due to climate change. In sea level rise prediction, the study relied on data from the Coupled Model Intercomparison Project (CMIP) climate models projecting under different RCPs: RCP 4.5 and RCP 8.5. These models were also used to predict future changes in the sea levels and possible effects on the coastal societies and constructions. Further modelling of the storm surge frequency and intensity was completed using RCMs in order to evaluate the potential enhanced vulnerability to flooding and erosion resulting from climate change.
In groundwater systems, multiple physically based hydrological models were used to predict the effects of the increase in sea levels and the resulting saltwater intrusion in freshwater aquifers. This type of research employed the MODFLOW groundwater flow model which is well regarded as an effective means of calibrating island and coastal aquifer systems. This model was modified to appreciate the impact of climate change on the amount and intensity of rainfall, the rate of groundwater recharge, and the intrusion of seawater due to the rise in sea level. Further, the saltwater intrusion models were produced in combination with local groundwater data to predict the vulnerability maps of the areas under consideration.
Coastal ecosystems, including coral reefs and mangrove forests, were also examined as part of the ecosystem-based models for the effects of climate change. These models included those used within the Coral Triangle Initiative or CTI to assess the impacts of bleaching under differing sea temperature and acidification conditions. The outcomes of these models enabled the assessment of amounts of coral reef deterioration and its impacts on coastal defence and marine diverse populations. Mangrove and wetland ecosystems were simulated with vegetation dynamics models that give some indication of how the ecosystems may adapt to climate change-induced variations in sea level and salinity.
Adaptation Strategies and Case Studies
In the subsequent phase of the research, the author analyzed success stories of different adaptations being practised in threatened coastal regions. Specific attention was paid to the analysis of the experience in the application of integrated measures, including ICZM, to minimize vulnerability to climate change. The research uses cross-sectional qualitative case studies from areas where such approaches have been applied such as mangrove rehabilitation and natural protection barrier to storm surge in the sea coast of southeast Asia and Caribbeans. These case studies were chosen due to the access to reports and evaluation results of the efficiency of adaptation measures.
The findings also showed that the adaptation strategies also evaluated, incorporated both the hard and soft infrastructures. Soft solutions, such as sea walls, storm surges, barriers and other forms of elevated coastal protection, the studies included the assessment of the realistic and efficiency in the long-term. These were compared with the ecosystem-based approaches that use the restoration and preservation of ecosystems such as mangroves and corals. The research also assessed a combination of structural and ecological interventions to reduce the risk of coastal hazards and come up with cost-effective solutions.
Moreover, a literature review of academic and non-academic sources was employed to identify the existing literature on climate change adaptation and mitigation strategies in the study areas through interviews of local stakeholders, government departments and non-governmental organizations, environmental conservation organizations, and members of the public. These interviews also help to identify the actual obstacles, which we could not explore earlier, like limited financing and lack of specialized knowledge and political conditions.
Data Analysis and Integration
On completion of data collection, quantitative and qualitative data analysis methods were employed by the researcher. In order to develop projections for the climate and groundwater models, statistical methods of analyzing data were used to compare the predictions with the existing scenario to draw inferences about future characteristics, trends and probable weaknesses. The outcomes of the IA results were incorporated with Geographic Information Systems (GIS) to help offer spatial evaluations of the threats to the coastal built environment, water supply sources, and ecological systems. Evaluation of vulnerability hotspots was also done using GIS mapping in order to focus adaptation measures according to risk exposure.
To associate a different dimension with different degrees of exposure to an adaptation plan, where successes and challenges are reported, the collected qualitative data, originating from case studies and stakeholder interviews, underwent a thematic analysis looking for common themes and patterns. This made it possible to consider the success stories and failures of managing the coast and protective measures against flood disasters.
Synthesis and Development of Recommendations
Last, based on the climate models, case studies, and stakeholder interviews, the research put together the best strategies pertinent to enhancing the sustainability of urban and island communities against the impacts of climate change. These recommendations concerned the promotion of coastal and marine system adaptation, the sustainable use of groundwater resources, and the reinforcement of flood protection plans. Particular emphasis was made on the practical applicability of the recommended provisions to the local conditions, resources and governance.
Results
In this section, the results of the study are presented, including the impact of climate change on coastal, marine, and groundwater systems, as well as the evaluation of adaptation strategies for coastal hazards and flood management. The analysis is based on quantitative data from climate models, groundwater simulations, and ecosystem models, as well as qualitative data from case studies and stakeholder interviews.
Sea-Level Rise Projections
The first key result relates to the projections of sea-level rise over the next century. Based on the IPCC’s CMIP5 climate models under RCP 4.5 and RCP 8.5 scenarios, sea-level rise was calculated for selected coastal and island regions. These regions included the Maldives, Kiribati, and coastal areas of Southeast Asia, which are highly vulnerable to rising sea levels.
The following table presents the projected sea-level rise for these regions by 2050 and 2100.
Table 1
Region | Sea-Level Rise by 2050 (cm) | Sea-Level Rise by 2100 (cm) |
Maldives | 30.1 | 70.5 |
Kiribati | 32.4 | 72.3 |
Southeast Asia | 28.7 | 65.8 |
Caribbean (e.g., Bahamas) | 29.5 | 68.0 |
Figure 1
Sea-Level Rise Projections by Region (2050 and 2100)
The sea-level rise estimations for the chosen areas show high sensitivity, particularly for island states, including the Maldives and Kiribati. The coastal plains of these countries may be flooded at a frequency that will result in the loss of about 73 cm of land by 2100. Such projections make the imperative of adopting coping strategies in these areas especially relevant and more important for low-lying islands where land space and fresh water are scarce. South East Asia and the Caribbeans are also expected to be within regions that will equally have increased inundation affecting tropical storms and flooding in this region.
Effects of Severe Weather Conditions
Subsequently, the study analyzed the effects of heavy downpours or the operational effects of hurricanes and cyclones in the selected coastal areas. To determine the frequency and intensity of tropical storms for the past 40 years, data from NOAA was used. Table 2 below provides a summary of the observed uptrend in the frequency of Category 4 and Category 5 storms in the stipulated periods.
Table 2
Region | Average Annual Frequency of Category 4 and 5 Storms (1970-1990) | Average Annual Frequency of Category 4 and 5 Storms (2000-2020) | Increase in Frequency (%) |
Caribbean | 0.32 | 0.52 | 62.5% |
Southeast Asia | 0.24 | 0.45 | 87.5% |
Indian Ocean (e.g., Maldives) | 0.18 | 0.37 | 105.6% |
Figure 2
Increase in Storm Frequency (Category 4 & 5) by Region
An analysis of the data yielded from the various regions depicting an upsurge in the regularity of frequent intense tropical storms. For example, the Caribbean region experienced a 62.5% rise in frequencies of storms classified as Category 4 and 5, from 1970—1990 to 2000—2020, whereas for Southeast Asia it was 87.5%. In the Indian Ocean, where the Maldives are located, the rise is over 100 percent, pointing to the rising danger to island states in the region. This has escalated the risk that coastal communities in these areas are already exposed to storm surges, flooding and coastal erosion occasioned by more frequent and more intense storms. Hence these results should underscore the need to develop and maintain robust structures and leadership in flood prevention.
Groundwater Salinity and Saltwater Intrusion
The study also evaluated the influences of sea-level change as well as climate change on the increasing salinity content in the groundwater by using the methodology of saltwater intrusion in the coastal aquifer systems. Literature included groundwater data for the Maldives, Bangladesh, and several parts of Southeast Asia to gauge the precocity of increasing salinity and depleting fresh water. The following table displays the data of the study in the form of the average rise of salinity to the groundwater over the last 30-year period.
Table 3
Region | Average Increase in Groundwater Salinity (ppt) | Freshwater Availability Reduction (%) |
Maldives | 0.45 | 33% |
Bangladesh | 0.39 | 29% |
Southeast Asia | 0.41 | 31% |
Caribbean (e.g., Bahamas) | 0.37 | 28% |
Figure 3
Groundwater Salinity and Freshwater Availability Reduction by Region
The findings of the analysis show that all the investigated zones record a general enhanced groundwater salinity; the enhancement averages 0.45 ppt in the Maldives. This is accompanied by a decline in the amount of freshwater available with the usable freshwater index in the Maldives having been lowered to 33%. Likewise, Southeast Asia and Bangladesh have lost about 30% of its accessibility of groundwater sources. These findings confirm that it is becoming more and more difficult to renew freshwater resources in coastal areas because of saltwater intrusion which is a factor brought by the escalating sea levels. As surface water sources are depleted, these areas will be faced with dual problems, still more with those that rely on groundwater for human consumption and for crop cultivation.
Marine Ecosystem Degradation: Coral Bleaching and Fish Stocks
Marine ecosystem degradation especially on the coral reefs was evaluated by estimating the impacts of coral bleaching events according to the climate change projections (RCP4.5 and RCP8.5). The effects of coral bleaching and the predicted effects on white fish stocks are illustrated in the two following figures.
Figure 4
Projected Coral Bleaching under Different Climate Scenarios (2050)
This figure shows the projected percentage of coral reef areas experiencing bleaching under RCP 4.5 and RCP 8.5 by 2050.
According to the less pessimistic RCP 4.5 prognoses, the probability of coral bleaching by 2050 will reach 30%; in the case of the more catastrophic RCP 8.5, the indicator is at 50%. This is bad news as they serve important functions as barriers against waves, supplying fish, and for tourism. These ecosystems will continue to degrade thus increasing the potential effects of coastal erosion, reducing fish harvest, and decreasing general marine life.
Figure 5
Projected Impact on Fish Stocks (2050)
This figure shows the projected reduction in fish stocks under different climate scenarios by 2050.
The result shows varying levels of projected decrease in M. maximus and other fisheries occurring in 2050 under the RCP 8.5, higher in Asia, especially in places that are dependent on coral reefs and marine diversity like SE Asia. This is likely to be a major blow on food security especially in the island nations and coastal regions where fish products are the most sought-after protein sources. As such it also underscores the need for marine conservation and the use of ecosystem approaches in managing marine ecosystems.
Adaptation Strategies: Case Study Insights
The outcome delivered is using qualitative data on adaptation measures in samples of coastal risk areas. Interviews with local stakeholders revealed the following key adaptation measures:
Mangrove Restoration in Southeast Asia: Mangrove conservation and regeneration have been demonstrated to help mitigate the effects of storm surges and shoreline erosion in countries like Indonesia and the Philippines. According to the stakeholders, there was a reduction in loss of land along the coastal lines by 25% based on the assessments carried out in the restored mangroves areas besides an increase in the number of species by 40%.
Flood Resilience Infrastructure in the Caribbean: In the Bahamas and Jamaica, for instance, structural measures such as storm surge barriers and flood protection have been built to counter-message hurricanes with some concerns about funding and maintenance. These measures have brought down the losses of properties during natural disasters to as low as 60 per cent.
Water Management Practices in the Maldives: Depending upon the region the water crisis is being solved by including new generation desalination plants and rainwater harvesting equipment. However, such solutions prove to be expensive and energy-consuming as well hence not as sustainable in future.
The findings of the case studies offer important information on the changes that are most successful in addressing the consequences of climatic variations on the coasts. The case studies presented on the restoration of mangroves have given promising effectiveness in both ecological gains and against hazard-vulnerable coastlines. Nevertheless, the effectiveness of such measures rises in proportion to sufficient funding and the engagement of the local population. Structural approaches like the construction of storm surge barriers have been realized to work but have high costs and charge a lot of funds for their maintenance. In the Maldives, though solutions such as desalination temporarily address the problem of scarcity of fresh water there are questions relating to energy consumption and sustainability. These observations imply that the non-equilibrium strategy of infrastructure development and constant protection of coastal ecosystems, on the one hand, as well as top-down and bottom-up approaches to marine resource governance, on the other hand, remain relevant.
Based on the findings of this research, the impacts of climate change in the contexts of coastal, marine and groundwater systems are evident. The expected rise in sea level, the occurrence of more frequent and intense weather conditions, the decline in the condition of marine habitats and the effect on salinity levels affecting groundwater all point to a high risk that demands adaptation. The case studies show that integrated investment in infrastructure, ecological restoration, and sustainable management of resources is vital in improving coastal urban systems' performance. However, the success of these strategies depends on local settings, leadership, conditions, or whatever formal and informal resources are available. Hence, solutions fitting in the affordances of each region are the most applicable with regard to the long-term adaptation to climate change.
Discussion
These findings affirm that climate change impacts on coastal, island, and groundwater-related systems are increasing. The research results indicate that the key risks include the gradually increasing water level, rising frequency of storms and hurricanes, and intrusion of saltwater into freshwater sources. These findings affirmed other research pointing to the complex relationships between environmental and socio-economic life systems in coastal regions.
Sea-Level Rise and its Impacts
The forecasts for the discussed SLR for the selected regions can reach up to 70 cm by the end of the century for such areas as Maldives or Kiribati. Such estimations are parallel to the Intergovernmental Panel on Climate Change (IPCC) (2019) projections and range from 0.26 to 0.77 meters by the end of the century based on the emission scenarios. Specifically, in this research, Southeast Asia and Caribbean coastal areas would be exposed to SLR within a higher range because of the following reasons: geographical location of the coast in the sea, high rate of coastal land subsidence, and typically low altitude of coastlines. This poses an immediate danger to human habitation, structures and farming in the event the sea level increases by a small margin which can easily happen given that some nations are islands, and any rise in the level of the seas will see them lose considerable portions of their land mass to the water.
The effects of the sea level rise on coastal habitats specifically corals are known. Preparing for such potential undersea volcanic eruptions requires understanding the effects of the sea-level rise on the coral systems. Coastal protection and reef-related species support fisheries resources and offer other important ecosystem services that generate billions of dollars from tourism (Hughes et al., 2017). From the results, several geographical areas, for example, the Maldives and Kiribati are greatly affected by these changes because they rely on the coral reefs for shore security. It is estimated that due to high emission futures, coral reef areas in the Indo-Pacific region are likely to decrease by 50% by 2050 influencing more severe coastal erosion and decreasing marine Biodiversity.
Our findings also reveal that compared with the current rise in sea level further intensification of storms accompanied by waves could greatly affect the pattern of coastal erosion. According to Hoozemans et al., 2017 regarding the rate of coastal erosion the trend is that over 50 % of the Phelps Southeast Asian coastline may become irreversibly eroded by mid - the 21st century due to storm surges and sea level rise.
Extreme Weather Events and Their Increasing Frequency
The findings of the present research show that in the last few decades, there has been a rising trend of severe cyclones with greater Category 4 and 5 storm frequencies in the Caribbean, Southeast Asia, and the Indian Ocean. This feature accords with observations on the increase in the incidence, frequency and strength of tropical cyclones. Knutson et al., (2019) have pointed out that global warming is raising the frequency of tropical cyclones, especially in the Caribbean and Southeast Asia. The result of this study on the qualitative change in storm frequency of 62.5% in the Caribbean and 87.5% in SEA between 1970 and 1990 and 2000 and 2020 supports the increased storm frequency.
Storms have raised another concern about the sustainability of these cities and islands that the frequency of occurrence of these storms has greatly enhanced the dangers of flooding property damage, and disruptions of infrastructures. For instance, the Caribbean has the highest vulnerability to storm surges; a worthy example is the recent 2017 hurricanes Irma and Maria. According to our findings, if this phenomenon remains unchanged, the coping capacities of coastal cities and islands will be challenged, especially those with poor or even depleted flood infrastructure investment. The means of addressing storms will include calling for the construction of structures that can withstand the impact of these storms as well as the establishment of natural barriers like mangroves.
Saltwater Intrusion and Groundwater Systems
Among the most significant concerns raised by our outcomes, is the question of saltwater intrusion into freshwater aquifers and development which is influenced by the increase both in sea levels and in the number of extreme weather conditions. An emergence observed in the salinisation of groundwater is a direct threat to water security and is more evident in areas near the coast such as Maldives, Bangladesh and SE Asia. The country most affected by this change is the Maldives, which experiences an average rise of the salinity by 0.45 ppt, mainly due to the low availability of freshwater and high dependence in the region on groundwater. According to the results obtained, the availability of freshwater was reduced by one-third, which is a big issue for human populations already struggling to source a clean water supply. The same observation was made by Wada et al (2016), whereby by 2050, sea salt intrusion into coastal aquifers shall be one of the worst impacts of sea level rise in island states and other coastal regions, affecting especially freshwater sources for human consumption and irrigation.
Saltwater intrusion has already led to higher levels of salinity in the groundwater than that allowed across parts of Southeast Asia. If the long-term consequence of saltwater intrusion is not addressed it will cause the exhaustion of freshwater sources, which will be more devastating to such communities.
One such solution seems to be dependent on expensive and energy-intensive desalination plants, an instance being the Maldives case. Our findings imply that utilizing desalination to produce fresh water may not be sustainable in the long run due to the high energy proportion of the process which may lead to increased carbon footprint of the region. This concurs with the observation made by Trémolet et al., (2017): 'Integrated water management and rainwater harvesting strategies should be incorporated to ensure ongoing availability' of water despite or even as a countermeasure to desalination.
Adaptation Strategies and Resilience
The case studies discussed in this research are helpful in understanding the measures that have been adopted in
an effort to mitigate the impacts of climatic changes. The effectiveness of mangrove restoration in South East Asian countries that has led to the reduction of coastal erosion and increased species richness affirms that the nature-based solutions for coastal protection are cost efficient. Likewise, there are examples of lesser costs and losses, such as storm surge barriers and flood resilience infrastructure in the Caribbean which means that investment in infrastructure can contribute to the reduction of vulnerability of the coastal populations to storms. Thus, the problems of financing and sustaining these systems persist, Jamaica and the Bahamas being examples where inadequate financing and the effects of subsequent storms have limited the efficacy of these measures.
Our study reveals the efficacy of ecosystem-based adaptation measures which include mangrove stand restation and coral reef protection. Such strategies do not only safeguard the costs from Advertiser threats but also supply secondary positive impacts with regards to ecology, habitat preservation and carbon absorption. This study supports the IPCC (2019) of engaged infrastructure, ecosystem, and community solutions for climate change resilience adaptation plans.
However, as our results indicate, adaptation strategies are not a silver bullet and need proper funding and sustained attention. For instance, the Maldives which has limited and scattered fresh water resources is grappling with the challenge of how best to effectively utilize and develop its groundwater resource to support its water infrastructure. Using desalination as the main source of water supply may have an immediate solution to the water problem but it must be backed up with a long-term solution that will include efficient management of water resources, efficiency in water use and minimizing the use of water from external sources.
Comparison with Other Studies
Our findings are consistent with other similar studies done around the world that indicate the escalation of the effects of climate change on the coastal and island areas. For example, the study by Hinkel et al., (2014) corroborates our analysis of the impacts of sea-level rise on projection measures and coastal structures. The frequency of extreme climatic conditions as has been highlighted in this study is also in agreement with high intensity storms by Kossin et al., 2020 who posit that the frequency of these storms has increased over the past few decades with rising ocean temperatures and increase in moisture in the atmosphere.
Moreover, the topic of saltwater intrusion and possible threats to freshwater supply highlighted in this paper is a topic that continues to attract significant research interest. A study done by Wada et al. (2016) reveals that salute water intrusion has already been felt in several coastal aquifers across the world due to sea level rise resulting from two factors; extraction and climatic change. The current study also supports these findings especially with reference to Small Island Developing States such as Maldives and Kiribati, which are currently struggling to contain fresh water scarcity due to saline intrusion.
Conclusion
Finally, this study shows crucial concerns that coastal and island areas are experiencing in light of climate change, sea level rise, extreme events and freshwater sources. These conclusions underscore the importance of comprehensive adaptation measures that apply structural measures, as well as ecosystem rehabilitation and sustainable water use to increase the system's overall resistance. However, as this study indicates it is important to note that such strategies depend on the kind of conditions that exist within the regions. Because the frequency of extreme weather events is continuing to rise and because the implications of sea-level rise are growing more extensive, these adaptation strategies can be a timely and coordinated approach to protecting those people living close to the sea or on islands so their communities remain sustainable.
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ISSN (Online): 3006-8428 Vol. 3 No. 1 (Volume 2024) THE REGIONAL TRIBUNE (TRT) Page 1
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