Low-lying Islands Research Articles

Nonlinear fractional arctic systems

In this contribution, the nonlinear fractional arctic sea ice model is given, and the solution of the model was obtained using a new proposed modified Adomian decomposition method. The result is compared with the integer-order model, and we observed that a model with fractional order gives a better result. We also observed that the effect of climate change on arctic sea ice could lead to a large-scale sea ice melting with sea-level rise for several meters, which could pose a major threat to low-lying island nations and coastal areas.

Sea Level Rise and Implications for Low-Lying Islands, Coasts and Communities, written by Michael Oppenheimer and Bruce C. Glavovic

Sea Level Rise and Implications for Low-Lying Islands, Coasts and Communities, written by Michael Oppenheimer and Bruce C. Glavovic

Why the low-lying islands of the Pacific and Indian Oceans are expanding?

Why the low-lying islands of the Pacific and Indian Oceans are expanding?

Effect of cut-off wall on freshwater storage in small islands considering ocean surge inundation

Freshwater lenses (FWL) underneath islands are often unique freshwater resources. Constructing cut-off walls in coastal islands to increase the FWL size has been proposed and tested effective. Meanwhile, seawater inundation induced by ocean surges on low-lying islands can cause the vertical intrusion of saltwater and salinization of FWL. Constructing cut-off walls can influence the post-inundation recovery once the FWL is salinized during the inundation. This influence has not been investigated and considered when discussing the feasibility of cut-off walls. In this study, we numerically simulated an ocean-surge inundation on a 2D, vertically oriented island constructed with a cut-off wall, using a coupled surface–subsurface approach. We varied the aquifer permeability and the depth of the cut-off wall. The effect of the cut-off wall on FWL was quantitatively assessed in terms of FWL volume and flushing time. The results show that the cut-off wall can significantly increase the volume of FWL, confirming previous studies, especially when it is constructed in high-permeability (>10−10.5 m2) islands and deeper. In addition, the cut-off wall can significantly reduce seawater infiltration by up to 40% during the inundation. Therefore, the recovery tends to be accelerated in the early stage, and in islands of low & intermediate permeability. However, the average recovery in high-permeability islands can be slowed down, because the cut-off wall reclaims larger and deeper space that is harder for flushing. As a first attempt to assess the feasibility of the cut-off wall construction from the perspective of FWL recovery, our study is important for the management of freshwater on islands facing the risk of ocean-surge inundation.

Regional sea level changes in the Indian shelf sea and its association with SST anomalies

Rising sea levels pose a potential threat to the densely populated areas along the Indian coastline and the low-lying islands, and cause disastrous impacts to coastal and offshore structures. Large fluctuations in sea surface temperature (SST) in the North Indian Ocean (NIO) is one of the contributing factors in inducing significant changes in sea level along the Indian coastline. Therefore, it is important to quantify the trends in sea level rise (SLR) in association with SST in this region. In this study, the seasonal climatology and variability of sea level anomaly (SLA) and SST is examined in the NIO (65 °E–92.5°E, 4.5 °N–25 °N). A comparative study is conducted based on two different datasets by using the reconstructed sea surface height anomalies (SSHA) for 58 years from 1952–2009 and Archiving, Validation and Interpretation of Satellite Oceanographic (AVISO) SLA dataset for 27 years from 1993–2019.The spatial correlation maps between SLA and SST reveal that AS exhibits strong positive correlation as compared to BoB throughout the year. In addition, the rate of increase in sea level is examined at twelve locations along the Indian coastline for pre-satellite era (1952–2009) and satellite altimeter era (1993–2019). In recent decades, a higher rate of increase as compared to long term trends (1952–2009) is observed, i.e., even exceeding the global mean SLR trend (3.2 mm yr −1). The highest rate of increase in annual sea level is observed at Mangalore (r=0.4 cm) and the lowest is observed at Haldia (r=0.03 cm) during the recent decades. However, during 1952-2009, the maximum rate of annual SLR is found at Okha (r=0.21 cm) and the minimum at Vishakhapatnam (r=0.11 cm). The analysis clearly elucidates that the sea level is continuously rising and accelerating and, four Indian coastal cities, namely, Vishakhapatnam, Mangalore, Mumbai and Chennai are the most susceptible of all.

Climate vulnerability and economic determinants: Linkages and risk reduction in Sagar Island, India; A geospatial approach

Climate vulnerability is the propensity to be adversely affected by climatic variability and natural hazards. People of low-lying islands face accelerating physical and non-physical stresses due to their greater exposure, higher sensitivity, and lower adaptive capacity towards climate change. Being home to over 0.2 million people, Sagar Island, the largest Island of Sundarban, is highly susceptible to coastal erosion, cyclonic storm surges, flooding, and embankment breaching, causing loss of land, property, and livelihood that eventually lead to displacements and induced migration. Over the past two decades, residents of this fragile sinking island of this world's largest mangrove forest have seen their homes engulfed, farmlands salinized and livelihood depleted by the rising sea. This study investigates the association between socio-economic vulnerabilities through the contextual indicators of land loss, productivity loss, loss of livelihood, and induced migration through regression modeling to find out linkages and scopes of risk reduction. The result reflects a significant positive correlation between land loss and loss of livelihood (p 0.0494*) that negatively correlates with the occurrence of in-migration (z −0.826), while the correlation between productivity loss and loss of livelihood is 0.6318. Mouzas like Dhablat, Shibpur, Beguakhali show outlier characteristics due to severe rates of erosion and embankment failure. The secondary data from the India Meteorological Department, National Centre for Ocean Information Services, have been used to identify considerable changes from cumulative erosion and accretion employing statistical and GIS techniques. This bottom-up assessment can contribute to disaster management and policy implications by identifying the particular intercession at the mouza level that increases the resilience of these vulnerable communities to climate change.

Extent change of protected mangrove forest and its relation to wave power exposure on Aldabra Atoll

Mangrove forests, vital for the conservation of biodiversity, protection of coastlines, and carbon capture, are decreasing globally at a rate higher than most other tropical forests. They are threatened by sea level rise, drought and storm surge, especially on low-lying islands where forests are directly exposed to the elements and have limited land area. We investigated changes in the spatial extent of mangroves on Aldabra Atoll, Seychelles – a protected area without direct human pressures, over 21 years using Landsat images. Over the 21-year study period, mean mangrove extent was 1283 ha with an overall net increase of 60 ha (0.23% year-1). The majority of extent changes were small (<2 ha) and contiguous to the existing mangrove extent. We then assessed the relation of mangrove cover change along the lagoon coastline with wave power (rate of energy transfer by waves), using fetch measures and local wind data. We found lower wave power values for stable mangrove areas than for areas that had gained or lost mangroves from 1997 to 2018. We identified wave power thresholds of 2.3 W m-1 for stable mangrove and 7.1 W m-1 for mangrove occurrence. These thresholds might be valuable for assessing threats and sites with the greatest potential for mangrove restoration across similar areas worldwide. Our results highlight the importance of quantifying mangrove extent changes at a local scale to assist with planning for the protection and restoration of this ecologically important habitat, given its vulnerability to the pressures associated with climate change.

Approaching Sea-Level Rise (SLR) Change: Strengthening Local Responses to Sea-Level Rise and Coping with Climate Change in Northern Mozambique

Mean sea-level is expected to rise significantly by 2100 in all scenarios, including those compatible with the objectives of the Paris Climate Agreement. Global sea level rise projections indicate devastating implications for populations, ecosystem services and biodiversity. The implications of the sea-level rise (SLR) on low-lying islands and coastal regions and communities are substantial and require deep-rooted coping measures. In the absence of adequate responses for coping, Mozambique is expected to record huge losses, with an impact on the economy and development in many sectors of its coastal regions mainly in northern Mozambique. This research aimed to perform projections on SLR in Mozambique, and to understand its role and implications on the north coast of the country. SLR was estimated through the analysis of model outputs that support the global estimates of the fifth IPCC report near the Mozambican coast, for each of the four representative concentration pathways (RCPs) scenarios. Regional coastline retreat and coastal erosion were estimated through the results of global sandy coastlines projections developed by Vousdoukas. Mean sea-level rise projections indicate that regional estimates for the Mozambican coast are relative higher than global estimates (~0.05 m) for all representative concentration pathways (RCPs). Yet, we highlight significant differences in sea-level rises of 0.5 m, 0.7 m or 1.0 m by 2100 compared to the global mean. It is expected that with the increase in the mean sea level in the northern part of the Mozambican coast, erosive effects will increase, as well as the retreat of the coastline until 2100. With this, the tourism sector, settlements, ecosystem services and local populations are expected to be significantly affected by 2050, with increased threats in 2100 (RCP4.5, RCP8.5). Local responses for coping are proposed and properly discussed for the RCP4.5 and RCP8.5 scenarios through 2100.

Climate change and hydrological risk in the Pacific: a Humanitarian Engineering perspective

AbstractPacific Island communities have adapted to floods, droughts and cyclones over many generations. Small and low-lying islands are particularly exposed to natural disasters, and many countries have limited access to water resources. Anthropogenic climate change is expected to further increase these environmental pressures. Any associated engineering response needs to consider the cultural, societal and historical context, and prioritise the agency of local communities to determine their preferred outcomes. It follows that Humanitarian Engineering, a discipline centred around strengths-based and context-appropriate solutions, has an important role to play in climate change adaptation. In this review, the interplay between hydroclimatology, geography and water security in the Pacific Islands is described and projected climate shifts summarised to highlight future adaptation challenges. A key source of uncertainty relates to the dynamics of two convergence zones that largely drive weather patterns. A broad overview of societal factors that present challenges and opportunities for Humanitarian Engineers is given. Finally, actions are recommended to inform climate change adaptation given the scientific uncertainty around hydrologic risks, and outline lessons for best practice Humanitarian Engineering in the Pacific. Enhancing data sharing, building resilience to climate variability and integrating traditional knowledge with convention engineering methods should be key areas of focus.

Sea level under climate change: Understanding the links between the past and the future

Rising global sea level, a consequence of climate change, results from an increase in the world ocean’s water volume and mass. Recent climate warming is responsible for producing the highest rate of global average sea-level rise of the past few millennia, and this rate will accelerate through the 21st century and beyond, exposing low-lying islands and coastal regions to significant flood risks. The flood risks can be compounded or diminished locally because changes in sea level are not uniform. In this review, we briefly discuss ice sheets as drivers of global and local sea levels, and how they could evolve under modern climate change. We underline some of the impacts of sea level change on coastal communities, and emphasize that local sea-level projections can be very different from estimates of the global average.

To Be or not to Be: State Extinction through Climate Change

Sea levels are rising. Within our lifetimes, several low-lying island states will be submerged. Until recently, the dominant position in legal circles has been that sinking island states lose their status as states once their territory is submerged. However, a contrary view is emerging. Writing in aid of island states, prominent legal scholars have advanced the position that the state, as a legal person, may continue to exist detached from territory. This proposition is supposed to aid island nations during the tumultuous times ahead. Maintaining the legal person of the state, we are told, allows access to international tribunals, facilitates coordination of international support, and protects the substantive rights of the individual citizens of island states facing climatic catastrophes. Legal scholars who advance this new position are more concerned with theoretical legal questions than the real challenges island states will inevitably face. What the people of island states need are options for communal resettlement. Continued statehood undermines communal resettlement efforts. No state will admit the people of an island state into its sovereign territory if they come as a State. Fighting for the continuation of the state post-submergence is therefore a disservice to island states. To protect the people of island states from becoming climate refugees, I propose a new pragmatic approach that trades statehood for life. Potential host states would only agree to accept communities from island states, if doing so will not entail competing sovereignty claims. Survival of the people of island states, therefore, is founded in state termination, not continuation. Based on this appreciation, I develop a legal framework of state-association that eliminates sovereignty clashes between potential host states and the people of island states. This framework secures communal resettlement options for the people of island states, guaranteeing their long-term survival.

Beyond internal conflict: The emergent practice of climate security

The field of climate and security has matured over the past 15 years, moving from the margins of academic research and policy discussion to become a more prominent concern for the international community. The practice of climate and security has a broad set of concerns extending beyond climate change and armed conflict. Different national governments, international organizations, and forums have sought to mainstream climate security concerns emphasizing a variety of challenges, including the risks to military bases, existential risks to low-lying island countries, resource competition, humanitarian emergencies, shocks to food security, migration, transboundary water management, and the risks of unintended consequences from climate policies. Despite greater awareness of these risks, the field still lacks good insights about what to do with these concerns, particularly in ‘fragile’ states with low capacity and exclusive political institutions.

Anthropogenic climate change on a non-linear arctic sea-ice model of fractional Duffing oscillator

Abstract In this contribution, a non-linear arctic sea-ice model of fractional Duffing oscillator is given. The solution of the model was obtained using a new proposed analytical method, which is an elegant combination of asymptotic and Laplace methods. The result obtained showed that this method is a very powerful and efficient technique for finding the analytical solution of nonlinear fractional differential equation. From the analysis of the result, we observed that the impact of anthropogenic climate change on arctic sea-ice could lead to flooding in many coastal areas and low-lying island nations.

Sea level rise, statehood and artificial islands for environmentally displaced persons under international law: Future of the Maldives

The Republic of Maldives is a small, South Asian archipelagic State consisting of low-lying is-lands, hence, climate change and sea level rise are not just mere words for us, the Maldivian people; they are a grim reality that is consuming our nation. The loss of a nation does not only mean the loss of home, substantial livelihood, natural wealth, and cultural identity; it also means the erosion of sovereignty and statehood at the international level. The analysis of applicable international laws and state practice indicates that the Maldives will not lose its statehood due to the loss of its territory resulting from sea level rise. The pragmatic way forward to protect the legal personality of statehood for low-lying island states such as the Maldives is to declare islands above the mean sea level, in case of complete inundation of nat-urally formed land, as Artificial Islands for Environmentally Displaced Persons, and to declare maritime borders established under the 1982 Law of the Sea Convention as non-ambulatory.

Smallest Late Pleistocene inhabited island in Australasia reveals the impact of post-glacial sea-level rise on human behaviour from 17,000 years ago

Late Pleistocene records of island settlement can shed light on how modern humans (Homo sapiens) adapted their behaviour to live on ecologically marginal landscapes. When people reached Sahul (Pleistocene New Guinea-Australia), between 65 and 50 ka, the only islands they would have encountered were in the tropical north. This unique geographic situation therefore offers the only possibility of modelling human adaptive behaviour to islands in Australasia during the Late Pleistocene. Cave excavation on the uplifted limestone island of Panaeati in the Massim region of Southeastern New Guinea revealed a cultural sequence commencing from 17,300–16,800 cal. BP, suggesting habitation of higher coastlines occurred as low-lying shorelines destabilised during the initial stages of deglacial sea-level rise. No cave use was evident between 12,400 and 4780 cal. BP when the continental shelf was fully inundated, and Panaeati reduced in size by 90%. It is likely that diminished coastlines and the reduced resources of low-lying islands could no longer support pre-agricultural populations during this time. Cultural groups that were better adapted to living on small islands returned to Panaeati by 4780–4490 cal. BP when sea levels had stabilised, lagoons formed, and coastal ecosystems had diversified. Investigations demonstrate the role of larger islands as refugia during deglacial sea-level rise and the effects on human dispersals and cultural diversity.

The Threat of a Rising Sea Level: Saving Statehood through the Adoption of Uti Possidetis Juris

Climate change has several adverse effects. One of these is ‘sea level rise’, which threatens two key requirements of statehood as stipulated by the declaratory theory of statehood and subsequently listed in the Montevideo Convention on the Rights and Duties of States. These are a defined territory and a permanent population. The focus of this paper is the implications of the rising sea level on the maritime boundaries, land territory and populations residing in small lowlying island nations. The central argument is that a rising sea level impugns the statehood of small low-lying island nations whose maritime boundaries are determined by ambulatory baselines. It further argues that a consistent rise in sea level may submerge small island nations, leading to their extinction. It concludes by proposing the principle of uti possidetis juris as a panacea to the retention of statehood of small island nations threatened by sea level rise.

Tropical Pacific Surface Wind Energy Spectra and Coherence: Basinwide Observations and Their Observing System Implications

AbstractThe tropical Pacific moored-buoy array spacing was based on wind coherence scales observed from low-lying islands in the western-central tropical Pacific. Since the array was deployed across the full basin in the mid-1990s, winds from the array have proven critical to accurately monitoring for decadal-scale changes in tropical Pacific winds and identifying spurious trends in wind analysis products used to monitor for long-term change. The array observations have also greatly advanced our ability to diagnostically model (hindcast) and thereby better understand the observed development of central Pacific sea surface temperature anomaly development associated with El Niño and La Niña events, although the eastern equatorial Pacific is not yet accurately hindcast. The original array-design assumptions that the statistics calculated from the western-central Pacific island records are representative of open-ocean conditions and other regions of the tropical Pacific have not been thoroughly reexamined. We revisit these assumptions using the basinwide wind observations provided by the array and find that key wind statistics change across the tropical Pacific basin in ways that could not be determined from the original island wind study. The island results provided a best-case answer for mooring zonal spacing with minimally redundant coherence between adjacent buoys. Buoy-observed meridional coherence scales are longer than determined from the islands. Enhanced zonal sampling east of 140°W and west of 180° is needed to obtain minimal redundancy (optimal spacing). Reduced meridional sampling could still yield minimal redundancy for wind and wind stress fields over the ocean waveguide.

Climate Change, Emotions and Religion: Imagining the Future in Central Oceania

ABSTRACT Pacific Islanders often respond emotionally and with recourse to their religious beliefs when faced with news about the projected consequences of climate change. In view of these responses, this paper argues that Pacific Islanders frequently combine their emotions with their religiosity in their efforts to shape their future. A case study of the atoll state of Kiribati illustrates this point. Given that most of this Pacific state’s islands are low-lying atolls or reef islands, it is widely considered to be particularly vulnerable to climate change effects. In this context, many citizens of Kiribati have recourse to their Christian beliefs to deal with feelings of uncertainty and imagine a future for their descendants. On the one hand, their religiosity helps them to cope with the worry over their land, fear of a rising sea level and sadness at the thought of a worst-case scenario and develop social resilience. On the other hand, they rely on their beliefs to confirm their love of their land and draw hope and gain strength from it in order to take adaptive measures.

Remote sensing reveals Antarctic green snow algae as important terrestrial carbon sink

We present the first estimate of green snow algae community biomass and distribution along the Antarctic Peninsula. Sentinel 2 imagery supported by two field campaigns revealed 1679 snow algae blooms, seasonally covering 1.95 × 106 m2 and equating to 1.3 × 103 tonnes total dry biomass. Ecosystem range is limited to areas with average positive summer temperatures, and distribution strongly influenced by marine nutrient inputs, with 60% of blooms less than 5 km from a penguin colony. A warming Antarctica may lose a majority of the 62% of blooms occupying small, low-lying islands with no high ground for range expansion. However, bloom area and elevation were observed to increase at lower latitudes, suggesting that parallel expansion of bloom area on larger landmasses, close to bird or seal colonies, is likely. This increase is predicted to outweigh biomass lost from small islands, resulting in a net increase in snow algae extent and biomass as the Peninsula warms.

Geobibliography and Bibliometric Networks of Polar Tourism and Climate Change Research

In late 2019, the Intergovernmental Panel on Climate Change (IPCC) released their much-awaited Special Report on the Ocean and Cryosphere in a Changing Climate (SROCC). High mountain areas, polar regions, low-lying islands and coastal areas, and ocean and marine ecosystems, were separately dealt by experts to reveal the impacts of climate change on these regions, as well as the responses of the natural and human systems inhabiting or related to these regions. The tourism sector was found, among the main systems, influenced by climate change in the oceanic and cryospheric environments. In this study, we deepen the understanding of tourism and climate interrelationships in the polar regions. In doing so, we step outside the climate resilience of polar tourism paradigm and systematically assess the literature in terms of its gaps relating to an extended framework where the impacts of tourism on climate through a combined and rebound effects lens are in question as well. Following a systematic identification and screening on two major bibliometric databases, a final selection of 93 studies, spanning the 2004–2019 period, are visualized in terms of their thematic and co-authorship networks and a study area based geobibliography, coupled with an emerging hot spots analysis, to help identify gaps for future research.