Search

Abstract In the past two decades there have been fears that many low-lying atoll islands around the world could disappear as a consequence of climate change and sea level rise, leading to mass migration and threatening the existence of several island nations. Here we show how sea level rise does not inevitably lead to coastal areas becoming uninhabitable, and that humans have an innate and often underestimated capacity to adapt to changes in their environment. To do so we showcase three instances of human- and earthquake-induced land subsidence that have taken place in the 21st century, where the coastal/island areas are still inhabited despite the challenge of living with higher water levels: the Tohoku coastline following the 2011 Tohoku Earthquake Tsunami (subsidence ∼0.4–1.0 m), the present day situation of coastal areas in Jakarta due to ground water extraction (>5.0 m), and the islands of Tubigon, Bohol in central Philippines after the 2013 Bohol Earthquake (∼1.0 m). Humans are able to adapt and arrive at solutions even when confronted with cases of rapid rises in water levels, and thus it is likely that in the future vulnerable coastlines will be engineered and largely remain at present day locations, particularly in densely populated areas. If anything, around densely populated areas it is more likely that humans will continue to encroach on the sea rather than the reverse. We caution, however, that small islands are not homogeneous, and many are unlikely to respond to rising sea levels in the manner that atolls do (in fact, many might just resort to build at higher elevations). Where engineering and other adaptation responses become necessary, the financial and human resource requirements may well be beyond capacity of some small islands, which could lead to impoverishment and associated challenges in many communities. Highlights • Lessons learnt from adaptation to land subsidence in different parts of the planet. • Evidence that it is unlikely that dense coastal settlements will be abandoned in the face of sea level rise. • Long-term perspective about adaptation strategies to sea level rise. [ABSTRACT FROM AUTHOR]

The Mekong delta in Vietnam and the Ganges/Brahmaputra River delta in Bangladesh are likely to be two of the deltas worst affected by climate change in the course of the 21st century. Due to sea level rise, and if significant adaptation measures are not taken, large areas of these low-lying coastlines could eventually become submerged. This paper will explore some of the consequences that climate change and sea level rise can have on maritime baselines and deltaic areas, according to publicized charts by the States involved and to the United Nations Convention on the Law of the Sea (UNCLOS). The study will argue that although great changes are likely to take place at the geographical level, due to the complex geomorphological nature of deltas and how they will be affected by sea level rise, these will not necessarily translate into changes in maritime baselines and the classification of these areas according to UNCLOS. Furthermore, other forms of adaptation to sea level rise, such as the construction of coastal defences, could turn the Mekong and Ganges/Brahmaputra River deltas into “polders”, with similar characteristics and problems as the Netherlands nowadays. [ABSTRACT FROM AUTHOR]

Abstract: Sea level rise could bring about an event that has not previously been seen in modern history, that of the physical disappearance of some low-lying Island States. The objective of this paper is to examine what are the likely scenarios for some of these islands in the course of the next century, and analyse for each scenario if these Island States could continue to claim an Exclusive Economic Zone or not. Also, it will analyse the possibility that Island States could continue having some sort of status analogous to statehood even if it was to lose all territory. Finally, the idea of a “government-in-exile” will be discussed, where the State could retain its identity waiting for a future re-emergence of the island. [Copyright &y& Elsevier]

Land subsidence has triggered severe coastal floods in Jakarta, whose mechanism has been extensively investigated by researchers and engineers. The government has also recognized this fact, which has partially contributed to the recent announcement that the capital will be relocated to East Kalimantan. However, it is not clear whether ordinary people perceive the progress of land subsidence as their own issue. To ascertain this, a field survey was conducted after a major coastal flood that took place in December 2017, which revealed that nearly half of the people living in a rapidly sinking coastal community were not aware of the ongoing land subsidence under their own houses. Severe flood and land subsidence were not strongly recognized as interlinked problems by local citizens. Rain-induced flooding is common in the community, and this may explain why a quarter of respondents did not fear the 2017 coastal flood, despite their houses being flooded, in some cases to a depth above their heads. Land subsidence has an adverse effect on flooding. Awareness building programs for normal citizens should be promoted, in order to articulate the significance of stopping groundwater extraction for mitigating land subsidence and the flooding it induces. "Do you feel your house is sinking?" This figure shows the results of our survey in March 2018, consisting of interviews with 29 residents on flood triggered by the 2017 flood event and perception on land subsidence. The ground elevation was estimated based on our survey in November 2017. About half of the population do not recognize that land subsidence is ongoing under their own houses. Three respondents in this figure who experienced the highest floods (almost 2 m high) believed that their houses are NOT sinking. We initially hypothesized that the experience of suffering severe inundation would make people establish connection between flood and land subsidence. However, this connection appears not to be straightforward for local inhabitants. [Display omitted] • Land subsidence exacerbates flooding. Their connection is scientifically obvious. • However, it is not clear whether ordinary people perceive the progress of land subsidence as their own issue. • Nearly half of the respondents living in a rapidly sinking coastal community were not aware of the ongoing land subsidence. • Severe flood and land subsidence are not clearly recognized as interlinked problems by local citizens. • Awareness building programs should be promoted to articulate the significance of stopping groundwater extraction. [ABSTRACT FROM AUTHOR]

Vulnerability assessments have suggested that many coastal cities are prone to the impacts of flooding induced by sea level rise. This paper aims to understand the dynamics of flood adaptation in Ho Chi Minh City, which has been dealing with such issues for years due to its topography and ongoing urbanization-induced land subsidence. The results suggest that adaptation is reactive to the flooding – creating inconvenience to people's lives and focusing on a hard measures approach. Despite the high exposure to increased risks in the future, a large proportion of the population surveyed is unaware of sea-level rise and land subsidence in the area. Social conflicts regarding the interaction between formal and informal adaptation suggest the decoupling of the process at different levels and a lack of communication between the government and local communities. This case study, showing examples of reactive and decoupled formal and informal adaptation, can provide insights and lessons for vulnerable coastal cities elsewhere on the planet on how to adapt to sea level rise. [Display omitted] • Current adaptation in Ho Chi Minh City is reactive to flooding and decoupled at different levels. • Despite the high exposure, a large portion of the vulnerable communities are unaware of future flood risk. • Social conflicts happened in the adaptation process suggest a lack of effective communication between stakeholders. [ABSTRACT FROM AUTHOR]

Current climate change discourses have expressed fear that many coastal communities would be forced to relocate in the face of rising water levels. However, despite the frequency and intensity with which such messages are being broadcasted throughout the world's media, there is little actual evidence of any relocation actually taking place, even though there are a number of past examples of relative sea level rise due to earthquake induced subsidence or groundwater extraction. Thus, in order to better understand the consequences of future sea level rise the authors analysed four instances of land subsidence that have taken place in the 20th and early 21st centuries (namely, adaptation strategies around Tokyo and Jakarta, and the experience of islands on the Danajon bank in the Philippines, and Kepulauan Seribu close to Jakarta). In all cases the inhabitants of densely populated coastal areas remain in place, despite the challenge of living with higher water levels. Adaptation was done through a five-phase process, starting with the construction of rather weak seawalls, which is then followed by the placement of pumps to drain water. Eventually, as the economic and technical capacities of coastal settlements improved, better seawalls were built, which then led to the reclamation of new areas, the elevation of entire districts or the construction of super levees. Thus, while it is clear that sea level rise will pose an additional financial strain on urbanised coastal areas, the authors found no evidence that any major coastal settlements will surrender a significant portion of its land area to the sea, given the range of adaptation options available. Rather, the opposite is true, and evidence indicates that new lines of defence will be built further into the water, effectively meaning that humans will encroach on the sea. • Adaptation to coastal land subsidence in highly urbanised cities goes through a five-stage process. • Past land subsidence can be used as a proxy to understand adaptation to future sea level rise. • Evidence for human relocation is lacking. [ABSTRACT FROM AUTHOR]

Located at the apex of the Coral Triangle, the Philippines is acknowledged as the world's center of shore fish biodiversity, and millions of Filipinos depend on these coastal resources for food and livelihood. In order to protect the coral reefs that form the base of many of these coastal ecosystems, Marine Protected Areas (MPAs) have been established throughout the country. However, although there is evidence of the benefits that come from establishing MPAs, there is still a need to improve their effectiveness by addressing the need for integrating environment, socio-economic, and governance pillars. In view of this, the present study used a multidisciplinary method of gathering data to measure the effectiveness of MPAs. The study also highlights the knowledge, attitude, and perception of stakeholders as the overlap between the three pillars of MPA sustainability, which were measured by conducting household surveys within the coastal community in which they are located. Based on the results of the data collection it was found that despite the efforts to inform the public of the existence of a protected area, a gap still remains between the knowledge of stakeholders and the actual coral cover/reef health. The Data Envelopment Analysis (DEA) also served as a useful framework to visualize the results of the newly proposed Sustainability Evaluation of Marine Protected Areas Index (SEMPAI). It is hoped that through future studies this index (though the multiple indicators that it uses) will be able to determine the efficiencies and inefficiencies of Decision-Making Units (DMUs), helping to improve the management and long-term sustainability of coastal settlements. • Developed a new methodology to evaluate Marine Protected Areas (MPAs). • There is a significant gap in the perception of the health of coral reefs and their real state in El Nido MPA. • The use of Data Envelopment Analysis (DEA) can be useful to measure the efficiency of MPAs. [ABSTRACT FROM AUTHOR]