Search Results (8)

Bangladesh is a global south hotspot due to climate change and sea level rise concerns. It is a highly disaster-prone country in the world with active deltaic shorelines. The shorelines are quickly changing to coastal accretion and erosion. Erosion is one of the water hazards to landmass sinking, and accretion relates to land level rises due to sediment load deposition on the Bay of Bengal continental shelf. Therefore, this study aimed to explore shoreline status with change assessment for the three study years 1991, 2006, and 2021 using satellite remote sensing and geographical information system (GIS) approaches. Landsat 5, 7 ETM+, and 8 OLI satellite imageries were employed for onshore tasseled cap transformation (TCT) and land and sea classification calculations to create shore boundaries, baseline assessment, land accretion, erosion, point distance, and near feature analysis. We converted 16,550 baseline vertices to points as the study ground reference points (GRPs) and validated those points using the country datasheet collected from the Survey of Bangladesh (SoB). We observed that the delta’s shorelines were changed, and the overall lands were accredited for the land-increasing characteristics analysis. The total accredited lands in the coastal areas observed during the time periods from 1991 to 2006 were 825.15 km², from 2006 to 2021 was 756.69 km², and from 1991 to 2021 was 1223.94 km² for the 30-year period. Similarly, coastal erosion assessment analysis indicated that the results gained for the period 1991 to 2006 and 2006 to 2021 were 475.87 km² and 682.75 km², respectively. Therefore, the total coastal erosion was 800.72 km² from 1991 to 2021. Neat accretion was 73.94 km² for the 30-year period from 1991 to 2021. This research indicates the changes in shorelines, referring to the evidence for the delta’s active formation through accretion and erosion processes of ‘climate change’ and ‘sea level rise’. This research projects the erosion process and threatens land use changes toward agriculture and settlements in the coastal regions of Bangladesh. Full article

In the face of unstoppable urbanisation, disaster risks are projected to increase, mainly in unplanned areas that usually lack disaster risk reducing infrastructure. In Africa, including South Africa, limited resources and capacity hinder the provision of such infrastructure. The objective of this study was to determine options for promoting disaster risk reducing infrastructure in informal settlements in Giyani Municipality, Limpopo Province, South Africa, a disaster risk-prone area. A case study was conducted to collect primary data from purposively selected experts and the SWOT factors from the Integrated Development Plan Report of 2019/2020. A TOWS analytical hierarchical process was applied to pairwise comparisons of factors to prioritize them using eigenvalues and generate strategic options for promoting disaster risk reduction infrastructure in the informal settlements of Giyani Local Municipality. In the TOWS results, the experts suggested integrating traditional authorities into the municipal development processes, implementing an environmental framework that includes disaster management policies and an integrated waste management plan, and developing innovative technological projects that provide up-to-date spatial planning data to provide disaster risk reducing infrastructure in informal areas. This study concludes that the provision of affordable housing, clean regular piped water, storm and sewer drainage systems, street lighting, accessible routes, solid waste collection, electricity, and healthcare services would reduce a range of disaster risks. Full article

The Ganga-Brahmaputra basin is highly sensitive to the impacts of climate change and experiences recurrent flooding, which affects large agricultural areas and poses a high risk to the population. The present study is focused on the recent flood disaster in the Ganga-Brahmaputra basin, which mainly affected the regions of Bihar, West Bengal, and Assam in India and neighboring Bangladesh during July, August, and September 2020. Using the Sentinel-1A Synthetic Aperture Radar (SAR) data, the flood extent was derived in the Google Earth Engine (GEE) platform. The composite area under flood inundation for July–September was estimated to be 25,889.1 km² for Bangladesh, followed by Bihar (20,837 km²), West Bengal (17,307.1 km²), and Assam (13,460.1 km²). The Copernicus Global Land Cover dataset was used to extract the affected agricultural area and flood-affected settlement. Floods have caused adverse impacts on agricultural lands and settlements, affecting 23.68–28.47% and 5.66–9.15% of these areas, respectively. The Gridded Population of the World (GPW) population density and Global Human Settlement Layer (GHSL) population dataset were also employed to evaluate flood impacts, which revealed that 23.29 million of the population was affected by floods in the Ganga-Brahmaputra basin. The highest impacts of floods can be seen from the Bihar state, as people reside in the lower valley and near to the riverbank due to their dependency on river water. Similarly, the highest impact was from Bangladesh because of the high population density as well as the settlement density. The study provided a holistic spatial assessment of flood inundation in the region due to the combined impact of the Ganga-Brahmaputra River basin. The identification of highly flood-prone areas with an estimated impact on cropland and build-up will provide necessary information to decision-makers for flood risk reduction, mitigation activities, and management. Full article

An extreme landscape is a spatially heterogeneous area with unusual topography that is prone to natural disasters but still exhibits interrelated structures and functions. One of the important functions of an extreme landscape is its ecological function. This study aimed to determine the structure and reveal the ecological functions of an extreme landscape in a tropical region of West Java, with special reference to Rongga Sub-district. The method used was a combination of remote sensing techniques and geographic information systems, which were required to process, analyze, and interpret Landsat 8 OLI/TIRS data. The landscape structure was quantified by landscape metrics, after which an analysis of ecological functions was carried out based on the constituent elements of the landscape. The results showed that the landscape structure of Rongga Sub-district consists of various elements of agroforestry land, open fields, settlements, shrubs, plantations, and rainfed and irrigated rice fields. Additionally, secondary forest land acted as a landscape matrix where rivers crossed as natural corridors. The amount of each element varied; agroforestry land had the highest value, indicating that this element showed a high degree of human intervention. Each patch was adjacent to other patch types, and the landscape diversity was quite high. The extreme topography of Rongga Sub-district supports the landscape connectivity and consequently the presence of wild animals in this area. Therefore, Rongga Sub-district has an essential ecological function as a refuge for protected animals living in non-conservation areas. Full article

The major global pressures of rapid urbanization and urban growth are being compounded by climate impacts, resulting in increased vulnerability for urban dwellers, with these vulnerabilities exacerbated during the COVID-19 pandemic. Much of this is concentrated in urban and peri-urban areas where urban development spreads into hazard-prone areas. Often, this development is dominated by poor-quality homes in informal settlements or slums with poor tenure security. Lessons from a resilience-building project in the Pacific shows that a fit-for-purpose (FFP) approach to land administration can provide solutions by increasing the number of households with security of tenure, and consequently, improving resilience outcomes as informal settlements grow. This paper specifically discusses the influence of FFP land administration on reducing vulnerabilities to external shocks, such as climate change and COVID-19. It proposes ways to be better manage urban growth through the responsible governance of land tenure rights and more effective land-use planning to improve resilience to multiple shocks and stresses, hence, delivering improved access to safe land and shelter. Land administration systems can contribute to enhanced resilience to the shocks of climate extremes and pandemics by improving tenure security and enhancing land-use planning controls. It is argued that climate change adaptation and disaster risk reduction need to be better mainstreamed into two major elements of land governance: (i) securing and safeguarding of land rights, and (ii) planning and control of land use. Full article

The Philippines is argued as the only Southeast Asian country where informal settlers’ communities have been self-organized and produced discernible impacts on the country’s urban policies. As one of the high risk countries, fifty percent of the country’s informal settlements are located in danger and disaster-prone areas. However, informal settlement upgrading has not reached its significance in disaster mitigation and community resilience building. At the national level, on-site upgrading is not established in disaster risk management or climate change adaptation strategies, which explains the lack of strategic approaches for local implementation. Metro Manila serves as a suitable backdrop in this sense to study informal settlement upgrading under the condition of high risk and rapid urbanization with a high civil society engagement. This study investigates the underlined reasons why upgrading strategically falls short in addressing disaster mitigation and community resilience building. Theoretically, it questions what on-site upgrading is about. Empirically, two hazard-prone informal settlement communities within Metro Manila are examined with their different risk profiles, community development needs and resilience priorities. The core issues of upgrading are, therefore, differentiated at the settlement level with communities’ innate socio-economic and eco-spatial features over time. Meanwhile, the paper heightens the necessity of tackling on-site upgrading at the settlement level and articulating settlements’ spatial correlations with the city development, so as to sustain upgrading outcomes. In addition, this study attempts at setting up a range of scenarios conditioned with COVID pandemic fallout. It endeavors to provide another facet of how to deal with adaptation and resilience. This includes the urgent strategy shift in the housing sector and its financial sustainability, innovative mechanisms to manage uncertainty and risks, lessons for post-COVID planning, etc. Full article

Santorini Island, located in the Southern Aegean Sea, is prone to tsunamis due to its proximity to the Hellenic subduction zone, which is one of the major tsunamigenic areas. Characteristic events, such as those of 365 A.D. and 1303 A.D. greatly affected the coasts of the Eastern Mediterranean Sea, causing significant loss of life and construction damage. Tsunami disaster risk is nowadays significantly higher due to the increased exposure of the buildings as a result of the economic and touristic growth of the Aegean Islands. This study focuses on the eastern coast of Santorini, since its morphology and human presence amplify the necessity to assess its building vulnerability. After conducting an exposure analysis at the settlements of the eastern coast, Kamari poses the highest physical, social and economic relative exposure to any potential natural hazard. The main objective of this research is to quantify the building stock’s vulnerability to tsunami hazard. For this purpose, a “worst-case run-up scenario” was developed. Considering the history of tsunamis in the Aegean Sea, an extreme sea-level rise after a 10 m a.s.l. tsunami run-up, caused by an earthquake with M_w~8.5, was assumed. The relative vulnerability of the buildings in Kamari was calculated via the application of the Papathoma Tsunami Vulnerability Assessment (PTVA-4) analytic model. The results indicate that 423 buildings are within the inundation zone, 58% of which are characterized as highly and very highly vulnerable to tsunamis, revealing the problematic characteristics of the building stock, offering important information to the decision-makers to mitigate a possible future tsunami impact. Full article

The most frequent disasters in Western Saudi Arabia are flash floods, earthquakes and volcanism, especially submarine volcanism potentially causing tsunamis in the Red Sea and submarine mass movements, dust storms and droughts. As the consequences and effects of the climate change are expected to have an increasing impact on the intensity and occurrence of geohazards as flash floods, length of drought periods, or dust storms, the systematic, continuous monitoring of these hazards and affected areas using satellite data and integration of the results into a geographic information systems (GIS) database is an important issue for hazard preparedness and risk assessment. Visual interpretation and digital image processing of optical aerial and satellite images, as well as of radar images, combined with Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), Shuttle Radar Topographic Mission (SRTM) and Advanced Land Observing Satellite (ALOS) PALSAR DEM data are used in this study for the mapping and inventory of areas prone to geohazards, such as flash floods or tsunami flooding. Causal or critical environmental factors influencing the disposition to be affected by hazards can be analyzed interactively in a GIS database. How remote sensing and GIS methods can contribute to the detection and continuously, standardized monitoring of geohazards in Western Saudi Arabia as part of a natural hazard geodatabase is demonstrated by several examples, such as the detection of areas prone to hydrological hazards, such as flash floods causing flooding of roads and settlements, the outlining of coastal areas of the Red Sea prone to tsunami flooding and storm surge, the mapping of traces of recent volcanic activity, and of fault/fracture zones and structural features, especially of ring structures. Full article