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Sea level rise due to climate change poses a serious threat to human populations in coastal areas. In planning possible countermeasures, it is important to consider the potential economic risks and the cost of any proposed adaptation. This paper examines the cost effectiveness of adaptation measures that combine mangrove afforestation (green infrastructure) and dike construction (gray infrastructure) in areas considered to be at risk of inundation. Based on data for 112 countries and regions where mangrove forests are present along the coastline, the global benefit/cost ratio for the combination of dikes and mangrove is approximately 1.5 times higher than the ratio for dike-only protection. It was found that this type of multiple protection scheme can reduce the number of dikes required and the overall cost of adaptation. [ABSTRACT FROM AUTHOR]

The objective of this study is to assess the global impact of sea level rise and to evaluate the effectiveness of adaptation. Global areas of inundation due to sea level rise are identified. The affected populations and the economic damage caused by inundation due to future climate change are estimated for a number of scenarios involving Representative Concentration Pathways (RCP) and Shared Socioeconomic Pathways (SSP). The effects of adaptation in coastal areas, specifically the effects of elevating dikes, are evaluated. According to study results, dikes 1 m in height may reduce the total inundated area by approximately 40% below the no-adaptation baseline under the same RCP. The cost of adaptation was estimated using an original cost database to establish the cost of protection in future socioeconomic scenarios. It was found that the incremental adaptation cost was less than the economic damage in almost all cases of RCP/SSP, providing an incentive to take action to respond to climate change. [ABSTRACT FROM AUTHOR]

Highlights: [•] Heavy metal contamination occurs in coastal lagoon sediments of the Pacific atoll. [•] Domestic wastewater causes significant contamination with Cr, Zn, Cu, Pb and Cd. [•] Mn and Ni are noteworthy elemental contaminants in open dumping area. [ABSTRACT FROM AUTHOR]

Abstract: The ability of five satellite sensor bands (IKONOS band 4, Terra ASTER bands 3 and 4, and Landsat ETM+ bands 4 and 5) was examined to extract the waterline at coral reef coasts (Majuro Atoll, Marshall Islands) using different wavelength regions (near infrared [NIR] and shortwave infrared [SWIR]) and different spatial resolutions (4, 15, and 30 m). After performing georeferencing and normalization of the images, density slicing was used to extract the waterline. Comparisons of extracted waterline positions with ground-level data for eight transects and global positioning system (GPS) tracks of the island shorelines showed that NIR bands were superior to SWIR bands because of the characteristics of the coral reef coasts, including a lack of foam and suspended sediments (which can affect the NIR wavelength region, if present) and the presence of remnant water on reef flats during low tide (which can affect the SWIR wavelength region). A linear relationship was found between the estimation errors of waterline positions and the spatial resolutions of the NIR sensors. Analysis on estimation errors and image costs showed that Terra ASTER band 3 was the most cost-effective sensor for extracting waterlines with reasonable accuracy. The results serve as general guidelines for using satellite-derived data to estimate intertidal topography and detect and monitor shorelines in coral reef environments. [Copyright &y& Elsevier]