Search Results (9)

Over the past 50 years, coastal erosion has become an increasingly critical issue worldwide, and Colombia’s Caribbean coast is no exception. In urban areas, this challenge is further complicated by hard protection structures, which, while often implemented as immediate solutions, can disrupt sediment transport and trigger unintended long-term consequences. This study examines shoreline changes in Riohacha, the capital of La Guajira Department, over a 35-year period (1987–2022), focusing on the impacts of coastal protection structures—specifically, the construction of seven groins and a seawall between 2006 and 2009—on coastal dynamics. Using twelve images (photographs and satellite) and the Digital Shoreline Analysis System (DSAS), the evolution of both beaches and cliffs has been analyzed. The results reveal a dramatic shift in shoreline behavior: erosion rates of approximately 0.5 m/year prior to the interventions transitioned to accretion rates of up to 11 m/year within the groin field, where rapid infill occurred. However, this sediment retention has exacerbated erosion in downstream cliff areas, with retreat rates reaching 1.8 ± 0.2 m/year. To anticipate future coastal evolution, predictive models were applied through 2045, providing insights into potential risks for infrastructure and urban development. These findings highlight the need for a strategic, long-term approach to coastal management that considers both the benefits and unintended consequences of engineering interventions. Full article

The increasing popularity of e-biking and e-mountain biking offers new opportunities for sustainable tourism and environmental education, particularly in mountain regions. This study focuses on the Italy–Switzerland “E-Bike” project, which integrates e-bike-friendly routes with scientific and cultural education across the Alps. By analyzing key points of interest along the routes, particularly glaciers and earth pyramids in Lombardy, we explore strategies for sustainable management, conservation, and public engagement. Glaciers (Forni and Ventina), facing rapid retreat due to climate change, represent sensitive environments requiring monitoring and visitor regulation. Similarly, earth pyramids in Postalesio exemplify fragile landforms shaped by erosion, requiring visitor management. This study highlights the need for strategic promotion, clear scientific communication, and sustainable tourism practices to balance conservation with accessibility. E-biking facilitates low-impact exploration of geosites, enhancing public awareness of environmental challenges while minimizing ecological footprints. Innovative digital tools (QR-coded virtual guides) enhance visitor education and engagement. By integrating e-bike tourism with geoheritage conservation, this study proposes guidelines for managing soft mobility in mountain areas, combining conservation needs with accessibility, and fostering public engagement. These findings contribute to broader discussions on sustainable tourism development, offering a replicable model for other regions seeking to harmonize recreation with environmental stewardship. Full article

Around the world, human populations and their supporting infrastructures are concentrated in coastal areas. With rising sea levels, these settlements and urban infrastructures are at risk of service interruptions, lasting damage and frequent climate-related hazards. Wastewater systems are especially vulnerable due to their proximity to coastlines. Despite the seriousness of sea-level-rise-induced challenges, a clear understanding of the risks and potential adaptations of coastal wastewater treatment systems and their associated landscapes in Australia has been overlooked. Further, there is a lack of urgency and awareness concerning this issue. In this study, we consider how scenario-based landscape design approaches might enhance current debates and approaches related to coastal change with particular reference to wastewater treatment systems and associated environmental landscapes. Adelaide is used as a case study, and a range of landscape planning exploratory scenarios are developed and evaluated to assess the possible consequences of different courses of action in uncertain contexts. We find that whilst wastewater treatment plants are threatened by climate-related hazards, there is an opportunity for landscape-scale environmental planning to manage risks and opportunities and improve ecological and economic outcomes. We also find that for wicked multidimensional problems, such as sea level rise, landscape scenario design testing can assist in identifying a number of creative adaptation approaches that are not immediately apparent. We find that approaches such as retreat, defense and accommodation are not mutually exclusive but can each share elements and strategies. The strategic potential of a more creative, scenario-based approach can therefore form a productive part of the sea level rise adaptation of coastal infrastructure landscapes in Australia and elsewhere. Full article

Recent observations and publications have presented the possibility of a high and accelerated sea-level rise (SLR) later this century due to ice sheet instability and retreat in Antarctica. Under a high warming scenario, this may result in a sea level in 2100 that is up to 2 m higher than present and 5 m in 2150. The large uncertainties in these projections significantly increase the challenge for investment planning in coastal strategies in densely populated coastal zones such as the Netherlands. In this paper, we present the results of two studies that were carried out within the framework of the Dutch Delta Programme. The first study showed that it is not only the absolute SLR that presents a challenge but also the annual rate of rise. The latter impacts the lifetime of constructions such as barriers and pumping stations. When the rate of sea-level rise increases up to several centimeters per year, the intended lifetime of a flood defense structure may be reduced from a century to several decades. This new challenge requires new technologies, experiments, strategies, and governance. The second study explored different strategies for the long term to adapt to high SLR (>1 m) and assessed the consequences thereof on adaptation and developments in the coming 2–3 decades. We believe that strategic choices have to be made regarding the permanent closure of estuaries, the pumping or periodic storage of high river discharges, agriculture in an increasingly saline coastal area, and the maintenance of the coastline by beach nourishments. These strategic choices have to be complemented by no-regret measures such as spatial reservations for future sand extraction (for beach nourishments) and future expansion of flood defenses, water discharge, and water storage. In addition, it is advised to include flexibility in the design of new infrastructure. Full article

Managed retreat has become a recommended adaptation strategy for hazard-prone coastal cities. The study aimed to improve considerations for the contextual factors that influence the success of managed retreat and resettlement projects in Metro Manila. Data were collected through a mixed-method approach consisting of a screening of relevant literature, a qualitative case analysis of resettlement projects, and a workshop series with Philippine stakeholders. It turned out that the resettlement of informal settlers is a central element of urban development. Though in-city resettlement is preferred, the majority of existing and planned projects are developed in off-city locations. The findings present a nuanced view of different retreat approaches. Not all in-city resettlements are successful, and the unpopular off-city projects have a potentially important role for urban and regional development. A strategic planning thread to develop concepts for qualitative off-city settlements that counteract uncontrolled urban sprawl with monofunctional residential areas for urban poor people was deduced. The other thread asks for pathways for inner-city development with innovative, vertical, in-city projects. A final observation was that climate change and the COVID-19 pandemic are worsening the situation in informal settlements, thus strengthening the argument for the planned decentralization of Metro Manila’s congested urban areas. Full article

The prospect of an ice-free Arctic in our near future due to the rapid and accelerated Arctic sea ice decline has brought about the urgent need for reliable projections of the first ice-free Arctic summer year (FIASY). Together with up-to-date observations and characterizations of Arctic ice state, they are essential to business strategic planning, climate adaptation, and risk mitigation. In this study, the monthly Arctic sea ice extents from 12 global climate models are utilized to obtain projected FIASYs and their dependency on different emission scenarios, as well as to examine the nature of the ice retreat projections. The average value of model-projected FIASYs is 2054/2042, with a spread of 74/42 years for the medium/high emission scenarios, respectively. The earliest FIASY is projected to occur in year 2023, which may not be realistic, for both scenarios. The sensitivity of individual climate models to scenarios in projecting FIASYs is very model-dependent. The nature of model-projected Arctic sea ice coverage changes is shown to be primarily linear. FIASY values predicted by six commonly used statistical models that were curve-fitted with the first 30 years of climate projections (2006–2035), on other hand, show a preferred range of 2030–2040, with a distinct peak at 2034 for both scenarios, which is more comparable with those from previous studies. Full article

Information on the timing of Arctic snow and ice melt onset, sea ice opening, retreat, advance, and closing, can be beneficial to a variety of stakeholders. Sea ice modelers can use information on the evolution of the ice cover through the rest of the summer to improve their seasonal sea ice forecasts. The length of the open water season (as derived from retreat/advance dates) is important for human activities and for wildlife. Long-term averages and variability of these dates as climate indicators are beneficial to business strategic planning and climate monitoring. In this study, basic characteristics of temporal means and variability of Arctic sea ice climate indicators derived from a satellite-based climate data record from March 1979 to February 2017 melt and freeze seasons are described. Our results show that, over the Arctic region, anomalies of snow and ice melt onset, ice opening and retreat dates are getting earlier in the year at a rate of more than 5 days per decade, while that of ice advance and closing dates are getting later at a rate of more than 5 days per decade. These significant trends resulted in significant upward trends for anomalies of inner and outer ice-free periods at a rate of nearly 12 days per decade. Small but significant downward trends of seasonal ice loss and gain period anomalies were also observed at a rate of −1.48 and −0.53 days per decade, respectively. Our analyses also demonstrated that the means of these indicators and their trends are sensitive to valid data masks and regional averaging methods. Full article

Analysis of written documents, projects and historical cartography of the 17th and 18th centuries allows reconstruction of the shore protection works performed at Callao (Peru) to defend the settlements and its boundary wall from storm waves and tsunamis. Groins appeared for the first time in early 18th century maps, together with gently sloping revetments in an unrealized project of the same period. Comparisons between Callao projects and those performed in Europe in the same centuries show a uniformity in design and construction materials that overpasses the environmental differences of the sites. Successes and failures followed each other and, although an understanding of coastal dynamics and the positive and negative effects of the various works were known, it was not possible to guarantee the stability of the walls and consequently the safety of the city from sea attack. A strategic retreat was even considered. Full article

Reservoir construction and land use change are altering sediment transport within river systems at a global scale. Changes in sediment transport can impact river morphology, aquatic ecosystems, and ultimately the growth and retreat of delta environments. The Lower Mekong Basin is crucial to five neighboring countries for transportation, energy production, sustainable water supply, and food production. In response, countries have coordinated to develop programs for regional scale water quality monitoring that including surface sediment concentrations (SSSC); however, these programs are based on a limited number of point measurements and due to resource limitations, cannot provide comprehensive insights into sediment transport across all strategic locations within the Lower Mekong Basin. To augment in situ SSSC data from the current monitoring program, we developed an empirical model to estimate SSSC across the Lower Mekong Basin from Landsat observations. Model validation revealed that remotely sensed SSSC estimates captured the spatial and temporal dynamics in a range of aquatic environments (main stem of Mekong river, tributary systems, Mekong Floodplain, and reservoirs) while, on average, slightly underestimating SSSC by about 2 mg·L${}^{-1}$ across all settings. The operational SSSC model was developed and implemented using Google Earth Engine and Google App Engine was used to host an online application that allows users, without any knowledge of remote sensing, to access SSSC data across the region. Expanded access to SSSC data should be particularly helpful for resource managers and other stakeholders seeking to understand the dynamics between surface sediment concentrations and land use conversions, water policy, and energy production in a globally strategic region. Full article