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This document is a discussion of the original paper titled "Coastal Defense Megaprojects in an Era of Sea-Level Rise: Politically Feasible Strategies or Army Corps Fantasies?" by D. J. Rasmussen, Robert E. Kopp, and Michael Oppenheimer. The authors review coastal defense megaprojects with storm surge barriers in the United States and discuss their feasibility. They compare the findings of the original paper with experiences from the implementation of coastal megaprojects in the Netherlands and identify key factors crucial for their feasibility and realization. The document concludes that coastal megaprojects with barriers are feasible and will be needed for future coastal protection and adaptation. [Extracted from the article]

Storm surge is the most serious marine disaster in China, and the inundation characteristics of storm surge are the key indicators of disaster severity. Especially in the context of relative sea level rise (RSLR), it is very important to rapidly and accurately estimate the inundation characteristics of storm surge for the risk assessment and emergency management of storm surge disasters. Taking Taizhou city, Zhejiang Province, as the study area, this paper constructed an RSLR scenario library considering absolute sea level rise, land subsidence and storm surge water increase. The scenario library includes 72 scenarios, consisting of a combination of four absolute sea level rise scenarios, three land subsidence scenarios, three timescales (2030, 2050 and 2100) and two storm surge water increase scenarios. Then, an improved passive inundation method was used to predict and analyze the inundation characteristics of storm surge under each scenario. This improved method combines the advantages of the accurate active inundation method and the rapid passive inundation method, and is suitable for rapid and accurate estimation of the storm surge inundation characteristics, which can meet the needs of a storm surge disaster risk assessment and emergency response. The prediction and analysis results show that a minor RSLR can also cause a large-scale inundation in coastal areas of Taizhou. When the value of RSLR exceeds the critical value (0.6 m), it may significantly increase the expansion of the inundation area of storm surge. At a relative sea level rise of 1.57 m (extreme scenario in 2100), the inland storm surge inundation of low-risk areas may become high-risk areas. Finally, the quantitative measures for preventing storm surge disasters were put forward according to the current situation of the coast in Taizhou. Without considering storm surge and superimposed general surge, the existing 20-year return period standard seawall can effectively protect against storm surge under various scenarios. In the case of maximum water increase, it is expected that effective protection will remain until 2030, but the standard of the seawall defense will need to be improved in 2050 and 2100. [ABSTRACT FROM AUTHOR]

The current scenario of understanding spatial objects with regards to land and marine environment seems lacking. Inevitably, the scenario in line with the global warming issues as being highly mentioned by world-bodies such as the United Nations (UN) on climate change, etc. Recently the statistics on earth surface temperature point towards high record temperatures that lead to sea-level rise and degradation of land surface area, in general. These situations caused other spatial objects (land and marine properties) to be affected by their physical properties' changes (including geometries and locations). Thus, this paper attempts to review various aspects related to digital twins of land and marine spatial objects with respect to issues and challenges of multiple data acquisition techniques considering accuracy, data standard, seamless and integrated georeferenced data within the scenario as being reported in the 6th IPCC document. The situation warrants us to explore different types of land and marine properties (static and dynamic) where static properties are defined as immovable objects and vice versa for the dynamic environment. This paper also discusses on a brief experiment utilizing MERIT DEM (Multi-Error-Removed Improved-Terrain Digital Elevation Model), existing building footprints, simulated bathymetry, and land use datasets. The experiment reveals the prediction of the sea level rise according to the IPCC report. The gist of this paper to serve a motivation for our near-future research in the context of geospatial components and sea level rise (SLR). [ABSTRACT FROM AUTHOR]

Coral reef islands are amongst the most vulnerable environments to sea‐level rise (SLR). Recent physical and numerical modeling studies have demonstrated that overwash processes may enable reef islands to keep up with SLR through island accretion. Sediment supply to these islands from the surrounding reef system is critical in understanding their morphodynamic adjustments, but is poorly constrained due to insufficient knowledge about sediment delivery rates. This paper provides the first estimation of sediment delivery rates to coral reef islands. Analysis of topographic and geochronological data from 28 coral reef islands indicates an average rate of sediment delivery of c. 0.1 m3 m−1 yr−1, but with substantial inter‐island variability. Comparison with carbonate sediment production rates from census‐based studies suggests that this represents one quarter of the amount of sediment produced on the reef platform. Results of this study are useful in future modeling studies for predicting morphodynamic adjustments of coral reef islands to SLR. Plain Language Summary: Low‐lying coral reef islands are under threat of sea‐level rise (SLR). However, when these islands are flooded, ocean waves can bring in sediment that can increase the island elevation. This would enable coral reef islands to better withstand flooding in the future. Knowing how much sediment is brought in will help in our understanding of future changes to these islands due to SLR. In this paper, we use data from 28 Indo‐Pacific coral reef islands to compute sediment supply to the islands. We find that on average 0.1 m3 of sediment (roughly 100 kg) is delivered each year for every meter of island shoreline. We further suggest that this implies that only one quarter of the sediments produced by the coral reef system is delivered to the island shoreline. Most of the sediment produced remains on the reef flat or is exported to the ocean or the lagoon. Our results will help future studies to predict more accurately how coral reef islands will adjust to SLR. Key Points: We provide the first estimates of carbonate sediment delivery rates to 28 coral reef islands using all data available from the literatureSediment delivery to the reef islands occurs at a rate of c. 0.1 m3 m−1 yr−1, but with substantial inter‐island variabilityWhere island building has been continuous through island history, long‐term delivery rates provide valuable estimates for contemporary rates [ABSTRACT FROM AUTHOR]

Coastal water supply infrastructure systems (CWSISs) are exposed to saltwater intrusion (SWI) exacerbated by sea level rise (SLR) stressors. However, most existing definitions of CWSIS resilience are confined to the system's global severity, while uncertainties from SLR are not considered. In this paper, we develop a CWSIS model considering uncertainties from SLR and define a new formula for resilience based on three components of system severity, i.e., social severity (SevS) affected by water shortages to end users, regional severity (SevR) caused by water shortages in water treatment plants (WTPs), and technological severity (SevT) considering water shortages in wells. A case study in Xingcheng is designed to (1) examine the resilience response of CWSISs to future SLR, (2) identify vulnerable components, and (3) compare the cost-effectiveness of different measures for enhancing resilience using scenario analysis with full consideration of future uncertainties from SLR. This paper contributes to the development of sustainability assessments for urban water systems subject to future sea level change. Finding response measures with high adaptiveness across a variety of future scenarios is crucial for establishing a sustainable urban water system in the long term. [ABSTRACT FROM AUTHOR]

Climate change and the associated sea level rise (SLR) are presenting newfound challenges to the port systems and coastal transportation infrastructure of southeast Texas. This paper introduces a Geographic Information Systems (GIS) based model designed to simulate inundation scenarios under various sea-level projections, aiming to assess the vulnerabilities of both port facilities and road networks. The study area encompasses a specific region within Jefferson County, southeast Texas, encompassing three major ports: Port Arthur, Beaumont, and Orange. Utilizing a high-resolution (1-m) Digital Elevation Model (DEM) derived from the 2017 LiDAR dataset, this model is integrated with NASA's sea-level rise projections to compute the extent and volume of inundation across low, medium, and high SLR scenarios. Drawing from monthly mean sea level data spanning from 1958 to 2020, the lowest SLR projections, derived from the relative sea-level trend measured at the Sabine Pass, TX gauge station, indicate a yearly increase of 6.16 mm, with a 95% confidence interval of +/- 0.74 mm. Projections for 2050 and 2,100 show the lowest SLR at 0.17 m and 0.48 m, respectively. In contrast, the medium to high RSLR projections under the IPCC SSP3-7.0 scenario for 2050 and 2,100 stand at 0.54 m and 1.34 m, respectively. The findings reveal that, under medium to high SLR scenarios, the extent of inundated areas in the study region is expected to expand by 12.4% in 2050 and 19.9% in 2,100, compared to the lowest SLR projection. Additionally, the length of submerged roadways is predicted to increase by 6.9% in 2050 and 13.3% in 2,100, in comparison to the lowest SLR projection. It is worth noting that some margin of error may be introduced due to factors such as the width of the port area and access roads, the high-resolution DEM, and the alignment of computed inundated areas with the existing topography. Overall, the manuscript highlights the urgency of proactive planning and underscores the importance of safeguarding critical infrastructure in the context of climate change and SLR. [ABSTRACT FROM AUTHOR]

The maritime outer limits of a coastal State depend profoundly on the structure of its coastline, which is likely affected by rising sea levels. This paper clarifies the legal effect of unilateral declarations by States in general and when establishing maritime outer limits in particular, and the impact of fundamental changes in circumstances on the validity of such declarations in order to offer recommendations for Vietnam. [ABSTRACT FROM AUTHOR]

Developed barrier systems (barrier islands and spits) are lowering and narrowing with sea‐level rise (SLR) such that habitation will eventually become infeasible or prohibitively expensive for most communities in its current form. Before reaching this state, choices will be made to modify the natural and built environment to reduce relatively short‐term risk. These choices will likely vary substantially even along the same developed barrier system as these landscapes are rarely uniformly managed alongshore. Building on the results from a companion paper, here we use a new modeling framework to investigate the complexities in barrier system dynamics that emerge as a function of alongshore variability in management strategies, accelerations in SLR, and changes in storm intensity and frequency. Model results suggest that when connected through alongshore sediment transport, barriers with alongshore variable management strategies—here, the construction of dunes and wide beaches to protect either roadways or communities—evolve differently than they would in the absence of alongshore connections. Shoreline stabilization by communities in one location influences neighboring areas managed solely for roadways, inducing long‐term system‐wide lags in shoreline retreat. Conversely, when barrier segments managed for roadways are allowed to overwash, this induces shoreline curvature system‐wide, thus enhancing erosion on nearby stabilized segments. Feedbacks between dunes, storms, overwash flux, and alongshore sediment transport also affect outcomes of climate adaptation measures. In the case of partial, early abandonment of roadway management, we find that system‐wide transitions to less vulnerable landscape states are possible, even under accelerated SLR and increased storminess. Plain Language Summary: Because humans inhabit barrier islands and spits (collectively referred to as "barriers") these landscapes, that would otherwise naturally change shape in response to storms and sea‐level rise (SLR), are influenced by efforts to protect development with wide beaches and tall dunes. These features interfere with a process called overwash, which transports sand landward during storms, building barrier elevation relative to sea level. Here, we use a new model to better understand how these interactions influence the habitability of barriers over time. Our simulations show that different management decisions made for adjacent coastal segments affect each other in positive and negative ways. When communities nourish beaches, adjacent to segments managed for roadways, some nourished sand reaches the adjacent segments, reducing shoreline erosion there. Conversely, portions of barriers that are managed only for roadways allow some overwash to reach the barrier interior; this negatively affects neighboring communities by enhancing their shoreline erosion rates. We find that early abandonment of dune management along portions of barriers may prevent highly vulnerable future states, such as barrier drowning. As communities explore choices for climate adaptation, our findings reveal the importance of coordination among decision makers in adjacent communities to avoid undesirable outcomes. Key Points: When management strategies vary alongshore, their effects are coupled via alongshore sediment redistribution, influencing barrier evolutionBeach nourishment (along portions of barriers) induces system‐wide lags in shoreline retreat, even decades after nourishment practices ceaseMore overwash (due to lower dunes or increased storminess) can prolong habitability, but drives increased nourishment frequency elsewhere [ABSTRACT FROM AUTHOR]

This editorial published in the journal Frontiers in Earth Science discusses the impacts, dynamics, and system responses of highly intervened estuaries. Estuaries are globally degraded and threatened environments due to human-engineered interventions, land use changes, and pollution. The article emphasizes the need to understand the interactions between different impacts and their effects in order to manage and restore highly intervened estuaries. It also presents original research papers on various aspects of estuarine systems, including morphological and hydrodynamic responses, changes in natural functions, physicochemical degradation, and strategies for restoration and recovery. Additionally, the article titled "Anthropocene" explores the concept of the Anthropocene epoch, which refers to the current geological era characterized by significant human impact on the Earth's ecosystems. The authors discuss the origins and implications of the term, as well as the controversies surrounding its definition and recognition within the scientific community. They also examine the various ways in which human activities have shaped the planet, including climate change, biodiversity loss, and pollution. The article provides a comprehensive overview of the Anthropocene concept and its relevance to understanding the relationship between humans and the environment. [Extracted from the article]

Deltas and coastal plains worldwide developed under the influence of relative sea level rise (RSLR) during the Holocene. In the Netherlands, Holocene RSLR results from both regional sea-level rise and regional subsidence patterns, mainly caused by glacial isostatic adjustment (GIA: Scandinavian forebulge collapse) and longer-term North Sea Basin tectono-sedimentary subsidence. Past coastal and inland water levels are preserved in geological indicators marking the gradual drowning of an area, for example basal peats. Such geological water-level indicators have been used in the Netherlands for varying types of research. However, uniform overviews of these data exist only for smaller local subsets and not for the entire Netherlands. In this paper we present a data set of 712 Holocene water-level indicators from the Dutch coastal plain that are relevant for studying RSLR and regional subsidence, compiled in HOLSEA workbook format. This format was expanded to allow for registering basal-peat type geological indicators, documenting Dutch-setting specific parameters and accompanying uncertainties, to assess indicative meaning, and to appropriately correct the raw vertical positions of the indicators. Overall, our new, internally consistent, expanded documentation provided for the water-level indicators encourages users to choose the information relevant for their research and report RSLR uncertainties transparently. From the indicators, 59 % was collected in 1950–2000, mainly in academic studies and survey mapping campaigns; 37 % was collected in 2000–2020 in academic studies and archaeological surveying projects, 4 % was newly collected (this study), the latter mainly in previously under sampled central and northern Netherlands regions. Prominent regional differences exist in the vertical position and abundance of the indicators. Older indicators in our data set are mostly located in the deeper seaward area of the Netherlands. These indicators correspond well with previous transgression reconstructions, that are partly based on the same data. The younger, landwards set of indicators in the Rhine-Meuse central and Flevoland regions corresponds with the transgression phase reaching further inland, from 8000 cal. BP onwards. Northern indicators of Middle Holocene age (8–5 ka cal. BP), in general lie 2–3 meters lower compared to those in the south. For younger data this difference is less, showing spatial and temporal variation in RSLR throughout the Netherlands. [ABSTRACT FROM AUTHOR]

Sea-level rise was a key factor changing environments during the Early Holocene in Northwest Europe. It affected Mesolithic hunter-gatherer communities by inundating large areas in the current North Sea, commonly referred to as Doggerland. In this paper we present novel inundation models for the southern North Sea providing visualisations of lateral inundation driven by sea-level rise and relate it to frequency analysis of radiocarbon dates from archaeological sites. These improve on previous studies that relied on bathymetric data, which includes post-inundation overprints of Holocene sedimentation and erosion, and thus significantly underestimates the timing of inundation in some areas. We constructed a paleoDEM (a composite elevation grid of the top of the Pleistocene) for the eastern part of the southern North Sea; and sea level surfaces that combine relative sea-level curves from glacio-isostatic adjustment models optimised for Britain and southern Scandinavia respectively. We corrected our paleoDEMs for tectonic background basin subsidence, and in the inundation modelling account for pre-compaction elevation of peat in coastal areas. We evaluated the impact of these model components on our results and describe the possible inundation history of Doggerland. We suggest earlier inundation than predicted by previous models, showing significant area loss around 10.5–10 ka cal BP. Palaeogeographic changes are compared with archaeological radiocarbon data using a dates-as-data approach. Composite Kernel Density Estimate and permutation tested Summed Probability Distributions are used as a proxy for the visibility, nature and intensity of human activity. Results indicate key periods of growth and decline recorded in the dataset, as well as regional differences in growth rate, some correlating with inundation phases. Chiefly, we find elevated growth rates around 10.5–10 ka in northwest Germany and the Netherlands, contemporaneous with the abovementioned phase of extensive area loss, and moreover, with changes in culture and practices on Early Mesolithic sites. However, the spatiotemporal distribution of archaeological data is significantly influenced by accessibility and preservation of sediments of a certain age. We discuss the importance of inundation modelling and sediment data in understanding how landscape taphonomy affects archaeological patterning, especially in dates-as-data approaches. [ABSTRACT FROM AUTHOR]

• Hazard zone methodology: The paper employs a hazard zone methodology, typically used for managing erosion risk to modern infrastructure, to assess and manage the risk to coastal archaeological heritage. • Coastal archaeological heritage at risk: Coastal archaeological heritage in Aotearoa/New Zealand is under threat from coastal erosion, with accelerated risk due to rising sea levels. • Projected sea-level rise impact: The study predicts that a relatively modest 20 cm of sea-level rise, expected by 2040, may put around 8 % (155) of coastal archaeological sites at risk, and a more significant 1 m of sea-level rise could threaten approximately 19 % (356) of sites. • Connection to indigenous communities: The coastal archaeological heritage is closely tied to Māori, the indigenous ancestral communities of Aotearoa/New Zealand. • Adaptive planning pathways: Scenarios are presented to assist stakeholders in assessing heritage risk, providing an opportunity for coastal managers to incorporate heritage considerations into adaptive planning pathways. Coastal archaeological heritage is in danger of being lost to coastal erosion, the risk of which is amplified by accelerating sea-level rise (SLR). In Aotearoa/New Zealand, coastal archaeological heritage is closely associated with indigenous ancestral communities, but our understanding of the spatiotemporal variability in coastal erosion risk for cultural heritage is limited. Coastal erosion hazard zones have typically been implemented to manage erosion risk to modern infrastructure at regional scales. In this study, we applied a hazard zone methodology in the context of coastal archaeological heritage for a selected region of Aotearoa (Te Tai Tokerau/Northland). Historical coastal change analyses reveal that most beaches in the region have been stable or slightly accretionary over the past ∼80 years, but a reversal of this trend is likely under the projected SLR, which is expressed in the coastal erosion hazard zones. Our analyses indicate that ∼8 % (155) of coastal archaeological sites in Te Tai Tokerau/Northland may be at risk of erosion with a relatively modest 20 cm of SLR, which is expected for the region by 2040, and ∼19 % (356) of sites are threatened by 1 m of SLR. Scenarios are presented that should assist a broad range of stakeholders to assess heritage risk and provide an opportunity for coastal managers to include heritage within adaptive planning pathways. [ABSTRACT FROM AUTHOR]

Skinner, W.K., 2024. Coastal hazard assessment from multidecadal profile response incorporating climate patterns and sea-level rise. Journal of Coastal Research, 40(3), 511–526. Charlotte (North Carolina), ISSN 0749-0208. A new method for coastal hazard assessment is described and demonstrated by reference to a 40-year cross-shore profile record in Papamoa, New Zealand. It is based on a mathematical interpretation of the envelope within which long-term historic cross-shore profiles vary and from which, for the required assessment period, the statistically significant fully accreted-state and fully eroded-state profiles can be determined. The Monte Carlo method is used to derive stochastic outcomes for long-term trend (LTT) and sea-level rise (SLR) on the basis of correlations with, and a long term proxy for, a decadal-scale climate pattern, which in the example case is the Interdecadal Pacific Oscillation. Sediment volumes for short-term fluctuation and the LTT are determined and conserved to reflect a consistent wave climate over the assessment period when appraising the effect of SLR. Dune biomass is accounted for when determining erosion scarp stability and hence the final extent of the current and future hazard zones. Results are presented in schematic form as excursions relative to a land benchmark and also as full end-state profiles extending from the dune backshore to the closure depth, with the latter determined by bar volume and profile. Various scenarios are appraised, including those that incorporate SLR predictions of the climate models of the Intergovernmental Panel on Climate Change. The relative risk of various scenarios is benchmarked to the probalistic expected outcome to produce a risk-based, site-specific assessment of coastal hazards. [ABSTRACT FROM AUTHOR]

The Devonian System in the Qinghai-Tibetan Plateau and its surrounding areas is widely distributed, diverse in lithotypes and rich in fossils. It records the crucial processes of continuous subduction and reduction of the Paleo-Asian Ocean in the northern hemisphere and the transformation of the Proto-Tethys Ocean into the Paleo-Tethys Ocean in the southern hemisphere. Thus, it is of great significance for explaining the global paleogeographic evolution, tectonic activities and biodiversity changes during this critical period. The blocks on both sides of the southern Tienshan suture zone and the Longmu Co-Shuanghu-Changning-Menglian suture zone belong to different sedimentary systems and paleobiogeographic realms and regions, showing important tectonic paleogeographic partitioning significance. The two suture zones represent the main branches of the Paleo-Asian Ocean and the Paleo-Tethys Ocean, respectively, and on this basis the Devonian System can be subdivided into three types: the Tienshan type, the Tethys type and the Gondwana type. Based on recent research progress on the Devonian stratigraphy and paleontology in combining provenance analysis and biotic characteristics in the Qinghai-Tibetan Plateau and surrounding areas, this paper aims to establish the latest integrative stratigraphic framework and conduct paleogeographic reconstruction, providing foundation for exploring the geological evolution and dynamic mechanisms of various terranes and blocks in the northern margin of Gondwana. The results indicate that the North Qiangtang, South Qiangtang, Simao, Baoshan and Tengchong terranes, as well as the Himalaya Tethys Zone and the South China Block have affinities with the Indian Block, while the Lhasa Terrane has affinities with the Australian Block, and may be located between the South China and Australian blocks. In the Emsian (Early Devonian), the South China Block separated from the northern margin of Gondwana, a process that was accompanied by the opening of the Jinshajiang-Ailaoshan Ocean. In the Middle Devonian, the mid-oceanic ridge of the Paleo-Tethys Ocean expanded rapidly, corresponding with a global sea-level rise, the widespread development of carbonate platforms and nadir values of Devonian seawater strontium isotopes. By the Late Devonian, the Paleo-Tethys Ocean had reached a considerable size, leading to abundant occurrences of Upper Devonian radiolarian cherts in the Paleo-Tethys suture zones. [ABSTRACT FROM AUTHOR]

The devastating consequences of tsunamis on coastal infrastructure have highlighted the urgent need for effective disaster risk reduction strategies. To mitigate tsunami disasters, the insurance industry plays a vital role in implementing risk transfer measures by providing financial protection against asset damage. However, the current research on catastrophe insurance policies for coastal infrastructure lacks consideration of climate change effects. It is essential to take into account the non-stationary effects of sea-level rise to develop long-term tsunami disaster mitigation measures and promote socioeconomic resilience in coastal communities. This paper aims to provide an insurance portfolio optimization framework for coastal residential buildings subjected to tsunamis considering non-stationary sea-level rise effects based on a stochastic simulation approach. A spatiotemporal probabilistic sea-level rise hazard assessment is carried out by utilizing available climate models and considering several emission scenarios. Tsunami propagation analyses under various sea-level rise cases are performed to evaluate the time-variant tsunami hazard curves based on Monte Carlo simulation. A life cycle-based stochastic insurance claim model associated with the cumulative loss of building assets is developed based on a non-stationary compound renewal process. Finally, a sample average approximation method is leveraged to estimate the optimum basic insurance premium rate by maximizing the insurer's profit under a cost-constrained insurance purchase decision of homeowners. As a case study, the proposed framework is applied to multiple municipalities situated in the tsunami-prone region of Kochi Prefecture, Japan. Sea-level rise substantially decreases the maximum profits of tsunami insurers and increases the premium rate and ruin probability. [ABSTRACT FROM AUTHOR]

In the face of current uncertainties about the processes of climate change and its consequences, the search for possible response strategies is urgently needed. One of the most serious repercussions of climate change, which threatens many coastal areas globally, is the sea-level rise. To deepen understanding of this phenomenon and its related impacts, several models have recently been developed to satisfy the unique needs of coastal zone management. These models are very useful because of their visualization and prediction capabilities as they aid in decision-making regarding the adaptation of current protected area investments. This review, therefore, provides evidence of the potential and effectiveness of recent mapping models for managing the effects of sea-level rise. This study examined current models for mapping flood risk areas as a result of sea-level rise. It also provides guidelines to help coastal zone managers and policymakers decide the applicability of various models at local, regional, and global scales. There is no universally accepted model, and each of the models reviewed in this paper has its strengths and weaknesses. However, the models provided by the National Oceanic and Atmospheric Administration are commonly used by organizations and others. These models are more accessible and comprehensible for scientists and individuals with limited scientific background knowledge on sea-level rise. [ABSTRACT FROM AUTHOR]

Satellite imagery is widely used to study beach changes. Studies based on satellite‐derived results predict that by 2100, half of the world's beaches will disappear. Although previous studies have been productive and alarming, the reliability of these findings has not been validated. This study presents an initial comprehensive assessment of the reliability of satellite‐derived beach shoreline changes and concludes that despite the use of state‐of‐the‐art subpixel shoreline identification technologies and water‐level correction methods based on beach profile shapes, the errors in satellite‐derived shoreline positions remain significant. Thus, adequate satellite imagery is crucial for enhancing the reliability of satellite‐derived beach changes. Furthermore, the historical water levels when the Landsat and Sentinel‐2 images were taken exhibited significant systematic deviations and both long‐term and short‐term changes. Consequently, the beach changes obtained through the direct statistics obtained from satellite imagery based on big‐data platforms such as the Google Earth Engine (GEE) are susceptible to systematic biases. The study also concluded that satellite‐derived beach changes based on adequate satellite imagery have distinct, significant, and diverse responses to human activities. Given the current context of intensified human activities and notable inaccuracies in satellite‐derived shoreline positions, fully utilizing satellite imagery to study beach changes can help establish stronger connections between beach changes and human activities. This contributes to a better understanding of beach evolution mechanisms and the need for beach restoration and protection, with multiple scientific, engineering, and social implications. Plain Language Summary: Beaches around the globe are currently facing significant threats due to the combined influence of rapid sea‐level rise and intensified human activities. Researchers have used satellite images to study beach changes, and the results are alarming. Some researchers even predict that by 2100, half of the world's beaches will have disappeared. However, the existing research has mainly evaluated the precision of satellite‐derived shoreline position data rather than satellite‐derived beach changes. Moreover, the identified beach changes are not clear enough to determine the links between beach changes and human activities. Based on all available Landsat and Sentinel‐2 images, this study presents the first comprehensive assessment of the reliability of satellite‐derived beach shoreline changes and demonstrates the distinct, remarkable, and diverse responses of a typical beach to human activities. The study revealed that the water levels when the satellite images were taken exhibited systematic deviations and both long‐term and short‐term changes. Consequently, water‐level corrections to the shoreline positions that were obtained through direct statistical analyses of satellite imagery are essential for reliably studying both global and local beach changes. Finally, adequate satellite imagery is recommended for identifying high‐precision beach changes. Key Points: This paper presents an initial comprehensive assessment of the reliability of satellite‐derived beach shoreline changesBeach changes obtained through the direct statistics obtained from satellite imagery on big‐data platforms are prone to systematic biasesAdequate satellite imagery is crucial for enhancing the reliability and revealing the impact of human activities [ABSTRACT FROM AUTHOR]

The Indus Delta plays an important role in the archaeology of the northern coast of the Arabian Sea. Little was known of this region until a few decades ago. The first surveys were carried out in the 1970s and were resumed by the present author in the 2010s. They have shown the great potential of the area for the interpretation of sea-level rise and its related human settlement between the beginning of the Holocene and the Hellenistic period. In this territory, several limestone terraces rise from the alluvial plain of the River Indus, which were islands in prehistoric and early historic times. Many archaeological artefacts, along with marine and mangrove shells, have been recovered from their surface and radiocarbon dated. These discoveries help us to follow the events that took place in the region in well-defined periods and interpret some aspects of the prehistoric coastal settlement in relation to the advance of the Indus Fan and the retreat of the Arabian Sea. The following questions are addressed in this paper: who settled these islands, when and why? During which prehistoric periods were mangrove and marine environments exploited? And what were the cultural characteristics of the communities that seasonally or permanently settled some of the present 'rocky outcrops'? [ABSTRACT FROM AUTHOR]

The recent, very active hurricane seasons, as well as emerging concerns related to the future effects of sea-level rise, hurricane intensification, and increased storm recurrence rates on coastal areas, make the prediction of storm-induced flood hazard a key priority when discussing coastal community resilience. To address this priority, researchers have placed substantial efforts in developing improved high-fidelity, numerical models to predict the storm surge for a given storm event. For promoting computational efficiency when utilizing these models within hazard estimation applications, metamodeling (also referred to as surrogate modeling) techniques have emerged as a popular strategy. The accuracy of such techniques in this context has been examined so far using cross-validation (CV) techniques or by testing their performance for a (very) small number of historical storms. This paper investigates this topic within a different setting, examining the resultant regional storm surge hazard maps, specifically using Gaussian process (GP) as the metamodel of choice. This is accomplished by examining the hazard products (hazard maps or curves) obtained by GP implementations, as well as the hazard products established through alternative, simplified Monte Carlo approaches. Examining this accuracy fills in an important knowledge gap and provides an answer to the question "what are the benefits in coastal hazard estimation by using metamodels?", while simultaneously improving the trustworthiness of the associated results within the context of coastal risk quantification. The selection of the storm ensemble supporting the GP development is also examined, and it is shown that an adaptive implementation provides distinct advantages. This implementation selects batches of storms in stages, leveraging the GP developed using the storms identified up to the current stage, to choose the next batch. Finally, a computationally efficient framework is presented to explicitly consider the uncertainty associated with the GP predictions to provide confidence bounds for the hazard products. [ABSTRACT FROM AUTHOR]

The Bering‐Bagley Glacier System (BBGS), Alaska, Earth's largest temperate surging glacier, surged in 2008–2013. We use numerical modeling and satellite observations to investigate how surging in a large and complex glacier system differs from surging in smaller glaciers for which our current understanding of the surge phenomenon is based. With numerical simulations of a long quiescent phase and a short surge phase in the BBGS, we show that surging is more spatiotemporally complex in larger glaciers with multiple reservoir areas forming during quiescence which interact in a cascading manner when ice accelerates during the surge phase. For each phase, we analyze the simulated elevation‐change and ice‐velocity pattern, infer information on the evolving basal drainage system through hydropotential analysis, and supplement these findings with observational data such as CryoSat‐2 digital elevation maps. During the quiescent simulation, water drainage paths become increasingly lateral and hydropotential wells form indicating an expanding storage capacity of subglacial water. These results are attributed to local bedrock topography characterized by large subglacial ridges that dam the down‐glacier flow of ice and water. In the surge simulation, we model surge evolution through Bering Glacier's trunk by imposing a basal friction representation that mimics a propagating surge wave. As the surge progresses, drainage efficiency further degrades in the active surging‐zone from its already inefficient, end‐of‐quiescence state. Results from this study improve our knowledge of surging in large and complex systems which generalizes to glacial accelerations observed in outlet glaciers of Greenland, thus reducing uncertainty in modeling sea‐level rise. Plain Language Summary: The Bering‐Bagley Glacier System (BBGS), Alaska, Earth's largest temperate surging glacier, recently surged in 2008–2013. A surge glacier cycles between a long period of normal flow and a short period of accelerated flow where large‐scale deformations, such as crevasses, occur. This paper focuses on investigating a surge in a large and complex system rather than a small glacier where most studies on surges have been conducted. We use a numerical model to simulate glacier evolution for both the quiescent phase and the initial surge phase of the BBGS. For each phase, we analyze the simulated elevation‐change and ice‐velocity, and infer information on the evolving hydrologic drainage system. During the quiescent phase, ice‐mass builds up at locations consistent with those observed and water drainage paths become longer with expanding capacity to store subglacial water. These results are attributed to local bedrock topography characterized by large subglacial ridges that act to dam the down‐glacier flow of ice and water. In the surge simulation, we model surge evolution through Bering Glacier by implementing a new friction representation that mimics a propagating wave. As the surge progresses through the glacier, drainage efficiency further degrades in the areas of fast‐moving ice. Key Points: Using a full‐Stokes approach informed by satellite observations, a quiescent and surge phase of the Bering‐Bagley Glacier System (BBGS) are simulatedLocal bed topography controls the formation of several reservoir areas, which lengthen down‐glacier drainage paths during quiescenceA friction representation for the surge phase is implemented based on observed properties of kinematic surge waves in the BBGS [ABSTRACT FROM AUTHOR]

This contribution to the Reflections section of Ocean Yearbook devoted to the memory of the late Professor Meinhard Doelle concerns the options available to coastal States in their responses to global sea level rise driven by anthropogenic climate change. These reflections seek to explore the main policy options and practical approaches based on physical interventions in this context and to assess the possible risks as well as benefits of those approaches. They also explore some of the more radical and cutting-edge technologies which are already being deployed. While addressing the physical intervention options and some of their practical and legal implications, this paper also addresses the importance of environmental impact assessments (EIAs) and capacity-building, both of which were key themes in Meinhard Doelle's work. [ABSTRACT FROM AUTHOR]

The understanding of the stratigraphic evolution of marine rift basins is important for both "pure" scientific and economic reasons. From a hydrocarbon exploration point of view the main goal is to develop tools to predict reservoir location, quality, and extent. Stratigraphic models try to do that, and only historical cases can be used to test those models. On the other hand, depositional model cannot precisely predict reservoir location as factors unique to the specific basin under analysis affect sediment distribution (basin physiography, type of flows, among others). This aspect can be assessed only on a case-by-case basis and can be used for initial hypothesis generation based on analogues. This paper shows a case history study based on the integration of well logs, and 3D seismic data across the Eastern Dampier sub-basin, Northwester Shelf of Australia. Advanced seismic interpretation techniques, calibrated to well data, enable the definition of a chrono-stratigraphic framework of the late syn-rift sequence (Late Jurassic) of the Lewis Trough, and the description of the sediment distribution through the interpretation of geomorphological features. During the Late Jurassic three different channel systems deliver sandstones to the deep-water part of the basin through multiple entry points. The timing of the sediment input seems to be linked to variation of sediment input as during that time relative sea-level was slowly rising. The location of the entry points is related to local physiography and defies any attempt of prediction based on general "rules." From a stratigraphic point view, the findings of the study support the idea that, in rift basin, mechanical subsidence is the primary control for accommodation space, with episodic pulses of extension followed by longer periods of tectonic quiescence. It is during these episodic movements along the basin's bounding faults that space for sedimentation is created. This interpretation is in striking contrast with the basic assumptions of the conventional sequence stratigraphy model. • Understanding the stratigraphic evolution of marine rift basins allows to predict reservoir location and extent. • The present paper analyzes the late syn-rift succession of the Lewis Trough to reconstruct the stratigraphic evolution of the basin infill. • Accommodation space in the Lewis Trough is primarily controlled by mechanical subsidence related to asymmetrical fault movement. • Turbiditic sedimentation occurs during sea-level rise, and it is related to an Increase in sediment supply. • IConventional sequence stratigraphic modeling cannot be applied to rift-basins. [ABSTRACT FROM AUTHOR]

Local governments face urgent challenges from sea-level rise (SLR), impacting coastal urban areas significantly. Despite a shared commitment to adapting to climate change and SLR-induced hazards, strategies for SLR adaptation vary significantly between cities, reflecting a spectrum of political, socio-economic, and cultural contexts. This paper examines potential SLR adaptation strategies in Shenzhen and Hong Kong, cities with different political and socio-economic frameworks, to understand the effectiveness of varied local adaptation pathways to meet adaptation objectives. Through an analysis of shoreline adaptation infrastructures, including natural shelters and hard defense structures, alongside historical coastal reclamation data from 1985 to 2020, we identify the most cost-effective adaptation pathway. Specifically, our cost-benefit analysis reveals that Shenzhen's "Hybrid management" pathway offers superior economic efficiency, increasing benefits by up to 63% for only a 7%–16% rise in protection costs. Conversely, Hong Kong's "Relative-risk Reduction" pathway shows less timely adaptation actions, indicating a need for more dynamic approaches. The findings highlight the pitfalls of overly rigid SLR adaptation strategies and the necessity for flexible, transition-capable adaptation pathways to better manage future uncertainties. Lessons learned from this study will enable refinement of local SLR adaptation pathway approaches and could significantly improve decision-making under uncertainty in other coastal cities based on investment perspective. • Integrate coastal structures and reclamation to explore SLR adaptation pathways. • Limited investments constrains the efficacy of nature-based adaptation strategies. • Prioritise adaptation options is critical to address uncertainty in SLR management. [ABSTRACT FROM AUTHOR]

Climate change is an existential threat to the environmental and socioeconomic sustainability of the coastal zone and impacts will be complex and widespread. Evidence from California and across the United States shows that climate change is impacting coastal communities and challenging managers with a plethora of stressors already present. Widespread action could be taken that would sustain California's coastal ecosystems and communities. In this perspective, we highlight the main threat to coastal sustainability: the compound effects of episodic events amplified with ongoing climate change, which will present unprecedented challenges to the state. We present two key challenges for California's sustainability in the coastal zone: 1) accelerating sea-level rise combined with storm impacts, and 2) continued warming of the oceans and marine heatwaves. Cascading effects from these types of compounding events will occur within the context of an already stressed system that has experienced extensive alterations due to intensive development, resource extraction and harvesting, spatial containment, and other human use pressures. There are critical components that could be used to address these immediate concerns, including comanagement strategies that include diverse groups and organizations, strategic planning integrated across large areas, rapid implementation of solutions, and a cohesive and policy relevant research agenda for the California coast. Much of this has been started in the state, but the scale could be increased, and timelines accelerated. The ideas and information presented here are intended to help expand discussions to sharpen the focus on how to encourage sustainability of California's iconic coastal region. [ABSTRACT FROM AUTHOR]

Sea‐level change threatens the U.S. East Coast. Thus, it is important to understand the underlying causes, including ocean dynamics. Most past studies emphasized links between coastal sea level and local atmospheric variability or large‐scale circulation and climate, but possible relationships with local ocean currents over the shelf and slope remain largely unexplored. Here we use 7 years of in situ velocity and sea‐level data to quantify the relationship between northeastern U.S. coastal sea level and variable Shelfbreak Jet transport south of Nantucket Island. At timescales of 1–15 days, southern New England coastal sea level and transport vary in anti‐phase, with magnitude‐squared coherences of ∼0.5 and admittance amplitudes of ∼0.3 m Sv−1. These results are consistent with a dominant geostrophic balance between along‐shelf transport and coastal sea level, corroborating a hypothesis made decades ago that was not tested due to the lack of transport data. Plain Language Summary: Sea‐level rise is an imminent threat to coastal communities worldwide, including the U.S. East Coast. Therefore, it is crucial to understand the processes driving regional sea‐level change. While past studies documented how coastal sea level may be influenced by large‐scale ocean circulation, less attention has been paid to the role of more local currents over the shelf and slope. Here we explore the relationship between coastal sea level along the northeastern U.S. and the Shelfbreak Jet, a current that flows along the shelfbreak from the Labrador Sea to Cape Hatteras (North Carolina). From 7 years of in situ data of both current velocities and water levels, we see that as coastal sea level rises, Shelfbreak Jet transport increases westward (and vice versa) on timescales of days to weeks. Our results lay the groundwork for understanding relationships between coastal sea level and local ocean dynamics elsewhere. Key Points: Daily Shelfbreak Jet transports and Southern New England coastal sea levels are anti‐correlated during 2014–2022The observed relationship between these two variables is consistent with geostrophic balanceFor this region, coastal sea levels are more sensitive to local ocean dynamics than to large‐scale circulation [ABSTRACT FROM AUTHOR]

The melting of ice sheets and global glaciers results in sea-level rise, a pole-to-equator mass transport increasing Earth's oblateness and resulting in an increase in the length of day (LOD). Here, we use observations and reconstructions of mass variations at the Earth's surface since 1900 to show that the climate-induced LOD trend hovered between 0.3 and 1.0 ms/cy in the 20th century, but has accelerated to 1.33 ± 0.03 ms/cy since 2000. We further show that surface mass transport fully explains the accelerating trend in the Earth oblateness observed in the past three decades. We derive an independent measure of the decreasing LOD trend induced by Glacial Isostatic Adjustment (GIA) of -0.80 ± 0.10 ms/cy, which provides a constraint for the mantle viscosity. The sum of this GIA rate and lunar tidal friction fully explains the secular LOD trend that is inferred from the eclipse record in the past three millennia prior to the onset of contemporary climate change. Projections of future climate warming under high emission scenarios suggest that the climate-induced LOD rate may reach 2.62 ± 0.79 ms/cy by 2100, overtaking lunar tidal friction as the single most important contributor to the long-term LOD variations. [ABSTRACT FROM AUTHOR]

In order to better understand the role of coral reefs around an isolated island in mitigating tsunami hazards, this study performed a horizontally two-dimensional (2DH) numerical study of tsunami-like solitary wave propagation and run-up around an idealized reef-fringed island. The shock-capturing Boussinesq wave model, the FUNWAVE-TVD is used in the present study and well-validated with existing experimental data for its robustness in predicting 2DH solitary wave processes around an island. Based on the validated model, the typical solitary propagation process around the reef-fringed island and the effects of morphological and hydrodynamic parameters on the maximum run-up heights were systematically investigated. It is found that coral reefs can effectively reduce maximum run-up heights around an isolated island. The reef flat's water depth, reef flat width, and reef surface roughness are the main factors affecting maximum run-up heights around an island, while the fore-reef slope has little impact. For the idealized reef-fringed island in this study, sea-level rise will cause coral reefs to lose their protective capability on the lee side, and the presence of coral reefs may even enhance tsunami hazards around an island when the reef flat width is very narrow or coral bleaching happens. [ABSTRACT FROM AUTHOR]

We investigate Venezuela's potential "futures" under Shared Socioeconomic Pathways (SSPs) through a systematic literature review, including systematic mapping and thematic analysis of 50 scientific articles. We categorised the SSP scenarios into two generational categories and classified the outcomes into positive, negative, and neutral futures. Under first-generation SSP scenarios, increasing poverty could be reversed, and the country's economic growth could be stimulated by adopting unambitious climate measures. However, second-generation SSP scenarios paint a more challenging picture. They suggest that Venezuela could face heat waves, droughts, an increase in diseases, loss of biodiversity, and an increase in invasive species and pests during the remainder of the 21st century as a direct consequence of climate change. Venezuela's geographic and topographic diversity could exacerbate these impacts of climate change. For instance, coastal areas could be at risk of sea-level rise and increased storm surges, while mountainous regions could experience more frequent and intense rainfall, leading to landslides and flash floods. The urgency of conducting additional research on the factors that could influence the severity of climate change's impact, considering Venezuela's geographic and topographic diversity, cannot be overstated. We also identified the critical need to explore alternative paths to move away from the current extractive development model. The potential actions in this regard could be instrumental in aligning the country with global adaptation and mitigation commitments. [ABSTRACT FROM AUTHOR]

Local government managers play a critical role in sustainability and climate adaptation planning, and in relation to land-use policy, but little is known about how managers' hazard risk concerns influence the implementation of resilience policy or how this relationship may vary across different landscapes and types of hazards. Linking managers' disaster concerns to their planning choices is particularly relevant to resilience planning for adaptation to climate change, since greenhouse gas emissions are global but the harms produced by climate change are local. Moreover, climate adaptation planning encompasses risks from multiple hazards. For a sample of cities in the state of Florida, USA, we report the findings of empirical analysis of the relationships between local government managers' hazard-specific climate-related disaster concerns and their resilience-planning priorities for four types of hazards: river flooding, sea-level rise, storm surge and hurricane/tornado winds. Drawing on data from a survey of local disaster managers and policy data on the implementation of adaptation-planning actions, the link between managers' concerns and plan implementation is identified and compared across communities and across types of hazards. The pooled logit regression results reveal that the differences observed among these hazards persist even after controlling for objective risks and relevant community characteristics. We discuss the nature of the differences across four hazards and explore the implications of the findings for the literature on land use and climate adaptation and for the education of local government managers. [ABSTRACT FROM AUTHOR]

The vast majority of ice-sheet modelling studies rely on simplified representations of the glacial isostatic adjustment (GIA), which, among other limitations, do not account for lateral variations in the lithospheric thickness and upper-mantle viscosity. In studies of the last glacial cycle using 3D GIA models, this has however been shown to have major impacts on the dynamics of marine-based sectors of Antarctica, which are likely to be the greatest contributors to sea-level rise in the coming centuries. This gap in comprehensiveness is explained by the fact that 3D GIA models are computationally expensive, rarely open-source and require a complex coupling scheme. To close this gap between "best" and "tractable" GIA models, we propose FastIsostasy here, a regional GIA model capturing lateral variations in the lithospheric thickness and mantle viscosity. By means of fast Fourier transforms and a hybrid collocation scheme to solve its underlying partial differential equation, FastIsostasy can simulate 100 000 years of high-resolution bedrock displacement in only minutes of single-CPU computation, including the changes in sea-surface height due to mass redistribution. Despite its 2D grid, FastIsostasy parameterises the depth-dependent viscosity and therefore represents the depth dimension to a certain extent. FastIsostasy is benchmarked here against analytical, as well as 1D and 3D numerical solutions, and shows good agreement with them. For a simulation of the last glacial cycle, its mean and maximal error over time and space respectively yield less than 5 % and 16 % compared to a 3D GIA model over the regional solution domain. FastIsostasy is open-source, is documented with many examples and provides a straightforward interface for coupling to an ice-sheet model. The model is benchmarked here based on its implementation in Julia, while a Fortran version is also provided to allow for compatibility with most existing ice-sheet models. The Julia version provides additional features, including a vast library of adaptive time-stepping methods and GPU support. [ABSTRACT FROM AUTHOR]

Tidal salt marshes offer crucial ecosystem services in the form of carbon sequestration, fisheries, property and recreational values, and protection from storm surges, and are therefore considered one of the most valuable and fragile ecosystems worldwide, where sea-level rise and direct human modifications resulted in the loss of vast regions of today's marshland. The extent of salt marshes therefore relies heavily on the interplay between upland migration and edge erosion. We measured changes in marsh size based on historical topographic sheets from the 1850s and 2019 satellite imagery along the Texas coast, which is home to three of the largest estuaries in North America (e.g., Galveston, Corpus Christi, and Matagorda Bays). We further distinguished between changes in high and low marsh based on local elevation data in an effort to estimate changes in local ecosystem services. Our results showed that approximately 410 km2 (58%) of salt marshes were lost due to coastal erosion and marsh ponding and nearly 510 km2 (72%) of salt marshes were created, likely due to upland submergence. Statistical analyses showed a significant relationship between marsh migration and upland slope, suggesting that today's marshland formed as a result of submergence of barren uplands along gently sloping coastal plains. Although the overall areal extent of Texas marshes increased throughout the last century (~100 km2 or 14%), economic gains through upland migration of high marshes (mostly in the form of property value (USD 0.7–1.0 trillion)) were too small to offset sea-level-driven losses of crucial ecosystem services of Texan low marshes (in the form of storm protection and fisheries (USD 2.1–2.7 trillion)). Together, our results suggest that despite significant increases in marsh area, the loss of crucial ecosystem services underscores the complexity and importance of considering not only quantity but also quality in marshland conservation efforts. [ABSTRACT FROM AUTHOR]

The Toarcian Oceanic Anoxic Event (T-OAE; ~183 Mya) was a globally significant carbon-cycle perturbation linked to widespread deposition of organic-rich sediments, massive volcanic CO2 release, marine faunal extinction, sea-level rise, a crisis in carbonate production related to ocean acidification, and elevated seawater temperatures. Despite recognition of the T-OAE as a potential analog for future ocean deoxygenation, current knowledge on the severity of global ocean anoxia is limited largely to studies of the trace element and isotopic composition of black shales, which are commonly affected by local processes. Here, we present the first carbonate-based uranium isotope (δ238U) record of the T-OAE from open marine platform limestones of the southeastern Tethys Ocean as a proxy for global seawater redox conditions. A significant negative δ238U excursion (~0.4‰) is recorded just prior to the onset of the negative carbon isotope excursion comprised within the T-OAE, followed by a long-lived recovery of δ238U values, thus confirming that the T-OAE represents a global expansion of marine anoxia. Using a Bayesian inverse isotopic mass balance model, we estimate that anoxic waters covered ~6 to 8% of the global seafloor during the peak of the T-OAE, which represents 28 to 38 times the extent of anoxia in the modern ocean. These data, combined with δ238U-based estimates of seafloor anoxic area for other CO2-driven Phanerozoic OAEs, suggest a common response of ocean anoxia to carbon release, thus improving prediction of future anthropogenically induced ocean deoxygenation. [ABSTRACT FROM AUTHOR]

The accelerated urban growth in Macaé had important consequences on socio-spatial organization, especially about housing spaces that became increasingly difficult to be accessed by the low-income population. The most devalued lands, such as mangroves and floodplains, were occupied by the low-income population. The proposal highlighted in this project focuses directly on the problem of rising sea levels and flooding in the urban space of Macaé, which is of social interest. A simulation of future scenarios with sea level rise above the current one, allowing the identification of areas flooded by marine transgression on a time scale of 100 years (for the year 2100). For this, the rate was chosen for the simulation: the greenhouse gas scenario RCP8.5, as given in IPCC's Fifth Assessment Report (AR5) of 2014. A radiative forcing that corresponds to more than 700 ppm CO2-eq, but less than 1500 ppm, the projected increase is 1 m to more than 3 m (medium confidence) and more than 3 m (medium confidence). This assessment is based on the average confidence in the contribution from thermal expansion and low confidence in the modeled contribution modeled contribution of the ice sheets. Therefore, the climate change-induced global mean sea level rise is caused by thermal expansion of ocean water and ocean mass gain, the latter being mainly due to a decrease in land ice mass. The estimated sea-level rise used for the projection of this study is 2.15, as proposed by Grinsted et al. in 2009. [ABSTRACT FROM AUTHOR]

Coastal regions are vulnerable to rising seas, increasing storm magnitude, and decimation of ecologically-fragile areas. Deltas are particularly sensitive to the balance between sea-level rise, land subsidence and sedimentation that determine relative elevation. Bangladesh has been highlighted as being at risk from sea-level rise. Integrating measurements from different methods can approach a more complete understanding of factors controlling areally and temporally varying subsidence rates. To augment our compilation of rates from stratigraphic wells, historic buildings, vertical strainmeters, RSETMH, and continuous Global Navigation Satellite System, we resurveyed 48 geodetic monuments in coastal Bangladesh ~18 years after the monuments were installed. A later resurvey of 4 sites showed that some sites with higher subsidence may be unstable, but we consider the subsidence pattern of all the sites. Sites with rates <2 mm/yr overlie thin (<35 m), sandy Holocene deposits located along interfluves between the main paleo-river valleys. As Holocene strata thicken seaward and become muddier, subsidence rates increase to 20-25 mm/y. Sites in incised valleys of the Ganges, Brahmaputra and Meghna Rivers, with Holocene sediments >100 m show subsidence rates of 20 ± 10 mm/y, with a slight seaward increase. Overall, subsidence rates increase with Holocene sediment thickness and the seaward shift from sandy to muddy sediments. Together with earlier measurements, we parse the different rates and mechanisms of subsidence. Earlier models show 2-3 mm/yr correspond to deep processes, such as isostasy. Within the shallow Holocene (<10 m), we estimate 5-8 mm/yr of subsidence from shallow, edaphic effects (tree roots, burrows, organic matter decomposition) and shallow (<10 m) sediment consolidation on short timescales. Below this, we estimate 3-6 mm/yr from compaction of the upper Holocene strata, with 2-5 mm/yr occurring in deeper Holocene strata. Subsidence rates in areas of active sedimentation, such as rice fields and mangrove forests, are greater than buildings and structures with deep foundations. Subsidence on timescales >300 y, which do not include edaphic effects, are up to ~5 mm/y. We note subsidence can be offset by active deltaic sedimentation, and does not necessarily indicate elevation loss. Collectively, the integration of these approaches allows us to begin quantifying the varied contributions to land subsidence from edaphic effects, Holocene sediment compaction, lithology, and time. Similar factors may contribute to the highly variable subsidence rates observed at other deltas worldwide. [ABSTRACT FROM AUTHOR]

Introduction: Future urban stormwater flood risk is determined by the confluence of both climate-driven changes in precipitation patterns and the effectiveness of flood mitigation systems, such as urban drainage and pump systems. This is especially true in coastal cities protected by levee systems like New Orleans, where even present-day rainfall would be enough to cause serious flooding in the absence of extensive stormwater drainage and pumping. However, while the uncertainties associated with climate change have been well studied, uncertainties in infrastructure performance and operation have received less attention. Methods: We investigated how these interrelated sets of uncertainties drive flood risk in New Orleans using a Robust Decision Making (RDM) approach. RDM is a framework for Decision Making Under Deep Uncertainty (DMDU) that leverages simulation models to facilitate exploration across many possible futures and the identification of decision-relevant scenarios. For our work, we leveraged a detailed Storm Water Management Model (SWMM) representation of the New Orleans urban stormwater management system to examine flood depths across the city when faced with different levels of future precipitation, sea-level rise, drainage pipe obstruction, and pumping system failure. We also estimated direct flood damage for each neighborhood in the city for this scenario ensemble. These damage estimates were then subjected to vulnerability analysis using scenario discovery—a technique designed to determine which combinations of uncertainties are most stressful to the system in terms of an outcome of interest (excess flood damage). Results: Our results suggest that key drivers of vulnerability depend on geographic scale. Specifically, we find that possible climate-driven precipitation increases are the most important determinant of vulnerability at the citywide level. However, for some individual neighborhoods, infrastructure operation challenges under present day conditions are a more significant driver of vulnerability than possible climate-driven precipitation increases. [ABSTRACT FROM AUTHOR]

Scientists predict ongoing global climate change to trigger adverse events affecting about 143 million people in the Global South by 2050, leading to various forms of migration and mobility. While existing literature extensively examines climate-induced migration, there is a lack of studies considering the compounding impacts of multiple climate hazards on migration, mobility, and immobility. To address this gap, we conducted a systematic literature review to explore how climate-induced stressors, specifically rising temperatures, water stress and droughts, and floods and sea-level rise, have affected populations in the Global South, leading to voluntary and/or forced migration. Our findings show that these stressors have displaced and profoundly impacted millions of people, resulting in both internal and transboundary migration. Climate-induced stressors often trigger migration through indirect pathways influenced by multiple intervening institutional, political, and socio-economic factors and programmatic and policy gaps. Effectively addressing challenges related to climate-induced migration necessitates adaptation strategies that adequately consider the impacts of these intervening factors while recognizing their differential effects on various socio-demographic groups. We argue that support from Global North countries, including compensation for loss and damage, along with continued institutional and financial support from international non-governmental organizations, is crucial for managing climate-induced migration in the Global South. Without proper planning and adequate resources, migration may escalate and significantly impact human security. The findings of this study can inform climate migration policies and assist adaptation and migration experts in identifying intervention mechanisms and opportunities for people-centered climate solutions. [ABSTRACT FROM AUTHOR]

Glacier flow modulates sea level and is governed largely by the viscous deformation of ice. Multiple molecular-scale mechanisms facilitate viscous deformation, but it remains unclear how each contributes to glacier-scale deformation. Here, we present a model of ice deformation that bridges laboratory and glacier scales, unifies existing estimates of the viscous parameters, and provides a framework for estimating the parameters from observations and incorporating flow laws derived from laboratory observations into glacier-flow models. Our results yield a map of the dominant deformation mechanisms in the Antarctic Ice Sheet, showing that, contrary to long-standing assumptions, dislocation creep, characterized by a value of the stress exponent n = 4, likely dominates in all fast-flowing areas. This increase from the canonical value of n = 3 dramatically alters the climate conditions under which marine ice sheets may become unstable and drive rapid rates of sea-level rise. [ABSTRACT FROM AUTHOR]

The Greenland Ice Sheet contributed 10.6 mm to global sea level rise between 1992 and 2018, and it is projected to be the largest glacial contributor to sea level rise by 2100. Here we assess the relative importance of two major sources of uncertainty in 21st century ice loss projections: (1) the choice of sliding law and (2) the surface mass balance (SMB) forecast. Specifically, we used the ice flow model Úa to conduct an ensemble of runs for 48 combinations of sliding law and SMB forecast for three major Greenland outlet glaciers (Kangerlussuaq (KG), Humboldt (HU) and Petermann (PG) glaciers) with differing characteristics and evaluated how the sensitivity to these factors varied between the study glaciers. Overall, our results show that SMB forecasts were responsible for 4.45 mm of the variability in sea level rise by 2100 compared with 0.33 mm sea level equivalent (SLE) due to sliding law. HU had the largest absolute contribution to sea level rise and the largest range (2.16–7.96 mm SLE), followed by PG (0.84–5.42 mm SLE), and these glaciers showed similar patterns of ice loss across the SMB forecasts and sliding laws. KG had the lowest range and absolute values (- 0.60 to 3.45 mm SLE) of sea level rise, and the magnitude of mass loss by SMB forecast differed markedly between HU and PG. Our results highlight SMB forecasts as a key focus for improving estimates of Greenland's contribution to 21st century sea level rise. [ABSTRACT FROM AUTHOR]

Anticipating and managing the impacts of sea‐level rise for nations astride active tectonic margins requires understanding of rates of sea surface elevation change in relation to coastal land elevation. Vertical land motion (VLM) can either exacerbate or reduce sea‐level changes with impacts varying significantly along a coastline. Determining rate, pattern, and variability of VLM near coasts leads to a direct improvement of location‐specific relative sea level (RSL) estimates for coastal hazard risk assessment. Here, we utilize vertical velocity field from interferometric synthetic aperture radar (InSAR) data, calibrated with campaign and continuous Global Navigation Satellite System data, to determine the VLM for the entire coastline of New Zealand. Guided by available knowledge of the seismic cycle, the VLM data infer secular, interseismic rates of land surface deformation. Using the Framework for Assessing Changes to Sea‐level (FACTS), we build probabilistic RSL projections using the same emissions scenarios employed in IPCC Assessment Report 6 and local VLM data at 8,179 sites, thereby enhancing spatial coverage that was previously limited to four tide gauges. We present ensembles of probability distributions of RSL for each scenario to 2150, and for low confidence sea‐level processes to 2300. Where land subsidence is occurring at rates >2 mm/y VLM makes a significant contribution to RSL projections for all scenarios out to 2150. Our approach can be applied to similar locations across the world and has significant implications for adaptation planning, as timing of threshold exceedance for coastal inundation can be brought forward (or delayed) by decades. Plain Language Summary: This study outlines an approach for deriving probabilistic projections of relative sea‐level change that account for changes in land surface elevation continuously along a coastline. Previous sea‐level projections that included vertical land movements (VLMs) were restricted to tide gauge locations. To provide spatial‐resolution required by practitioners for effective adaptation planning, we have combined elevations measured using satellite radar data with measurements from land‐based Global Navigation Satellite System (GNSS) receivers to build a continuous VLM database showing land uplift and subsidence (sinking) for the entire coastline of New Zealand. We integrate these data into probabilistic sea‐level projection methodology used in Intergovernmental Panel on Climate Change (IPCC) Assessment Report 6 (AR6) for the range of future climate scenarios. Our approach could be applied to any region of the world where the coastline is affected by VLM due to secular tectonic deformation. Downward land movement >2 mm/y makes a significant contribution in sea‐level projections for all climate scenarios out to the end of this century. This means that adaptation planning decision thresholds, such as those linked to the impacts of coastal flooding and inundation, may be brought forward by decades. Key Points: Anticipating impacts of sea‐level rise for active tectonic margins requires location‐specific knowledge of vertical land movement (VLM)VLM from geodetic measurements integrated with IPCC AR6 projections to provide probabilistic RSL estimates for dynamic coastlinesDownward VLM > 2 mm/y makes a significant contribution to RSL projections bringing forward adaptation decision thresholds by decades [ABSTRACT FROM AUTHOR]

Quaternary crustal movement of the Japanese islands caused the rapid uplift of mountain ranges and the relative subsidence of coastal and inland basins. Chronostratigraphic and facies analyses of Pliocene to Quaternary sediments of 33 areas in the central Honshu reveals that the Tectono-sedimentary History developed in the following four stages. 1) From the Pliocene to the early Early Pleistocene, inland basins formed and turbidite accumulated in deep sea basins. 2) From the late Early Pleistocene to the early Middle Pleistocene, the uplift of the island arc occurred, and the subsiding areas of the inland basins expanded and differentiated, while in marine areas the slopes were buried by fan-deltas as the fan area expanded. 3) In the late Middle Pleistocene, the crustal uplift of the island arc was accelerated, and at the same time sediments accumulated in coastal basins in correspondence with sea-level changes. 4) Since the Late Pleistocene, terraces were formed due to falling sea-level and crustal uplift. It is considered that these characteristics of such Quaternary crustal movements were formed through large-scale uplift of island arc crust and sea-level change. Especially after the late Middle Pleistocene (0.43 Ma), it is possible that the current topography was formed by a new large uplift movement and sea-level rise of about 1,000 m. The formation of the island arc by large-scale uplift and sea-level rise cannot be explained by the plate subduction or collision. [ABSTRACT FROM AUTHOR]

Submarine pipelines have become integral for transporting resources and drinking water across large bodies. Therefore, ensuring the stability and reliability of these submarine pipelines is crucial. Incorporating climate change impacts into the design of marine structures is paramount to assure their lifetime safety and serviceability. Deterministic design methods may not fully consider the uncertainties and risks related to climate change compared to risk-based design models. The latter approach considers the future risks and uncertainties linked to climate and environmental changes, thus ensuring infrastructure sustainability. This study pioneers a Hybrid 3D Hydrodynamic Monte Carlo Simulation (HMCS) Model to improve the reliability-based design of submarine pipelines, incorporating the effects of climate change. Current design approaches may follow deterministic methods, which may not systematically account for climate change's comprehensive uncertainties and risks. Similarly, traditional design codes often follow a deterministic approach, lacking in the comprehensive integration of dynamic environmental factors such as wind, waves, currents, and geotechnical conditions, and may not adequately handle the uncertainties, including the long-term effects of climate change. Nowadays, most countries are developing new design codes to modify the risk levels for climate change's effects, such as sea-level rises, changes in precipitation, or changes in the frequency/intensity of winds/storms/waves in coastal and marine designs. Our model may help these efforts by integrating a comprehensive risk-based approach, utilizing a 3D hydrodynamic model to correlate diverse environmental factors through Monte Carlo Simulations (MCS). The hybrid model can promise the sustainability of marine infrastructure by adapting to future environmental changes and uncertainties. Including such advanced methodologies in the design, codes are encouraged to reinforce the resilience of maritime structures in the climate change era. The present design codes should inevitably be reviewed according to climate change effects, and the hybrid risk-based design model proposed in this research should be included in codes to ensure the reliability of maritime structures. The HMCS model represents a significant advancement over existing risk models by incorporating comprehensive environmental factors, utilizing advanced simulation techniques, and explicitly addressing the impacts of climate change. This innovative approach ensures the development of more resilient and sustainable maritime infrastructure capable of withstanding future environmental uncertainties. [ABSTRACT FROM AUTHOR]

The climate crisis poses a grave threat to numerous small island developing states (SIDS), intensifying risks from extreme weather events and sea level rise (SLR). This vulnerability heightens the dangers of coastal erosion, chronic water quality degradation, and dwindling coastal resources, demanding global attention. The resultant loss of ecological persistence, functional services, and ecosystem resilience jeopardizes protection against wave action and SLR, endangering coastal habitats' economic value, food security, infrastructure, and livelihoods. Implementing integrated strategies is imperative. A thorough discussion of available strategies and best management practices for coastal ecosystem restoration is presented in the context of SIDS needs, threats, and major constraints. Solutions must encompass enhanced green infrastructure restoration (coral reefs, seagrass meadows, mangroves/wetlands, urban shorelines), sustainable development practices, circular economy principles, and the adoption of ecological restoration policies. This requires securing creative and sustainable funding, promoting green job creation, and fostering local stakeholder engagement. Tailored to each island's reality, solutions must overcome numerous socio-economic, logistical, and political obstacles. Despite challenges, timely opportunities exist for coastal habitat restoration and climate change adaptation policies. Integrated strategies spanning disciplines and stakeholders necessitate significant political will. [ABSTRACT FROM AUTHOR]

This document is an introduction to a thematic set on Asian climate published in the journal Quaternary Research. It explains that Asia is not only the largest continent but also home to the majority of humankind, with a wide range of environments. The document highlights the importance of understanding past climate changes and their impacts on landcover, vegetation, ice distributions, sea-level changes, and human society developments. It also emphasizes the need to study external forces and their impact on Asia, as well as the role of glaciations and sea-level changes. The document briefly summarizes four papers included in the thematic set, which cover topics such as glaciation patterns, sea-level rise, grassland changes, and climate impacts in the Tengger Desert. The authors express gratitude to the PAGES Organizing team and reviewers for their contributions. [Extracted from the article]

The aim of this paper is to evaluate the position of the Holocene transgression on the coast of the Valencia Gulf. To achieve this goal, a sedimentological and micropaleontological analysis of samples of fossil benthic foraminifera in cores from six boreholes drilled in three different wetlands (Almenara marsh, Moro marsh and Valencia lagoon) was carried out. In order to assess the extent of sea level change, at least three factors must be taken into account: 1) eustatic rise (global scale) 2) neotectonics (regional scale) and 3) the sedimentary factor (local and regional scale). Regarding the first factor, some authors have noted that the Holocene transgression reached +1 m above the current sea level in this area. As for the second factor, while the Valencia lagoon is located on a subsiding coast the northernmost marshes are located on a tectonically stable coast. Finally, sedimentation rates are highly variable depending on the area; whereas in the Valencia lagoon the shoreline generally shifts seawards (progradation) in the northernmost areas the coast is currently undergoing retrogradation, although the anthropic factor clearly interferes with this pattern. One of the main conclusions is that in the Valencian coast the Holocene maximum relative sea level did not exceed the present-day one, except in the case of the subsiding area of the Valencia lagoon. The calculation of sedimentation rates, the relative sea-level curve and the evolution of the water column in the different wetlands seem to corroborate it. Radiocarbon and AAR analyses allowed us to date the maximum extent of the Holocene transgression on the Valencian coast at around 5500 cal yr BP in all cases. Despite the different subsidence the three studied wetlands reflected the predominant marine influence until 5500–5200 BP, which was later followed by a growing fluvial or continental incidence, when glacioeustatic adjustments defined the patterns of coastal progradation. [Display omitted] • Location of the MIS 1 coastline position in three West Mediterranean wetlands. • The global Holocene eustatic rise invaded the three wetlands at least 5300 years BP. • Subsidence rate determined different MIS 1 relative sea-level rise in the wetlands. • Tectonic stability in the northern wetlands involved slower relative sea-level rise. [ABSTRACT FROM AUTHOR]

This paper discusses a model of coastal barrier progradation where the development of a prograded plain was a product of the successive formation of foredune ridges followed by their burial by transgressive sand sheets and dunefields. The results are based on direct lithological data from drill holes and geomorphological analyses, indirect geophysical data (GPR), and 14C and OSL dating. Barrier progradation started at 6.69 ka (OSL) or 7.2 ka (14C), under sea-level rise. At around 5.0 ka (OSL), or thereabouts, a forced regression condition started to operate, when sea-level started to fall after it reached a maximum of 2.34 ± 0.8 m. During barrier progradation sets of foredunes were formed, and at least some of them were buried by sands of transgressive dunefields (TDF), which later evolved to transgressive sand sheets (TSS). A total of 11+ phases of TSS and a modern phase of TDF were formed in a time span of 6.69 ka (OSL) or 7.2 ka (14C), corresponding to one phase formed at each 560 or 600 yrs. Two models of possible development of the surface of Curumim barrier are proposed. • Arare record of aforedune plain buried by transgressive sandsheets formation. • The cyclic formation of transgressive dunefieldsand transgressive sand sheets. • The foredune/beach contact as a proxy of sea-level position. • Distinct contributions of normal and forced regressionon barrier progradation. • Possibletransformation of a transgressive dunefield in a transgressive sand sheet. [ABSTRACT FROM AUTHOR]

Background: Shallow, tropical coral reefs face compounding threats from climate change, habitat degradation due to coastal development and pollution, impacts from storms and sea-level rise, and pulse disturbances like blast fishing, mining, dredging, and ship groundings that reduce reef height and complexity. One approach toward restoring coral reef physical structure from such impacts is deploying built structures of artificial, natural, or hybrid (both artificial and natural) origin. Built structures range from designed modules and repurposed materials to underwater sculptures and intentionally placed natural rocks. Restoration practitioners and coastal managers increasingly consider incorporating – and in many cases have already begun to incorporate – built structures into coral reef-related applications, yet synthesized evidence on the ecological (coral-related; e.g., coral growth, coral survival) and physical performance of built structures in coral ecosystems across a variety of contexts (e.g., restoration, coastal protection, mitigation, tourism) is not readily available to guide decisions. To help fill this gap and inform management decisions, we systematically mapped the global distribution and abundance of published evidence on the ecological (coral-related) and physical performance of built structure interventions in shallow (≤ 30 m), tropical (35°N to 35°S) coral ecosystems. Methods: To identify potentially relevant articles, we used predefined and tested strategies to search two indexing platforms, one bibliographic database, two open discovery citation indexes, one web-based search engine, one novel literature discovery tool, 19 organizational websites, and information requested from stakeholders. Discovered articles were screened according to preset eligibility criteria first by title and abstract and second by full text. Articles included during full text screening were coded to extract metadata following a predefined framework. We analyzed and visualized the evidence base to answer our primary and secondary research questions and to identify knowledge clusters and gaps. Findings are reported in a narrative synthesis. Results: Our search discovered > 20,000 potentially relevant unique articles, of which 258 were included in the systematic map. The evidence base spans 50 countries, and the volume of evidence increased over the past five decades. Built structures were most commonly installed for coral restoration (61%) or coastal protection (12%). Structures were predominately characterized as artificial (87%), with fewer hybrid or natural interventions. Evidence clusters existed for intentionally designed artificial structures and outcomes associated with coral-related ecological performance, including coral mortality, growth, recruitment, cover, and diversity. Pronounced evidence gaps occurred at the intersection of several ecological coral-related performance outcomes (e.g., connectivity, microbiome) across all types of built structures; gaps also existed across most ecological coral-related outcomes for artwork and repurposed artificial structures. Physical performance of built structures was most frequently evaluated for outcomes related to waves (n = 14) and sediment and morphology (n = 11) with pervasive evidence gaps across other outcomes like storm surge and water level. Conclusions: While the systematic map highlighted several evidence clusters, it also revealed pronounced evidence gaps surrounding the coral-related ecological and physical performance of built structures in coral ecosystems. The compiled evidence base will help inform policy, management, and future consideration of built structures in reef-related applications, including habitat restoration, environmental mitigation, and coastal protection. Map findings also point to promising future research avenues, such as investigating seascape-scale ecological effects of and the physical performance of built structures. [ABSTRACT FROM AUTHOR]

We show that steric sea‐level varies with a period of 18.6 years along the western European coast. We hypothesize that this variation originates from the modulation of semidiurnal tides by the lunar nodal cycle and associated changes in ocean mixing. Accounting for the steric sea level changes in the upper 400 m of the ocean solves the discrepancy between the nodal cycle in mean sea level observed by tide gauges and the theoretical equilibrium nodal tide. Namely, by combining the equilibrium tide with the nodal modulation of steric sea level, we close the gap with the observations. This result supports earlier findings that the observed phase and amplitude of the 18.6‐year cycle do not always correspond to the equilibrium nodal tide. Plain Language Summary: The orbital position of the moon and the gravity pull it exerts on the earth varies with a period of 18.6 years. This cycle is called the lunar nodal cycle and it results in small variations of yearly averaged sea level (∼1–2 cm). Understanding this variability is important because it allows, for example, to quickly detect an acceleration in local sea‐level rise due to global warming. Here we show that the lunar nodal cycle also has an influence on the temperature and salinity in the surface 400m of the ocean. As a result, the ocean density changes and amplifies sea level variations along the western European coast. We make the hypothesis that since the lunar nodal cycle also influences the amplitude of the semidiurnal tides, and since those tides are known to be responsible for a large part of ocean mixing, a change in ocean mixing could be the cause of the ocean density variability that we observe. Key Points: Steric sea level changes are influenced by the 18.6‐year lunar nodal cycle along the western European coastThis influence could result from the modulation of semidiurnal tides by the lunar nodal cycle and the associated change in ocean mixingThis finding is a step toward resolving the long‐standing discrepancy between the theoretical long‐period nodal tide and observed signal [ABSTRACT FROM AUTHOR]

Many barrier islands and spits (collectively, "barriers") throughout the world are highly developed. As low‐lying, sandy coastal landforms, barrier systems are naturally reshaped by processes associated with storms and sea‐level rise (SLR). The resulting landscape changes threaten development, and in response, humans employ defensive measures that physically modify barrier geometry to reduce relatively short‐term risk. These measures include the construction of large dunes, emplacement of beach nourishment, and removal of washover. Simulations conducted using a new coupled modeling framework show that, over decades to centuries, measures to protect roadways and communities alter the physical characteristics of barrier systems in ways that ultimately limit their habitability. We find that the pathway toward uninhabitability (via roadway drowning or community narrowing) and future system states (drowning or rebound) depends largely on dune management—because building dunes blocks overwash delivery to the barrier interior—and on initial conditions (barrier elevation and width). In the model, barriers can become lower and narrower with SLR to the point of drowning. The timing and occurrence of barrier drowning depends on randomness in the timing and intensity of storms and dune recovery processes. We find that under a constant rate of SLR, negative feedbacks involving storms can allow barriers that do not drown to rebound toward steady‐state geometries within decades after management practices cease. Plain Language Summary: Barrier islands and spits (collectively referred to as "barriers") can naturally keep up with sea‐level rise primarily through a process called overwash. During overwash, sand from the beach is washed landward past the dunes by storm waves, leading to increases in barrier height (elevation) and width. Tall dunes, built to protect roadways and oceanfront properties, prevent overwash from elevating the existing barrier landscape. Here we use a new model to show that over many decades to centuries, an unintended consequence of rebuilding tall dunes in the aftermath of storms, which then block future overwash, is the narrowing and lowering of barriers relative to sea level. In some cases, this leads to complete drowning of the barrier interior. In other cases, once humans stop rebuilding dunes, the landscape recovers in as little as a few decades. Key Points: Counterintuitively, with higher dune design heights and lower/wider initial barrier geometries, barriers become uninhabitable soonerRandomness in dune‐storm interactions dictates whether or not a barrier drowns after management ceasesSimulations suggest barrier systems can recover in height, width, and cross‐shore position quickly (within decades) after management ceases [ABSTRACT FROM AUTHOR]