Search

Satellite observations of the Antarctic surface since the 1990s, coupled with geophysical surveys of the flow and form of its giant ice sheet, have revealed accelerating loss of ice to the oceans. This, coupled with a reduction in floating sea ice surrounding the continent and the occurrence of unprecedented heatwaves, point to a continent being changed irreversibly by fossil-fuel burning and the global heating that results. A changing Antarctic continent will have global consequences, including sea level rise of possibly more than 1 meter in this century (and much more afterward) and by a reduced ability to naturally reflect incoming solar energy—which would lead to further heating by absorption on land and at sea as the ice pack retreats. [ABSTRACT FROM AUTHOR]

Glaciers are the ambassadors of climate change. Their worldwide decline has serious impacts on natural hazards, the water cycle, and sea level rise. The monitoring of glaciers documents the increasingly rapid melting, which has culminated in a suite of extreme years—for example, 2023 in North America and the European Alps. Numerical simulations of future glacier change, supported by a large basis of observational data, allow us to understand the enormous changes ahead and prepare us for a world without glaciers. Technical approaches to reduce glacier melting have been developed and are applicable locally—for example, in connection with tourist activities—but they clearly fail at the larger scale. [ABSTRACT FROM AUTHOR]

Municipal bond markets began pricing sea-level rise (SLR) exposure risk in 2013, coinciding with upward revisions to worst-case SLR projections and accompanying uncertainty around these projections. The effect is larger for long-maturity bonds and not solely driven by near-term flood risk. We use a structural model of credit risk to quantify the implied economic impact and distinguish between the effects of underlying asset values and of uncertainty. The SLR exposure premium exhibits a trend different from house prices and is unaffected by house price controls. Together, our results highlight the importance of climate uncertainty in driving municipal bond prices. Authors have furnished an Internet Appendix , which is available on the Oxford University Press Web site next to the link to the final published paper online [ABSTRACT FROM AUTHOR]

Density-driven steric seawater changes are a leading-order contributor to global mean sea level rise. However, intermodel differences in the magnitude and spatial patterns of steric sea level rise exist at regional scales and often emerge during the spinup and preindustrial control integrations of climate models. Steric sea level results from an eddy-permitting climate model, GFDL CM4, are compared with a lower-resolution counterpart, GFDL-ESM4. The results from both models are examined through basin-scale heat budgets and watermass analysis, and we compare the patterns of ocean heat uptake, redistribution, and sea level differ in ocean-only [i.e., Ocean Model Intercomparison Project (OMIP)] and coupled climate configurations. After correcting for model drift, both GFDL CM4 and GFDL-ESM4 simulate nearly equivalent ocean heat content change and global sea level rise during the historical period. However, the GFDL CM4 model exhibits as much as a 40% increase in surface ocean heat uptake in the Southern Ocean and subsequent increases in horizontal export to other ocean basins after bias correction. The results suggest regional differences in the processes governing Southern Ocean heat export, such as the formation of Antarctic Intermediate Water (AAIW), Subpolar Mode Water (SPMW), and gyre transport between the two models, and that sea level changes in these models cannot be fully bias-corrected. Since the process-level differences between the two models are evident in the preindustrial control simulations of both models, these results suggest that the control simulations are important for identifying and correcting sea level–related model biases. [ABSTRACT FROM AUTHOR]

Complex changes in coastlines are increasing with climate, sea level, and human impacts. Remote Sensing (RS) and Geographic Information Systems (GIS) provide critical information to rapidly and precisely monitor environmental changes in coastal areas and to understand and respond to environmental, economic, and social impacts. This study aimed to determine the temporal changes in the coastline of the Seyhan Basin, Türkiye, using Landsat satellite images from 1985 to 2023 on the Google Earth Engine (GEE) platform. The approximately 50 km of coastline was divided into three regions and analyzed using various statistical techniques with the Digital Shoreline Analysis System (DSAS) tool. In Zone 1, the maximum coastal accretion was 1382.39 m (Net Shoreline Movement, NSM) and 1430.63 m (Shoreline Change Envelope, SCE), while the maximum retreat was -76.43 m (NSM). Zone 2 showed low retreat and accretion rates, with maximum retreat at -2.39 m/year (End Point Rate, EPR) and -2.45 m/year (Linear Regression Rate, LRR), and maximum accretion at 0.99 m/year (EPR) and 0.89 m/year (LRR). Significant changes were observed at the mouth of the Seyhan delta in Zone 3. According to the NSM method, the maximum accretion was 1337.72 m, and maximum retreat was 1301.4 m; the SCE method showed a maximum retreat of 1453.65 m. EPR and LRR methods also indicated high retreat and accretion rates. Statistical differences between the methods were assessed using the Kruskal–Wallis H test and ANOVA test. Generally, NSM and EPR methods provided similar results, while other methods varied by region. Additionally, the Kalman filtering model was used to predict the coastline for 2033 and 2043, identifying areas vulnerable to future changes. Comparisons were made to determine the performance of Kalman filtering. In the 10-year and 20-year future forecasts for determining the coastline for the years 2033 and 2043 with the Kalman filtering model, it was determined that the excessive prediction time negatively affected the performance in determining the coastal boundary changes. [ABSTRACT FROM AUTHOR]

Rice cultivation is crucial in providing global food needs, particularly in highland areas with distinct environ mental conditions. Adapting promising rice lines suitable for highland ecosystems is essential to ensure sus tainable rice production in such regions. This study assesses the agronomic performance, heritability, and correlation of traits in new promising rice lines adapted to highland ecosystems. The latest promising rice lines are designed with the unique environmental conditions of highland regions in mind. This research was conducted in Buntu Barana’ Village, Tikala Sub-district, with an elevation of 858.4 m above sea level. The study was carried out in rain-fed semi-irrigated paddy fields. The research was conducted from May 2023 to January 2024. The research methodology involves testing various agronomic traits for yield production components of the new type of promising rice lines at different highland locations. The research procedures included the selection of viable seed strains, seeding, fertilization, balanced irrigation, control of plant pest organisms, harvesting, and postharvesting. Evaluated agronomic traits encompass plant height, days to maturity, number of productive til lers, length of panicles, number of filled grains per panicle, and grain yield. Additionally, heritability analysis is performed to assess the extent to which observed trait variations are attributed to genetic factors. Research findings reveal significant variations in agronomic traits among the new type of promising rice lines. The highest grain yield is achieved in genotype UKIT102-2-056, which is 8.3 tons per hectare of paddy rice. These lines exhibit objective adaptation to the highland ecosystem, with some lines demonstrating superior performance in specific parameters, especially early maturity, namely 97 days after planting. Heritability analysis indicates that certain traits have high heritability levels, suggesting a significant role of genetic factors in controlling these traits. Furthermore, this study unveils correlation patterns among the observed agronomic traits. Significant positive and negative correlations among several traits indicate complex interrelationships among these agro nomic characteristics. These findings offer further insights into the relationships between these traits and can be utilized to develop more adaptive rice lines in highland environments. [ABSTRACT FROM AUTHOR]

Over the last sixty ears, Singapore has expanded its land footprint over twenty-five percent by reclaiming land from the sea. Its outsized demand for sand to resource these projects has rendered regional sand markets precarious, and successive countries have banned sand exports to Singapore. Nevertheless, the Singapore government has committed to spending $SG one billion (US$ 767 million) a year until 2100 to mitigate sea level rise. While this includes a range of strategies, from improving drainage infrastructure to exploring adaptive solutions, in the main this involves reclaiming vast amounts of land from the sea to act as a bulwark against rising tides. These plans for resilience will be examined through the spectre of Long Island, a proposed project that will act as a barrier against sea level rise and incorporate nature-based solutions that are emblematic of resilience fetishism, all the while obscuring the more foundational element of this resilience, which is sand that will be obtained through granular arbitrage. [ABSTRACT FROM AUTHOR]

To save saltmarshes and their valuable ecosystem services from sea level rise, it is crucial to understand their natural ability to gain elevation by sediment accretion. In that context, a widely accepted paradigm is that dense vegetation favors sediment accretion and hence saltmarsh resilience to sea level rise. Here, however, we reveal how dense vegetation can inhibit sediment accretion on saltmarsh platforms. Using a process‐based modeling approach to simulate biogeomorphic development of typical saltmarsh landscapes, we identify two key mechanisms by which vegetation hinders sediment transport from tidal channels toward saltmarsh interiors. First, vegetation concentrates tidal flow and sediment transport inside channels, reducing sediment supply to platforms. Second, vegetation enhances sediment deposition near channels, limiting sediment availability for platform interiors. Our findings suggest that the resilience of saltmarshes to sea level rise may be more limited than previously thought. [ABSTRACT FROM AUTHOR]

Excavations at Māngere Wastewater Treatment Plant, Auckland, in 2020 provided New Zealand's richest and most diverse fossil faunas of mid-Pliocene age (Waipipian Stage, 3.7–3.0 million years old). The vast excavated heap of sandy shell was extensively searched and sieved resulting in the recovery of 266 fossil taxa, (particularly rich in Mollusca including 77 Bivalvia, 105 Gastropoda, 32 Foraminifera, 13 Ostracoda, 11 Bryozoa). The fauna includes several undescribed taxa and additional warm-water Pliocene records for New Zealand. The fauna is most similar in composition and age to the fauna obtained from the Otahuhu Brewery well in the late 1940s. The fauna contains a mixture of taxa from many different shallow marine habitats, from intertidal and subtidal rocky shores and intertidal and shallow subtidal soft sediment flats to exposed and semi-exposed subtidal sandy habitats down to depths of 30–40 m. The shelly deposit is inferred to have accumulated in a current swept subtidal channel during one of the mid-Pliocene warm periods when sea level was high and had flooded an incised river valley that flowed from east to west across the Auckland region. [ABSTRACT FROM AUTHOR]

Late Pleistocene and Holocene sedimentation records changes in glacio-eustatic cycles, oceanography, active tectonics, and sediment supply. Here, we use high-resolution seismic-reflection profiles in Te Tai-o-Aorere Tasman Bay to investigate sedimentary deposit distributions associated with sea-level cyclicity over ∼140 ka. We identify nine seismic stratigraphic units below the inner continental shelf, interpret their character based on stratal relationships and acoustic properties, and infer ages using global sea level. The sequence includes stacked deposits and unconformities associated with the shifting shoreline over glacial cycles. Prominent erosional features include a lowstand ravinement surface and two transgressive surfaces formed during sea-level rise following the last two glacial maxima of ∼20 ka and ∼140 ka. The youngest surface marks the base of post-glacial sediment accumulated since ∼12 ka in the study area. Post-glacial sediment includes five seismically mappable units, covering an area of ∼1400 km2 and deposit volume of ∼9 km3. Time-averaged sediment accumulation rates are estimated to range from a maximum of ∼1.6–2.8 m/kyr to ∼0.5–0.9 m/kyr. Sequence stratigraphy interpreted in Te Tai-o-Aorere Tasman Bay is representative of accumulation in a relatively wide-shelf, sheltered inner bay setting supplied by mountainous catchments, and provides stratigraphic context necessary for future stratigraphic and tectonics studies. [ABSTRACT FROM AUTHOR]

The Canterbury Basin is a portion of the mostly submerged continent of Zealandia that formed along the eastern portion of the Gondwanan front. Based on tectonic subsidence analyses of IODP Expedition 317 boreholes and Clipper-1 well data, we argue for a rapid subsidence event (∼84 Ma to ∼76 Ma) which we interpret as transit away from a region of mantle upwelling. Breakup was followed by thermal subsidence between 76 Ma and 20 or 10 Ma. Sea-level estimates based on our data are consistent with eustatic estimates in the literature between 76 and 30 Ma. From about 7 Ma to 3.8 Ma, there is evidence that over a kilometre of uplift could have occurred within the basin. This uplift event is consistent with earlier suggestions of lower mantle delamination based on local volcanism and the thickness of the lithosphere. Isostatic calculations are consistent with the hypothesis that delamination of some dense mantle lithosphere could account for the uplift seen in our tectonic subsidence analyses. [ABSTRACT FROM AUTHOR]

The coastlines of the southwestern Pacific are dynamic environments that have been repeatedly reshaped by tectonic forces as well as changing global climate and sea level. It has been theorized that much of the north coast of New Guinea was sparsely inhabited until stabilization of coastal flats fallowing the Mid-Holocene Thermal Maximum and resulting marine high stand. We report on environmental proxy indicators measured in core samples taken near modern day Aitape, Papua New Guinea. These cores record the formation of a large lagoonal system on the modern coastal flats by 5800 cal BP. This lagoon infilled over the next several 1000 years as sea level dropped, with the modern coastal flats stabilizing by 1400 cal BP. A charcoal record spanning the period between 6200 and 1400 cal BP documents substantial increases in influx between ~6200 and 6000 cal BP and particularly from ~3000 to 2600 cal BP. Comparison to regional charcoal and ENSO records suggests that increasing aridity and ENSO intensity may drive regional patterning in fire records, however, localized charcoal records are also heavily influenced by human activity. Between 3000 and 2600 cal BP, forest management practices in the Aitape area, currently focused on tree crops and horticulture characterized by long fallowing and limited burning, shifted to a regime characterized by large scale forest clearance and shorter fallowing. We hypothesize that increasing population driven by abundant Mid-Holocene lagoonal resources may have been difficult to maintain as lagoons infilled and climate became more variable, leading to horticultural intensification. [ABSTRACT FROM AUTHOR]

Where are the harbour structures of the thriving Hellenistic and Roman city of Dor? Recent underwater and coastal surveys and excavations, together with geoarchaeological and geophysical studies, provide strong evidence of the devastating impact of a sea level rise in Hellenistic Dor, as well as of recovery and renewed resilience in the Roman Period. This evidence includes two previously unknown new harbour installations: a very large maritime structure, tentatively identified as a Roman quay (in the North Bay), and a Hellenistic coastal fortification system protecting an anchorage (in the South Bay). [ABSTRACT FROM AUTHOR]

Coastal morphology is persistently changing in structure and environment because of natural and anthropogenic effects. Consequently, determining the spatiotemporal variability of coastal areas has become a significant source of concern. The study focuses on automatic delineation of the shoreline using edge detection algorithms; quantification of the morphological changes using a digital shoreline analysis system (DSAS); and retrieval of coastal bathymetry using linear wave dispersion relation from optical imagery for the period 2005–2020. The Canny algorithm shows efficiency in detecting shoreline precisely (95.6%). The highest erosions for net shoreline movement (NSM) are −31.71 m and −50.43 m/yr for end point rate (EPR) during 2014–2017, whereas the maximum accretions for NSM are 25.37 m and 8.64 m/yr for EPR during 2011–2014. The linear regression rate (LRR) and weighted linear regression (WLR) measure shoreline shift over a 15-year period, with the maximum rates of accretion and erosion being 1.01 m/yr and −1.02 m/yr, respectively. Shoreline prediction was carried out using the Kalman filter model for the year 2021 and was concurrently validated with field DGPS measurements. The retrieved bathymetry over the study area agrees with in situ bathymetry data with a mean bias error (MBE) of 0.39, a correlation coefficient (r) of 0.821, and a coefficient of determination (R2) of 0.742. The study also illustrates the effects of changes in mean sea level (MSL) height and coastal bathymetry on coastal morphology. Coastal bathymetry shows an inverse relationship (r = −0.765) with NSM, whereas MSL height shows a positive relationship with NSM (r = 0.403). [ABSTRACT FROM AUTHOR]

Over the course of the last century, storm surge barriers have been built in several countries and proven to be successful in preventing flooding. However, the operation, reliability, and remaining life of these structures have come under increased pressure due to changing demands, intensified utilisation, and climate change. Yet, there is relatively little known about how these factors affect the remaining life of storm surge barriers. To address this issue, a framework is presented to assess the impacts of external drivers on the remaining life in a systematic manner. The framework considers both the technical state and functional performance and uses scenarios to evaluate the impact of external drivers. The application of the framework is demonstrated for the Hollandsche IJssel barrier (the Netherlands). The results indicate that sea level rise (SLR) is the dominant physical driver. Even in moderate SLR scenarios, the lifespan of the barrier may end in the 2040s if the functional performance with respect to flood protection and navigation cannot be improved. Ultimately, the study demonstrates how the remaining life of storm surge barriers could be assessed systematically and the impact of external drivers on the remaining life could be evaluated. [ABSTRACT FROM AUTHOR]

The newly introduced Upper Cretaceous (Cenomanian–Turonian) Bourzal Formation, outcropped in the Ziban Mounts of the eastern Algerian Saharan Atlas near Biskra, presents a diverse sedimentary sequence approximately 235 m thick. This formation is characterized by alternating layers of carbonate, marl, and gypsum, reflecting dynamic depositional conditions during its formation, The Bourzal Formation is divided into two distinct informal units. The lower unit A, measuring 125 m, consists of thin to thick-bedded limestone interspersed with marl and gypsum beds. The upper unit B, spanning 110 m, is marked by alternating layers of fossiliferous marl, limestone, and dolostone. Detailed field surveys and microfacies analysis led to the identification of eight microfacies types within the formation. These microfacies correspond to three primary depositional environments: tidal flat, lagoon, and shoal. This variety in microfacies and environments indicates significant changes in depositional depth and energy conditions during the formation's development. The overall depositional setting of the Bourzal Formation is interpreted as a homoclinal ramp, specifically the inner ramp zone. This interpretation is based on the observed facies associations and their vertical relationships. Relatively shallow water depths characterize the inner ramp setting and are typically influenced by wave and tidal processes, the alternation between carbonate-dominated and evaporite-bearing layers suggests fluctuations in sea level or climate conditions during deposition. [ABSTRACT FROM AUTHOR]

In the context of climate change, sea level rise and land planning, systemic approaches based on resilience principles are required for the adaptation of coastal areas. In this paper, a new conceptual framework is proposed in which an area and its flood protection system are considered to be two nested social-ecological systems (SESs). Other types of networks of structures, especially transportation infrastructure (ports and waterways, roads and railways) can also be represented, in relation to the areas where they are located, as nested SESs. This conceptual framework, based mainly on the concept of social-ecological resilience, is recommended to develop a common adaptation strategy shared between infrastructure managers and land use planners. It also allows the complementary use of the concepts of technical, ecological and social resilience by different actors to meet specific objectives, which may concern the management of natural or anthropogenic structures or the revision of institutions. [ABSTRACT FROM AUTHOR]

Sea level rise is not a problem for the future alone. It is already affecting many small to medium cities on the East Coast of the USA. These cities are adapting to their problems without sufficient help from the federal or state government. To escape the perils of short-term reactionary ad hoc measures to deal with such problems, there is a need to utilize longer-term visions and frameworks. One such approach, Adaptation Pathway Planning, requires the involvement of locally affected people. This study looks at the perceptions and preferred adaptation solutions of the residents of St. Augustine and the Hyde Park neighborhood in Tampa, FL, two cities that are already experiencing the worsening flooding effects caused by rising seas. The results show that those living in areas at higher risk, and which are already experiencing frequent tidal flooding, had a greater knowledge of this risk and a higher desire for increased action from multiple levels of government. Also, such people were more aware of what their municipalities were already doing to adapt. Finally, when faced with two different scenarios of the possible rise in sea levels by 2050, those presented with the higher scenarios were more likely to choose a wider range of adaptation countermeasures. All this indicates the need to carefully consider the awareness of residents regarding the effects of sea level rise and how long-term adaptation should be discussed with them. [ABSTRACT FROM AUTHOR]

At nuclear power plants, risk analysis concerning environmental extremes is crucial. Based on historical data, estimation of return levels is usually performed. For long return periods, a problem is that the related uncertainties of the return levels often get large. Moreover, models need to take into account possible effects of climate change. In this paper, extreme sea levels close to Swedish nuclear power plants are considered. Non-stationary statistical models and the related results of conditional prediction during a typical time horizon of an infrastructure are studied. The influences of parameters in extreme-value distributions and the lengths of observation records are discussed. The effect of land uplift in parts of the Baltic Sea is seen. [ABSTRACT FROM AUTHOR]

Most living shoreline site selection and design decision support tools are based upon existing environmental conditions. We developed a web-based, geospatial tool called Future Shorelines that integrates high-resolution landscape elevation data and a matrix of locally derived NOAA Interagency Sea Level Rise Scenarios to characterize future conditions of submergence and shoreline translation induced by sea level rise. Once the practitioner selects a location of interest, sea level rise scenario (e.g., high), and target year (e.g., 2050), the tool will generate plan view and cross-sectional informational graphics specific to their choices. This information can then be paired with other menu options, like parcel ownership, to facilitate the planning and construction of nature-based shoreline stabilization solutions that (1) are located where opportunities for horizontal migration are optimized, (2) remain accessible for monitoring and maintenance, and (3) perform as intended over the design life of the installation. The tool's menu options and the user interface were informed by project partner input solicited during numerous workshops convened over the duration of the 2-year project. This coproduction created a product that was familiar to the end user and therefore increased the likelihood that it would be utilized by them during the planning and design of living shoreline projects. Although developed for use in the Indian River Lagoon, located along the east-central Florida coast, it can be seamlessly replicated for application in other coastal regions of the USA where the requisite data are available. [ABSTRACT FROM AUTHOR]

Mangroves can increase their elevation relative to tidal flooding through biogeomorphic feedbacks but can submerge if rates of sea-level rise are too great. There is an urgent need to understand the vulnerability of mangroves to sea-level rise so local communities and resource managers can implement and prioritize actions. The need is especially pressing for small islands, which have been identified as an area of concern by the IPCC. We developed a generalizable modeling framework for tidal wetlands (WARMER-3) that accounts for species interactions and the belowground processes that dictate soil elevation building relative to sea levels. The model was calibrated with extensive field datasets, including accretion rates derived from 29 soil cores, over 300 forest inventory plots, water level, and elevation. The model included five mangrove tree species and was applied across seven regions around the Pacific Island of Pohnpei, Federated States of Micronesia, where mangrove forest is a critical ecosystem that supports subsistence living for local communities. We explored mangrove resilience and carbon accumulation under six sea-level rise scenarios. We also conducted an analysis to determine the sea-level rise rate threshold above which mangroves would be lost. The results suggest that Pohnpei mangroves can build their elevations relative to low and moderate rates of sea-level rise to prevent submergence, with limited loss of mangrove area through 2150. Under higher sea-level rise rates, however, forest elevation decreased substantially relative to mean sea level and there was extensive loss of mangrove area by that year. Regarding mangrove community composition, for all sea-level rise scenarios, the model predicted a change to increasing relative abundance of flood tolerant species and decreasing relative abundance of high-elevation species, which started to being realized by 2100. Variation in sediment supply, water levels, and elevation capital led to differential vulnerability around the island. We identified a threshold for Pohnpei mangroves where if local sea-level rise rates exceed 7.8 ± 2.2 mm/year they are projected to eventually submerge and be lost. Our modeling framework is novel by addressing both species interactions and critical belowground processes to better understand potential tidal ecosystem responses to sea-level rise. [ABSTRACT FROM AUTHOR]

Seawater intrusion (SWI) is a concern for coastline-saturated aquifers because it increases salinity, which contaminates and degrades groundwater quality. Rising sea levels and other natural processes, as well as anthropogenic activities such as overpumping, are the causes of intrusion. Because these experiments are the most reliable methods for study, this study focused on the experimental investigation of SWI in a hypothetical stratified aquifer with parallel and perpendicular stratification and a sloping beach boundary. Stratified media were formed by stacking layers in parallel and perpendicular layers in different combinations. Sensitivity analysis was performed with 10-, 20-, and 30-cm gaps for interactions with 4-layer formations with height to toe length expanding from 0.12 to 2.33. High-resolution images were captured at specified intervals and demarcated for a clear visualization of intrusion. A homogenous base case was used to evaluate the feasibility of the proposed method and the results were compared with those of a sandbox apparatus and found to be consistent in terms of the shape of the wedge and the toe length. The height of the intrusion ranges from 28.3 to 32.2 cm. The intrusion was fast and accurate due to the higher permeability of the material. It was concluded that the toe length–height ratio varies from 0.43 to 7.0. For materials with lower permeabilities, this ratio is small because the intrusion is slow but steady in both directions; however, for materials with higher permeabilities, this ratio corresponds to a higher value. The intrusion is restricted to the individual layer until it encounters an impervious layer and follows a proportional pattern with an increasing area of intrusion as the opening area increases. Practical Applications: This study focused on determining the intrusion behavior in coastal aquifers with monotonically increasing permeability under a layered stratification condition and subjected to the application of inclined boundaries. The study revealed that the use of a glass box apparatus with an inclined ocean–aquifer boundary is the best practical approach for studying intrusion. The occurrence of intrusion due to density differences and heterogeneity represents a case of passive seawater intrusion. The heterogeneity of the aquifer varies at the regional scale; thus, the results obtained from this study may be applied to real-world scenarios by implementing upscaling, temporal dynamics, heterogeneity, and desired boundary conditions. To quantify the intrusion in parallel stratification, a ratio of toe length to height of the intrusion is devised, which is the best approach to follow. The intrusion in the parallel configuration directly depends on the face of the inclined formation subjected to seawater, which forms a parabolic profile, while for the perpendicular configuration, the potential to intrude decreases with each layer as the intrusion is subjected to one layer at a time, initially leading to a parabolic profile that changes to linear in subsequent layers. [ABSTRACT FROM AUTHOR]

Less than 7% of the world's population live at an altitude above 1500 m. Yet, as many as 67% of medalists in the 2020 men's and women's Olympic marathon, and 100% of medalists in the 2020 men's and women's Olympic 5000 m track race may have been born or raised above this otherwise rare threshold. As a possible explanation, research spanning nearly a quarter of a century demonstrates that indigenous highlanders exhibit pulmonary adaptations distinct from their lowland counterparts. These adaptations may then promote endurance performance. Indeed, healthy indigenous highlanders often exhibit a larger aerobic exercise capacity compared to sea‐level residents who travel to high altitude. However, questions remain on whether high‐altitude birth is advantageous for sea‐level competitions. In this review, we ask whether being born at a high altitude generates an ergogenic advantage for endurance performance in the Summer Olympics—a venue that is generally held at sea level. In so doing, we distinguish between three groups of high‐altitude residents: (i) the indigenous highlander, (ii) the highland newcomer, and (iii) the highland sojourner. Concentrating specifically on altitude‐induced alterations to pulmonary physiology beginning in the perinatal period, we propose that if altitude‐related maladaptations are avoided, genomic and developmental alterations accompanying highland birth may present benefits for endurance competitions at sea level. [ABSTRACT FROM AUTHOR]

Climate change is one of the key foci of critical geopolitics in the twenty‐first century, with a proliferation of scholarship considering the international conferences, imaginaries, and securitisations of the climate crisis. Since 2019, Tuvalu has been using human bodies submerged in water – including diplomats, children, and politicians ‐ within its diplomacy to draw attention to the severity of the climate crisis. By examining contemporary Tuvaluan climate diplomacy, this article advocates for a greater engagement with feminist geopolitics to interrogate the embodied practices of climate diplomacy. It draws upon fieldwork conducted in the South Pacific in 2018 and 2019 including at the 50th Pacific Island Forum in Tuvalu. Firstly, this article explores the 2019 visit of the Secretary General of the United Nations to Tuvalu ‐ arguing the photoshoot of him wearing a formal suit in the lagoon connected the imaginary of Tuvalu as a ‘sinking island’ to a wider international community. Secondly, it considers the use of Tuvaluan schoolchildren playing in the water during the 50th Pacific Island Forum. It argues this constituted a vital territorial conjuncture that drew attention to Australia's inaction on climate change and the risk to Tuvalu's future from the rise of sea level. Thirdly, it considers the body of Simon Kofe, Foreign Minister of Tuvalu, during his addresses to COP26 and COP27 from firstly the lagoon in Funafuti and then the metaverse, to examine the shifting narratives of Tuvalu's future within its climate diplomacy. This article argues that climate diplomacy is a deeply embodied practice and human geography scholarship must be more attentive to the geopolitical work that bodies do within climate diplomacy to understand the temporalities and spatialities of diplomacy better. [ABSTRACT FROM AUTHOR]

Southeast Greenland contributes significantly to global sea level rise, with mass loss having increased by about 600% over the past 30 years due to enhanced melt and dynamic instabilities of marine-terminating glaciers. Accurate modelling of glacier dynamics is crucial to minimise uncertainties in predictions of future sea level rise, necessitating detailed reconstructions of long-term glacial histories. One key complexity in these models that is not well understood or documented is ice flow piracy, where ice is redirected between catchment basins, significantly influencing regional glacier dynamics and mass balance. Here, we document and characterise the collapse of Midgaard Glacier in Southeast Greenland using a multi-data approach, providing a 90-year record of the area's complex glacial history. Initiated over 80 years ago, this collapse triggered catchment-scale dynamic changes in several neighbouring glaciers, impacting local glacial stability throughout the 20th century and into the present. Our analysis reveals that catchment-scale ice flow piracy can cause substantial disturbances in mass balance evolution and catchment reconfigurations, independent of climatic conditions. These findings underscore the importance of understanding long-term changes in complex glacier systems to make accurate predictions of future glacial mass loss and associated sea-level rise. This study explores the 90-year collapse of the Midgaard Glacier, one of the greatest mass losers in the entire Greenland ice sheet. The study reveals complex ice flow piracy and demonstrates the impact of Midgaard's collapse on the dynamics of glaciers at a regional scale. [ABSTRACT FROM AUTHOR]

The escalating threat of climate change has placed global coastal communities at risk, with rising sea levels and intensified storm events presenting unprecedented challenges. Coastal vulnerability assessments, conducted every 3–5 years, are crucial. This empirical study assesses the Coastal Vulnerability Index (CVI) for the distinct coastal contexts of Dawlish, Happisburgh (England), and Aberystwyth (Wales). The CVI method consists of the Physical Coastal Vulnerability Index (PCVI) and the Economic Coastal Vulnerability Index (ECVI), which provide a multidimensional assessment of vulnerability for coastal zones. This integrated index allows for a nuanced evaluation of vulnerability, distinguishing between sites based on various factors. Additionally, this study conducted a correlation analysis to understand the associations between the parameters. The findings demonstrate that physical features like beach and dune widths significantly impact a location's natural defences, and economic factors such as property values and population density are equally crucial in determining societal risks and potential financial repercussions. The Combined Coastal Vulnerability Index (CCVI) results confirm the effectiveness of incorporating a diverse range of variables. Despite its substantial economic value, it reveals that Dawlish requires targeted protective measures, whereas Happisburgh needs an increased focus on its most vulnerable sectors. Aberystwyth emerges as the area with the highest overall vulnerability, underscoring the need for comprehensive coastal management practices. The study's conclusions emphasize the essential role of adaptive, integrated management strategies in enhancing coastal resilience against the complex threats posed by climate dynamics. Moving forward, the indices established herein advocate for their use in strategic planning and policymaking to strengthen coastal regions in the face of sea-level rise and climatic variability. This investigation lays the groundwork for future research, aimed at refining and expanding these methodologies, aspiring to develop a detailed national coastal vulnerability atlas, a critical tool for informed decision-making and safeguarding at-risk communities. [ABSTRACT FROM AUTHOR]

Intertidal salt production sites existed continuously around the Mediterranean since classical antiquity, and their remains are present in large numbers along the Dalmatian (east Adriatic) coast. Most of them are preserved and dated to medieval times. This study aims to develop complementary proxies identifying the salt production layer in submerged ancient saltpans of Lavsa, a remote island on the central Dalmatian coast, to date the saltwork units by optically stimulated luminescence (OSL) and use them to infer changes in sea level. The significance of the study is in the application of molecular fossil analyses identifying the hypersaline layer in the sediments from a core drilled in the saltpan's site. The molecular fossil analyses correlate with the results of micro and macrofossil analyses and geochemical findings, all representing the saltwork unit. The depth of the hypersaline layers and the OSL dates provide relative sea level (RSL) lower limiting points of −145 ± 5 cm at 1309 ± 33 CE, probably the time when salt production started in Lavsa, and −115 ± 5 cm at 1364 ± 52 CE when saltwork activities ended. These limiting points extend the known RSL index point in Lavsa Island of −92 ± 8 cm, with an updated average age of 1337 ± 62 CE, correlating with the historical records. Medieval lower sea levels were also observed in the northern and southern parts of the east Adriatic coast as well as in other parts of the Mediterranean, probably driven by climate-related events, generating centennial-scale fluctuations in past sea levels that cannot be predicted by glacial isostatic adjustment (GIA) models. [ABSTRACT FROM AUTHOR]

Understanding millennial changes in relative sea level (RSL) and coastal responses in stable regions is crucial for deciphering the intricate relationship between natural dynamics and human adaptation. This interdisciplinary study explores the interplay between mid-to-Late Holocene sea-level fluctuations and tectonic along the mid-Tyrrhenian coast. The study area, located between the Fondi and Garigliano coastal plains, held great significance in ancient times. In particular, the strategic role of Formia, a monitoring point for the Tyrrhenian Sea, made this city one of the most important commercial hub during Roman occupation, leading to a significant urbanization of the coastal stretch testified by well-preserved remains nowadays scattered along the submerged or semi-submerged coastal sectors. This study reconstructs the mid-to-Late Holocene morpho-evolution and RSL changes in the study area by creating a geodatabase made of 52 sea-level markers (SLMs) derived from direct geoarchaeological measurements, stratigraphic and palaeoecological interpretations of new borehole data, and previously published stratigraphic data. Specifically, the radiocarbon dating of three peat samples provided new data ranging between 7.62 ± 47 and 1.00 ± 51 ka BP on the sea level history in the area. Based on our dataset, between 9.0 and 8.0 ka BP, the sea level rose from −19 m to −6.5 m at a rate of about 15.6 mm/y, slowing to 0.8 mm/y afterwards, stabilizing at its current position. Results suggest that during the 1st century BC, local sea level was no higher than −0.55 ± 0.29 m. The collected RSL data support the hypothesis of tectonic stability of this sector during the last 2.0 ka, testified by the position of the SLMs in accordance with the glacio-hydro-isostatic adjustment (GIA) models and supported by the determination of average vertical ground movement rates of −0.017 ± 0.23 mm/y. Finally, in terms of coastal changes the overlay between new data from geoarchaeological surveys, reinterpretation of previously-published stratigraphic data, and geomorphological analysis allowed us to deduce a general coastal progradation trend in the historical time for both low-lying and rocky sectors, due to natural and anthropogenic forcing factors. [ABSTRACT FROM AUTHOR]

Guanabara Bay, located in the Metropolitan Region of Rio de Janeiro, one of the largest urban coastal areas in the Southern Hemisphere, is subject to intense maritime traffic due to the presence of several ports. These facilities are affected by sea level fluctuations, influenced by atmospheric and astronomical forces, which motivates synoptic and climatological analysis, including meteorological and astronomical tidal phenomena. This study aimed to assess the evolution of tidal components and the relative mean sea level (MSL) between 1990 and 2021, as well as the atmospheric influence on extreme meteorological tide events, in which the MSL exceeded ±2 and ±3 (±29.98 and ±44.97 cm) standard deviations. The results have shown that, albeit small, the main tidal components (M2, S2, O1, M4, Q1, K1, K2 and N2) indicated positive trends in the increase of amplitude and phase, despite the small quantities. For the relative MSL, an increase of 0.30 cm·year−1 was observed in agreement with estimates from global series from satellite altimeters and climate model predictions. Pressure and wind field analyses led to the identification of seasonal variability and the pattern of evolution of atmospheric systems associated with extreme events. In the case of positive surges, very intense winds from the SW, extending along the S/SE Brazilian coast, are caused by the presence of a high‐pressure centre over the continent and low‐pressure centres over the ocean, leading to water piling up. In turn, negative surges are caused by the presence of an anticyclone over the ocean, generating NE winds parallel to the coast of Rio de Janeiro, inducing Ekman transport and lowering the sea level. Therefore, the extreme sea level events in the Guanabara Bay are not triggered by local forces, but rather depend on the temporal persistence and direction of winds along the S/SE Brazilian coast. [ABSTRACT FROM AUTHOR]

Mangrove forests enhance Small Island Developing States' resilience to climate change, yet in 2020, a mangrove dieback impacted ~ 25% of mangrove-containing islands in the Maldives. Using remote sensing, dendrology and sediment geochemistry, we document a significant decrease in mangrove health post-2020 (NDVI: 0.75 ± 0.09) compared to pre-2020 (0.85 ± 0.04; P < 0.0001). Dead trees showed reduced stomatal conductance (δ13C: − 26.21 ± 0.11 ‰) relative to living ones (− 27.66 ± 0.14 ‰), indicating salinity stress. Critically, sea-level rise (30.50 ± 23.30 mm/year) outpaced mangrove sediment accretion (6.40 ± 0.69 mm/year) five-fold between 2017 and 2020. We attribute this dieback to salinity stress driven by record-high sea levels in 2020, linked to an extreme positive Indian Ocean Dipole event. These findings reveal the vulnerability of mangrove ecosystems to rapid sea-level rise and highlights the urgent need for adaptive conservation strategies in Small Island Developing States. [ABSTRACT FROM AUTHOR]

This paper delves into the complexities of maritime delimitation in the context of sea level rise (SLR) and ice-covered regions, examining several factors and legal implications. Through academic discussion and technical analysis, the adjustments is required in approaches to the Exclusive Economic Zone and the continental shelf boundaries' delimitation amidst SLR, while the different models adopted by adjacent and opposite states are presenting. As a result, the paper provides a comprehensive overview of common issues surrounding baseline determination, particularly in relation to SLR and the challenges posed by off-shore features. Legal dynamics concerning 'submarine ridges' versus 'oceanic ridges' are explored, highlighting the complexities inherent in maritime boundary delineation. Additionally, the dynamics of basepoint selection in ice-covered regions is investigated, emphasizing essential criteria for navigation and offering case studies from the Antarctic and Arctic here. Through this exploration, the paper contributes to a deeper understanding of the challenges and considerations involved in maritime delimitation amidst SLR, offering valuable insights from both technical and legal perspectives. [ABSTRACT FROM AUTHOR]

The tropical Angolan upwelling system (tAUS) is a highly productive ecosystem of great socio-economic importance. Productivity peaks in austral winter and is linked to the passage of remotely forced upwelling coastal trapped waves (CTWs), where the strength of the productivity peak is associated with the amplitude of the upwelling CTW. Here, we analyze the year-to-year variability in the timing and amplitude of the austral winter upwelling CTW by examining sea surface temperature, sea level anomaly, and wind fields. Our results show that the timing of the CTW is influenced by variability in the equatorial region and along the southern African coast. Weaker equatorial easterlies from April to July delay the generation of the upwelling Kelvin wave, leading to a later arrival of the upwelling CTW. In contrast, the amplitude of the CTW is primarily influenced by variability in the eastern equatorial Atlantic and the central South Atlantic, where the South Atlantic Anticyclone is located. A cooling in the eastern equatorial Atlantic three to four months before the arrival of the CTW causes stronger zonal winds, ultimately leading to a stronger austral winter upwelling CTW. Our results suggest that the timing and amplitude of the upwelling CTW in the tAUS during austral winter are predictable on seasonal time scales. [ABSTRACT FROM AUTHOR]

Flooding poses a severe global threat, necessitating advanced methodologies to assess and manage its risks effectively. This study introduces a novel approach that integrates Geographic Information System (GIS) with hydrologic-hydraulic modeling to evaluate the combined drivers of current and future flood risks. The method is applied to the development Bonita Bay in southwest Florida. It occurs in a region highly susceptible to flooding due to its low elevation and proximity to tidal waters. The innovative integration of GIS with hydrologic-hydraulic models enables detailed assessment and visualization of flood inundation areas under multiple flood drivers including design storms, land use changes, groundwater rise, and sea-level rise. This allows for the seamless simulation of complex flood interactions with only minor adjustments to the model for the identified drivers. The results indicate significant increases in initial water storage caused by sea and groundwater level rise and amplified storm runoff from land use changes. A 2% increase in flooded areas is projected with stronger design storms, and a 5% increase by 2,100 compared to 2024. This approach provides a robust framework for developing tailored flood mitigation strategies and can be adapted to various coastal regions globally. [ABSTRACT FROM AUTHOR]

The time series of PALSAR-2 and Sentinel-1 images reveal inflation at the volcanic flank and contraction at the crater for approximately 5 months before the 2017 eruption of Shinmoe-dake volcano, Japan. While the observation of inflation at the volcano's flank is ubiquitous, few studies have reported crater contraction preceding an eruption. The flank inflation stopped after the 2017 eruption, while the contraction at the crater continued until the 2018 eruption. We found that a pipe-shaped deformation source above sea level best fits the observation preceding the 2017 eruption. Suppose the flux of ejected materials constrains the conduit radius during the previous 2011 eruption. In that case, the amount of deformation of the pipe-shaped deformation source, whether open or closed at its top, is too large to be realistic. Although constraining the conduit radius from the eruption flux overestimates the pressure change of the pipe-shaped deformation source, water-saturated fractures along the volcanic conduit could extend the effective conduit radius of the pressure source. We propose one potential scenario for the mechanism of the crater contraction preceding volcanic eruptions based on the combination of compaction due to cooling by ambient groundwater and material withdrawal within the conduit. The groundwater inflows from the ambient aquifer through cracks in the porous conduit wall, which are generated by conduit expansion during the magma ascent. Decoupling from the conduit wall due to a decrease in volume of the material promotes material instability and crater contraction. The interaction between the groundwater and the magma triggers the 2017 eruption of Shinmoe-dake volcano, as previous studies have reported. [ABSTRACT FROM AUTHOR]

The southwest region of Bangladesh is particularly vulnerable to a range of climatic threats, including cyclones, prolonged flooding, sea level rise, saltwater intrusion, drought, and riverbank erosion. The study investigates how these different drivers affect aquaculture systems and aims to provide critical insights for sustainable management. The survey work focused on the problems, vulnerabilities, migration, and adaptive strategies of communities of the southwest region of Bangladesh, that rely heavily on shrimp, fish, and crab production for their livelihoods. Data were collected from the 80 respondents across four unions (Atulia, Burigoalini, Gabura, and Bhurulia) in Shyannagar Upazila, Satkhira District, using a structured questionnaire survey and focus group discussions. Findings reveal that climate change events have significantly changed shrimp farming in enclosures, pond aquaculture, and crab point management, and negatively impacted livelihoods. Pond aquaculture appeared to be the most vulnerable to climate change conditions, followed by shrimp farming in enclosures and crab points. Furthermore, the adverse effects of climate change compelled human migration within the study area, primarily driven by the search for employment. This study provides evidence of the effects of various climate change stressors on shrimp, fish, and crab production systems and the adaptive difficulties of the communities dependent on aquatic ecosystems. As the natural calamity like cyclone cannot be prevented, understanding the impact of previous events may help people of the affected area as well as the policy makers to plan for better survival. [ABSTRACT FROM AUTHOR]

Processes of transport and deposition of large-scale pyroclastic density currents, which transport 102-103 km3 of material, are still poorly understood. The volcanic explosivity index (VEI) 7 Campanian Ignimbrite pyroclastic density current is one such poorly understood case that is subject to lively scientific debates about its origin and processes. The Campanian Ignimbrite is related to the 39.8 ka eruption that formed the partly submarine and active Campi Flegrei caldera in Italy. The related pyroclastic density current extended over an area of more than 6000 km2 on land around the caldera, with a final runout of ~75 km, and surmounted mountain ridges higher than 1000 m above sea level, even at distal reaches. We used physical characteristics of the ignimbrite to understand the transport and emplacement dynamics of the Campanian Ignimbrite pyroclastic density current. Thickness, mass, and clast-size distributions across paleotopography were used to infer that the main transport system was a dilute, density-stratified pyroclastic density current, which was at least 1.5 km thick, which was short-lived (possibly as short as ~20 min), and which had a mass flow rate of ~1011 kg/s. At its base, high-concentration undercurrents formed and interacted with the rough paleotopography, laying down a low-aspect-ratio ignimbrite sheet when on flat plains, but generating back-flows from ridges and channeling in paleovalleys. The deposit is predominantly a massive valley-pond ignimbrite facies, even across rough mountain terrains. The absence of veneer facies on steep slopes reflects the near-Newtonian rheology of the undercurrents, interpreted as fluidized dense granular flows. This work advances the interpretations of pyroclastic density current deposits, which do not necessarily directly reflect conditions in the transport system. [ABSTRACT FROM AUTHOR]

The Messinian-Zanclean boundary in the Mediterranean basin marks the end of the Messinian salinity crisis (MSC) at approximately 5.33 Ma. The mechanism behind the return to normal marine conditions after the MSC are debated, with two main hypotheses proposed: an instantaneous reflooding of the Mediterranean at the base of the Zanclean, following its near-complete desiccation, or a gradual sea level rise in a non-desiccated basin during the late MSC phase (Lago-Mare). Our objectives are to refine the age model of the Pollenzo section in the Piedmont basin, Italy, and to elucidate environmental variability during this phase. We employ high-resolution biomagnetostratigraphic and cyclostratigraphic analyses, integrated with statistical multivariate and cluster analyses, and tie the results with other Italian Mediterranean reference sections of the basal Zanclean. The proposed age model is based on biostratigraphic markers (planktic foraminifera and calcareous nannofossils), alongside the identification of the base of the Thvera subchron. Although no astrochronological tuning was proposed, the influence of orbital parameters variation on calcareous plankton was noted, especially at tie of eccentricity maxima. Our results indicate a gradual restoration of open marine conditions after the MSC, spanning from 5.33 to 5.23 Ma. We observe a transition from a more marginal environment to more open marine conditions at the termination of MSC. Our findings challenge the notion of an abrupt transition at the end of the MSC, emphasizing the gradual nature of environmental change in the northernmost Mediterranean basin, from the late Messinian to the early Zanclean. [ABSTRACT FROM AUTHOR]

Miami‐Dade County (MDC) has over 112,000 septic systems, some of which are at risk of compromise due to water table rise associated with sea level rise. MDC is surrounded by protected water bodies, including Biscayne Bay, with environmentally sensitive ecosystems and is underlain by highly transmissive karstic limestone. The main objective of the study is to provide first estimates of the locations and magnitudes of septic return flows to discharge endpoints. This is accomplished by leveraging MDC's county‐scale surface‐groundwater model using pathline analysis to estimate the transport and discharge fate of septic system flows under the complex time history of groundwater flow response to pumping, canal management, storms, and other environmental factors. The model covers an area of 4772 km2 in Southeast Florida. Outputs from the model were used to create a 30‐year (2010 to 2040) simulation of the spatial–temporal pathlines from septic input locations to their termination points, allowing us to map flow paths and the spatial distribution of the septic flow discharge endpoints under the simulated conditions. Most septic return flows were discharged to surface water, primarily canals 52,830 m3/d and Biscayne Bay (5696 m3/d), and well fields (14,066 m3/d). Results allow us to identify "hotspots" to guide water quality sampling efforts and to provide recommendations for septic‐to‐sewer conversion areas that should provide most benefit by reducing nutrient loading to water bodies. [ABSTRACT FROM AUTHOR]

The article discusses the Coastal Flood Hazard Workshop held by the Scripps Institution of Oceanography in San Diego, California, focusing on advancements in predicting and evaluating coastal flood hazards in a changing climate. The workshop aimed to assess state-of-the-art methods, identify knowledge gaps, and determine future research pathways to inform community-level flood risk and adaptation planning. It highlighted advancements in both long-term flood projection models and operational forecast models, emphasizing the need to bridge scales and integrate various sources of data for accurate flood predictions. The article also addresses identified knowledge gaps and future research avenues, emphasizing the importance of sustained observations, satellite monitoring, community engagement, and interdisciplinary collaboration in improving coastal flood forecasting and mitigation efforts. [Extracted from the article]

A comprehensive study of the Mundrothruthu (MT) core (70 cm) from the Asthamudi wetland in Kollam, Kerala, India reveals three climate phases during the Little Ice Age (LIA) through multi-proxy investigations. The period (1507–1518 CE) shows high agricultural activity indicated by abundant diatom diversity, significant terrestrial influx, and freshwater runoff. Elevated TOC% and δ13C TOC values suggest high temperature and a warm, humid climate, likely driven by high terrestrial influx and transport of organic matter from the nearby surroundings. This may have increased the organic matter influx to the estuary leading to high TOC% and more negative δ1³C values. The second phase (1519–1548 CE) is characterized by increased marine incursion due to enhanced tidal currents, evidenced by a rise in marine palynomorphs, mixed terrestrial and marine organic matter, less negative δ13C values, and increased mud content. This shift likely reflects changes in sea level or tidal dynamics. The final period (1548–1804 CE) is marked by further enhancement of marine taxa, lower TOC%, and δ13C TOC values, indicating reduced atmospheric CO 2 and a temperature decrease of about 1 °C. This period is associated with reduced solar insolation and a southward shift of the Inter Tropical Convergence Zone (ITCZ). The study highlights both synchronous and asynchronous climatic behavior on the southwest coast of India relative to global changes during the LIA. Initially warm and humid with high agricultural productivity, the region gradually shifted to marine-dominated conditions due to tidal dynamics and broader climatic shifts. These findings underscore the complex interplay between local and global climatic factors during the LIA. [ABSTRACT FROM AUTHOR]

Himalayan orogeny and consequent climatic changes, such as the strengthening of the Asian monsoon, are considered as two main drivers in shaping local biogeography. The mountainous Sinopoda spiders, which are widely distributed in East Asia and Southeast Asia and especially abundant in the mountains near the Himalayas, represent an ideal model lineage for investigating Himalayan biogeography. This is due to their high diversity, limited dispersal ability, and wide elevational distribution, ranging from sea level up to 3500 meters. We investigated the evolutionary history of Sinopoda spiders, focusing on ecological, molecular, and morphological traits in relation to local geological events and fluctuations in Neogene (23.0–2.6 Ma) Asian monsoon patterns. Distribution modeling results show that extant Sinopoda spiders are sensitive to humidity fluctuations. They are mainly distributed in two distinct habitats: areas with moderate precipitation at high altitude (relatively cold) and areas with high precipitation at low altitude (relatively warm). The biogeographical and elevation reconstruction analyses show that as the Himalayas rose and the Asian monsoon intensified, Sinopoda spiders (Sparassidae: Heteropodinae) moved out of the Himalayas (ca 18.1 Ma) then 'down' the rising mountain slopes (ca 9.6 Ma). We then see a secondary return to the mountains (ca 3.3 Ma) as the severity of the East Asian monsoon decreased. We hypothesize that our 'out of Himalaya' dispersal pattern hypothesis will also apply to closely related spider groups with limited ballooning ability (e.g. Lycosidae, Thomisidae) or other organisms with low vagility (such as herpetofauna) that are sensitive to humidity and possess similar geographical distributions. [ABSTRACT FROM AUTHOR]

This research introduces a novel index for the South Atlantic High Pressure (SAHP) system to enhance understanding of regional climate variability and change. Subtropical highs significantly influence regional climates, yet comprehensive indices to measure their behaviours are lacking. Utilizing ERA5 reanalysis data from 1940 to 2023, the proposed index estimates a weighted centroid of the area surrounding the maximum sea level pressure within a 3 hPa range. This method ensures robustness and flexibility in contiguous area estimation specific to subtropical high events. Results showed the index effectively reflects the position and intensity of the SAHP. The study reveals that latitudinal variability of the SAHP has a strong unimodal structure, whereas longitudinal variability exhibits a bimodal structure. Seasonal patterns of the index show noticeable changes, with winter (JJA) and spring (SON) months having relatively high index values compared to summer (DJF) and autumn (MAM) months, underscoring the intra‐annual variability of the SAHP index. During ENSO events, the mean centroid position of the SAHP shifts significantly, moving westwards and polewards during El Niño and showing greater stability during La Niña. The index, with minimal computation requirements and flexibility, can be applied across diverse datasets, aiding in the assessment of future subtropical high changes. [ABSTRACT FROM AUTHOR]

Late Campanian terrestrial communities of western Canada are best known from the fluvial–paralic deposits of the Dinosaur Park Formation (DPF) in Dinosaur Provincial Park (DPP), Alberta. However, a growing list of localities from isolated DPF outcrops, outside of the DPP area, offers a glimpse into palaeocommunities that evolved isochronously with DPP biotas in greater proximity to the Western Interior Seaway. Over the past decade, one such locality was explored along Lake Diefenbaker in Saskatchewan Landing Provincial Park. The initial palaeoecological analysis of this marginal marine community was based on palynomorph and vertebrate microfossil diversity and has laid a foundation for the current study of its monodominant ceratopsian bonebed. The latter has resulted in new occurrences of Centrosaurus apertus and of the elmisaurine Citipes elegans for Saskatchewan based on incomplete yet diagnostic specimens. Centrosaurus apertus is unequivocally identified by a parietal bar bearing two prominent P1 and P2 hooks, which expands the geographical and habitat range of this species to the most coastal environment known from the DPF. Furthermore, the presence of Centrosaurus apertus suggests that the DPF in this region of Saskatchewan is closer in age to the lower DPF than to the uppermost DPF in DPP, which is at odds with a previous palynostratigraphic interpretation. The faunal composition of this bonebed also supports the presence of a widely distributed metacommunity across these deposits. This contribution demonstrates how evidence from multiple localities in the DPF along a spatial gradient, beyond the temporal gradient available within DPP alone, expands the picture of this metacommunity as a potential model system for biotic turnover in response to sea level rise at a geological temporal scale. [ABSTRACT FROM AUTHOR]

The present study is a preliminary step towards the detection of cosmic rays at higher altitude in the Great Himalayan range. Present work is an attempt to see the possibility of the presence of cosmic rays at a height of 3800 m from the sea level in the Great Himalayan range. An experiment was planned for the search of galactic cosmic rays (GCR) using CR39 track etch detectors at the Patsio DRDO (Defence Research and Development Organization) laboratory in the Great Himalayan range, India at a height of 3800 m from the sea level and 32° 45′ N, 77° 15′ E. CR39 detectors were etched in 8N NaOH solution + 3% ethyl alcohol at 70 °C to visualize the tracks produced in the exposed detectors under optical microscope. A detection threshold of CR39 detector down to Z = 18 (Z/β ~ 27) was obtained. After scanning, fine tracks were observed and it was concluded that that high Z cosmic rays may be present at an altitude of 3800 m from the sea level in the Great Himalayan range. [ABSTRACT FROM AUTHOR]

The Antarctic Ice Sheet (AIS) has been losing ice mass and contributing to global sea level rise (GSLR). Given its mass that is enough to cause ∼58 m of GSLR, accurate estimation of mass balance trend is critical for AIS mass loss monitoring and sea level rise forecasting. Here, we present an improved approach to reconciled solutions of mass balance in AIS and its regions from multiple contributing solutions using the input-out, altimetric, and gravimetric methods. In comparison to previous methods, such as IMBIE 2018, this approach utilizes an adaptive data aggregation window to handle the heterogeneity of the contributing solutions, including the number of solutions, temporal distributions, uncertainties, and estimation techniques. We improved the regression-based method by using a two-step procedure that establishes ensembled solutions within each method (input-output, altimetry, or gravimetry) and then estimates the method-independent reconciled solutions. For the first time, 16 contributing solutions from 8 Chinese institutions are used to estimate the reconciled mass balance of AIS and its regions from 1996 to 2021. Our results show that AIS has lost a total ice mass of ∼3213±253 Gt during the period, an equivalent of ∼8.9±0.7 mm of GSLR. There is a sustained mass loss acceleration since 2006, from 88.1±3.6 Gt yr−1 during 1996–2005 to 130.7±8.4 Gt yr−1 during 2006–2013 and further to 157.0±9.0 Gt yr−1 during 2014–2021. The mass loss signal in the West Antarctica and Antarctic Peninsula is dominant and clearly presented in the reconciled estimation and contributing solutions, regardless of estimation methods used and fluctuation of surface mass balance. Uncertainty and challenges remain in mass balance estimation in East Antarctica. This reconciled estimation approach can be extended and applied for improved mass balance estimation in the Greenland Ice Sheet and mountain glacier regions. [ABSTRACT FROM AUTHOR]

The Holocene infill of an intermittently open-closed barrier estuary (Painkalac Creek/Aireys Inlet) was examined on the southern margins of Australia, through aerial LiDAR, coring, sedimentology, radiocarbon dating and pollen analysis. It is found that almost all the accommodation space within the estuary has been occupied, with a thick sequence (>9 m) of sediments being deposited rapidly soon after flooding by the sea. The rate of sedimentation was 4.8 mm/year which closely matches the rate of sea level rise (4.5 mm/year) during the 1200 year period that the estuary infilled, from around 8000–6800 years ago. The evidence of estuarine deposition above the elevation of the modern intertidal zone provides significant further evidence for the presence of the mid-Holocene highstand sea level in this relatively unstudied part of the Australian coast. The pattern of infill departs from the traditional barrier evolution models. The first phase of infill was likely tide dominated with subtidal sand shoals being found landward of a subtidal bedrock sill. Once a beach-barrier sequence formed, the estuary infilled in a more traditional manner, with lateral progradation of a flood tide delta and central mud basin infill. The barrier estuary of Painkalac Creek therefore has undergone a complex evolutionary history, characterised by a change in process dominance from classic tidal to wave-dominated form. Infill occurred in a keep-up (or fast catch-up) mode, with geological control occurring in regard to the presence of an intertidal bedrock sill at the mouth of the estuary. [ABSTRACT FROM AUTHOR]

AMS radiocarbon-dated palynological evidence from Embilikala Lagoon in Bundala National Park (one of the Ramsar wetland sites) on the southeast coast of Sri Lanka indicates palaeoenvironmental changes during the last 2,700 years. The persistence of fewer mangroves (eg Rhizophoraceae taxa) suggests that sea level low stands occurred between 2,700 and 1750 cal yr BP. From the later age, the relative sea level rose, and reached the present sea level at 950 cal yr BP as indicated by the mangrove maximum. At 2,250, 700–400 and 200–150 cal yr BP, the sudden increase in marine dinoflagellate cysts (eg Spiniferites mirabilis) and foraminifera (Globigerinoides ruber) suggests increased marine influence. This is consistent with a decrease in mangrove habitats. Between 2,700 and 950 cal yr BP, severely degraded dry monsoon forests and minimal levels mangrove suggest human and marine influences were the critical drivers for changing the major vegetation types along the southeastern coast. Vegetation changes have been drastic over the last millennia. [ABSTRACT FROM AUTHOR]

Purpose: Tibetan patients undergoing total knee arthroplasty (TKA) have greater fluctuations in perioperative haemoglobin levels and blood hypercoagulability. This study was to investigate whether ethnicity and altitude affect perioperative blood loss and the risk of complications after TKA. Methods: We retrospectively enrolled 1,116 patients undergoing TKA for knee osteoarthritis at our hospital between January 2016 and September 2021. We divided patients into four groups according to whether they were of Tibetan or Han ethnicity and whether they lived above or below 2500 m above sea level. Primary outcomes were total, intraoperative, and hidden blood losses, while secondary outcomes were complications and homologous transfusion. Factors associated with increased blood loss were analyzed by multivariate regression. Results: Total blood loss was higher among patients residing at high altitude compared with lower altitude, whether they were of Han (794.6 mL vs. 667.2 mL, P = 0.020) or Tibetan (904.4 mL vs. 663.8 mL, P < 0.001). Total blood loss was similar between the two ethnic groups at the same altitude. Altitude, but not Tibetan ethnicity, remained associated with increased blood loss after being analyzed by multivariate regression. Complications among the four groups were generally similar, although the frequency of calf muscular venous thrombosis was higher among Tibetan patients, while the frequency of blood transfusion was higher among Han subjects. Conclusions: Our findings indicate that residence at high altitude, but not ethnicity, may contribute to increased total blood loss during TKA. Thrombotic complications were more frequent among Tibetan than Han patients. [ABSTRACT FROM AUTHOR]

Antarctica has been proposed as a significant source of the meltwater that entered the oceans during meltwater pulse 1B (MWP1B) approximately 11 500 yr ago. Support for this scenario has been provided by evidence that the deep fjords of coastal Antarctica, which were heavily glaciated at the maximum of glaciation, were deglaciated at this time. Further support for this scenario was provided by the observation that the inter-hemispheric sea-level teleconnection associated with significant Southern Hemisphere deglaciation at this time provided an explanation of the highly non-monotonic relative sea-level histories recorded at sites on the coast of Scotland, a region which had also been heavily glaciated at the last glacial maximum. Furthermore, it has been argued that a significant contribution to MWP1B must have also been delivered to the oceans by the abrupt Northern Hemisphere warming that occurred at the end of the Younger Dryas (YD) cold reversal, which also occurred approximately 11 500 yr ago. Our focus in this paper is to distinguish between these two possible primary sources of MWP1B. The investigation of how local alterations to ice thicknesses are able to explain evidence which has previously been used to argue for an Antarctic dominant MWP1B will lead us to the conclusion that the Laurentide may be primary source of MWP1B. [ABSTRACT FROM AUTHOR]