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Louisiana lost nearly 5,000 km2 of its coastal land area due to relative sea level rise (including local, regional, and global factors driving relative sea level change) since 1932, mirroring both the hazards associated with sea level rise and the time horizons of sea level rise impacts expected this century. This represents an opportunity to examine the relationship between long-term population changes and shoreline change. Based on detailed land change data for the period 1932–2010 and a small area population estimation technique for the period 1940–2010, we examine intra-parish population changes in relation to shoreline changes for the one million plus residents living in the ten coastal parishes of Louisiana. We find that since 1940, only two of the ten coastal parishes exhibited landward population movement, which we define as movement perpendicular to the shoreline, exceeding 1 km. Three parishes exhibited seaward population movement in excess of 1 km. Overall, we find very little net intra-parish landward population movement for the region. Our findings suggest that coastal Louisiana's historical population has not moved in concert with observed shoreline encroachment. We also find a potential tipping point related to population migration when a neighborhood loses at least 50% of its land area. Our findings suggest that this lack of landward population movement could be attributable to either localized adaptation strategies or migrations to other landward areas. [ABSTRACT FROM AUTHOR]

In coming decades, sea level rise associated with climate change will make some communities uninhabitable. Managed retreat, or planned relocation, is a proactive response prior to catastrophic necessity. Managed retreat has disruptive health, sociocultural, and economic impacts on communities that relocate. Health impacts include mental health, social capital, food security, water supply, sanitation, infectious diseases, injury, and health care access. We searched peer-reviewed and gray literature for reports on small island or coastal communities at various stages of relocation primarily due to sea level rise. We reviewed these reports to identify public health impacts and barriers to relocation. We identified eight relevant small communities in the USA (Alaska, Louisiana, and Washington), Panama, Fiji, Papua New Guinea, Solomon Islands, and Vanuatu. Affected populations range from 60 to 2700 persons and are predominantly indigenous people who rely on subsistence fishing and agriculture. Few reports directly addressed public health issues. While some relocations were successful, barriers to relocation in other communities include place attachment, potential loss of livelihoods, and lack of funding, suitable land, community consensus, and governance procedures. Further research is needed on the health impacts of managed retreat and how to facilitate population resilience. Studies could include surveillance of health indicators before and after communities relocate due to sea level rise, drought, or other environmental hazards. Lessons learned may inform relocation of both small and large communities affected by climate change. [ABSTRACT FROM AUTHOR]

Seasonal variations of sea level have an important impact on coastal groundwater level and salinity. Consequently, they cause spatiotemporal changes in the seawater/freshwater interface. The oceanic tide effect on groundwater dynamics and salinity was investigated in the coastal aquifers of Sahel Doukkala, Morocco. Continuous monitoring of water level and electrical conductivity (EC) was carried out in two coastal wells (drawing from two different aquifers) over a period of 9 months. The main objective of the study was to characterize the aquifers’ exposure to anthropic pumping operations and oceanic tide oscillations. The obtained results showed that oceanic tide has a significant effect on groundwater level as well as on water salinity. The fluctuation periods of groundwater level and tidal level were found to be equal, with a specific time lag. Hydraulic diffusivity was calculated using both confined- and semi-confined-aquifer methods and by analyzing both the time lag and amplitude damping factor. Results indicate hydraulic diffusivity differences between the two aquifers. In addition, there were apparent differences depending on whether time lag or amplitude was analyzed, possibly due to effects of heterogeneity within the aquifers. A detailed study of water EC variation revealed the significant influence of daily and synodic tide on groundwater salinity. Water EC variations were significant when hydraulic diffusivity is higher, indicating that sea-level oscillations induce freshwater/seawater interface movement and consequently influence the groundwater quality. [ABSTRACT FROM AUTHOR]

For now, the question about future sea level change in the Mediterranean remains a challenge. Previous climate modelling attempts to estimate future sea level change in the Mediterranean did not meet a consensus. The low resolution of CMIP-type models prevents an accurate representation of important small scales processes acting over the Mediterranean region. For this reason among others, the use of high resolution regional ocean modelling has been recommended in literature to address the question of ongoing and future Mediterranean sea level change in response to climate change or greenhouse gases emissions. Also, it has been shown that east Atlantic sea level variability is the dominant driver of the Mediterranean variability at interannual and interdecadal scales. However, up to now, long-term regional simulations of the Mediterranean Sea do not integrate the full sea level information from the Atlantic, which is a substantial shortcoming when analysing Mediterranean sea level response. In the present study we analyse different approaches followed by state-of-the-art regional climate models to simulate Mediterranean sea level variability. Additionally we present a new simulation which incorporates improved information of Atlantic sea level forcing at the lateral boundary. We evaluate the skills of the different simulations in the frame of long-term hindcast simulations spanning from 1980 to 2012 analysing sea level variability from seasonal to multidecadal scales. Results from the new simulation show a substantial improvement in the modelled Mediterranean sea level signal. This confirms that Mediterranean mean sea level is strongly influenced by the Atlantic conditions, and thus suggests that the quality of the information in the lateral boundary conditions (LBCs) is crucial for the good modelling of Mediterranean sea level. We also found that the regional differences inside the basin, that are induced by circulation changes, are model-dependent and thus not affected by the LBCs. Finally, we argue that a correct configuration of LBCs in the Atlantic should be used for future Mediterranean simulations, which cover hindcast period, but also for scenarios. [ABSTRACT FROM AUTHOR]

Fine-grained sediments in southern Finland were deposited during the retreat of the continental Fennoscandian ice-sheet at around 13,000 cal BP, leaving subsequent ice-contact deposits and postglacial lake and, finally, the modern brackish water Baltic Sea basin (BSB). As a result of the strong glacioisostatic land uplift of the region, these sediments today lie above sea-level in coastal Finland. The recent expansion of cities to locations where superficial sediments are more challenging for construction purposes has increased the need for comprehensive understanding of the properties and geometry of these fine-grained superficial deposits. Commonly used site-specific lithostratigraphical characteristics of clayey deposits run the risk of ambiguous correlation between sites because of different types of postglacial depositional settings. The present study applies an allostratigraphical approach to classify late- and postglacial clayey deposits using examples from four sedimentary basins in the vicinity of the city of Espoo along the southern coast of Finland. This entails a reinterpretation of 17 core logs collected during the period 2006-2009 and reported in earlier studies, combined with examination of five new cores collected in 2016 coupled with borehole measurements of resistivity-temperature and electrical resistivity tomography (ERT). Physical proxies and sediment characteristics demonstrate that grey postglacial lacustrine silty (Ancylus Lake) clay is truncated at the top by an undulating erosional surface (unconformity), which is covered by a silt to sand layer a few centimetres thick that has a gradual-bioturbated upper contact to the greenish-grey brackish water (Litorina Sea) mud. Sediments above and below the unconformity are intensely bioturbated, and black mottling of Fe-monosulphide is observed in the brackish water mud. Evidently, this unconformity is of high engineering-geological significance because the organic-rich brackish water mud has a poorer bearing capacity and higher abundance of sulphide minerals that form sulphuric acid upon oxidation. It is demonstrated that this unconformity is spatially well recognised and provides a key stratigraphic marker for wider and more accurate comparison between sites with fine-grained deposits in the Helsinki metropolitan area and potentially in other urban areas in the northern Baltic Sea region. [ABSTRACT FROM AUTHOR]

Having great impacts on human lives, global warming and associated sea level rise are believed to be strongly linked to anthropogenic causes. Statistical approach offers a simple and yet conceptually verifiable combination of remotely connected climate variables and indices, including sea level and surface temperature. We propose an improved statistical reconstruction model based on the empirical dynamic control system by taking into account the climate variability and deriving parameters from Monte Carlo cross-validation random experiments. For the historic data from 1880 to 2001, we yielded higher correlation results compared to those from other dynamic empirical models. The averaged root mean square errors are reduced in both reconstructed fields, namely, the global mean surface temperature (by 24-37%) and the global mean sea level (by 5-25%). Our model is also more robust as it notably diminished the unstable problem associated with varying initial values. Such results suggest that the model not only enhances significantly the global mean reconstructions of temperature and sea level but also may have a potential to improve future projections. [ABSTRACT FROM AUTHOR]

There is a pressing need to find ways to communicate information about climate change effectively and in terms that resonate with diverse audiences. We conducted a survey-experiment to evaluate how textual and visual frames that highlight coastal flooding in two major US cities as a result of future sea level rise shape individuals’ perceptions about the effects on coastal communities, concern for these places, and belief in climate change’s existence. We build on extant literature by focusing on the impact of an understudied frame using animated maps that illustrate future flooding that will occur as global temperatures rise. We find that exposure to such messages increases perceptions that sea level rise will have negative impacts on coastal communities, concern for these communities, and belief in climate change. [ABSTRACT FROM AUTHOR]

Designing decision analytical models requires making choices that can involve a range of trade-offs and interactions between epistemic and ethical considerations. Such choices include determining the complexity of a model and deciding what types of risk will be assessed. Here, we demonstrate how model design choices can involve trade-offs between the epistemic benefits of representational completeness and simplicity, which interact with ethical considerations about fairness and human life. We illustrate this point by focusing on modeling studies that assess flood risks in New Orleans, Louisiana. Addressing the ethical and epistemic implications of model design choices can help clarify the scope of factors necessary to inform ethically sound and economically efficient decision-making. [ABSTRACT FROM AUTHOR]

The hydraulic diffusivity gives a measure of diffusion speed of pressure disturbances in groundwater system; large values of hydraulic diffusivity lead to fast propagation of signals in aquifer. This research provides a novel design and derives spectral representation to determine hydraulic diffusivity using spectral analysis of groundwater levels coupled with time-dependent boundary adjacent to marine system and no flow boundary in aquifer system. To validate the proposed method, water levels of fluctuated boundary and groundwater well in a sandy confined aquifer were collected. The hydraulic diffusivity is then obtained by an inverse process in the non-linear complex form of spectral relationship. The method essentially is constructed on the conceptual design of natural forcing transmitted in large aquifer. It is unlike the conventional field pumping test which is only used to determine hydraulic properties of groundwater in small range around the well. Hydraulic diffusivity of the confined aquifer is determined using real observation and then checked by comparing to the published range. It suggests that without local aquifer test to estimate hydraulic diffusivity in a coastal aquifer using spectral representation with its relevant flow system and boundary has become feasible. [ABSTRACT FROM AUTHOR]

Sea-level rise, as a result of global warming, may lead to more natural disasters in coastal regions where there are substantial aggregations of population and property. Thus, this paper focuses on the impact of sea-level rise on the recurrence periods of extreme water levels fitted using the Pearson type III (P-III) model. Current extreme water levels are calculated using observational data, including astronomical high tides and storm surges, while future extreme water levels are determined by superposing scenario data of sea-level rise onto current extreme water levels. On the basis of a case study using data from Shandong Province, China, results indicated that sea-level rise would significantly shorten the recurrence periods of extreme water levels, especially under higher representative concentration pathway (RCP) scenarios. Results showed that by the middle of the century, 100-year current extreme water levels for all stations would translate into once in 15-30 years under RCP 2.6, and once in ten to 25 years under RCP 8.5. Most seriously, the currently low probability event of a 1000-year recurrence would become common, occurring nearly every 10 years by 2100, based on projections under RCP 8.5. Therefore, according to this study, corresponding risk to coastlines could well be increase in future, as the recurrence periods of extreme water levels would be shortened with climate change. [ABSTRACT FROM AUTHOR]

Coastal flood risk will likely increase in the future due to urban development, sea-level rise, and potential change of storm surge climatology, but the latter has seldom been considered in flood risk analysis. We propose an integrated dynamic risk analysis for flooding task (iDraft) framework to assess coastal flood risk at regional scales, considering integrated dynamic effects of storm climatology change, sea-level rise, and coastal development. The framework is composed of two components: a modeling scheme to collect and combine necessary physical information and a formal, Poisson-based theoretical scheme to derive various risk measures of interest. Time-varying risk metrics such as the return period of various damage levels and the mean and variance of annual damage are derived analytically. The mean of the present value of future losses (PVL) is also obtained analytically in three ways. Monte Carlo (MC) methods are then developed to estimate these risk metrics and also the probability distribution of PVL. The analytical and MC methods are theoretically and numerically consistent. A case study is performed for New York City (NYC). It is found that the impact of population growth and coastal development on future flood risk is relatively small for NYC, sea-level rise will significantly increase the damage risk, and storm climatology change can also increase the risk and uncertainty. The joint effect of all three dynamic factors is possibly a dramatic increase of the risk over the twenty-first century and a significant shift of the probability distribution of the PVL towards high values. In a companion paper (Part II), we extend the iDraft to perform probabilistic benefit-cost analysis for various flood mitigation strategies proposed for NYC to avert the potential impact of climate change. [ABSTRACT FROM AUTHOR]

The observational data on sea level at Tyulenii Island station were compared with the results of the Caspian Sea level simulation with the three-dimensional hydrodynamic model with different spatial horizontal resolution (3 and 1 nautical miles). The sea motion is induced by the air pressure gradients and tangential wind stress that are obtained from the COSMO model forecast and specified on the surface. The results of diagnostic calculations of the sea level for June-October 2014 and 60 forecasts for September 2014 demonstrated that the model with the 1-mile resolution meets the simulation accuracy requirements of the Hydrometcenter of Russia and can be used for the short-range forecasting of the Caspain Sea level. [ABSTRACT FROM AUTHOR]

The North Atlantic Oscillation (NAO) has significant effects on sea levels, weather, and climate. In this study, the sea level trends and the effects of the North Atlantic Oscillation Indices (NAOI) on annual mean sea level data were assessed for the Black Sea and the Eastern Mediterranean Sea. The trends of sea level and NAOI were determined using Mann-Kendall dimensionless z statistics. Generally, upward sea level trends were detected for the Black Sea and the Eastern Mediterranean Sea. In the Black Sea, significant and continuous upward trends were detected after the year 1950. Weaker trends were detected for the Eastern part of the Mediterranean Sea. Sea level trends were correlated with trends in NAO indices; negative correlations were detected for the Black Sea, whereas positive correlations were found for the Eastern Mediterranean Sea. Paired t tests were performed to determine the turning points for all sea level data sets. The value of t was positive for all data sets, which means that the mean value of the data set before the turning point was smaller than the mean value of the data set after the turning point. [ABSTRACT FROM AUTHOR]

We present climate and surface mass balance (SMB) of the Antarctic ice sheet (AIS) as simulated by the global, coupled ocean-atmosphere-land Community Earth System Model (CESM) with a horizontal resolution of $${\sim }1^\circ$$ in the past, present and future (1850-2100). CESM correctly simulates present-day Antarctic sea ice extent, large-scale atmospheric circulation and near-surface climate, but fails to simulate the recent expansion of Antarctic sea ice. The present-day Antarctic ice sheet SMB equals $$2280 \pm 131$$ $$\mathrm {Gt\,year^{-1}}$$ , which concurs with existing independent estimates of AIS SMB. When forced by two CMIP5 climate change scenarios (high mitigation scenario RCP2.6 and high-emission scenario RCP8.5), CESM projects an increase of Antarctic ice sheet SMB of about 70 $$\mathrm {Gt\,year^{-1}}$$ per degree warming. This increase is driven by enhanced snowfall, which is partially counteracted by more surface melt and runoff along the ice sheet's edges. This intensifying hydrological cycle is predominantly driven by atmospheric warming, which increases (1) the moisture-carrying capacity of the atmosphere, (2) oceanic source region evaporation, and (3) summer AIS cloud liquid water content. [ABSTRACT FROM AUTHOR]

The authors comment on the article "Closed-form analytical solutions for assessing the consequences of sea-level rise on groundwater resources in sloping coastal aquifers" published in a previous issue of the journal. They state concerns over the impact of sea-level rise on seawater intrusion, and mention limitations to the article associated with the choice of mathematical model and inland boundary condition. They mention the possibility of employing the Strack single potential approach.

The formulation and the algorithm of solving an ocean model for the prediction and assimilation of the observed data which makes it possible to reconstruct the circulation in the deep-water parts of the sea and at a shallow water shelf, as well as to describe the large time-space variability in the surface level, are considered. The model uses a vertical hybrid σ- z coordinate system: the several upper tens of meters of the ocean are described in the σ-coordinate system and the rest of the water column is described in the z coordinates. Such hybridization extends the possibilities of models for reconstructing thermo-hydrodynamic processes in different sea basins and the World Ocean. The differential formulation of the model in the σ- z coordinate system is presented; the simplified records of several operators that are allowable in the case of a small thickness of the ocean σ-layer are described. The construction of a computational grid, approximation of the bottom topography on it, and discretization of equations and boundary conditions of the models are considered; an approach to describing the bottom friction at shallow waters is offered. The results of the comparative experiments in the z and σ- z coordinate models are analyzed. [ABSTRACT FROM AUTHOR]

Sea-level rise is a major coastal issue in the 21st century because many of the world's built assets are located in the coastal zone. Coastal erosion and flooding are serious threats along the coast of Ghana, particularly, the eastern coast where the Volta delta is located. Past human interventions, climate change and the resultant rise in sea-levels, increased storm intensity and torrential rainfall have been blamed for these problems. Accelerated sea-level rise and storm surge pose serious threat to coastal habitat, bio-diversity and socio-economic activities in the coastal zone of Ghana and elsewhere. There is the need for an holistic assessment of the impacts of sea-level rise on the coast zone in order to formulate appropriate adaptation policies and strategies to mitigate the possible effects. Using the eastern coast of Ghana as a case study, this paper assesses the physical impacts of accelerated sea level rise and storm surge on the coastal environment. It evaluates adaptation policies and plans that could be implemented to accommodate the present and any future impacts. Field investigation and Geographic Information System (GIS) are among the methods used for the assessment. The outcome of the assessment has provided comprehensive knowledge of the potential impacts of accelerated sea-level rise and storm surge on the eastern coast. It has facilitated identification of management units, the appraisal of alternate adaptation policies and the selection of the best policy options based upon the local conditions and environmental sustainability. Among other things, this paper reveals that the eastern coast of Ghana is highly vulnerable to accelerated sea-level rise and therefore, requires sustainable adaptation policies and plans to manage the potential impacts. It recommends that various accommodation policies, which enable areas to be occupied for longer before eventual retreat, could be adapted to accommodate vulnerable settlements in the eastern coast of Ghana. [ABSTRACT FROM AUTHOR]

Local sea level can deviate from mean global sea level because of both dynamic sea level (DSL) effects, resulting from oceanic and atmospheric circulation and temperature and salinity distributions, and changes in the static equilibrium (SE) sea level configuration, produced by the gravitational, elastic, and rotational effects of mass redistribution. Both effects will contribute to future sea level change. To compare their magnitude, we simulated the effects of Greenland Ice Sheet (GIS) melt by conducting idealized North Atlantic 'water-hosing' experiments in a climate model unidirectionally coupled to a SE sea level model. At current rates of GIS melt, we find that geographic SE patterns should be challenging but possible to detect above dynamic variability. At higher melt rates, we find that DSL trends are strongest in the western North Atlantic, while SE effects will dominate in most of the ocean when melt exceeds ~20 cm equivalent sea level. [ABSTRACT FROM AUTHOR]

The Sundarbans mangrove ecosystem, shared by India and Bangladesh, is recognized as a global priority for biodiversity conservation. Sea level rise, due to climate change, threatens the long term persistence of the Sundarbans forests and its biodiversity. Among the forests’ biota is the only tiger ( Panthera tigris) population in the world adapted for life in mangrove forests. Prior predictions on the impacts of sea level rise on the Sundarbans have been hampered by coarse elevation data in this low-lying region, where every centimeter counts. Using high resolution elevation data, we estimate that with a 28 cm rise above 2000 sea levels, remaining tiger habitat in Bangladesh’s Sundarbans would decline by 96% and the number of breeding individuals would be reduced to less than 20. Assuming current sea level rise predictions and local conditions do not change, a 28 cm sea level rise is likely to occur in the next 50–90 years. If actions to both limit green house gas emissions and increase resilience of the Sundarbans are not initiated soon, the tigers of the Sundarbans may join the Arctic’s polar bears ( Ursus maritimus) as early victims of climate change-induced habitat loss. [ABSTRACT FROM AUTHOR]

With polar temperatures ∼3–5 °C warmer than today, the last interglacial stage (∼125 kyr ago) serves as a partial analogue for 1–2 °C global warming scenarios. Geological records from several sites indicate that local sea levels during the last interglacial were higher than today, but because local sea levels differ from global sea level, accurately reconstructing past global sea level requires an integrated analysis of globally distributed data sets. Here we present an extensive compilation of local sea level indicators and a statistical approach for estimating global sea level, local sea levels, ice sheet volumes and their associated uncertainties. We find a 95% probability that global sea level peaked at least 6.6 m higher than today during the last interglacial; it is likely (67% probability) to have exceeded 8.0 m but is unlikely (33% probability) to have exceeded 9.4 m. When global sea level was close to its current level (≥-10 m), the millennial average rate of global sea level rise is very likely to have exceeded 5.6 m kyr-1 but is unlikely to have exceeded 9.2 m kyr-1. Our analysis extends previous last interglacial sea level studies by integrating literature observations within a probabilistic framework that accounts for the physics of sea level change. The results highlight the long-term vulnerability of ice sheets to even relatively low levels of sustained global warming. [ABSTRACT FROM AUTHOR]

The IPCC Fourth Assessment Report (AR4) published in 2007 presents the most complete and authoritative assessment of the status of scientific knowledge on all aspects of climate change. This paper presents an updated assessment of the risks from anthropogenic climate change, based on a comprehensive review of the pertinent scientific literature published since finalisation of the AR4. Many risks are now assessed as stronger than in the AR4, including the risk of large sea-level rise already in the current century, the amplification of global warming due to biological and geological carbon-cycle feedbacks, a large magnitude of “committed warming” currently concealed by a strong aerosol mask, substantial increases in climate variability and extreme weather events, and the risks to marine ecosystems from climate change and ocean acidification. Some topics remain the subject of intense scientific debate, such as past and future changes in tropical cyclone activity and the risk of large-scale Amazon forest dieback. The rise in greenhouse gas emissions and concentrations has accelerated recently, and it is expected to accelerate further in the absence of targeted policy interventions. Taken together, these findings point to an increased urgency of implementing mitigation policies as well as comprehensive and equitable adaptation policies. [ABSTRACT FROM AUTHOR]

The Tibetan Plateau (TP) exerts significant impacts on its surroundings through its thermal and dynamical processes. In recent decades, especially since 2000, the TP has been experiencing a more rapid warming than its surrounding regions. This study uses Moderate Resolution Imaging Spectroradiometer (MODIS) monthly averaged land surface temperature (LST) product to detect the recent warming trend with respect to elevations over the entire TP, because the number of weather stations from China Meteorological Administration (CMA) is rather limited in the western TP and, furthermore, are unavailable for areas higher than 4,800 m above sea level (ASL). The trend of MODIS LST is first validated against the warming trend estimated from near-surface air temperatures measured at CMA stations and the warming rate dependence on elevation is then derived from MODIS LST. The results indicate that the warming rate increases from 3,000 to 4,800 m ASL, and then becomes quite stable with a slight decline near the highest elevations. This altitudinal dependence of the warming rate has a significant implication for TP water resources and environmental changes, since most glaciers and snow surfaces are located above 5,000 m ASL over the TP. [ABSTRACT FROM AUTHOR]

A review of the article "Ocean impact on decadal Atlantic climate variability revealed by sea-level observations" by Gerard D. McCarthy, Joël J.-M. Hirschi, David A. Smeed, and others which was published on page 508 of the same issue is presented.

The article focuses on findings reported by scientist Thomas Wahl and his colleagues who have analyzed sea-level across the U.S. Gulf Coast and have found that typical differences in sea level between summer and winter have increased, which increases the chance of hurricane-related flooding.

The article reports on the possibility that climate warming and the rise of sea levels will increase the frequency of local extremes in storm surges along much of the coastline in the U.S.

The article focuses on the accuracy of coastal tide gauges near dams in measuring the sea-level increase caused by climate change, wherein Julia Fiedler and Clinton Conrad from the University of Hawaii in Honolulu, Hawaii found an annual increase of approximately 2.3 millimeters in global sea levels from 1900-2010, which is quicker than results revealed by tide gauges.