Sea Level Rise In Combination Research Articles

Epidemiological evidence on drinking water salinity and blood pressure: a scoping review

In addition to diet, drinking water can be an important contributor to the total body burden of salts. Water salinity (defined as the amount of dissolved salts in a body of water) has been associated with adverse health effects. We mapped the current research on drinking water salinity and its effects on blood pressure (BP). We aimed to identify knowledge gaps in the methodology and tools used in the epidemiological literature to address water salinity effects on BP. We performed a scoping review of epidemiological studies by searching PubMed and Web of Science databases from 1980 to 2022. Reviews, study comparisons, meta-analyses, commentaries, viewpoints, correspondence, protocols, studies in clinical settings, animal or in vitro studies, or not in English, were excluded. Epidemiologic studies including systolic/diastolic BP and/or the risk of hypertension as the main health outcome and drinking water salts (sodium, potassium, calcium, magnesium, including electrical conductivity and total dissolved solids) as the main exposures were included. After screening 246 articles, 29 articles were retained. Most studies were conducted in Bangladesh and USA (n = 9 and n = 9, respectively). The majority of studies were cross-sectional (n = 18; 62%). The study populations were adults (55%) or children (35%) or both (10%). Only eight (28%) studies did not collect urine samples and only three studies (10%) did not record participant BP. About half of the studies (n = 15, 52%) reported a positive significant (p < 0.05) association between salts in drinking water and higher BP and/or risk of hypertension; while 24% and 24% reported non-significant (p > 0.05) and significant (p < 0.05) negative associations (with lower BP mainly attributed to higher Mg, Ca, and K (rather than Na) levels in drinking water). More longitudinal studies are warranted to investigate the impact of drinking water salinization on cardiovascular health and risk of hypertension. Under a changing climate, this may be particularly important for coastal populations, as sea level rise in combination with the overexploitation of groundwater would differentially perturb the salinity of their drinking water supplies.

Interactive effects of sea-level rise and nitrogen enrichment on the decay of different plant residues in an oligohaline estuarine marsh

Sea-level rise (SLR) and nitrogen (N) enrichment are two critical issues that affect coastal marshes. They affect organic matter decomposition in soils and, thus, affect the marshes’ ability to sequester carbon. However, the impacts of SLR and N enrichment, especially their interactive effects, on the decomposition of different quality plant residues in soils remains unclear. Using in-situ weirs and litterbags, we examined the effects of SLR (three times the natural flooding duration), N enrichment (48 g N m−2 yr−1), and the combination of SLR and N enrichment, on the decomposition of buried Cyperus malaccensis shoot, and root and rhizome (R&R) residues over 549 days in the Minjiang Estuary, China. Individual SLR and N enrichment treatments significantly promoted shoot decomposition by promoting plant growth, but not for R&Rs because of their inability to increase porewater NH4+ levels. Interestingly, combined SLR and N enrichment significantly promoted both shoot and R&R decomposition. Moreover, we observed significant interactive effects between SLR and N enrichment on the decay of both residues, with antagonistic and synergistic effects on the decay of shoots and R&Rs, respectively. Although SLR or N enrichment, or their combined effect, affected plant residue decomposition differently, substrate quality appeared to be the chief factor governing organic matter decomposition. Overall, shoot decay rates (0.0023–0.0048 d−1) were significantly greater than those for R&Rs (0.0026–0.0031 d−1) and more sensitive to SLR, N enrichment, and combined treatments. Our results indicate that estimating the combined effect of SLR and N enrichment based on the addition of individual effects is often inaccurate and that substrate quality directs deviance. This study highlights the importance of quantifying the interactive effects of multiple global change factors and distinguishing substrate quality.

Climate Change Impacts on Coastal Wave Dynamics at Vougot Beach, France

Wave dynamics contribute significantly to coastal hazards and were thus investigated at Vougot Beach by simulating both historical and projected future waves considering climate change impacts. The historical period included a major storm event. This period was projected to the future using three globally averaged sea level rise (SLR) scenarios for 2100, and combined SLR and wave climate scenarios for A1B, A2, and B1 emissions paths of the IPCC. The B1 wave climate predicts an increase in the occurrence of storm events. The simulated waves in all scenarios showed larger relative changes at the beach than in the nearshore area. The maximum increase of wave energy for the combined SLR and wave scenarios was 95%, while only 50% for the SLR-only scenarios. The effective bed shear stress from waves and currents showed different spatial variability than that of the wave height, emphasizing the importance of interactions between nearshore waves and currents. Increases in the effective bed shear stress (combined scenarios: up to 190%, and SLR-only scenarios: 35%) indicate that the changes in waves and currents will likely have significant impacts on the nearshore sediment transport. This work emphasizes that combined SLR and future wave climate scenarios need to be used to evaluate future changes in local hydrodynamics and their impacts. These results provide preliminary insights into potential future wave dynamics at Vougot Beach under different climate change scenarios. Further studies are necessary to generalize the results by investigating the wave dynamics during storm events with different hydrodynamical conditions and to evaluate potential changes in sediment transport and morphological evolution due to climate change.

Sea Level Rise in Indonesia: The Drivers and the Combined Impacts from Land Subsidence

Sea level changes play an important role as an indicator of climate change. However, without climate change, the sea level itself shows strong regional patterns, both in space and time, that could deviate significantly from global averages. The spatial variability of sea level changes in Indonesia can be divided based on its drivers, i.e., climatic and seasonal weather-driven and non-climatic and geological-driven. Seasonally, the sea level in Indonesia is generally high in northwest monsoon and low in southeast monsoon. Nevertheless, there is a possibility of extreme natural phenomenon influences that generate anomalies and a thermosteric process that also affects the sea level. On the non-climatic and geological theory, the uniqueness of the tectonic setting in Indonesia will create spatial variations in regional sea levels, as both static and dynamic changes in a long period of time. Land subsidence is also often regarded as a significant contributor to the rise of relative sea level in coastal environments. Combined with the rise in sea level, land subsidence will escalate coastal flooding risks, contribute to shoreline retreat, and be further aggravated by anthropogenic forces such as groundwater extraction and land development. This scientific review will summarize the spatial variation of sea level rise in Indonesia, examines the underlying drivers that control it, and provides an overview of the combined sea level rise and land subsidence as a significant threat in Indonesia.

Projections of future beach loss along the mediterranean coastline of Egypt due to sea-level rise

Beach loss and shoreline retreat caused by sea level rise (SLR) is considered one of the most worldwide significant issues. The Mediterranean coastline of Egypt (approximately 1066 km) is likely to face beach erosion, particularly in the low-lying and sandy coastal areas in the future as a direct response to SLR. Consequently, the projection of future shoreline recession and corresponding beach loss due to SLR using the Bruun rule were investigated to assess the proper impacts of SLR on the shoreline recession and beach loss. In addition, the uncertainties ratios associated with SLR scenarios and sediment sizes were assessed. Furthermore, this study investigated the influence of local land subsidence in combination with SLR scenarios on the shoreline recession and associated beach loss along the Nile Delta coastline. The ensemble-mean regional SLR data included representative concentration pathway (RCP) scenarios and 21 models of the Coupled Model Intercomparison Project Phase 5 (CMIP5). The projected shoreline retreats and associated average beach loss in the future 2081–2100 were ranged from 12.6 m and 11.3 km2 to 41.9 m and 19.2 km2 for the ensemble-mean SLR RCP2.6 and RCP8.5, respectively. The uncertainty caused by the sediment size of 0.15 to 0.35 mm ranged from 17% to 30% for RCP2.6 and RCP8.5, respectively. The projected annual shoreline retreats ranged from 0.36 to 0.65 m/yr for the ensemble-mean SLR in combination with local land subsidence for RCP2.6 and 0.48 to 0.85 m/yr for RCP8.5, respectively. Highly vulnerable areas to shoreline recession for SLR and local land subsidence were detected from EL-Manzala lake to Port Said coastlines, Abo Qir bay, from Rosetta to Damietta promontories, and Alexandria coastline. Thus, shoreline retreat and associated beach loss due to SLR is an urgent issue that should be addressed through the integrated coastal zone management strategies of Egypt.

Has dyke development in the Vietnamese Mekong Delta shifted flood hazard downstream?

Abstract. In the Vietnamese part of the Mekong Delta (VMD) the areas with three rice crops per year have been expanded rapidly during the last 15 years. Paddy-rice cultivation during the flood season has been made possible by implementing high-dyke flood defenses and flood control structures. However, there are widespread claims that the high-dyke system has increased water levels in downstream areas. Our study aims at resolving this issue by attributing observed changes in flood characteristics to high-dyke construction and other possible causes. Maximum water levels and duration above the flood alarm level are analysed for gradual trends and step changes at different discharge gauges. Strong and robust increasing trends of peak water levels and duration downstream of the high-dyke areas are found with a step change in 2000/2001, i.e. immediately after the disastrous flood which initiated the high-dyke development. These changes are in contrast to the negative trends detected at stations upstream of the high-dyke areas. This spatially different behaviour of changes in flood characteristics seems to support the public claims. To separate the impact of the high-dyke development from the impact of the other drivers – i.e. changes in the flood hydrograph entering the Mekong Delta, and changes in the tidal dynamics – hydraulic model simulations of the two recent large flood events in 2000 and 2011 are performed. The hydraulic model is run for a set of scenarios whereas the different drivers are interchanged. The simulations reveal that for the central VMD an increase of 9–13 cm in flood peak and 15 days in duration can be attributed to high-dyke development. However, for this area the tidal dynamics have an even larger effect in the range of 19–32 cm. However, the relative contributions of the three drivers of change vary in space across the delta. In summary, our study confirms the claims that the high-dyke development has raised the flood hazard downstream. However, it is not the only and not the most important driver of the observed changes. It has to be noted that changes in tidal levels caused by sea level rise in combination with the widely observed land subsidence and the temporal coincidence of high water levels and spring tides have even larger impacts. It is recommended to develop flood risk management strategies using the high-dyke areas as retention zones to mitigate the flood hazard downstream.

Projected changes of the southwest Australian wave climate under two atmospheric greenhouse gas concentration pathways

Incident wave energy flux is responsible for sediment transport and coastal erosion in wave-dominated regions such as the southwestern Australian (SWA) coastal zone. To evaluate future wave climates under increased greenhouse gas concentration scenarios, past studies have forced global wave simulations with wind data sourced from global climate model (GCM) simulations. However, due to the generally coarse spatial resolution of global climate and wave simulations, the effects of changing offshore wave conditions and sea level rise on the nearshore wave climate are still relatively unknown. To address this gap of knowledge, we investigated the projected SWA offshore, shelf, and nearshore wave climate under two potential future greenhouse gas concentration trajectories (representative concentration pathways RCP4.5 and RCP8.5). This was achieved by downscaling an ensemble of global wave simulations, forced with winds from GCMs participating in the Coupled Model Inter-comparison Project (CMIP5), into two regional domains, using the Simulating WAves Nearshore (SWAN) wave model. The wave climate is modeled for a historical 20-year time slice (1986–2005) and a projected future 20-year time-slice (2081–2100) for both scenarios. Furthermore, we compare these scenarios to the effects of considering sea-level rise (SLR) alone (stationary wave climate), and to the effects of combined SLR and projected wind-wave change. Results indicated that the SWA shelf and nearshore wave climate is more sensitive to changes in offshore mean wave direction than offshore wave heights. Nearshore, wave energy flux was projected to increase by ∼10% in exposed areas and decrease by ∼10% in sheltered areas under both climate scenarios due to a change in wave directions, compared to an overall increase of 2–4% in offshore wave heights. With SLR, the annual mean wave energy flux was projected to increase by up to 20% in shallow water (< 30 m) as a result of decreased wave dissipation. In winter months, the longshore wave energy flux, which is responsible for littoral drift, is expected to increase by up to 39% (62%) under the RCP4.5 (RCP8.5) greenhouse gas concentration pathway with SLR. The study highlights the importance of using high-resolution wave simulations to evaluate future regional wave climates, since the coastal wave climate is more responsive to changes in wave direction and sea level than offshore wave heights.

Assessing water quality of the Chesapeake Bay by the impact of sea level rise and warming

The influence of sea level rise and warming on circulation and water quality of the Chesapeake Bay under projected climate conditions in 2050 were estimated by computer simulation. Four estuarine circulation scenarios in the estuary were run using the same watershed load in 1991-2000 period. They are, 1) the Base Scenario, which represents the current climate condition, 2) a Sea Level Rise Scenario, 3) a Warming Scenario, and 4) a combined Sea Level Rise and Warming Scenario. With a 1.6-1.9°C increase in monthly air temperatures in the Warming Scenario, water temperature in the Bay is estimated to increase by 0.8-1°C. Summer average anoxic volume is estimated to increase 1.4 percent compared to the Base Scenario, because of an increase in algal blooms in the spring and summer, promotion of oxygen consumptive processes, and an increase of stratification. However, a 0.5-meter Sea Level Rise Scenario results in a 12 percent reduction of anoxic volume. This is mainly due to increased estuarine circulation that promotes oxygen-rich sea water intrusion in lower layers. The combined Sea Level Rise and Warming Scenario results in a 10.8 percent reduction of anoxic volume. Global warming increases precipitation and consequently increases nutrient loads from the watershed by approximately 5-7 percent. A scenario that used a 10 percent increase in watershed loads and current estuarine circulation patterns yielded a 19 percent increase in summer anoxic volume, while a scenario that used a 10 percent increase in watershed loads and modified estuarine circulation patterns by the aforementioned sea level rise and warming yielded a 6 percent increase in summer anoxic volume. Impacts on phytoplankton, sediments, and water clarity were also analysed.

Perceived and projected flood risk and adaptation in coastal Southeast Queensland, Australia

Evidence on the impacts of climate change is rapidly increasing but there is little change to the speed of climate adaptation by governments and individuals. There are multiple barriers to climate adaptation, including among others: the lack of the public understanding of risks, lack of leadership and availability of resources to adapt. In this study, we assess to what extent coastal residents understand their properties’ flood risk, and what predicts their risk perception and adaptation behaviour. We surveyed 420 individuals in South East Queensland projected to be within the permanent or temporary flood zone in 2100 based on combined sea-level rise and storm surge scenarios. We assessed the correlations between the projected (i.e. objective) and perceived risk of inundation, adaptation behaviour, and the individual characteristics considered to influence risk perception and adaptation. While we found a correlation between perceived and some objective flood risks, perceived risk only partially reflected objective risk. Other factors that influenced risk perception were previous experience of flooding events, belief in climate change, risk aversion, age and gender. Factors driving risk perception varied with the type (permanent, temporary) and frequency of flooding event (1 in 20 or 1 in 100 years). Previous experience with extreme event impacts and belief in climate change influenced all future perceived risks. However, even after being impacted by an extreme event, adaptation was moderate (58 %). Personal as well as environmental factors influence the likelihood of adaptation. The moderate adaptation response within our case study is likely a result of most respondents considering large flooding events to be rare and of limited impact, and anticipating future government aid to overcome flooding damage costs. Existing attitudes towards risk, which influence the extent of proactive adaptation, should be of concern to governments who will likely be facing these costs at increasing frequencies.

Tides, sea-level rise and tidal power extraction on the European shelf

An established numerical tidal model has been used to investigate the impact of various sea-level rise (SLR) scenarios, as well as SLR in combination with large-scale tidal power plants on European shelf tidal dynamics. Even moderate and realistic levels of future SLR are shown to have significant impacts on the tidal dynamics of the area. These changes are further enhanced when SLR and tidal power plants are considered in combination, resulting in changes to tidal amplitudes, currents and associated tidal dissipation and bed shear stresses. Sea-level rise is the dominant influence on any far-field impacts, whereas tidal power plants are shown to have the prevailing influence over any changes close to the point of energy extraction. The spatial extent of the impacts of energy extraction is shown to be affected by the sea level when more than one tidal power plant in the Irish Sea was considered. Different ways to implement SLR in the model are also discussed and shown to be of great significance for the response of the tides.

Mid- to late-Holocene coastal environmental changes in southwest Florida, USA

During the Holocene, Florida experienced major changes in precipitation and runoff. To better understand these processes, shallow marine sediment cores from Charlotte Harbor (southwest Florida) were studied, covering approximately the past 9000 years. Whole core XRF scanning was applied to correlate different sediment cores on a river to sea transect. Biomarkers were used to identify periods with increased runoff and primary productivity. The mid-Holocene sediments are characterized by a relatively large input of terrestrially derived organic matter, with a maximum in precipitation and runoff around 5 kyr BP. This maximum can be linked to large-scale changes in the hydrological cycle involving shifts of the ITCZ, Bermuda-Azores High and Polar Front. Around 3.5 kyr BP, Charlotte Harbor changed from a runoff-dominated environment to a more oligotrophic and marine setting. Although other studies suggest that, around this time, precipitation in Florida increased, this is not reflected by the Charlotte Harbor records. Possibly, wetter conditions in Florida due to gradual, ongoing, sea level rise in combination with increased precipitation, resulted in accumulation of organic matter on land. Increased sedimentation rates, terrestrial input and primary productivity observed in the upper part of the record are likely a consequence of human impact during the past century. Throughout the record, indications for storm activity can be recognized as coarser grained layers consisting of quartz sands or shell debris. These layers are rare during the mid Holocene, but between 3.2 and 2 kyr BP, their numbers increase, suggesting an increase in tropical cyclone activity in the Gulf of Mexico.

INCREASED OVERTOPPING SECURITY OF DYKES: A POTENTIAL FOR COMPENSATING FUTURE IMPACTS OF CLIMATE CHANGE

Anticipated acceleration of sea level rise in combination with expected higher set-up of storm surges will require strengthening of coastal protection structures. Dykes e. g. must then be heightened according to the existing design rules taking only hydrodynamical loads into consideration. Alternatively the development of new design rules taking both hydrodynamical loads and the strength of the available soil for the construction of a dyke might allow the explo-ration of up to now undetected safety margins. In order to explore these possibilities the German Coastal Engineering Research Council has provided the funds for a research project targeting these aims. First results of this project are presented in this paper on the background of achieved improvements for the determination of design wave run-up on coastal and estuarine sea dykes.

Severn Barrage, UK—environmental reappraisal

The biological and chemical regimes of the Severn Estuary are severely stressed by its physical regime. Estuarine flora and fauna naturally adapt to habitat conditions. The Severn is dynamic and turbid to such a degree, however, as to put it beyond the tolerance of most species. The foreshores have an exceptionally low carrying capacity for shorebirds and provide poor feeding and nursery areas for fish. Parts of the subtidal bed regime are barren and few support any live organisms. The turbid water excludes sunlight and suppresses dissolved oxygen. The ecosystem is limited to the most hardy and immature estuarine organisms and these are only present as a result of continual recruitment from the Bristol Channel. Furthermore, combined sea level rise, increased storminess and foreshore erosion are sustaining the downward spiral in ecosystem biodiversity. This severe suppression is natural; it is not induced by anthropogenic contaminants. Should a tidal power barrage be built, mean water level and shelter would increase and current strengths diminish. Large-scale reductions in suspended load and greater bed stability would encourage colonisation. Mixed substrates would develop, leading to biodiverse and abundant invertebrate and vertebrate communities. It is unusual for a major engineering project to result in the large-scale invasion of a suppressed ecosystem by organisms; this is an inevitable consequence of this project.

Impact of hydrodynamics on development and morphology of intertidal seagrasses in the Wadden Sea

Field surveys and in situ experiments were conducted to determine the impact of hydro- dynamics (in particular tidal currents) on the development and structure of intertidal seagrass beds. Field observations in the Sylt-Romo Bight (German Wadden Sea, North Sea) from 1997 to 1999 re- vealed dense seagrass beds with a high biomass in sheltered areas, whereas at exposed sites seagrass beds occurred only sparsely with a comparatively low biomass. In addition, the shoot length and leaf length were distinctly higher at sheltered sites than in exposed beds. Cross transplantation experi- ments and enclosure experiments between sheltered and exposed seagrass sites showed that the den- sity as well as the shoot morphology (leaf number per shoot, shoot length, leaf length and leaf width) were drastically reduced after transplantation into an exposed bed, and were even lower than seagrass values of the adjacent exposed seagrasses after 6 wk. In contrast, the seagrass density as well as the length of shoots and leaves increased distinctly after transplantation into a sheltered seagrass bed. By means of an in situ 'three-current flume', experimentally modifying current flow at the same site, it was shown that increasing tidal current velocities resulted in decreased densities and length values in seagrass shoots, despite growing under the same habitat conditions. These results suggest that strong hydrodynamics directly affect the development and architecture of Zostera noltii beds by reducing seagrass density and shoot morphology, as well as the extent of seagrass beds. Since changes in envi- ronmental conditions are ongoing (e.g. higher storm frequency, sea level rise in combination with man-made protective structures, such as dikes and dams), it is suspected that increasing hydrody- namics might contribute to losses in intertidal seagrass beds.