Implications Of Sea Level Rise Research Articles

Holocene paleoceanographic variability in Robertson Bay, Ross Sea, Antarctica: A marine record of ocean, ice sheet, and climate connectivity

Accelerating ocean-driven basal melting of Antarctic ice shelves in recent decades has implications for sea level rise and global overturning circulation. Here, we reconstruct oceanographic conditions at the confluence of the Ross Sea and the Southern Ocean by analyzing a multi-proxy Holocene marine sedimentary record collected from Robertson Bay. A ramped pyrolysis oxidation radiocarbon age-depth model provides a timeline for glacial behavior and oceanographic changes over the last 6700 years. The diatom assemblage, magnetic susceptibility, grain size, total organic carbon and nitrogen, trace elements, and bulk δ13C are used as proxies for changing ocean and glacial conditions, which we interpret in the context of modern oceanographic measurements.Our record shows evidence of persistent ice cover in the northwestern Ross Sea during the Antarctic mid-Holocene climate optimum (ca. 5 cal kyr BP). Based on this observation, we suggest that meltwater and iceberg discharge associated with ice sheet retreat in the Ross Sea region altered local oceanography during the mid-Holocene. The onset of modern style oceanographic conditions in Robertson Bay occurred at ca. 4 cal kyr BP. Stable late Holocene conditions in are punctuated by a period of enhanced polynya activity and upwelling of nutrient rich Circumpolar Deep Water ca. 0.8 cal kyr BP and an increase in the seasonal duration of sea ice after 0.7 cal kyr BP, during the Little Ice Age. The response of the marine environment in Robertson Bay to mid-Holocene ice sheet retreat and natural climate variability during the last millennium underscores the sensitivity of the Antarctic ice-ocean interface to projected changes in coming decades.

Estimation of Surface Ice Velocity of Durung Drung Glacier, Western Himalaya using COSI-Corr from Landsat images

Glaciers all over the world have been experiencing recession at varying rates. Alterations in glacial retreat, volume, and mass have direct implications for sea level rise and have implications for the overall health of glaciers. Measuring the surface ice velocity of glaciers presents challenges due to the rugged terrain and harsh climate at high altitudes, making field observations difficult. This study aims to address these challenges by focusing on the calculation of the surface ice velocity of the Durung Drung glacier in Zanskar Valley, Ladakh. Landsat- 7 & 8 panchromatic bands with a resolution of 15 m were used in conjunction with the COSI-Corr module of ENVI image processing software to derive surface ice velocity. The method involved the crosscorrelation of Landsat images from 1999/2000 and 2019/2020. The COSI-Corr module used in this study provided three key outputs: east–west displacement, north–south displacement, and signal-to-noise ratio. These outputs are essential for understanding the movement of the glacier and evaluating the quality of the image correlation. The results indicate that the surface velocity of Durung Drung glacier was 71 ± 6.1 m yr−1 in 1999/2000, which increased (by ∼ 50 %) to 140 ± 7.4 m yr−1 in 2019/2020. An increasing trend in velocity manifests the rising trend in temperature in the western Himalaya. Analysis of CRU TS4 gridded data reveals an increase in temperature while precipitation decreased during 1976–2020. The study recommends that the annual variations in surface ice velocity are a consequence of temperature fluctuations that influence the availability of meltwater.

Enterococci pathways to coastal waters and implications of sea level rise

Highly urban coastal communities in low lying areas and with high water tables are vulnerable to sea-level rise and to corresponding increases in coastal groundwater levels. Stormwater conveyance systems are under increased risk. Rising groundwater levels affect the hydraulics of the stormwater system thereby increasing contaminant transport, for example the fecal indicator bacteria enterococci, to coastal waters. This study offers a unique opportunity to evaluate the impacts of increased contaminant transport on marine coastal environments. Here we assessed historic and recent coastal water quality, stormwater sampling data, groundwater monitoring and tidal elevations near the coastline, in the context of altered hydraulics within the system. Two pathways of enterococci to marine waters were identified. Direct discharge of contaminated stormwater runoff via the stormwater outfalls and tidally driven contaminated groundwater discharge. As sea level continues to rise, we hypothesize that a diminished unsaturated zone coupled with altered hydraulic conditions at the coastal groundwater zone will facilitate the transport of enterococci from urban sediments to the study site (Park View Waterway in Miami Beach, FL USA). We recommend improvements to the stormwater conveyance system, and maintenance of the sanitary sewer system to mitigate these impacts and minimize transport of enterococci, and other stormwater pollutants to coastal waters. The results of this study can be useful to interpret high enterococci levels in low lying coastal areas where groundwater is influenced by rising sea water levels.

Development of a regional climate change model for Aedes vigilax and Aedes camptorhynchus (Diptera: Culicidae) in Perth, Western Australia.

Mosquito-borne disease is a significant public health issue and within Australia Ross River virus (RRV) is the most reported. This study combines a mechanistic model of mosquito development for two mosquito vectors; Aedes vigilax and Aedes camptorhynchus, with climate projections from three climate models for two Representative Concentration Pathways (RCPs), to examine the possible effects of climate change and sea-level rise on a temperate tidal saltmarsh habitat in Perth, Western Australia. The projections were run under no accretion and accretion scenarios using a known mosquito habitat as a case study. This improves our understanding of the possible implications of sea-level rise, accretion and climate change for mosquito control programmes for similar habitats across temperate tidal areas found in Southwest Western Australia. The output of the model indicate that the proportion of the year mosquitoes are active increases. Population abundances of the two Aedes species increase markedly. The main drivers of changes in mosquito population abundances are increases in the frequency of inundation of the tidal wetland and size of the area inundated, increased minimum water temperature, and decreased daily temperature fluctuations as water depth increases due to sea level changes, particularly under the model with no accretion. The effects on mosquito populations are more marked for RCP 8.5 when compared to RCP 4.5 but were consistent among the three climate change models. The results indicate that Ae. vigilax is likely to be the most abundant species in 2030 and 2050, but that by 2070 Aedes camptorhynchus may become the more abundant species. This increase would put considerable pressure on existing mosquito control programmes and increase the risk of mosquito-borne disease and nuisance biting to the local community, and planning to mitigate these potential impacts should commence now.

Implications of increased intertidal inundation on seagrass net primary production

Seagrass meadows are productive and functionally important seafloor habitats that are declining in many parts of the world under pressure from human activities. Seabed light availability is inversely related to water depth, thus sea level rise associated with global warming may impinge upon seagrass productivity and its contributions to coastal ecosystems. Across natural variation in seagrass bed depth driven by tidal oscillations and distance from shore, we quantified seafloor oxygen exchange every 15 min for three days and nights at sites in New Zealand using aquatic eddy covariance to better understand the implications of sea level rise on shallow seagrass. Four sites of differing mean depth (1.5–4.0 m deep at high tide) were net producers of oxygen when photosynthetically active radiation at the seabed was >87.5 μmol photons m−2 s−1, with net oxygen production >4 mmol m−2 h−1 at all sites during peak sunlight hours. The effect of light attenuation on dissolved oxygen production was evident when comparing fluxes in the morning (low tide) and evening (high tide), with relatively similar incident light levels arriving at water surface at these times of day. The shallowest site was expected to receive the greatest amount of light at the seabed and be most productive. However, the second shallowest site was the most productive, due to higher seagrass cover and clearer water (less light attenuation in the water column). Higher cover of seagrass likely reduced sediment resuspension while increasing photosynthetic capacity (i.e., more photosynthetic biomass). The existence of turbid fringes of water near the upper shore and climate-related shifts in suspended sediment concentrations may interfere with predictions of shoreward migration of seagrass meadows, which are already complicated by interactions with upper intertidal vegetation (e.g., mangroves) and human built structures (e.g., seawalls).

A multi-scale assessment of the impact of salinity on the desorption of chromate from hematite: Sea level rise implications

The solubility and transport of Cr(VI) is primarily controlled by adsorption-desorption reactions at the surfaces of soil minerals such as iron oxides. Environmental properties such as pH, ionic strength, and ion competition are expected to affect the mobility and fate of Cr(VI). Sea level rise (SLR), and consequent seawater intrusion, is creating a new biogeochemical soil environment at coastal margins, potentially impacting Cr(VI) retention at contaminated sites. We employed in-situ ATR-FTIR spectroscopy and DFT calculations to investigate at the molecular level the adsorption of Cr(VI) on the hematite surface and its desorption by sulfate, as a function of pH and ionic strength. We further used a batch experiment to assess Cr(VI) desorption at varying artificial seawater (ASW) concentrations. IR results demonstrate the complexity of Cr(VI) adsorption, showing a combination of monodentate inner-sphere complexation at high pH and dichromate outer-sphere (∼75%) at low pH. The Cr(VI)-complexes exhibited desorption induced by increasing pH values (58% of desorption) and sulfate competition (∼40% desorption). ASW desorbed ∼20% more Cr(VI), even at just 1% concentration. Our findings provide insight into Cr(VI)-adsorption complexation that controls the retention and remobilization of Cr(VI) on Fe-oxide minerals. The results point to an elevated risk of Cr(VI) mobilization in contaminated soils affected by SLR.

Localized uplift, widespread subsidence, and implications for sea level rise in the NewYork City metropolitan area.

Regional relative sea level rise is exacerbating flooding hazards in the coastal zone. In addition to changes in the ocean, vertical land motion (VLM) is a driver of spatial variation in sea level change that can either diminish or enhance flood risk. Here, we apply state-of-the-art interferometric synthetic aperture radar and global navigation satellite system time series analysis to estimate velocities and corresponding uncertainties at 30-m resolution in the NewYork City metropolitan area, revealing VLM with unprecedented detail. We find broad subsidence of 1.6 mm/year, consistent with glacial isostatic adjustment to the melting of the former ice sheets, and previously undocumented hot spots of both subsidence and uplift that can be physically explained in some locations. Our results inform ongoing efforts to adapt to sea level rise and reveal points of VLM that motivate both future scientific investigations into surface geology and assessments of engineering projects.

Assessing the Toxicity of Sea Salt to Early Life Stages of Freshwater Mussels: Implications for Sea Level Rise in Coastal Rivers.

Sea levels across the planet are rising, particularly along the eastern coast of the United States. Climate-induced sea level rise can result in the inundation and intrusion of seawater into freshwater drainages. This would alter salinity regimes and lead to the salinization of coastal freshwater ecosystems. Increased salinity levels in freshwater can negatively affect freshwater-dependent species, including native mussels belonging to the order Unionida, which are highly sensitive to changes in water quality. Sea salt is largely made up of sodium and chloride ions, forming sodium chloride, a known toxicant to freshwater mussels. However, sea salt is a mixture that also contains other major ions, including potassium, sulfate, calcium, strontium, and magnesium, among others. Freshwater mussels exposed to sea salt would be exposed to each of the sea salt ions at the same time, resulting in a mixture toxicity effect. The mixture toxicity of these ions on early life stages of freshwater mussels is largely unknown because most research to date has evaluated individual salt ions in relative isolation. Therefore, we conducted acute toxicity tests on early life stages (glochidia and juvenile) of three freshwater mussel species that inhabit Atlantic Slope drainages (nonsalinity-adapted Atlanticoncha ochracea, salinity-adapted A. ochracea, Sagittunio nasutus, and Utterbackiana implicata). Glochidia and juveniles of each species were exposed to a control and six concentrations of Instant Ocean® Sea Salt (IOSS), a synthetic sea salt that closely resembles the ionic composition of natural sea salt. Exposure concentrations were 1 part(s) per thousand (ppt), 2 ppt, 8.5 ppt, 12.5 ppt, 17 ppt, and 34 ppt. We calculated the median effect concentration (EC50) for each of the eight acute toxicity tests and found that glochidia were more sensitive than juveniles to IOSS. At hour 24 EC50s for the glochidia ranged from 0.38 to 3.6 ppt, with the most sensitive freshwater mussel being the nonsalinity-adapted A. ochracea, exhibiting an EC50 of 0.38 ppt (95% confidence interval [CI] 0.33-0.44). Juvenile freshwater mussels exhibited EC50s at hour 96 ranging from 5.0 to 10.4 ppt, with the least sensitive freshwater mussel being the nonsalinity-adapted A. ochracea, exhibiting an EC50 of 10.4 ppt (95% CI 9.1-12.0). Our results show that acute exposure to sea salt adversely affects freshwater mussel viability, particularly glochidia. This information can be used to enhance freshwater mussel conservation strategies in regions that are or will be impacted by climate-induced sea level rise and associated freshwater salinization. Environ Toxicol Chem 2023;42:2478-2489. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Sea level rise implications on future inland migration of coastal wetlands

Coastal wetlands provide essential ecosystem functions, including coastal protection, improvement in water quality and carbon sequestration, which are threatened due to sea level rise (SLR) – a well-documented aspect of anthropogenic climate change. While there are numerous articles on SLR impacts on wetlands, data about the interactions between natural or human-made barriers and future SLR projections e.g. coastal squeeze are still sparse. If wetlands are bounded by natural formations or human-made structures, coastal wetlands could be permanently lost in a warming climate. Here we delineate impacts of SLR on wetland inland migration under a changing climate in six locations around the world with a particular focus on the consequences of human-made structures along coastlines in Europe, specifically along the largest continuous coastal wetland system in the world, the Wadden Sea. Various locations around the world (North America, South America, Europe, Africa, Asia and Australia) were chosen to analyze the impacts of regional SLR on wetland dynamics under climate change scenario. Our results show that places like Bangladesh, India and Myanmar have much larger areas at risk with nearly 10% of their coastal wetlands, whereas the wetlands in northern Australia seem to have a low area at risk to be lost with not even 1%. For the North Sea coast, wetlands where we had access to data from human-made infrastructure, we show that due to the built infrastructure, the wetland areas do not have the opportunity to evolve landward and hence, are expected to disappear permanently.

The adsorption of arsenate and p-arsanilic acid onto ferrihydrite and subsequent desorption by sulfate and artificial seawater: Future implications of sea level rise

Sea level rise (SLR) is estimated to impact 25% of the world's population along coastal areas leading to an increase in saltwater intrusion. Consequently, changes in the soil biogeochemistry of currently non-saline and/or well-drained soils due to saltwater intrusion are of major concern. Saltwater intrusion is expected to affect farmland across large broiler producer regions, where large amounts of manure containing organic arsenicals were applied over the past decades. To determine how SLR may impact the speciation and mobility of adsorbed inorganic and organic As, we used in situ real-time attenuated total reflectance–Fourier transform infrared spectroscopy (ATR-FTIR) to determine the adsorption and desorption mechanisms of As(V) and 4-aminophenylarsonic (p-ASA, a poultry feed additive) on ferrihydrite (Fh) in the presence of sulfate at varying pH. The adsorption of As(V) and p-ASA increased at lower pH, with As(V) showing IR features consistent with the formation of inner-sphere of As-Fh surface complexes, while p-ASA also formed others structures as H-bonded As-surface complexes, likely mediated by outer-sphere complexes, based on our FTIR and batch experiments data. No observable As(V) or p-ASA desorption from the Fh surface was promoted by sulfate, however sulfate adsorption on the Fh surface was remarkably larger for p-ASA than for As(V). Complimentary, we carried out batch studies of As(V) and p-ASA desorption by Fh, using artificial seawater (ASW) at varying concentrations. The 1% ASW desorbed ∼10% of initially sorbed p-ASA, while at 100% ASW desorbed ∼40%. However, <1% of As(V) was desorbed by 1% ASW solution and only ∼7.9% were desorbed at 100% ASW. The spectroscopic data support the more extensive desorption of p-ASA compared to As(V) observed in batch experiments, suggesting that organoarsenicals may be easily desorbed and, after conversion to inorganic forms, pose a risk to water supplies.

Conservation and Sustainability of Coastal City Tourism In the Advent of Seal Level Rise in Durban, South Africa

Given the socioeconomic significance of oceans in South Africa and the threat of climate change, it is vital to understand the effects on coastlines and tourism. With very little known about the implications of sea level rise in Southern Africa, this study investigates its impact on tourism and conservation of coastlines in Durban, South Africa. The study conducted in 2021 used primary data collected through key informant interviews ( n = 10), an online questionnaire (303), direct field observations, and archival data from the National Oceanic and Atmospheric Administration. Trend analysis for climate data was done using Mann Kendal Trend Analysis, while the content and thematic analysis were used to assess qualitative data. The study found that the compounded effect of sea level rise of 1.49 mm/year in Durban between 1971 and 2018 poses a threat to the beach and coastal tourism. The compounded impact of sea level rise, sea surges, coastal storms, and high tides often results in high levels of beach erosion and coastal flooding, threatening tourism infrastructure. The municipality has embarked on a beach nourishment program, dune restoration, and coastal defense mechanisms to preserve and conserve the beachfront to ensure coastal tourism sustainability.

Land loss implications of sea level rise along the coastline of Colombia under different climate change scenarios

The sea level has risen notably in recent decades compared to the most recent millennia. This poses serious threats to infrastructure, local jobs, environment and human population over the next century, especially in coastal zones. In this paper, the most up-to-date understanding of the climate system and climate change was used to investigate impacts of sea level rise on potential land loss along the Caribbean and Pacific coastlines of Colombia. Sea level rise projections published in August 2021 by the Intergovernmental Panel on Climate Change in the Sixth Assessment Report were used to identify the area at risk of land loss. Moreover, the potential socio-economic implications of these changes were discussed in regions affected by the projected sea level rises. We examined five Shared Socioeconomic Pathways for the 21st century (SSP1-1.9, SSP1-2.6, SSP2-4.5. SSP3-7.0, SSP5-8.5). Our results suggest a sea level rise of 1.04 m in the worst-case scenario (SSP5-8.5) which would threaten an area of 2840.64 km2. The land use in the affected zones was determined. The area at risk will impact 12 departments or 86 municipalities with different social, environmental, economic, and cultural conditions along the coastline of Colombia, that need to be considered when devising and implementing mitigation policies.

The Implication of Sea-level Rise Toward the Small Island Nation of Maldives: Legal Perspective

Climate change has always been a major issue and a long discussion in the international community. One of the tangible manifestations of climate change is rising sea levels. Sea level rise also has a significant impact on small island countries or micro-countries which are geographically small and have very low land elevations. The impact of sea level rise will pose a threat that is quite dangerous for the existence of a small island nation like the Maldives. This article applies normative legal research methods using a conceptual approach, cases and regulations. This study aims to examine the implications of sea level rise on the Maldives perspective and provide options in the form of legal construction to solve this problem. This research found that The UNCLOS does not provide explicit reference against the sea-level rise effected by climate change. However, International community have been making progress to address this issue with a numbers of conferences. This study suggest that The Maldives government should have maximized the implementation of its laws and regulation to mitigate air space pollution coming from GHG Emission. The consistency of its implementation is the important key to mitigate the impact of this sea level rises.

Sea ice-free corridors for large swell to reach Antarctic ice shelves

Sea ice can attenuate Southern Ocean swell before it reaches Antarctic ice shelves and imposes flexural stresses, which promote calving of outer ice-shelf margins and influence ice shelf stability. An algorithm is developed to identify sea ice-free corridors that connect the open Southern Ocean to Antarctic ice shelves from daily satellite sea ice concentration data between September 1979 and August 2019. Large swell in the corridors available to impact the ice shelves is extracted from spectral wave model hindcast data. For a selection of ice shelves around the Antarctic coastline, corridors are assessed in terms of duration and areal extent. The availability of large swell to impact certain ice shelves through the corridors is evaluated from spectral wave data for daily statistical properties and the number of large swell days per year. Results integrated over a large number of ice shelves are used to assess overall trends. Large variations are found between individual ice shelves for both corridors and available swell, with contrasting trends between the West and East Antarctic Ice Sheet. The findings indicate ice shelves likely to experience prolonged periods of appreciable outer margin flexure due to large swell action, such as the Fimbul, Shackleton and Ross Ice Shelves, which could exacerbate climate-driven weakening and decreasing buttressing capacity, with implications for sea-level rise.

Southern Ocean sea surface temperature synthesis: Part 2. Penultimate glacial and last interglacial

The last interglacial (LIG: ∼130 to 115 thousand years before present) is often used as an analogue for near-future climate warming. Antarctic Ice Sheet response to LIG warming is of particular interest, because of its implications for sea level rise. Comparison between LIG climate simulations and proxy-based reconstructions of Southern Ocean sea surface temperature (SST) remains challenging, due to high uncertainties in both reconstructions and simulations. In this two-part study, the accompanying paper (Part 1) addressed uncertainties in the SST reconstructions by evaluating proxies relevant to Southern Ocean SST, and made recommendations for which proxies and respective calibrations are most reliable on glacial-interglacial time scales in this region. In the second part (this paper), we now apply these recommendations to a synthesis of Southern Ocean SST over the penultimate glacial and LIG. Similar to previous studies, we find that LIG warming at 40°S to 60°S reached 1.6 ± 1.1 °C (annual mean) or 1.9 ± 1.3 °C (austral summer: JFM) relative to present. Annual/summer cooling in the penultimate glacial maximum reached −3.6 ± 1.0 °C/−4.0 ± 1.2 °C, similar to the last glacial maximum. Compared with the previous LIG SST syntheses, our reported uncertainties more strongly reflect geographic variability and dating errors, as we have reduced errors in the individual temperature reconstructions and do not date records by aligning peaks in their SST. However, the reconstruction errors are still important, and we do not recommend detailed interpretation of temperature records from small numbers of sites. Instead, comparisons of our new synthesis with model simulations should focus only on the regional average.

Implications of sea-level rise for overwash enhancement at South Portugal

Implications of sea-level rise for overwash enhancement at South Portugal

Pricing climate risk: Are flooding and sea level rise risk capitalised in Australian residential property?

This research tests if contemporary house prices reflect the flood vulnerability of properties. In particular, future sea level rise is likely to expose properties to flood risk that are currently considered safe from these adverse events. Using a comprehensive dataset comprising of statutory rating valuation information and sales transactions, a hedonic framework is applied to estimate the potential price effects of current flood risk and future sea level rise. A valuation discount effect is identified for properties in known flooded areas while sea level rise has no detectable effect on valuations or sales data. The lack of a sea level rise discount in this analysis may be due to the absence of clear and comprehensive information on sea level rise available to home purchasers, myopic buyer behaviour, relatively affordable insurance premiums in areas not yet affected and no concrete plans for requiring buyers and owners to contribute to community or dwelling adaptation costs. Our results also indicate that buildings are in a significantly worse state of maintenance and repair if they are located in both current flood zones and areas that are likely to be under water when sea levels rise further. Generally, the lack of a price discount highlights that purchasers may be under-prepared for the future challenges and implications of sea level rise and the ancillary effects of future flooding, inundation and storm surges.

Sea level rise and coastal flooding threaten affordable housing

The frequency of coastal floods around the United States has risen sharply over the last few decades, and rising seas point to further future acceleration. Residents of low-lying affordable housing, who tend to be low-income persons living in old and poor quality structures, are especially vulnerable. To elucidate the equity implications of sea level rise (SLR), we provide the first nationwide assessment of recent and future risks to affordable housing from SLR and coastal flooding in the United States. By using high-resolution building footprints and probability distributions for both local flood heights and SLR, we identify the coastal states and cities where affordable housing—both subsidized and market-driven—is most at risk of flooding. We provide estimates of both the expected number of affordable housing units exposed to extreme coastal water levels and of how often those units may be at risk of flooding. The number of affordable units exposed in the United States is projected to more than triple by 2050. New Jersey, New York, and Massachusetts have the largest number of units exposed to extreme water levels both in absolute terms and as a share of their affordable housing stock. Some top-ranked cities could experience numerous coastal floods reaching higher than affordable housing sites each year. As the top 20 cities account for 75% of overall exposure, limited, strategic and city-level efforts may be able to address most of the challenge of preserving coastal-area affordable housing stock.

Implications of Sea Level Rise for Bee Communities in Rural Eastern Virginia Coastal Habitats

In the coastal mid-Atlantic region of the USA, landscapes are a mosaic of upland habitats (woodland, grassland, old fields and farmland) and low-lying coastal salt marsh. Flooding and salinization of coastal areas due to sea-level rise result in the conversion of upland habitats to salt marsh, and change the relative proportion of habitat types surrounding coastal farmland. This has the potential to influence population sizes of organisms living in this area and could alter the ecosystem services, such as pollination, that these habitats provide. To examine the potential outcome of these habitat conversions, we used blue vane traps at 14 sites along the Eastern Shore of Virginia (USA) to compare the bee communities of salt marsh, old fields and agricultural fields. Although there was no difference among habitat types for total bee abundance per site, we found that the coastal marsh is depauperate in bee species relative to old fields and agricultural fields, and that the bee species using the marsh habitat tend to be specialists of plant families that are common in the marsh (Asteraceae and Malvaceae) but are relatively uncommon in local agriculture. Thus, the transition of upland areas to marsh not only has the potential to impact agricultural productivity directly through salt water intrusion, ultimately it may also reduce the species richness of native bees available to provide pollination services to coastal agriculture.

Adaptation to uncertain sea-level rise; how uncertainty in Antarctic mass-loss impacts the coastal adaptation strategy of the Netherlands

Uncertainties in the rate and magnitude of sea-level rise (SLR) complicate decision making on coastal adaptation. Large uncertainty arises from potential ice mass-loss from Antarctica that could rapidly increase SLR in the second half of this century. The implications of SLR may be existential for a low-lying country like the Netherlands and warrant exploration of high-impact low-likelihood scenarios. To deal with uncertain SLR, the Netherlands has adopted an adaptive pathways plan. This paper analyzes the implications of storylines leading to extreme SLR for the current adaptive plan in the Netherlands, focusing on flood risk, fresh water resources, and coastline management. It further discusses implications for coastal adaptation in low-lying coastal zones considering timescales of adaptation including the decisions lifetime and lead-in time for preparation and implementation. We find that as sea levels rise faster and higher, sand nourishment volumes to maintain the Dutch coast may need to be up to 20 times larger than to date in 2100, storm surge barriers will need to close at increasing frequency until closed permanently, and intensified saltwater intrusion will reduce freshwater availability while the demand is rising. The expected lifetime of investments will reduce drastically. Consequently, step-wise adaptation needs to occur at an increasing frequency or with larger increments while there is still large SLR uncertainty with the risk of under- or overinvesting. Anticipating deeply uncertain, high SLR scenarios helps to enable timely adaptation and to appreciate the value of emission reduction and monitoring of the Antarctica contribution to SLR.