Regional Sea Level Rise Research Articles

Early Ipswichian (last interglacial) sea level rise in the channel region: Stone Point Site of Special Scientific Interest, Hampshire, England

Constraining the speed of sea level rise at the start of an interglacial is important to understanding the size of the ‘window of opportunity’ available for hominin migration. This is particularly important during the last interglacial when there is no evidence for significant hominin occupation anywhere in Britain. There are very few finer grained fossiliferous sequences in the Channel region that can be used to constrain sea level rise and they are preserved only to the north of the Channel, in England. Of these, the sequence at Stone Point SSSI is by far the most complete. Data from this sequence has been previously reported, and discussed at a Quaternary Research Association Field Meeting, where a number of further questions were raised that necessitated further data generation. In this paper, we report new data from this sequence – thin section analysis, isotopic determinations on ostracod shells, new Optical Stimulated Luminescence ages and Amino Acid Recem analyses. These show early sea level rise in this sequence, starting during the pre-temperate vegetation zone IpI, but no early warming. The implications of this almost certainly last interglacial sequence for the human colonisation of Britain and our understanding of the stratigraphic relationship of interglacial estuarine deposits with their related fluvial terrace sequences is explored.

Evaluating regional resiliency of coastal wetlands to sea level rise through hypsometry-based modeling.

Sea level rise (SLR) threatens coastal wetlands worldwide, yet the fate of individual wetlands will vary based on local topography, wetland morphology, sediment dynamics, hydrologic processes, and plant-mediated feedbacks. Local variability in these factors makes it difficult to predict SLR effects across wetlands or to develop a holistic regional perspective on SLR response for a diversity of wetland types. To improve regional predictions of SLR impacts to coastal wetlands, we developed a model that addresses the scale-dependent factors controlling SLR response and accommodates different levels of data availability. The model quantifies SLR-driven habitat conversion within wetlands across a region by predicting changes in individual wetland hypsometry. This standardized approach can be applied to all wetlands in a region regardless of data availability, making it ideal for modeling SLR response across a range of scales. Our model was applied to 105 wetlands in southern California that spanned a broad range of typology and data availability. Our findings suggest that if wetlands are confined to their current extents, the region will lose 12% of marsh habitats (vegetated marsh and unvegetated flats) with 0.6m of SLR (projected for 2050) and 48% with 1.7m of SLR (projected for 2100). Habitat conversion was more drastic in wetlands with larger proportions of marsh habitats relative to subtidal habitats and occurred more rapidly in small lagoons relative to larger sites. Our assessment can inform management of coastal wetland vulnerability, improve understanding of the SLR drivers relevant to individual wetlands, and highlight significant data gaps that impede SLR response modeling across spatial scales. This approach augments regional SLR assessments by considering spatial variability in SLR response drivers, addressing data gaps, and accommodating wetland diversity, which will provide greater insights into regional SLR response that are relevant to coastal management and restoration efforts.

COLLABORATIVE STRATEGIES FOR SEA LEVEL RISE ADAPTATION IN HAMPTON ROADS, VIRGINIA

INTRODUCTION The Hampton Roads region is located in southeastern Virginia where the Chesapeake Bay meets the Atlantic Ocean. The region includes seventeen municipal governments and has a large federal government presence with 26 federal agencies represented (See Figure 1). The region has a population that exceeds 1.7 million and is home to the deepest water harbor on the U.S. East Coast. Hampton Roads' economy is dependent on the local waterways and houses the world's largest naval facility, the sixth largest containerized cargo complex and supports a thriving shipbuilding and repair industry as well as a tourism industry. However, the region's vast coastline also contributes to its vulnerability from climate change. Hampton Roads is experiencing sea level rise at twice the global rate with regional projections in the January 2017 National Oceanic and Atmospheric Administration (NOAA) report, Global and Regional Sea Level Rise Scenarios for the United States, of 1.9 feet of sea level rise at the low end and 11.5 feet of sea level rise under the most extreme case between 2000 and 2100 (NOAA, 2017). Planning for adaptation to sea level rise requires regional partnerships and strategies, especially for watersheds that cross municipal boundaries. While many of the municipalities in the region are forward thinking in their approaches to sea level rise, there is not a regional plan for adaptation and current federal funding models do not support analysis of and planning for sea level rise impacts on a regional scale. For coastal communities to be successful in sea level rise adaptation, there has to be a national understanding that water knows no borders and only collaborative problem-solving approaches that cross municipal boundaries will move regions toward adaptation. Functional boundaries of ecosystems or watersheds need to be the focus of adaptation rather than political boundaries of local, state, and federal entities. Coordination and collaboration between entities is the only way to achieve optimal outcomes.

A Numerical Simulation of Long-Term Sea Level Change in the East Asian Marginal Seas

ABSTRACT Kim C.-H.; Jang C. J., and Kim M.-W., 2018. A Numerical Simulation of Long-Term Sea Level Change in the East Asian Marginal Seas. In: Shim, J.-S.; Chun, I., and Lim, H.S. (eds.), Proceedings from the International Coastal Symposium (ICS) 2018 (Busan, Republic of Korea). Journal of Coastal Research, Special Issue No. 85, pp. 546–550. Coconut Creek (Florida), ISSN 0749-0208. To investigate the regional sea level rise (SLR) and its possible mechanisms in the East Asian Marginal Seas (Yellow Sea (YS), East China Sea (ECS) and Japan/East Sea (JES)) sea level variation was simulated using the global ocean-sea ice coupled model (GFDL MOM5-SIS) forced with European Centre for Medium-range Weather Forecasts reanalysis data for 58 years (1958–2015). Seasonal variation in the simulated sea level shows comparable amplitude and phase to those of the satellite altimetry for 1993–2014 in each sea region. Rates of the simulated SLR are compared with those of the reconstructed sea level (Hamlington et al., 2011) ...

A dual model for emulation of thermosteric and dynamic sea-level change

Future thermosteric and dynamic sea-level changes are often projected by process-based climate models. Emulation of such computationally expensive models helps enable model intercomparison over a range of forcing scenarios and thus enables additional analysis of sea-level rise projection uncertainty. Current emulation methods use linear response functions to estimate global mean sea-level response. Here, we introduce a novel dual model to emulate global mean thermosteric sea-level rise that incorporates short- and long-term responses to climate forcing. This nonlinear response function outperforms existing linear response functions over six illustrative general circulation models and the four representative concentration pathways. To emulate dynamic sea-level projections, we introduce a linear pattern scaling model that relates regional sea-level changes to global mean thermosteric sea-level rise. Pattern scaling is shown to reproduce strongly forced sea-level trends. Our results demonstrate effective emulation of global and regional sea-level rise, which can facilitate the consideration of sea-level rise projection uncertainty critical to the analysis of sea-level rise hazard.

The Dynamics of the Developing Calcarenite Member of Pamutuan Formation In Cintaratu Area, Pangandaran, West Java

The investigated area is located in Cintaratu, Parigi District, Pangandaran Regency in the Southeastern part of Southern Mountain of West Java. The rock unit in the investigated area is described as the Calcarenite Member of the Pamutuan Formation. The present study applying detailed lithologic and paleontologic description reveals five lithologic units. Combining the field method with microscopic analysis leads to the verification of the age and environments of this carbonate rocks. The study concludes the development of reef complex in Early Mid Miocene, followed by the high energy of the dynamic environment producing the fragments of the lime clasts embedded in the packstone, indicates the deposition in the fore slope. The regression took place and moved the deposition environment to the low-energy condition at the back of the reef, producing bioclastic packstone containing larger foram. Rising seawater level amplified the dynamics of the seawater in mid-Middle Miocene. The formation of planktic packstone marked an initial transgression phase that was well-represented as regional transgressive in Southeast Asia. This phase continued until interbedded calcareous mudstone and sandstone were produced. Finally, in Late Mid Miocene the sea level regressive accumulated coarse materials of calcarenite grain size containing fragments of larger foram within shallower deposition environment. The NNW-SSE elongated distribution of five units of Calcerinite Member pointed out the configuration of Middle Miocene coastal line. In Early Middle Miocene, various carbonate rocks formation was primarily controlled by tectonic activities. Afterward, the rock deposition affected by the regional sea level rise and drop during Mid to Late Middle Miocene. The detailed description of the Calcarenite Member, therefore, contributed to the understanding of the paleogeography of Mid Miocene age and the dynamics of the environmental deposition.

Internal climate variability and projected future regional steric and dynamic sea level rise

Observational evidence points to a warming global climate accompanied by rising sea levels which impose significant impacts on island and coastal communities. Studies suggest that internal climate processes can modulate projected future sea level rise (SLR) regionally. It is not clear whether this modulation depends on the future climate pathways. Here, by analyzing two sets of ensemble simulations from a climate model, we investigate the potential reduction of SLR, as a result of steric and dynamic oceanographic affects alone, achieved by following a lower emission scenario instead of business-as-usual one over the twenty-first century and how it may be modulated regionally by internal climate variability. Results show almost no statistically significant difference in steric and dynamic SLR on both global and regional scales in the near-term between the two scenarios, but statistically significant SLR reduction for the global mean and many regions later in the century (2061–2080). However, there are regions where the reduction is insignificant, such as the Philippines and west of Australia, that are associated with ocean dynamics and intensified internal variability due to external forcing.

Mapping Sea Level Rise Behavior in an Estuarine Delta System: A Case Study along the Shanghai Coast

Abstract Sea level rise (SLR) is a major projected threat of climate change that is expected to affect developing coastal cities located in estuarine delta regions. Shanghai is one such city, being located in the Yangtze River Delta (YRD). It is difficult, however, for decision-makers to implement adaptation due to the uncertain causes, magnitudes, and timings of SLR behaviors. This paper attempts to map the causes and magnitudes of SLR behaviors on a decadal scale. We analyze the tidal level records from 11 tidal gauge stations and the corresponding bathymetry measurements around these stations since 1921. We identify three new SLR behaviors along the Shanghai coast due to anthropogenic geomorphologic changes (AGCs), besides the well-known eustatic sea level rise (ESLR), tectonic subsidence (TS), and urban land subsidence (ULS). The first new behavior is regional sea level rise (RSLR), which occurs as a result of land reclamation and deep waterway regulation. The second is regional sea level fall (RSLF), which occurs because the channel bed is eroded due to sediment supply decline in the river catchment. The last SLR behavior is local tidal datum rise (LTDR). Thus, we project that the magnitude of SLR for the Shanghai coast ranges from 10 cm to 16 cm from 2011 to 2030. Clarifying SLR behaviors is important to aid local decision-makers in planning structural and non-structural measures to combat escalating flood damage costs in an estuarine delta system; this field is full of future challenges.

Sea Level 2017 Conference Looks to Coastal Sea Level Rise Impact

International World Climate Research Programme/Intergovernmental Oceanographic Commission (WCRP/IOC) Open Science Conference on Regional Sea Level Rise and Its Impacts; New York, New York, 10–14 July 2017

Northern North Atlantic Sea Level in CMIP5 Climate Models: Evaluation of Mean State, Variability, and Trends against Altimetric Observations

The northern North Atlantic comprises a dynamically complex area with distinct topographic features, making it challenging to model oceanic features with global climate models. As climate models form the basis for assessment reports of future regional sea level rise, model evaluation is important. In this study, the representation of regional sea level in this area is evaluated in 18 climate models that contributed to phase 5 of the Coupled Model Intercomparison Project. Modeled regional dynamic height is compared to observations from an altimetry-based record over the period 1993–2012 in terms of mean dynamic topography, interannual variability, and linear trend patterns. As models are expected to reproduce the location and magnitude but not the timing of internal variability, the observations are compared to the full 150-yr historical simulations using 20-yr time slices. This approach allows one to examine modeled natural variability versus observed changes and to assess whether a forced signal is detectable over the 20-yr record or whether the observed changes can be explained by internal variability. The models perform well with respect to mean dynamic topography. However, model performances degrade when interannual variability and linear trend patterns are considered. The modeled regionwide average steric and dynamic sea level rise is larger than estimated from observations, and the marked observed increase in the subpolar gyre is not consistent with a forced response but rather a result of internal variability. Using a simple weighting scheme, it is shown that the results can be used to reduce uncertainties in sea level projections.

Building Blocks: A Quantitative Approach for Evaluating Coastal Vulnerability

Climate change and associated factors such as global and regional sea-level rise; the upsurge in high-intensity flooding events; and coastal erosion are pulse and press disturbances that threaten to increase landslides in coastal regions. Under these circumstances; a rigorous framework is required to evaluate coastal vulnerability in order to plan for future climate change scenarios. A vast majority of coastal vulnerability assessments across the globe are evaluated at the macro level (city scale) but not at the micro level (small town scale); particularly in the United Kingdom (UK). In order to fill this vital research gap; the current study established a coastal vulnerability index termed here as the Micro Town Coastal Vulnerability Index (MTCVI) and then applied it to Barton-on-Sea; which is a small coastal town of the Hampshire region; England; UK. MTCVI was evaluated for Barton-on-Sea coastal vulnerability by integrating both novel and existing parameters. Results suggest that the entire shoreline frontage (2 km) exhibits very high coastal vulnerability and is prone to various coastal hazards such as landslides; erosion; and wave intrusion. This suggests that Barton-on-Sea coastal amenities will require a substantial improvement in shoreline protection measures. In this study; GIS (geographic information system) coastal vulnerability and landslide maps were generated; and these maps can be used by the local authorities; district councils; coastal engineers; and planners to improve and design coastal management strategies under the climate change scenarios. Meanwhile; the methodology used in this study could also be applied to any other suitable location in the world depending on the availability of the data.

Quantifying and Predicting the Contribution of Sea-Level Rise to Shoreline Change in Ghana: Information for Coastal Adaptation Strategies

ABSTRACT Evadzi, P.I.K.; Zorita, E., and Hunicke, B., 2017. Quantifying and predicting the contribution of sea-level rise to shoreline change in Ghana: Information for coastal adaptation strategies. The purpose of this study is to estimate the contribution of sea-level rise (SLR) in Ghana over the last decades and provide an estimation of shoreline retreat due to the projections of regional SLR. This study first analyzes historical shoreline change in Ghana from 1974 to 2015 using satellite images and orthophotos. Second, this study quantifies the SLR contribution to historical shoreline change using sea-level trend estimates from satellite observations, results from digital elevation model analysis, and shoreline change rates. This study finally makes predictions of shoreline in Ghana on the basis of modified Intergovernmental Panel on Climate Change Fifth Assessment Report representative concentration pathways (RCPs) scenarios for Ghana. On average, sea level has risen by about 5.3 cm over the last 21 y...

Understanding the spatial variation of sea level rise in the North Sea using satellite altimetry

AbstractThis paper examines the spatial variation of sea surface height trends in the North Sea Basin as seen by satellite altimetry and assesses its underlying causes. Changes in the potential temperature and salinity of the North Sea are transposed into corresponding changes in sea surface height and regional anomalies of linear sea level trend calculated. The same is carried out for the meteorological processes which act on the sea surface. The steric and meteorological regional sea level rise anomalies are summed with those from contributions from land ice and compared against the values seen by satellite altimetry over the period 1993–2014. Results show that there is good agreement between the observations and the reconstruction. The local meteorological contribution appears to be most important in describing regional variation in linear sea level rise and is reinforced with a local halosteric contribution which shows a similar spatial pattern.

Moving the Conversation from “Us vs. Them” to Just “Us”: Insights from the AAAS S&T Policy Forum

Moving the Conversation from “Us vs. Them” to Just “Us”: Insights from the AAAS S&T Policy Forum

Understanding extreme sea levels for broad-scale coastal impact and adaptation analysis

One of the main consequences of mean sea level rise (SLR) on human settlements is an increase in flood risk due to an increase in the intensity and frequency of extreme sea levels (ESL). While substantial research efforts are directed towards quantifying projections and uncertainties of future global and regional SLR, corresponding uncertainties in contemporary ESL have not been assessed and projections are limited. Here we quantify, for the first time at global scale, the uncertainties in present-day ESL estimates, which have by default been ignored in broad-scale sea-level rise impact assessments to date. ESL uncertainties exceed those from global SLR projections and, assuming that we meet the Paris agreement goals, the projected SLR itself by the end of the century in many regions. Both uncertainties in SLR projections and ESL estimates need to be understood and combined to fully assess potential impacts and adaptation needs.

Partitioning the relative contributions of organic matter and mineral sediment to accretion rates in carbonate platform mangrove soils

In coming decades, the global rate of sea-level rise (SLR) is projected to accelerate beyond rates observed over the past several millennia when mangrove wetlands have expanded in tropical, sub-tropical and temperate regions. There is substantial uncertainty about how distinct mangrove ecotypes inhabiting a wide range of geomorphic settings will respond to SLR acceleration, including the thresholds at which they will submerge permanently. In this study, the relative contributions of soil organic and inorganic matter (SOM and SIM) to 210Pb-derived accretion rates were examined at 23 mangrove sites in southwest Florida, USA and the Yucatan Peninsula in Mexico. These sites are situated atop carbonate platforms where there is wide variation in the availability of SIM (generally marine marl). To account for this variability, research sites were classified by SIM presence based on the SOM content (%) estimated using loss-on-ignition: organic sites (SOM>70%), intermediate sites (SOM=40–70%) and mineral sites (SOM<40%).SOM accumulation rates were largely the same in the three soil classes during the past century (p<0.05); however, SIM accumulation rates in the intermediate and mineral sites were approximately 5 and 20 times greater, respectively, than rates in the organic sites. Despite this substantial difference in total mass accumulation rates, accretion rates were not statistically different between soil classes (p<0.05). Our analysis revealed that the rate of SOM accumulation is the best predictor of accretion rates, while the rate of SIM accumulation primarily predicts soil dry bulk density. These findings indicate that SOM and SIM do not contribute additively to soil volume. This is contrary to findings from North American coastal wetlands broadly, suggesting a unique characteristic of carbonate platform mangrove soils that lack a regular, substantive supply of terrigenous SIM.Overall, accretion rates in the FL sites and a Yucatan site on the Caribbean Sea are maintaining pace with regional rates of SLR over the past 100-year and 50-year timespans, whereas the sites in Celestun Lagoon, MX (located on the Gulf of Mexico) exhibit an accretion deficit. Estimates of regional SLR rates range from 4.6 to 12.2mmyr−1 by the year 2060. Based on accretion rates observed in the past century, some of these sites may be able to keep pace with the lower SLR estimate, but there is no evidence that any of these sites can match the higher rate.

Synthesizing long-term sea level rise projections – the MAGICC sea level model v2.0

Abstract. Sea level rise (SLR) is one of the major impacts of global warming; it will threaten coastal populations, infrastructure, and ecosystems around the globe in coming centuries. Well-constrained sea level projections are needed to estimate future losses from SLR and benefits of climate protection and adaptation. Process-based models that are designed to resolve the underlying physics of individual sea level drivers form the basis for state-of-the-art sea level projections. However, associated computational costs allow for only a small number of simulations based on selected scenarios that often vary for different sea level components. This approach does not sufficiently support sea level impact science and climate policy analysis, which require a sea level projection methodology that is flexible with regard to the climate scenario yet comprehensive and bound by the physical constraints provided by process-based models. To fill this gap, we present a sea level model that emulates global-mean long-term process-based model projections for all major sea level components. Thermal expansion estimates are calculated with the hemispheric upwelling-diffusion ocean component of the simple carbon-cycle climate model MAGICC, which has been updated and calibrated against CMIP5 ocean temperature profiles and thermal expansion data. Global glacier contributions are estimated based on a parameterization constrained by transient and equilibrium process-based projections. Sea level contribution estimates for Greenland and Antarctic ice sheets are derived from surface mass balance and solid ice discharge parameterizations reproducing current output from ice-sheet models. The land water storage component replicates recent hydrological modeling results. For 2100, we project 0.35 to 0.56 m (66 % range) total SLR based on the RCP2.6 scenario, 0.45 to 0.67 m for RCP4.5, 0.46 to 0.71 m for RCP6.0, and 0.65 to 0.97 m for RCP8.5. These projections lie within the range of the latest IPCC SLR estimates. SLR projections for 2300 yield median responses of 1.02 m for RCP2.6, 1.76 m for RCP4.5, 2.38 m for RCP6.0, and 4.73 m for RCP8.5. The MAGICC sea level model provides a flexible and efficient platform for the analysis of major scenario, model, and climate uncertainties underlying long-term SLR projections. It can be used as a tool to directly investigate the SLR implications of different mitigation pathways and may also serve as input for regional SLR assessments via component-wise sea level pattern scaling.

Quantifying the impact of basin dynamics on the regional sea level rise in the Black Sea

Abstract. Satellite altimetry measurements show that the magnitude of the Black Sea sea level trends is spatially uneven. While the basin-mean sea level rise from 1993 to 2014 was about 3.15 mm yr−1, the local rates of sea level rise varied from 1.5–2.5 mm yr−1 in the central part to 3.5–3.8 mm yr−1 at the basin periphery and over the northwestern shelf and to 5 mm yr−1 in the southeastern part of the sea. We show that the observed spatial differences in the dynamic sea level (anomaly relative to the basin-mean) are caused by changes in the large- and mesoscale dynamics of the Black Sea. First, a long-term intensification of the cyclonic wind curl over the Black Sea, observed in 1993–2014, strengthened divergence in the center of the basin and led to the rise of the sea level in coastal and shelf areas and a lowering in the basin's interior. Second, an extension of the Batumi anticyclone to the west resulted in ∼ 1.2 mm yr−1 higher rates of sea level rise in the southeastern part of the sea. Further, we demonstrate that the large-scale dynamic sea level variability in the Black Sea can be successfully reconstructed using the wind curl obtained from an atmospheric reanalysis. This allows for the correction of historical tide gauge records for dynamic effects in order to derive more accurate estimates of the basin-mean sea level change in the past, prior to the satellite altimetry era.

Role of Perturbing Ocean Initial Condition in Simulated Regional Sea Level Change

Multiple lines of observational evidence indicate that the global climate has been getting warmer since the early 20th century. This warmer climate has led to a global mean sea level rise of about 18 cm during the 20th century, and over 6 cm for the first 15 years of the 21st century. Regionally the sea level rise is not uniform due in large part to internal climate variability. To better serve the community, the uncertainties of predicting/projecting regional sea level changes associated with internal climate variability need to be quantified. Previous research on this topic has used single-model large ensembles with perturbed atmospheric initial conditions (ICs). Here we compare uncertainties associated with perturbing ICs in just the atmosphere and just the ocean using a state-of-the-art coupled climate model. We find that by perturbing the oceanic ICs, the uncertainties in regional sea level changes increase compared to those with perturbed atmospheric ICs. Thus, in order for us to better assess the full spectrum of the impacts of such internal climate variability on regional and global sea level rise, approaches that involve perturbing both atmospheric and oceanic initial conditions are necessary.

Causes of accelerating sea level on the East Coast of North America.

The tide‐gauge record from the North American East Coast reveals significant accelerations in sea level starting in the late twentieth century. The estimated post‐1990 accelerations range from near zero to ∼0.3 mm yr−2. We find that the observed sea level acceleration is well modeled using several processes: mass change in Greenland and Antarctica as measured by the Gravity Recovery and Climate Experiment satellites; ocean dynamic and steric variability provided by the GECCO2 ocean synthesis; and the inverted barometer effect. However, to achieve this fit requires estimation of an admittance for the dynamical and steric contribution, possibly due to the coarse resolution of this analysis or to simplifications associated with parameterization of bottom friction in the shallow coastal areas. The acceleration from ice loss alone is equivalent to a regional sea level rise in one century of 0.2 m in the north and 0.75 m in the south of this region.