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Recent events in the USA have highlighted a lack of resilience in the coastal population to coastal flooding, especially amongst disadvantaged and isolated communities. Some low income countries, such as Cuba and Bangladesh, have made significant progress towards transformed societies that are more resilient to the impacts of cyclones and coastal flooding. To understand how this has come about a systematic review of the peer-reviewed and grey literature related to resilience of communities to coastal flooding was undertaken in both countries. In both Cuba and Bangladesh the trust between national and local authorities, community leaders and civil society is high. As a consequence evacuation warnings are generally followed and communities are well prepared. As a result over the past 25 years in Bangladesh the number of deaths directly related to cyclones and coastal flooding has decreased, despite an increase of almost 50 % in the number of people exposed to these hazards. In Cuba, over the course of eight hurricanes between 2003 and 2011, the normalised number of deaths related to cyclones and coastal floods was an order of magnitude less than in the USA. In low-income countries, warning systems and effective shelter/evacuation systems, combined with high levels of disaster risk reduction education and social cohesion, coupled with trust between government authorities and vulnerable communities can help to increase resilience to coastal hazards and tropical cyclones. In the USA, transferable lessons include improving communication and the awareness of the risk posed by coastal surges, mainstreaming disaster risk reduction into the education system and building trusted community networks to help isolated and disadvantaged communities, and improve community's resilience.

Coastal flooding caused by extreme sea levels can produce devastating and wide-ranging consequences. The ‘SurgeWatch’ v1.0 database systematically documents and assesses the consequences of historical coastal flood events around the UK. The original database was inevitably biased due to the inconsistent spatial and temporal coverage of sea-level observations utilised. Therefore, we present an improved version integrating a variety of ‘soft’ data such as journal papers, newspapers, weather reports, and social media. SurgeWatch2.0 identifies 329 coastal flooding events from 1915 to 2016, a more than fivefold increase compared to the 59 events in v1.0. Moreover, each flood event is now ranked using a multi-level categorisation based on inundation, transport disruption, costs, and fatalities: from 1 (Nuisance) to 6 (Disaster). For the 53 most severe events ranked Category 3 and above, an accompanying event description based upon the Source-Pathway-Receptor-Consequence framework was produced. Thus, SurgeWatch v2.0 provides the most comprehensive and coherent historical record of UK coastal flooding. It is designed to be a resource for research, planning, management and education.

China is amongst the countries most severely affected by coastal and marine disasters. In this study, the annual variation and geographic distribution of the direct economic losses and fatalities caused by rapid-onset coastal and marine disasters in China have been analysed. This was based on a collection of historical documents and official records. The five main hazards include storm surges, rough seas, sea ice, red tides and green tides. The results show that: (1) Storm surges caused the most economic losses (92% of the total); (2) At national scale, direct economic losses induced by coastal and marine disasters fluctuated with no clear trend; the number of fatalities per year declined, and in relative terms both economic losses and fatalities decreased dramatically throughout time; (3) Substantial heterogeneity exists across the 11 provincial-level administrative regions in terms of the spatial pattern and temporal trends of coastal and marine hazards, exposure, vulnerability and observed impacts. Guangzhou, Fujian, Zhejiang and Hainan provinces experienced the highest direct economic losses and fatalities due to repeated typhoon-induced storm surges. The decline in adverse impacts caused by hazards is due to substantial progress in coastal and marine disaster prevention and migration in China, largely thanks to institutional measures, plus adaptation and mitigation actions at both national and regional levels. Coastal China still faces growing risks due to socio-economic development, climate change, as well as subsidence and new emerging marine disasters (e.g. green tides). Further management needs to promote integrated solutions across socio-economic development, disaster risk reduction and environmental conservation in coastal regions. This should happen at national and international levels as disasters can affect neighboring countries, and their marine environments and socio-ecological systems. Lessons may be learnt from countries experiencing similar problems over the long-term.

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., Uncertainties in contemporary extreme sea levels (ESL) from mean sea level rise (SLR) projections have been overlooked in broad-scale risk and adaptation studies. Here, the authors quantify the uncertainties in present-day global ESL estimates and find that they exceed those from global SLR projections.

Energetic swell waves present a significant coastal hazard. Overtopping is particularly sensitive to these longer period waves, potentially resulting in coastal flooding. In narrow tidal seas which are linked to large oceans, such as the English Channel, the importance of swell for design considerations is not immediately obvious. However, historical experience shows occasional severe impacts from long period waves, such as on 6th February 1904, 13th February 1979 and most recently two events in February 2014. When wave buoy measurements are analyzed using spectral partitioning methods, it is possible to identify swell wave systems with significant energy within the overall spectrum. This often coincides with the occurrence of storm waves, which might mask the presence of the swell component without such analysis. Two case studies where flooding occurred during storm events are examined in this paper. It has been possible to associate individual spectral components with the occurrence of overtopping of coastal defences at a particular location. Further investigation of the characteristics and frequency of energetic swell waves are recommended to enhance prediction and the design of coastal defences, and hence reduce their consequences.

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Geomorphic modelling is a key method to understand the soft cliff recession process to predict future rates of retreat and responses to climate change. A range of process-based models have been used; however the influence of varied vertical lithology has yet to be quantified. This paper describes modifications to the 2D SCAPE (Soft Cliff and Platform Erosion) model, carried out to explore such interactions between vertical changes in cliff resistive strength and prevailing coastal conditions. As expected, weaker (/more resistant) layers lead to more (/less) rapid retreat. However, this effect is strongly influenced by the position of such layers relative to mean sea level, where the erosive potential is greatest. Moreover, model simulations reveal that layers of variable resistance give an asymmetric response in terms of both rates of retreat and the timeframe for the effect to be realised. For example, a reduction of material strength of 1/5 (in comparison to the remainder of the cliff) about mean sea level results in a rapid 130% increase in the rate of retreat in comparison to the introduction of a five times more resistant layer of the same characteristics. This variation in response can be attributed to the different magnitudes of feedback governing profile reshaping associated with the change in lithology. For example, the introduction of a weaker layer amplifies erosion through its greater erosive potential combined with steepening of the overlying section. The results have important implications for the management of coastal cliffs exhibiting variable stratigraphy, combined with the potential for future interactions with sea-level rise.

While planning coastal risk management strategies, coastal managers need to assess risk across a range of spatial and temporal scales. GIS-based tools are one efficient way to support them in the decision making process through a scenarios analysis starting from social, economic and environmental information integrated into a common platform. However, this integration process requires a significant effort from a team of scientists in terms of a) identifying the appropriate scales and data resolution for analysing social, environmental and economic issues; b) selecting and linking an appropriate set of tools to build a coupled model; c) representing key emerging (and hence challenging) research issues, such as risk perception and social resilience in the model; d) developing multi-criteria analysis to integrate social, environmental, economic impacts; and e) accounting for the expectations of the stakeholders and therefore optimizing the opportunity for them to interact with the tool development and with the final tool itself. In this spirit, this paper presents an open-source Spatial Decision Support System developed within the THESEUS Project to help decision makers to scopeg optimal strategies to minimise coastal risks. The exploratory tool allows the users to perform an integrated coastal risk assessment, to analyse the effects of different combinations of engineering, social, economic and ecologically based mitigation options, across short (2020s), medium (2050s) and long-term (2080s) scenarios, taking into account physical and non-physical drivers, such as climate change, subsidence, population and economic growth.

Soft cliff retreat has often triggered a hard adaptation response by the building of seawalls and groynes. On adjacent undefended coasts erosion continues, resulting in set-backs. This paper examines the impact of coastal defences on the adjacent coast from historic records and present practices, and explores possible future response. Continued set-back often leads to outflanking of defences, making them ineffective at their extremities, particularly at the down-drift end where it is most severe. Solutions to outflanking usually involve extending defences, initiating a cycle of set-back, outflanking and further extensions. Multiple defence extensions and continued retreat of the unprotected adjacent coast results in artificial headland formation. Over several decades, headlands experience foreshore steepening and reduced sediment availability, making them more difficult and expensive to defend. Shoreline management plan policies of managed retreat advocate selective defence abandonment, which may change the nature of artificial headland formation. Defence abandonment and new engineering works must be planned, anticipating the processes described in this paper. This will reduce unexpected changes and reduce maintenance and emergency work costs.

Coastal flood damage and adaptation costs under 21st century sea-level rise are assessed on a global scale taking into account a wide range of uncertainties in continental topography data, population data, protection strategies, socioeconomic development and sea-level rise. Uncertainty in global mean and regional sea level was derived from four different climate models from the Coupled Model Intercomparison Project Phase 5, each combined with three land-ice scenarios based on the published range of contributions from ice sheets and glaciers. Without adaptation, 0.2-4.6% of global population is expected to be flooded annually in 2100 under 25-123 cm of global mean sea-level rise, with expected annual losses of 0.3-9.3% of global gross domestic product. Damages of this magnitude are very unlikely to be tolerated by society and adaptation will be widespread. The global costs of protecting the coast with dikes are significant with annual investment and maintenance costs of US 12-71 billion in 2100, but much smaller than the global cost of avoided damages even without accounting for indirect costs of damage to regional production supply. Flood damages by the end of this century are much more sensitive to the applied protection strategy than to variations in climate and socioeconomic scenarios as well as in physical data sources (topography and climate model). Our results emphasize the central role of long-term coastal adaptation strategies. These should also take into account that protecting large parts of the developed coast increases the risk of catastrophic consequences in the case of defense failure.

Deltas provide diverse ecosystem services and benefits for their populations. At the same time, deltas are also recognised as one of the most vulnerable coastal environments, with a range of drivers operating at multiple scales, from global climate change and sea-level rise to deltaic-scale subsidence and land cover change. These drivers threaten these ecosystem services, which often provide livelihoods for the poorest communities in these regions. The imperative to maintain ecosystem services presents a development challenge: how to develop deltaic areas in ways that are sustainable and benefit all residents including the most vulnerable. Here we present an integrated framework to analyse changing ecosystem services in deltas and the implications for human well-being, focussing in particular on the provisioning ecosystem services of agriculture, inland and offshore capture fisheries, aquaculture and mangroves that directly support livelihoods. The framework is applied to the world's most populated delta, the Ganges-Brahmaputra-Meghna Delta within Bangladesh. The framework adopts a systemic perspective to represent the principal biophysical and socio-ecological components and their interaction. A range of methods are integrated within a quantitative framework, including biophysical and socio-economic modelling and analyses of governance through scenario development. The approach is iterative, with learning both within the project team and with national policy-making stakeholders. The analysis is used to explore physical and social outcomes for the delta under different scenarios and policy choices. We consider how the approach is transferable to other deltas and potentially other coastal areas.

This chapter presents the Coastal Fluvial Flood (CFFlood) meta-model that has been developed and integrated into a participatory integrated assessment tool to facilitate a two-way interactive process. The goal of the model is to allow users to explore flood impacts and adaptation options under a range of climate and socio-economic change scenarios in Europe. The tool enables users to understand the socio-economic flood impacts and wetland change/loss due to changes in model parameters within ranges that are designed to reflect future uncertainty. Changes in flood frequency due to changes in river flows and relative sea-level rise are used to determine the flood extent and depth, which are combined with information on urban land use, population density, and Gross Domestic Product (GDP) to estimate impacts. Wetland changes and losses in the floodplain are assessed considering three influencing factors of accommodation: space, sediment supply, and rate of relative sea-level rise. The benefits of a number of adaptation measures including flood protection upgrades, realignment of flood defenses, resilience measures, and mixed responses for reducing flood risks are assessed. Flood impact simulations show that future climate and socio-economic conditions significantly influence socio-economic impacts, especially when coastal flooding is increased due to sea-level rise. In contrast, impacts caused by fluvial flooding may decrease in Southern Europe and parts of Western Europe due to the decrease in precipitation. Incremental losses of coastal wetland habitats (i.e., saltmarsh and intertidal flats) are simulated with the increase of sea-level rise. Under high-end scenarios, impacts increase substantially unless there are corresponding adaptation efforts.

The final publication is available at Springer via http://dx.doi.org/10.1007/s10113-016-0972-9 The potential impact of climate change on port operations and infrastructures has received much less attention than the corresponding impact for beach systems. However, ports have always been vulnerable to weather extremes and climate change could enhance such occurrences at timescales comparable to the design lifetime of harbour engineering structures. The analysis in this paper starts with the main climatic variables affecting harbour engineering and exploitation. It continues with a review of the available projections for such variables first at global scale and then at a regional scale (Catalan coast in the western Mediterranean) as a study case for similar environments in the planet. The detailed assessment of impacts starts from downscaled projections for mean sea level and wave storms (wind not considered in the paper). This is followed by an analysis of the port operations and infrastructure performance that are relevant from a climate perspective. The key climatic factors here considered are relative sea level, wave storm features (height, period, direction and duration) and their combined effect, which is expected to produce the highest impacts. The paper ends with a discussion and some examples of analyses aiming at port adaptation to future climate change.

This paper presents a multi-sectoral evaluation of the global and regional consequences of future climate change across indicators representing impacts on heat extremes, water resources, river and coastal flooding, droughts, agriculture and energy use. It estimates change in physical hazard and resource base under different rates of climate change, characterising the uncertainty in regional climate change with scenarios constructed from CMIP5 climate models. Socio-economic impacts are estimated for each combination of rate of climate change and socio-economic scenario. The analysis adopts a novel approach using relationships between level of warming and impact to rapidly estimate impacts under any climate forcing. At the global aggregate scale, all the consequences of climate change considered here are adverse: the frequencies of droughts, floods and heatwaves all increase, with large increases under the highest rates of warming. Under the highest forcing (RCP8.5), by 2100 the median estimate of the average annual likelihood of a major heatwave at a point is 97% (compared with 5% now). The median estimate of the proportion of time in hydrological drought is 27% (up from 7% now), but a high-end estimate is 36%. The median estimate of the average likelihood of the current 2% river flood is 7%, but the high-end estimate is over 11%. The socio-economic impacts of climate change are determined by socio-economic scenario. The paper presents projections of indicators at the regional scale, by climate and socio-economic scenario, and these can provide the basis for subsequent assessments.The range in estimated consequences of climate change can be very large, especially at the regional scale, partly due to uncertainty in future emissions and future socio-economic conditions, but also due to scientific uncertainty in how climate changes in response to future emissions. The relative importance of these three main sources of uncertainty varies between indicators. By 2100 for most indicators the range across socio-economic scenario is greater than the range across the forcing levels considered here. For the indicators dependent on temperature, the largest source of scientific uncertainty is in the estimated magnitude of equilibrium climate sensitivity, but for the indicators determined by precipitation change the largest source of scientific uncertainty is in the estimated spatial and seasonal pattern of changes in precipitation.

This paper describes the extension of a state-of-the-art one-line model in terms of alongshore sediment transport rate by linking with a cross-shore profile model through the OpenMI-based Pipistrelle interface. In order to combine these two models, three additional modules (Drift Interpolation module, Vector-to-Scalar module and Orientation Updating module) need to be developed, so that the two models which are based on different assumptions, coordinate systems and set-ups can be linked seamlessly. The existing two models and the three new modules are able to work together as a whole composition (i.e. the combined model) based on the OpenMI standard. This combined model aims to improve the one-line model in terms of alongshore sediment transport and beach morphological response predictability. It adopts both the modified Coastal Engineering Research Centre, USA (CERC) formula and the Energetics approach to calculate the alongshore sediment transport. Tests at a real curved coast demonstrate that the model is numerically stable, effective in computing and able to give reasonable predictions of shoreline change. It demonstrates that further research on linking existing models is promising.

This paper presents a first assessment of the global effects of climate-induced sea-level rise on the erosion of sandy beaches, and its consequent impacts in the form of land loss and forced migration of people. We consider direct erosion on open sandy coasts and indirect erosion near selected tidal inlets and estuaries, using six global mean sea-level scenarios (in the range of 0.2-0.8m) and six SRES socio-economic development scenarios for the 21st century. Impacts are assessed both without and with adaptation in the form of shore and beach nourishment, based on cost-benefit analysis that includes the benefits of maintaining sandy beaches for tourism. Without nourishment, global land loss would amount to about 6000-17,000km2 during the 21st century, leading to 1.6-5.3million people being forced to migrate and migration costs of US$ 300-1000billion (not discounted). Optimal beach and shore nourishment would cost about US$ 65-220billion (not discounted) during the 21st century and would reduce land loss by 8-14%, forced migration by 56-68% and the cost of forced migration by 77-84% (not discounted). The global share of erodible coast that is nourished increases from about 4% in 2000 to 18-33% in 2100, with beach nourishment being 3-4 times more frequent than shore nourishment, reflecting the importance of tourism benefits. In absolute terms, with or without nourishment, large countries with long shorelines appear to have the largest costs, but in relative terms, small island states appear most impacted by erosion. Considerable uncertainty remains due to the limited availability of basic coastal geomorphological data and models on a global scale. Future work should also further explore the effects of beach tourism, including considering sub-national distributions of beach tourists.

Barrier beaches often overlie backbarrier deposits composed of poorly consolidated sediments. Hence, they can consolidate significantly if loaded. A retreating barrier beach provides such a load. In the static situation of beach nourishment, the increased load of the raised beach volume will also cause increased consolidation. These can lower beach elevation promoting wave overtopping, overwashing and retreat. However, there is limited research concerning the role of consolidation on the stability of barrier beaches worldwide. This paper focuses on this issue using Hurst Spit on the UK south coast as a study site where consolidation is a known significant process (Nicholls, 1985; Burt et al., 2018). It is a storm beach composed of shingle (pebble and cobble) sediments and formerly retreated at 2 to 3 m/yr, Since the later 1990s it has been more stabilized by a major nourishment (Bradbury and Kidd, 1998), but continues to retreat slowly (Figure 1). A second nourishment phase is now being actively assessed following major damage in the large storm of 14 February 2014. In this context, the role of consolidation has been analyzed via new data collection, consolidation modelling and morphodynamic modelling. This paper presents these results and their implications.

The IPCC's global mean sea-level rise scenarios do not necessarily provide the right information for coastal decision-making and risk management.

Sea-level rise and extreme events have the potential to significantly impact coastal energy infrastructure through flooding and erosion. Disruptions to supply, transportation and storage of energy have global ramifications and potential contamination of the natural environment. On a European scale, there is limited information about energy facilities and their strategic plans for adapting to climate change. Using a Geographical Information System this paper assesses coastal energy infrastructure, comprising (1) oil/gas/LNG/tanker terminals and (2) nuclear power stations. It discusses planning and adaptation for sea-level rise and extreme events. Results indicate 158 major oil/gas/LNG/tanker terminals in the European coastal zone, with 40 % located on the North Sea coast. There are 71 operating nuclear reactors on the coast (37 % of the total of European coastal countries), with further locations planned in the Black, Mediterranean and Baltic Seas. The UK has three times more coastal energy facilities than any other country. Many north-west European countries who have a high reliance on coastal energy infrastructure have a high awareness of sea-level rise and plan for future change. With long design lives of energy facilities, anticipating short, medium and long-term environmental and climatic change is crucial in the design, future monitoring and maintenance of facilities. Adaptation of coastal infrastructure is of international importance, so will be an ongoing important issue throughout the 21st century.

Due to complexities of creating sea-level rise scenarios, impacts of climate-induced sea-level rise are often produced from a limited number of models assuming a global uniform rise in sea level. A greater number of models, including those with a pattern reflecting regional variations would help to assure reliability and a range of projections, indicating where models agree and disagree. This paper determines how nine new patterned-scaled sea-level rise scenarios (plus the uniform and patterned ensemble mean rises) influence global and regional coastal impacts (wetland loss, dry land loss due to erosion and the expected number of people flooded per year by extreme sea levels). The DIVA coastal impacts model was used under an A1B scenario, and assumed defences were not upgraded as conditions evolved. For seven out of nine climate models, impacts occurred at a proportional rate to global sea-level rise. For the remaining two models, higher than average rise in sea level was projected in northern latitudes or around populated coasts thus skewing global impact projections compared with the ensemble global mean. Regional variability in impacts were compared using the ensemble mean uniform and patterned scenarios: The largest relative difference in impacts occurred around the Mediterranean coast, and the largest absolute differences around low-lying populated coasts, such as south, south-east and east Asia. Uniform projections of sea-level rise impacts remain a useful method to determine global impacts, but improved regional scale models of sea-level rise, particularly around semi-enclosed seas and densely populated low-lying coasts will provide improved regional impact projections and a characterisation of their uncertainties.

National infrastructure is as much a priority in countries with a large stock of ageing infrastructural assets as it is for rapidly industrialising economies. Increasing attention is being paid to the risk and opportunities that the growing interdependence between infrastructural systems brings. However, there is no current methodology to enable long-term planning and future performance assessment of interdependent infrastructural systems. This paper makes the case for a long-term, cross-sectoral approach to analysing and planning the performance of national infrastructure systems. Such an approach is required to develop credible long-term visions for infrastructure provision and to analyse system performance across a range of possible futures. A preliminary version of a system-of-systems analysis for the UK is presented as an example. The implementation of a comprehensive, model-based approach is currently well under way.

England and Wales has a long history of recognising coastal change, where coastal morphology adjusts in response to changing patterns of erosion and accretion, especially in the vicinity of ports and reclamations in estuaries. The long history of responses to coastal change can be linked to the history of coastal engineering, the wider development of coastal management; and most recently shoreline management, as a policy framework for managing flood and erosion risks on changing coasts. Coastal change is ongoing and long-term so that management is necessarily a process and effective delivery requires an adequate monitoring programme to inform management decisions. Monitoring also enables adaptive and flexible solutions to be implemented that take account of the inherent uncertainties such as future climate, promoting well adapted rather than mal-adapted outcomes. Given the current concerns about accelerated rates of sea-level rise and climate change this paper considers the development of both shoreline management and the supporting national monitoring programme in England to assess whether the SMP process remains useful in these circumstances. The lessons and experience are widely transferable.

Jonkman, S.N.; Hillen, M.M.; Nicholls, R.J.; Kanning, W., and van Ledden, M., 2013. Costs of adapting coastal defences to sea-level rise—new estimates and their implications. The cost of upgrading and raising coastal defences is an important consideration in societal response to sea-level rise. Currently available unit cost estimates have a limited empirical basis. This article presents new information on the unit costs of adapting coastal defences for three specific case studies in low-lying delta regions: The Netherlands, New Orleans, and Vietnam. Typical measures include dikes, flood walls, storm surge barriers, and nourishment. These unit cost estimates are significantly higher than earlier estimates that are still the main source of costs for global vulnerability assessments. Factors affecting these unit costs include local economic factors (material and labour costs), design choices related to the alignment of the system, and the types of measures for implementation of the system in an urba...

The adoption of the Convention on Wetlands of International Importance in Ramsar, Iran in 1971 committed the UK to conserve and sustainably use intertidal mudflats and saltmarshes for the benefit of present and future generations. Through consideration of their importance and value, current status, the characteristics, causes and consequences of their loss, and the associated responses to loss, this paper reviews the UK progress towards the conservation and sustainable use of intertidal mudflats and saltmarshes. Uncertainties in their current status and trends make it difficult to assess the overall net change in extent across the UK. However, it is apparent that losses due to erosion continue to exceed gains from intertidal mudflat and saltmarsh reparation (IMSR) schemes in south-east and southern England. IMSR schemes in the UK have been generally limited to relatively small-scale trials in comparison to elsewhere in Europe and in the USA. No research to date has unequivocally identified the causes of erosion. Regardless of the cause, the loss of intertidal mudflats and saltmarshes has adverse impacts on the provision of ecosystem services upon which humans and other species depend. The evidence presented in this paper suggests that alongside further science-based research, there is a need to develop a decision-making process capable of accommodating complexity, uncertainty and multiple diverse perspectives, through which more informed, timely decisions and more effective, concerted actions to conserve and sustainably use intertidal mudflats and saltmarshes can be taken.

International audience; This paper assesses historic changes in mean sea level around the coastline of the North Sea, one of the most densely populated coasts in the world. Typically, such analyses have been conducted at a national level, and detailed geographically wider analyses have not been undertaken for about 20 years. We analyse long records (up to 200 years) from 30 tide gauge sites, which are reasonably uniformly distributed along the coastline, and: (1) calculate relative sea level trends; (2) examine the inter-annual and decadal variations; (3) estimate regional geocentric (sometimes also referred to as ‘absolute’) sea level rise throughout the 20th century; and (4) assess the evidence for regional acceleration of sea-level rise. Relative sea level changes are broadly consistent with known vertical land movement patterns. The inter-annual and decadal variability is partly coherent across the region, but with some differences between the Inner North Sea and the English Channel. Data sets from various sources are used to provide estimates of the geocentric sea level changes. The long-term geocentric mean sea level trend for the 1900 to 2011 period is estimated to be 1.5 ± 0.1 mm/yr for the entire North Sea region. The trend is slightly higher for the Inner North Sea (i.e. 1.6 ± 0.1 mm/yr), and smaller but not significantly different on the 95% confidence level for the English Channel (i.e. 1.2 ± 0.1 mm/yr). The uncertainties in the estimates of vertical land movement rates are still large, and the results from a broad range of approaches for determining these rates are not consistent. Periods of sea level rise acceleration are detected at different times throughout the last 200 years and are to some extent related to air pressure variations. The recent rates of sea level rise (i.e. over the last two to three decades) are high compared to the long-term average, but are comparable to those which have been observed at other times in the late 19th and 20th century.

Extreme sea-level events (e.g. caused by storm surges) can cause coastal flooding, and considerable disruption and damage. To understand the impacts or hazards expected by different sea levels, waves and defence failures, it is useful to monitor and analyse coastal flood events, including generating numerical simulations of floodplain inundation. Ideally, any such modelling should be calibrated and validated using information recorded during real events, which can also add plausibility to synthetic flood event simulations. However, such data are rarely compiled for coastal floods. This paper demonstrates the capture of such a flood event dataset, and its integration with defence and floodplain modelling to reconstruct, archive and better understand the regional impacts of the event. The case-study event comprised a significant storm surge, high tide and waves in the English Channel on 10 March 2008, which resulted in flooding in at least 37 distinct areas across the Solent, UK (mainly due to overflow and outflanking of defences). The land area flooded may have exceeded 7 km2, with the breaching of a shingle barrier at Selsey contributing to up to 90 % of this area. Whilst sea floods are common in the Solent, this is the first regional dataset on flood extent. The compilation of data for the validation of coastal inundation modelling is discussed, and the implications for the analysis of future coastal flooding threats to population, business and infrastructure in the region.

Climate mitigation policies are rarely assessed in terms of the proportion of climate impacts they can avoid both regionally and globally. Research shows that policies with a 50% chance of remaining below a 2 °C rise in temperature may reduce the impacts of climate change by 20–65% by 2100, relative to pathways with a temperature rise of 4 °C.

Modelling coastal morphological changes at decadal to centennial time scales is required to support sustainable coastal management world-wide. One approach involves coupling of landform-specific components (e.g. cliff, beach, dunes, estuaries, etc.) that have been independently developed. An alternative, and novel approach explored in this paper is to capture the essential characteristics of the landform-specific models using a common spatial representation within an appropriate software-environment. In the proposed Coastal Modelling Environment (CoastalME), change in coastal morphology is formulated by means of dynamically linked raster and geometrical objects. A grid of raster cells provides the data structure for representing quasi-3D spatial heterogeneity and sediment conservation. Other geometrical objects (lines, areas and volumes) that are consistent with, and derived from, the raster structure represent a library of coastal elements (e.g. shoreline, beach profiles and estuary volumes) as required by different landform-specific models. As a proof-of-concept, we illustrate the potential capabilities of CoastalME by integrating a cliff-beach model. We verify that CoastalME can reproduce behaviours of each individual landform-specific model. Their integration within the framework of CoastalME reveals behaviours that emerge from landforms interaction and which have not previously been captured, such as the influence of the regional bathymetry on the local alongshore sediment transport gradient. This is the first step of the framework development, which provides an alternative to directly coupling existing models.

Migration is often mentioned as a major potential impact of climate change for small island states, especially low-lying atolls. Understanding future migration flows, including the potential role of environmental change, requires an interdisciplinary approach, focusing both on environmental and socio-economic factors. This paper presents a detailed analysis of contemporary migration decision-making processes in a small island nation—the Maldives—based on a survey conducted in 2015. The results challenge the view that climate change is influencing contemporary migration behaviour in the Maldives. The survey shows how attitudes influence intention to migrate both internally and internationally. Existing analysis of the national census shows a strong urbanisation trend, with significant net migration to the capital island Male and its environs, dominating national migration flows. People consider perceived employment and educational opportunities, quality of health services, and expectations about general quality of life, happiness, and social environment. In addition, many Maldivians have a high intention to migrate internationally. Hence, the reduction of barriers to international migration by, for example, establishment of international migrant networks, or policies enabling migration from the Maldives, is likely to increase international migration. Maldivians widely express knowledge and concern about climate change and sea-level rise, recognising the high vulnerability of the island nation. However, such considerations are not presently important in their decisions about migration.

The Sundarbans mangrove ecosystem, located in India and Bangladesh, is recognized as a global priority for biodiversity conservation and is an important provider of ecosystem services such as numerous goods and protection against storm surges. With global mean sea-level rise projected as up to 0.98m or greater by 2100 relative to the baseline period (1985-2005), the Sundarbans – mean elevation presently approximately 2 m above mean sea-level – is under threat from inundation and subsequent wetland loss; however the magnitude of loss remains unclear. We used remote and field measurements, geographic information systems and simulation modelling to investigate the potential effects of three sea-level rise scenarios on the Sundarbans within coastal Bangladesh. We illustrate how the Sea Level Affecting Marshes Model (SLAMM) is able to reproduce the observed area losses for the period 2000-2010. Using this calibrated model and assuming that mean sea-level is a better proxy than the SLAMM assumed mean lower low water for Mangrove area delineation, the estimated mangrove area net losses (relative to year 2000) are 81-178 km2, 111-376 km2 and 583-1393 km2 for relative sea-level rise scenarios to 2100 of 0.46m, 0.75m and 1.48m, respectively and net subsidence of ±2.5 mm/year. These area losses are very small (

The final publication is available at Springer via http://dx.doi.org/10.1007/s10113-016-1052-x The Catalan coast as most of the developed Mediterranean coastal zone is characterized by the coincidence of stresses and pressures on the natural system with a high exposure and low adaptive capacity. Due to this, climate change-induced effects will increase natural hazards and aggravate their associated impacts and, in consequence, it is necessary to assess their effects for proper long-term management. In this work, we assess the impact of sea-level rise (SLR)-induced shoreline retreat on the Catalan coast for three scenarios ranging from 0.53 to 1.75 m by the year 2100. Implications are analysed in terms of affectation of two main functions provided by beaches, i.e. recreation and protection. Obtained results show that CC will be a serious threat to analysed functions since the expected enhanced shoreline retreat will severely decrease the recreational carrying capacity and the capacity of protection in the near future under tested scenarios. The actual level of development along the coastal zone reduces the natural resilient capacity of beaches to SLR in such a way that the lack of accommodation space can be identified as a main factor for the estimated impacts.

Maritime disruptions can have severe negative implications including affecting business operations, regional and national economies and causing damage to vessels. This study analysed maritime disruptions in UK ports, coastal areas and surrounding seas from 1950 to 2014, systematically assessing their scale, duration, extent and consequences. Disruptions are a single or sequence of hazardous events that negatively affect ‘business as usual’ conditions, ranging from minor to major disruption and even loss of life. To express this range, a severity scale was developed and applied. A database of maritime disruptions and their severities was constructed using data archaeology, identifying 88 events, primarily caused by wind storms (36 %), human error (23 %), mechanical faults (14 %) and storm surges (12 %). All events other than human error or mechanical faults occurred between October and March (typically associated with autumn/winter storms and depressions), with 65 % recorded between November and January. Maritime disruptions from weather events tended to have regional/national impacts, whereas human error or mechanical faults were usually locally severe. Since 2000, ports demonstrated more frequent disruption to wind storms due to mechanization, increased delay and closure reporting, and refined health and safety regulations. Most frequently affected were the sea areas Fair Isle and Dover, and the Felixstowe and Dover ports. Through time, primary impacts shifted from extensive flooding and structural damage to financial impacts and disruption, associated with adaptation including implementation/upgrading of coastal defences, storm warning systems and legislation. Port and governmental bodies responded adaptively (e.g. Thames Barrier construction and development of automatic tracking systems). The UK’s maritime disruption vulnerability has altered significantly since 1950 and continues to evolve.

In this paper we analyse the spatial footprint and temporal clustering of extreme sea level and skew surge events around the UK coast over the last 100 years (1915–2014). The vast majority of the extreme sea level events are generated by moderate, rather than extreme skew surges, combined with spring astronomical high tides. We distinguish four broad categories of spatial footprints of events and the distinct storm tracks that generated them. There have been rare events when extreme levels have occurred along two unconnected coastal regions during the same storm. The events that occur in closest succession (

Pycroft et al. (Environ Resour Econ 1–29, 2015) used incorrect and outdated data to study the economic impact of sea level rise. They misinterpret some of their input data, and fail to exploit the strengths of their computable general equilibrium model and previously developed methods to study impacts and adaptation.

The Dynamic Interactive Vulnerability Assessment Wetland Change Model (DIVA_WCM) comprises a dataset of contemporary global coastal wetland stocks (estimated at 756 × 10^3 km^2 (in 2011)), mapped to a one-dimensional global database, and a model of the macro-scale controls on wetland response to sea-level rise. Three key drivers of wetland response to sea-level rise are considered: 1) rate of sea-level rise relative to tidal range; 2) lateral accommodation space; and 3) sediment supply. The model is tuned by expert knowledge, parameterised with quantitative data where possible, and validated against mapping associated with two large-scale mangrove and saltmarsh vulnerability studies. It is applied across 12,148 coastal segments (mean length 85 km) to the year 2100. The model provides better-informed macro-scale projections of likely patterns of future coastal wetland losses across a range of sea-level rise scenarios and varying assumptions about the construction of coastal dikes to prevent sea flooding (as dikes limit lateral accommodation space and cause coastal squeeze). With 50 cm of sea-level rise by 2100, the model predicts a loss of 46–59% of global coastal wetland stocks. A global coastal wetland loss of 78% is estimated under high sea-level rise (110 cm by 2100) accompanied by maximum dike construction. The primary driver for high vulnerability of coastal wetlands to sea-level rise is coastal squeeze, a consequence of long-term coastal protection strategies. Under low sea-level rise (29 cm by 2100) losses do not exceed ca. 50% of the total stock, even for the same adverse dike construction assumptions. The model results confirm that the widespread paradigm that wetlands subject to a micro-tidal regime are likely to be more vulnerable to loss than macro-tidal environments. Countering these potential losses will require both climate mitigation (a global response) to minimise sea-level rise and maximisation of accommodation space and sediment supply (a regional response) on low-lying coasts.

The impacts of climate change on people’s livelihoods have been widely documented.1 It is expected that climate and environmental change will hamper poverty reduction, or even exacerbate poverty in some or all of its dimensions. Changes in the biophysical environment, such as droughts, flooding, water quantity and quality, and degrading ecosystems, are expected to affect opportunities for people to generate income. These changes, combined with a deficiency in coping strategies and innovation to adapt to particular climate change threats, are in turn likely to lead to increased economic and social vulnerability of households and communities, especially amongst the poorest.

Coastal and estuarine margins are home to an increasing proportion of the global human population and its activities. Within this context, landforms play a critical role in mediating the translation of erosion and flood risk to human receptors in environmental settings that are vulnerable to the likely impacts of climate change. Predicting how coastal and estuarine landforms will evolve in response to changes in sea level and wave climate is thus of considerable importance. This is naturally a modelling problem but previous efforts have often failed to translate generic principles into models that do justice to the place-specific interactions between contemporary processes, antecedent geology, sea level history, historical morphology, engineering interventions and, not least, broader societal concerns. Progress clearly requires better models but, as we argue here, more sophisticated conceptual frameworks are also needed. Accordingly, we outline a new Coastal and Estuarine System Mapping (CESM) approach that captures the configuration of estuarine, coastal and inner shelf landform complexes within a unifying framework that also explicitly resolves the multitude of human interventions that influence shoreline change. An illustrative application to the Suffolk coast of eastern England demonstrates the potential of CESM to encourage a more participatory approach to regional shoreline management and the application of scientific understanding to the challenge of living with human and climate change impacts at the coast.

Owing to globalization, the potential impacts of climate change/sea-level rise in one country/region are likely to affect and be felt elsewhere. Such indirect impacts could be significant but have ...

Coastal flooding is a problem of increasing relevance in low-lying coastal regions worldwide. In addition to the anticipated increase in likelihood and magnitude of coastal floods due to climate change, there is rapid growth in coastal assets and infrastructure. Sustainable and integrated coastal flood management over large areas and varying coastline types cannot be simply treated as local combinations of flood defences and floodplains. Rather, a system level analysis of floodplains is required to structure the problem as a first step before applying quantitative models. In this paper such a model is developed using system diagrams and the Source-Pathway-Receptor (SPR) concept, to structure our understanding of large and complex coastal flood systems. A graphical systems model is proposed for the assessment of coastal flood systems with regard to individual elements and their topological relationships. Two examples are discussed – a unidirectional model for a large-scale flood system, and a multi-directional model for a smaller-scale system, both based on the Western Scheldt estuary. The models help to develop a comprehensive understanding of system elements and their relationships and provide a holistic overview of the coastal flood system. The approach shows that a system level analysis of floodplains is more effective than simple topographic maps when conveying complex information. The models are shown to be useful as an apriori approach for making the assumptions about flood mechanisms explicit and for informing inputs to numerical models. ispartof: Natural Hazards and Earth System Sciences vol:12 issue:5 pages:1431-1439 status: published

Summary This study investigates variations in soft cliff retreat and the impact of coastal defences along 55 km of the Holderness coast between 1845 and 2005. The analysis of three approximately 50-year periods (1854–1905, 1905–1952, 1952–2005) gives a retreat rate of between 0.8±0.4 m/yr and 2.1±0.4 m/yr. Retreat varies spatially and temporally due to natural causes and human activity, especially 19 th century beach mining and coastal defence construction. Defences reduce sediment input and modify the sediment budget, usually resulting in a sediment deficit down-drift, leading to the development of a set-back. Using data from historical and modern Ordnance Survey maps, aerial photographs, and Differential Geographical Positioning System (DGPS) surveys, the cliff top was selected as a reference feature. Set-back due to defence construction at Barmston, Hornsea (two periods), Mappleton and Withernsea (two periods) was analysed, giving six different time periods. Short time periods are unreliable due to large mapping uncertainties and natural variability. Two cases showed excess retreat for tens to thousands of metres down-drift over a long time period since defence construction. Two cases were indicative of excess retreat, but require more time to elapse after defence construction (in these cases >20 years) to reach a definitive conclusion. Two cases were inconclusive, but possibly maintained a constant retreat rate post-defence construction. Hence, at the scale of Holderness, defences have changed the pattern of erosion rather than stopping it. Accelerated retreat down-drift of defences can threaten human infrastructure and buildings and reduce the efficiency of defences. This should be recognized in shoreline management planning.

This paper demonstrates a methodology for integrating existing models for the rapid simulation of coastal flood events across a large and varied case study area on the UK south coast. Following validation against observations from real coastal floods, synthetic events driven by realistic waves and water levels and the full range of failure mechanisms were modelled for a range of loadings to generate peak flood water depths and an overview of impacts across this spectrum of possible floods. Overtopping is relatively important compared to breaching as coastal floodplains are small. This modelling system supports multiple potential applications, such as planning flood warnings, coastal defence upgrade, and land use, including under sea-level rise. The concepts drawn from this study are transferable to similar coastal regions.