Background As climate change progresses, it is critical to assess the equity of health impacts, adaptation interventions and policies. Climate change can contribute to coastal hazards like flooding resulting in loss of life, property and land, leading to potential long-term physical or mental health impacts. Additionally, some UK coastal populations often face social deprivation and limited healthcare access, which can be worsened by environmental changes.Methods We conducted a scoping review of UK evidence on (a) inequalities in coastal flood risk and (b) the equity of measures to manage climate-related flood risks. Interventions included plans, flood insurance and infrastructure, including natural flood management. Following the screening of 19 329 references, we included 11 papers in the final review.Results Four studies examined the differentials in current and future coastal flood impacts, and seven assessed the equity of adaptation measures. Coastal flood risk is unevenly distributed across the UK. Policies and practices like household insurance and property resilience measures may increase inequalities, while community engagement, planning and structural solutions can reduce disparities, depending on local context and implementation.Conclusions Adaptation to UK coastal flood risk requires both short-term and long-term strategies. Approaches relying on individual behaviour or household income may worsen health inequalities. Further evaluations and better evidence are needed to improve flood planning and incident management. Climate change presents a challenge for organisations to deliver national and local policy responses ensuring that adaptation is effective and equitable in the immediate and longer term.

This short communication highlights the emergence of complex design coastal reclamation for high-end property development, which we term 'prestige reclamation'. The prestige reclamation planiforms are typically symbols, showcasing national pride, or highly crenulate designs to maximise the perimeter: area ratios, ensuring the greatest waterfront potential on the newly constructed artificial shores. Numerous questions arise as these new coasts are built: 1) what is the ecological impact of such developments, and does it differ from existing industrial and agricultural reclamations; 2) how might the complex designs affect the water quality within and around the reclamations; and finally 3) for these developments geared towards high end real-estate, recreation and tourism, how have the developments affected people living in and near these new coasts? We recognise that we stand at a crucial point in time to study these prestige reclamations, with rising sea levels, a global biodiversity crisis and a tempestuous financial climate. Therefore, this topic demands further attention and global collaboration to collectively study impact and provide alternatives to the growing demand of coastal land.

We quantify the projected impacts of alternative levels of global warming upon the climatically determined geographic ranges of plants and vertebrates in six countries (China, Brazil, Egypt, Ethiopia, Ghana and India), accounting for uncertainties in regional climate projection. We quantify in a spatially explicit fashion the species richness remaining or lost, allowing the identification of climate refugia which we define as areas where > 75% of the species currently present remain in a world with a particular level of global warming above pre-industrial levels. In all countries and in both taxa, species richness declines with warming, as does the proportion of each country remaining a climate refugium for plants or vertebrates. In percentage terms, refugia loss relative to a 1961–1990 baseline period is greatest in India and Brazil, and least in Ghana and Ethiopia for the same level of warming, and is greater for plants than for vertebrates. Taking account of present land uses (i.e. area still considered natural), and using species richness of plants as a proxy to indicate biodiversity more generally, the proportion of land acting as climate refugia for biodiversity in five of the countries variously declines from 32–75% of a country in the 1961–1990 baseline period to 20–64% for 1.5 °C global warming, 11–53% for 2 °C, 3–33% for 3 °C and 2–24% for 4 °C warming. In Ethiopia, India, Brazil and China, climate refugia decline rapidly with warming while in Ghana and China some refugia persist even with 3–4 °C of warming. Only small percentages of Brazil, India and China are both climate refugia and lie within protected areas; hence, an expansion of the protected area networks in these countries would be required to deliver climate resilient biodiversity conservation. These percentages are larger in Ethiopia and Ghana and, in some areas of Ghana, the only remaining refugia are in protected areas, the remaining landscape converted to other uses.

In the UK, coastal flooding and erosion are two of the primary climate-related hazards to communities, businesses, and infrastructure. To better address the ramifications of those hazards, now and into the future, the UK needs to transform its scattered, frag-mented coastal data resources into a systematic, integrated portal for quality-assured, pub-licly accessible open data. Such a portal would support analyses of coastal risk and resilience by hosting, in addition to data layers for coastal flooding and erosion, a diverse array of spatial datasets for building footprints, infrastructure networks, land use, popula-tion, and various socio-economic measures and indicators derived from survey and census data. The portal would facilitate novel combinations of spatial data layers to yield scientifi-cally, societally, and economically beneficial insights into UK coastal systems.

Small, low-lying atoll islands are often seen as helpless in the face of rising sea levels. New research from the University of Southampton shows that these island nations can adapt sustainably by sensitively raising and reclaiming land. Research leader Sally Brown reports.

Coastal defences have long provided protection from erosion and flooding to cities, towns and villages. In many parts of the world, continued defence is being questioned due to both environmental, sustainability and economic considerations. This is exemplified in England and Wales, where strategic Shoreline Management Plans envisage realignment of many protected coasts, often with low population densities, over the coming decades. The policy transition from protection to realignment is often resisted by affected communities and can have high political costs. Whilst some preparations for such transitions have been made, the communities affected are often not fully aware of the implications of policy change, and this brings the potential for blight. In this paper, we investigate the challenges of implementing transitions in coastal policy within England and Wales. The analysis is based on data obtained from three workshops held in 2019 that were attended by council members, engineers, planners, scientists and other relevant professionals. Five conditions are found to promote contention: (i) policy actors with competing priorities and different decision making time frames (immediate to decadal to a century); (ii) divergence between regulations and ad hoc political decisions (e.g. in relation to the demand for new housing); (iii) limited or non-existent funding to support policy transition; (iv) community expectation that protection is forever; and (v) a disconnection between people and ongoing coastal change. Our research indicates that transitions can be better supported through: (1) integrated multi-scalar preparedness for coastal change; (2) an accessible evidence base and future vision to nurture political confidence in adaptation; and (3) defined, time-bound and accessible diverse funding streams to achieve transitions. Critically, these generic actions need to be embedded within the local political and planning system to facilitate transition to more sustainable coasts and their communities.

"Sengupta et al 2023_reclamation_data_Final.xlsx"- Data on total coastal land reclamation done by cities with a population >1 million. This data was created after processing Landsat images for 135 cities between 2000 and 2020. The area of reclaimed land is given in hectares. A GIS version (.shp file) of this data will be launched soon. Please connect @d.sengupta@stoton.ac.uk for more information. "Sengupta et al_2023_reclaimed_POI_landuse.xlsx"- Data provide coordinates of land use POIs obtained from openstreetmaps database over reclaimed land for identified 106 coastal cities. These land use classes are divided into Residential/commercial, Industry, Tourism, Transport, Agriculture, Recreational and Under-construction.

Low-lying atoll nations (e.g. the Maldives, Kiribati, Tuvalu, Marshall Islands) are highly vulnerable to climate change, especially sea-level rise (SLR). Stringent climate change mitigation will slow but not stop SLR, which will continue for centuries, mandating additional long-term adaptation. At the same time, urbanisation is concentrating population in a few centres, especially around capital islands which creates additional pressure as most atoll nations are ‘land-poor’. This paper demonstrates how structural adaptation using land claim and island raising can be utilised within an adaptation pathway approach to sustain enough islands and land area above rising sea levels to satisfy societal and economic needs over multiple centuries. This approach is illustrated using the Maldives, especially around the capital and its environs (Greater Malé). Raising, expanding and connecting ‘urban’ islands can provide multiple benefits. Significant developments have already occurred in Greater Malé and further developments there and for other urban centres in the Maldives are expected. Migration to urban centres, especially Malé, is widespread and this adaptation approach assumes this trend continues, implying many other islands are depopulated or abandoned. Tourism is core to the Maldives economy and tourist islands require a different ambience to urban islands. They could be sustained with sympathetic soft engineering reinforcing the natural processes that produce atolls. While land advance and island raising provides a technical solution for SLR, any application must also address the additional policy, human, physical, engineering and economic/financial challenges that are raised. Nonetheless, by aligning adaptation through land advance/raising with existing development trends, atoll nations have the potential to persist and prosper for many centuries even as sea levels inevitably rise. This provides a realistic alternative to widespread assumptions about forced migration and ultimate national abandonment. The lessons here may find wider application to other small island settings and even mainland coasts.

Increasing population size and economic dependence on the coastal zone, coupled with the growing need for residential, agricultural, industrial, commercial and green space infrastructure, are key drivers of land reclamation. Until now, there has been no comprehensive assessment of the global distribution of land use on reclaimed space at the coast. Here, we analyze Landsat satellite imagery from 2000 to 2020 to quantify the spatial extent, scale, and land use of urban coastal reclamation for 135 cities with populations in excess of 1 million. Findings indicate that 78% (106/135) of these major coastal cities have resorted to reclamation as a source of new ground, contributing a total 253,000 ha of additional land to the Earth's surface in the 21st century, equivalent to an area the size of Luxembourg. Reclamation is especially prominent in East Asia, the Middle East, and Southeast Asia, followed by Western Europe and West Africa. The most common land uses on reclaimed spaces are port extension (>70 cities), followed by residential/commercial (30 cities) and industrial (19 cities). While increased global trade and the rapid urbanization have driven these uses, we argue that a city's prestigious place‐making effort to gain global reputation is emerging as another major driver underlying recent reclamation projects to create tourist and green spaces Meanwhile, the study suggests that 70% of recent reclamation has occurred in areas identified as potentially exposed to extreme sea level rise (SLR) by 2100 and this presents a significant challenge to sustainable development at the coast.

Adaptation to sea-level rise (SLR) will be necessary to protect people at risk from flooding due to a combination of tide, surge and SLR in the future. This adaptation commitment requires adequate time and resources to prepare for the impacts of SLR that are expected within this century and beyond (here until 2150). In this study, we address the question of “when” in addition to “how much” adaptation to SLR is needed. We use a scenario-neutral approach to assess the amount of people at risk from flooding under different SLR magnitudes. We combine this scenario neutral approach with SLR projections for the SSPs in AR6 and population growth scenarios in the coastal zone to identify the timing, in which the number of additional people affected by SLR alone or in combination with a 100-year storm event will exceed a set of thresholds. The comparison of the timing for different SSPs demonstrates that it is rather a question of “when” than “if” these thresholds will be exceeded. Some countries will need to adapt to SLR within the next few decades to prevent an additional 1–5 million people from becoming affected by flooding. Other countries have more time for adaption but will face a rapid increase in the number of people at risk from flooding beyond 2100. Combining SLR impacts with projected population change further increases the number of people at risk in the middle of this century for most SSPs. Considering low-confidence high-end SLR scenarios that include the possibility for a more rapid melting of the ice sheets may shift expected impacts approximately 50 years forward. This means that adaptation needs to be implemented faster and sooner than previously anticipated, which may have consequences for the available adaptation options. Ignoring the potential and long-term (including beyond 2100) commitment for adaptation may lead to an adaptation gap and subsequently expensive retrofitting of infrastructure, creation of stranded assets, and less time to adapt at greater cost. In contrast, acknowledging and acting upon the long-term adaptation commitment can encourage timely adaptation and its alignment with other societal ambitions.

Small island developing States, such as those in the Pacific, are often prone to multiple hazards that have potential to result in disaster and / or restrict development. Hazard data can be limited in resolution or omitted in or near SIDS' coasts, but a growing and improved range of datasets are becoming available. Through an analysis of approximately 100 policy documents on hazards and disaster risk management in Pacific island nations, we found: limited information on hazards and how they manifest to disasters at local levels, thus not fully connecting drivers and subsequent risk; at times a non-specific multi-hazard approach prompting the need to address more specific hazards; and restricted temporal and spatial scales of analysis that potentially limit continuity of actions where mitigation methods evolve. These limitations suggest that appropriate and timely high resolution hazard data is needed from the top-down to underpin the design and development of local disaster risk management plans, simultaneous to local, bottom-up knowledge and interpretation to bring the realities of such hazard data to life. Developing and ensuring openly available hazard data will enable island States to develop more robust, inclusive disaster risk management plans and mitigation policies, plus aid inter-island comparison for communal learning.

Adaptation to sea-level rise (SLR) will be necessary to protect people at risk from flooding due to a combination of tide, surge and SLR in the future. This adaptation commitment requires adequate time and resources to prepare for the impacts of SLR that are expected within this century and beyond (here until 2150). In this study, we address the question of “when” in addition to “how much” adaptation to SLR is needed. We use a scenario-neutral approach to assess the amount of people at risk from flooding under different SLR magnitudes. We combine this scenario neutral approach with SLR projections for the SSPs in AR6 and population growth scenarios in the coastal zone to identify the timing, in which the number of additional people affected by SLR alone or in combination with a 100-year storm event will exceed a set of thresholds. The comparison of the timing for different SSPs demonstrates that it is rather a question of “when” than “if” these thresholds will be exceeded. Some countries will need to adapt to SLR within the next few decades to prevent an additional 1–5 million people from becoming affected by flooding. Other countries have more time for adaption but will face a rapid increase in the number of people at risk from flooding beyond 2100. Combining SLR impacts with projected population change further increases the number of people at risk in the middle of this century for most SSPs. Considering low-confidence high-end SLR scenarios that include the possibility for a more rapid melting of the ice sheets may shift expected impacts approximately 50 years forward. This means that adaptation needs to be implemented faster and sooner than previously anticipated, which may have consequences for the available adaptation options. Ignoring the potential and long-term (including beyond 2100) commitment for adaptation may lead to an adaptation gap and subsequently expensive retrofitting of infrastructure, creation of stranded assets, and less time to adapt at greater cost. In contrast, acknowledging and acting upon the long-term adaptation commitment can encourage timely adaptation and its alignment with other societal ambitions.

The management of coastal flood risk is adapting to meet the challenges and increased risks posed by population change as well as by climate change, especially sea level rise. Protection is being targeted to areas where the benefits are highest, while elsewhere there is a shift towards more localized “living with floods” and “resilience” approaches. Such decentralized approaches to flood risk management (FRM) require a diverse range of stakeholder groups to be engaged as “flood risk citizens”. Engagement of households in FRM is central to this process. Despite significant research on stakeholder engagement in coastal and flood risk management, there is less focus on the nature of responsibility in coastal adaptation. There is no framework by which to assess the different types of responsibility in hazard management and adaptation, and little research on the implications of expecting these responsibilities of stakeholder groups. In this paper, we identify five types of responsibility that are embedded throughout the disaster risk reduction cycle of managing coastal flooding. We build this “typology of responsibility” on existing work on the evolution of stakeholder engagement and stakeholder responsibility relationships in risk management processes, and a dataset of institutional stakeholder interviews and households surveys conducted across three case studies in England, the United Kingdom, in 2018 and 2019. We analyze the interviews using thematic analysis to explore institutional stakeholder perceptions of responsibility in coastal FRM, and analyze the household survey through descriptive and inferential statistics. By developing the first disaster risk reduction focused typology of responsibility for coastal flooding, we provide researchers and decision-makers with a tool to guide their planning and allocation of responsibilities in risk management for floods and other climate-driven hazards.

The Paris Agreement aims to constrain global warming to ‘well below 2 °C’ and to ‘pursue efforts’ to limit it to 1.5 °C above pre-industrial levels. We quantify global and regional risk-related metrics associated with these levels of warming that capture climate change–related changes in exposure to water scarcity and heat stress, vector-borne disease, coastal and fluvial flooding and projected impacts on agriculture and the economy, allowing for uncertainties in regional climate projection. Risk-related metrics associated with 2 °C warming, depending on sector, are reduced by 10–44% globally if warming is further reduced to 1.5 °C. Comparing with a baseline in which warming of 3.66 °C occurs by 2100, constraining warming to 1.5 °C reduces these risk indicators globally by 32–85%, and constraining warming to 2 °C reduces them by 26–74%. In percentage terms, avoided risk is highest for fluvial flooding, drought, and heat stress, but in absolute terms risk reduction is greatest for drought. Although water stress decreases in some regions, it is often accompanied by additional exposure to flooding. The magnitude of the percentage of damage avoided is similar to that calculated for avoided global economic risk associated with these same climate change scenarios. We also identify West Africa, India and North America as hotspots of climate change risk in the future.

Land subsidence is impacting large populations in coastal Asia via relative sea-level rise (RSLR). Here we assesses these risks and possible response strategies for China, including estimates of present rates of RSLR, flood exposure and risk to 2050. In 2015, each Chinese coastal resident experienced on average RSLR of 11 to 20 mm/yr. This is 3 to 5 times higher than climate-induced SLR, reflecting that people are concentrated in subsiding locations. In 2050, assuming these subsidence rates continue, land area, population and assets exposed to the 100-year coastal flood event is 20%-39%, 17%-37% and 18%-39% higher than assuming climate change alone, respectively. Realistic subsidence control measures can avoid up to two thirds of this additional growth in exposure, with adaptation required to address the residual. This analysis emphasizes subsidence as a RSLR hazard in China that requires a broad-scale policy response, utilizing subsidence control combined with coastal adaptation.

Without adaptation, sea-level rise (SLR) will put more people at risk of flooding. This requires a timely and adequate commitment to adaptation. In this paper, we show how adaptation needs to unfold over time to manage climate-induced SLR. We use a novel scenario-neutral approach, applied globally and subsequently combined with SLR and population scenarios, to assess when, where, and how fast to adapt up to 2150. As rates of SLR accelerate, adaptation needs to occur at an increasing pace or at a larger scale. While it is certain that adaptation will be necessary, it is uncertain when and how fast. After only ∼ 0.15 m SLR relative to 2020, 1 million people need to adapt to permanent submergence and the amount of people at risk of a 100-year flood increases with 21% to 83 million people. This would occur in the next 30 (20–45) years for RCP4.5 and within 25 (18–36) years under RCP8.5, assuming no change in protection or population. The uncertainty in timing increases with higher SLR, albeit for some impacts it can still a matter of time. Population at risk of a 100-year flood doubles after 0.75 m SLR which could occur by ∼ 2080 (2068–2088), 2100 (2085–2130), or 2150 (2115-beyond 2150) under a high-end, RCP8.5, or RCP4.5 scenario respectively. The rate, at which the risk increases, differs strongly per country. In some countries an additional 1–5 million people of the present population will be at risk of a 100-year flood within the next two decades, while others have more time to adapt but will see rapid growth of risk past 2100. Combining SLR impacts with projected population change further increases the number of people at risk of a 100-year flood by ∼13% between 2040–2060 (under both RCP8.5-SSP5 and RCP4.5-SSP2). This can be managed through protecting, floodproofing or limiting developments in high-risk areas. A commitment to adaptation is inevitable to maintain risk at present levels. With increasing warnings of the potential for accelerated SLR due to rapid ice sheet melt, adaptation may need to happen faster and sooner than previously anticipated which can have consequences for how to adapt. Failure to acknowledge the potential and long-term (including beyond 2100) adaptation commitment in development and adaptation planning may lead to a commitment gap and subsequently expensive retrofitting of infrastructure, creation of stranded assets, and less time to adapt at greater cost. In contrast, considering the long-term adaptation commitment can support timely adaptation and alignment with other societal goals.

Sea levels will rise, even with stringent climate change mitigation. Mitigation will slow the rate of rise. There is limited knowledge on how the costs of coastal protection vary with alternative global warming levels of 1.5 to 4.0 °C. Analysing six sea-level rise scenarios (0.74 to 1.09 m, 50th percentile) across these warming levels, and five Shared Socioeconomic Pathways, this paper quantifies the economic costs of flooding and protection due to sea-level rise using the Dynamic Interactive Vulnerability Assessment (DIVA) modelling framework. Results are presented for World Bank income groups and five selected countries from the present to 2100. Annual sea flood damage costs without additional adaptation are more influenced by socio-economic development than sea-level rise, indicating that there are opportunities to control risk with development choices. In contrast, annual sea dike investment costs are more dependent on the magnitude of sea-level rise. In terms of total costs with adaptation, upper middle, low middle and low income groups are projected to have higher relative costs as a proportion of GDP compared with high income groups. If low income countries protected now, flood costs could be reduced after 2050 and beyond. However, without further adaptation, their coasts will experience growing risks and costs leaving them increasingly reliant on emergency response measures. Without mitigation or adaptation, greater inequalities in damage costs between income groups could result. At country level, annual sea flood damage costs without additional adaptation are projected to rapidly increase with approximately 0.2 m of sea-level rise, leaving limited time to plan and adapt.

Drivers of environmental change are causing novel combinations of pressures on ecological systems. Prediction in ecology often uses understanding of past conditions to make predictions to the future, but such an approach can breakdown when future conditions have not previously been encountered. Individual-based models (IBMs) consider ecological systems as arising from the adaptive behaviour and fates of individuals, and have potential to provide more reliable predictions. To demonstrate potential, we review a lineage of related IBMs addressing the effects of environmental change on waterbirds, comprising 53 case studies of 28 species in 32 sites in 9 countries, using the Drivers-Pressures-State-Impact-Response (DPSIR) environmental management framework. Each case study comprises the predictions of an IBM on the effects of one or more drivers of environmental change on one or more bird species. Drivers exert a pressure on the environment which is represented in the IBMs as changes in either the area or time available for feeding, the quality of habitat, or the energetic cost of living within an environment. Birds in the IBMs adapt to increased pressure by altering their behavioural state, defined as their location, diet and the proportion of time spent feeding. If the birds are not able to compensate behaviourally, they suffer a physiological impact, determined by a decrease in body energy reserves, increased mortality or decreased ability to migrate. Each case study assesses the impact of alternative drivers and potentially ways to mitigate impacts to advise appropriate conservation management responses. We overview the lessons learned from the case studies and highlight the opportunities of using IBMs to inform conservation management for other species. Key findings indicate that understanding the behavioural and physiological processes that determine whether or not birds survive following a change in their environment is vital, so that mitigation measures can be better targeted. This is especially important where multiple hazards exist so that sensitivities and worse case scenarios can be better understood. Increasing the involvement of stakeholders to help inform and shape model development is encouraged, and can lead to better representation of the modelled system, and wider understanding and support for the final model.