We analyse a 36-year hydrodynamic and morphological dataset from the Hasaki coast, Japan, comprising 501 wave storm events (405 individual and 96 clustered events) to investigate the impact of storm dynamics and clustering on beach erosion. Focusing on the wave component of storms, events are identified using wave height thresholds. Daily and weekly beach profile measurements from the Hasaki Oceanographic Research Station are used to quantify erosion. The study examines the seasonal influences on Hasaki beach, the characteristics and temporal evolution of storms, and their associated erosional impacts. Moreover, we test two supervised machine learning (ML) algorithms, support vector regression (SVR), and deep neural network (DNN), in predicting shoreline change using 16 wave, storm, and morphological features. SVR showed reasonable accuracy on the training dataset but underperformed on testing, while DNN failed to produce reliable predictions on both. With SVR yielding an R2 of 0.18 and DNN 0.27 on the testing dataset, we conclude that, given the limited data and available features, such ML models may not generalise well. However, separate analyses using observed data reveal clear seasonal variations in wave storm dynamics and distinct behaviours of clustered events associated with beach erosion, highlighting important insights beyond the ML results.

Despite coastal regions’ importance and vulnerability to climate change, Ghana’s coasts remain underexplored through social-ecological systems (SES) approaches, with limited attention to Indigenous and local communities’ adaptive responses to contemporary challenges. We conducted a study with the aims of (1) identifying the changes in coastal SES as perceived by the Akplabanya community and (2) examining the Akplabanya community’s human adaptation responses to those changes. During two months of fieldwork in Akplabanya, we used four data collection methods: participant observation, semi-structured interviews, key informant interviews, and focus group discussions. We found social-ecological changes related to five themes: (i) coastal climate change (sea-level rise), (ii) resource change (changes in land use), (iii) agrobiodiversity loss (changes in livestock), (iv) pollution (unsustainable practices) and (v) population change (increasing population). As adaptation responses to these changes, the community adaptive responses we found were (a) place (sense of place), (b) agency (emergence of food markets), (c) Indigenous and local knowledge (weakening of Indigenous knowledge), (d) collective action (collective solutions), (e) institutions (partnerships) and (f) learning (awareness). Our study highlights the urgent need for targeted research in regions like Ghana to guide and improve adaptation policy interventions for scientists, policymakers and researchers.

It is often inferred that rising sea levels will result in widespread coastal recession. Erosion appeared prevalent in a worldwide compilation of evidence derived from maps and aerial photographs undertaken in the 1980s by the Commission on the Coastal Environment. Eric Bird, chair of the commission, inferred that >70% of sandy coastlines had retreated, a generalisation that has been widely cited. We reconsider these findings in respect of subsequent advances in shoreline mapping, including greater precision possible using geographical information systems and more frequent remote sensing imagery with increased spatial, spectral and temporal resolution. Satellite-derived shorelines now enable broad global and regional generalisations about shoreline position. Beaches fluctuate over a range of timescales, meaning that trends in their position are highly dependent on techniques and temporal scales adopted for monitoring. Recent global- and regional-scale shoreline assessments indicate that many sandy shorelines have been stable, and that detectable retreat has occurred on fewer beaches than previously inferred. Accretion is apparent on some coasts, particularly where engineering interventions protect or have reclaimed land. There is considerable variability in the behaviour of monitored beaches, and it is not yet possible to decipher a response to the gradual centimetre-scale rise in sea level of recent decades. Instead, we re-emphasise the several other factors that were considered to contribute to recession by the Commission, many of which relate to a change in sediment budget. To provide insights into future coastline behaviour, a better understanding of the multiple drivers on individual beaches is needed to discriminate between erosional events and longer-term trends in shoreline position.

The long-term development of coral reef frameworks and the net vertical accretion of reefs fundamentally underpins the provisioning of most reef-related ecosystem services. One area of particular concern at present is how rates of reef accretion are changing under ecological decline and what the consequences of this may be for the capacity of reefs to keep pace with near-future sea-level rise (SLR). This may have major implications for the capacity of reefs to maintain their coastal protective functions and to support reef island stability. Both are issues relevant to understanding future tropical coastal risk. Long-term (millennial timescale) rates of reef accretion are relatively well constrained, including through past periods of sea-level fluctuations. However, widespread and persistent ecological degradation of coral communities has caused many reefs to diverge significantly from their past accretion trajectories. This renders historical analogues increasingly unreliable for projecting future accretion potential. Addressing this necessitates a reorientation towards considering reef accretion rates across shorter (ecological to geomorphic) timescales, i.e., over years to multi-decades. This is essential if we are to better constrain contemporary reef accretion rate and SLR interactions at timescales relevant to predicting emerging coastal risks and understanding future implications for reef-derived benefits. Here, we review existing approaches for quantifying vertical reef accretion rates of modern reefs. These methods span data recovered from fossil outcrops or core-derived records, the conversion of carbonate budget data, direct in situ measurements and emerging remote sensing and image-based techniques. The review explores the advantages and limitations of these different approaches and outlines options for developing an integrated framework to link past, present and future reef accretion potential.

The impacts of climate change have become more widespread and frequent, and society is beginning to recognise the connection between it and the biodiversity crisis. Communities have the capacity to play a key role in the success of multi-stakeholder nature restoration projects, but examples of successful projects, in which communities are the architects of the action – as opposed to the recipients of it – are not well documented. This study used a participatory evaluation research approach to explore a multi-stakeholder, community-led restoration project at Harper’s Island Wetlands, Co. Cork, Ireland to understand the elements of success and to extract key learnings for other communities. In order to rapidly upscale nature restoration and biodiversity protection globally, there is an urgent need to gain speed and momentum, identifying innovative approaches and disseminating them appropriately. The insights from this case study highlight four key components to be considered by groups at the beginning of community-led projects: setting up a core committee, assigning clear roles within the committee, creating a short-, medium- and long-term strategy and beginning practical tasks as soon as possible. This research serves as a step towards preparing blueprints to inform research, policy and practice in this space to enable stakeholders to respond collectively

Addressing sea-level rise and coastal flooding requires adaptation strategies tailored to specific coastal environments. However, a lack of detailed geomorphological data on global coasts impedes effective strategy development. This research maps seven coastal environments worldwide, and for each environment analyzes the effect of coastal changes on coastal populations by including sea-level change, extreme sea-level events with varying return periods and population growth from 1950 to 2050. It identifies the historical exposure of low-lying deltaic and estuarine flood areas (>48% of total population) and reveals that flood exposure will significantly increase for barrier islands and strandplains by 2050 (with over a 40% rise in exposure), particularly along African coastlines. Population growth emerges as the primary factor behind the increased exposure. While sea-level rise is projected to contribute between 26% and 65% of the increased inundated area by 2050 compared to a 10-year extreme sea-level event, varying by coastal environment. The findings highlight the critical need for mitigation measures that account for the distinct responses of different coastal types to sea-level rise, posing various risks over varying timescales.

While adapting to future sea-level rise (SLR) and its hazards and impacts is a multidisciplinary challenge, the interaction of scientists across different research fields, and with practitioners, is limited. To stimulate collaboration and develop a common research agenda, a workshop held in June 2024 gathered 22 scientists and policymakers working in the Netherlands. Participants discussed the interacting uncertainties across three different research fields: sea-level projections, hazards and impacts, and adaptation. Here, we present our view on the most important uncertainties within each field and the feasibility of managing and reducing those uncertainties. We find that enhanced collaboration is urgently needed to prioritize uncertainty reductions, manage expectations and increase the relevance of science to adaptation planning. Furthermore, we argue that in the coming decades, significant uncertainties will remain or newly arise in each research field and that rapidly accelerating SLR will remain a possibility. Therefore, we recommend investigating the extent to which early warning systems can help policymakers as a tool to make timely decisions under remaining uncertainties, in both the Netherlands and other coastal areas. Crucially, this will require viewing SLR, its hazards and impacts, and adaptation as a whole.

The Arctic is at the forefront of climate change, undergoing some of the most rapid environmental transformations globally. Here, we examine the impacts of climate change on the livelihoods in the coastal Inuit community of Hopedale, Nunatsiavut, Canada. The study examines recently evolved adaptation strategies employed by Inuit and the challenges to these adaptations. We document changing sea ice patterns, changing weather patterns and the impact of invasive species on food resources and the environment. Utilising knowledge co-production and drawing upon Indigenous knowledge, we monitor the changes and multiple stresses through direct observations, engagement with rights holders and community experiences to characterise climate risks and associated changes affecting livelihoods. We use both decolonising research and participatory methodologies to develop collaboration and partnership, ensuring that monitoring reflects local priorities and realities while also fostering trust and collaboration. We showcase that monitoring environmental trends involves more than data collection; it includes observing and analysing how environmental changes affect community well-being, particularly in terms of food security, cultural practices, economic activities, mental health, sea ice changes and weather patterns. The paper contributes to a nuanced understanding of Inuit resilience and experiences in confronting climate risks and the broader implications for Indigenous communities confronting climate challenges.

With coastal populations rising at three times the global average, sustainable ways of safeguarding human needs around access and use of the coast alongside lasting ecosystem health of coastal environments must be developed. At the same time, human populations are facing the challenge of managing coastal access on the back of a legacy of human interventions that have already altered – and have often had unintended or unforeseen impacts on – the coastal system and its functioning.

We chart the history of the evolution of North Bull Island in Dublin Bay as an example of major unforeseen sedimentation in a coastal estuarine bay following the construction of river mouth training walls. We investigate the impact of a constructed causeway on the evolved ‘naturescape’ by comparing accretion and elevation change on the mid-marsh either side of the access road over a 32-month period (autumn 2021 to summer 2024) and measuring water levels either side of the causeway on six spring tides on consecutive days characterised by varying meteorological conditions in early September 2023. The results allow us to consider the potential implications a lack of physical connectivity may cause for the future of the two artificially separated back-barrier lagoon environments.

Mangrove restoration efforts have been ongoing, but with varying levels of success, requiring spatial and temporal monitoring to better understand the stocks and drivers of success. Here, we used multi-spectral remote sensing and spatial regression techniques to examine mangrove distribution and restoration potential in the Vietnamese Southern Coastal (VSC) region from 1988 to 2023, an area where multiple episodes of mangrove restoration have been attempted over the past decades. Our results show that 51.5% of the mangrove area has recovered from previous losses, while 48.5% has been lost during the 1988–2023 period. Significant gains were observed between 2018 and 2023, accounting for 77.8% of the total restoration. However, over 40,000 ha of mangroves were lost during each decade between 1988 and 2018, primarily due to land-use changes. Regression analyses estimated a sustainable mangrove cover increase of 9.9% (23,407 ha) and persistence of 22.5% (52,936 ha), mainly in protected areas and low-impact zones. Conversely, 9.8% (23,056 ha) of mangroves in erosion-prone and human-disturbed regions face continued decline. Our study demonstrated the effectiveness of integrating long-term Normalised Difference Vegetation Index time-series analysis with spatial regression to monitor mangrove ecosystems. These techniques offered a scalable framework for global mangrove monitoring and restoration planning, supporting evidence-based conservation policies.

Coastal systems are a major source of food for Indigenous communities. Climate change poses a high risk to coastal communities’ food security. Successful climate change adaptation practices are essential to ensure food security among Indigenous peoples. Yet, limits and constraints challenge climate change adaptation practices. Our study seeks to identify these limits and constraints in the context of food security among coastal Indigenous peoples. We performed a global scale systematic literature review using 155 scholarly articles to examine the constraints and limits to climate adaptation in the coastal food security and Indigenous peoples’ context. The three research questions are as follows: (i) What are the key constraints? (ii) What are the limits? (iii) What are the ways of overcoming the constraints? First, we found that, globally, the main constraints to adapting to climate change in coastal food security settings are related to governance, institutions and policies. Second, most limits are soft, to be solved, compared to hard limits on coastal systems. Third, we unveiled ways of overcoming the constraints, such as restoring coastal food system resilience, improving food accessibility and building the adaptive capacity of Indigenous peoples. The findings of the study provide valuable insights for policymakers, researchers and other relevant stakeholders involved in decision-making regarding coastal food security in the climate change adaptation context.

The 5th International Polar Year (IPY-5) in 2032–2033 represents an important next step in the legacy of the oldest continuous climate research program created by humanity, which intentionally began during a Solar Maximum with IPY-1 in 1882–1883, following the Little Ice Age. Current IPY-5 planning by the International Arctic Science Committee (IASC) and Scientific Committee on Antarctic Research (SCAR) is “From IPY-4 to IPY-5” with scope since 2007–2008, considering relevant large-scale polar process, international activities and UN decades. Additionally, there are essential features to incorporate into IPY-5 planning with Indigenous knowledge as well as next-generation leadership along with international science connections across the United Nations, involving core integration of data system and Earth–Sun system research, which accelerated with the International Geophysical Year (IGY) in 1957–1958 that was renamed from IPY-3. As memorialized in the 1959 Antarctic Treaty: “the International Geophysical Year accords with the interests of science and the progress of all mankind.” Importantly, at the height of the Cold War with “forever” legacy, the 1959 Antarctic Treaty became the first nuclear arms agreement, applying science diplomacy among allies and adversaries alike based on “matters of common interest.” Recognizing current challenges to enable inclusive dialogues – especially in the Arctic – planning for IPY-5 is far enough into the future to be imaginative and hopeful but close enough to be practical, especially to produce synergistic outcomes that inspire and empower next-generation leaders across the International Decade of Sciences for Sustainable Development from 2024 to 2033. Planning “From IPY-3 to IPY-5” – this invited Cambridge Prisms Perspective extends and amplifies the IASC-SCAR concept with its visionary principles – “striving for holistic, systemic, transdisciplinary research approaches” – for the benefit of all on Earth across generations.

Wetlands in hypersaline environments are especially vulnerable to loss and degradation, as increasing coastal urbanization and climate change rapidly exacerbate freshwater supply stressors. Hypersaline wetlands pose unique management challenges that require innovative restoration perspectives and approaches that consider complex local and regional socioecological dynamics. In part, this challenge stems from multiple co-occurring stressors and anthropogenic alterations, including estuary mouth closure and freshwater diversions at the catchment scale. In this article, we discuss challenges and opportunities in the restoration of hypersaline coastal wetland systems, including management of freshwater inflow, shoreline modification, the occurrence of concurrent or sequential stressors, and the knowledge and values of stakeholders and Indigenous peoples. Areas needing additional research and integration into practice are described, and paths forward in adaptive management are discussed. There is a broad need for actionable research on adaptively managing hypersaline wetlands, where outputs will enhance the sustainability and effectiveness of future restoration efforts. Applying a collaborative approach that integrates best practices across a diversity of socio-ecological settings will have global benefits for the effective management of hypersaline coastal wetlands.

Coastal landforms and associated archaeological records are at risk of erosion from a combination of rising sea levels and increasingly frequent high-intensity storms. Improved understanding of this risk can be gained by braiding archaeological and geomorphological methodologies with Indigenous knowledge.1 In this article, archaeological, geomorphological and mātauranga (a form of Indigenous knowledge) are used to analyse a prograded Holocene foredune barrier in northern Aotearoa/New Zealand. Anthropogenic deposits within dune stratigraphy are radiocarbon-dated and used as chronological markers to constrain coastal evolution, alongside geomorphological analyses of topographic data, historical aerial photographs and satellite imagery. These investigations revealed that the barrier is eroding at a rate of 0.45 m/year. A midden in the foredune, which has been radiocarbon dated to 224–270 B.P. (95% Confidence), has been exposed by coastal erosion, confirming that the barrier is in the most eroded state it has been within the past ~300 years. Vertical stratigraphy reveals the presence of midden and palaeosol deposits capped by dune sand deposits in the foredune, indicating that vertical accretion of the foredune continued over the last ~200 years, despite the barrier now being in an eroding state. Mātauranga played a vital role in this project, as it was the coastal taiao (environmental) monitoring unit of Patuharakeke (a Māori sub-tribe) that discovered the midden. The ecological mātauranga shared also played a vital role in this project, adding experiential evidence to empirical observations. The work of local Indigenous groups, like Patuharakeke, demonstrates the active use of mātauranga, woven with Western science methods to preserve or capture the knowledge contained within archaeological sites at risk of being lost to coastal erosion. In this study, we present a method for weaving mātauranga, geomorphological and archaeological approaches to gain a deeper understanding of coastal landscape development.