Challenges to climate change adaptation in coastal small towns:Examples from Ghana, Uruguay, Finland, Denmark, and Alaska

The ability of a coastal settlement to adapt to climate change is largely dependent upon access to a range of resources, which many coastal towns and small cities lack. Coastal small towns of less than 10,000 are therefore at a significant disadvantage compared to larger settlements when it comes to adaptation. One way to begin to overcome this disadvantage is to compare coastal small towns in order to identify efficiencies and support knowledge sharing. In this article we present and analyse five case studies of coastal small towns: Fuvemeh, Ghana; Kiyú, Uruguay; Hanko, Finland; Lemvig, Denmark; and Nome, Alaska, USA. A number of key outcomes and lessons were identified which highlights the need for a formal network of international coastal small towns to encourage and develop knowledge sharing practices going forward. A further lesson is the importance of using a range of indicators in order to establish the regional/national importance of a town. Basing this solely on population size can result in an erroneous interpretation of the significance (and therefore adaptive capacity) of a coastal small town. Finally, despite many barriers to adaptation in coastal small towns, being small offers some potential advantages, such as the possibility of being able to form a community consensus more easily, using 3D visualisations for adaptation planning, and having managed realignment as a realistic management option. It is imperative that climate change resilience in coastal small towns is increased by focussing on overcoming barriers and developing appropriate adaptation approaches by governments, non-governmental organisations, business, and researchers

Challenges to climate change adaptation in coastal small towns: examples from Ghana, Uruguay, Finland, Denmark, and Alaska

The ability of a coastal settlement to adapt to climate change is largely dependent upon access to a range of resources, which many coastal towns and small cities lack. Coastal small towns of less than 10,000 are therefore at a significant disadvantage compared to larger settlements when it comes to adaptation. One way to begin to overcome this disadvantage is to compare coastal small towns in order to identify efficiencies and support knowledge sharing. In this article we present and analyse five case studies of coastal small towns: Fuvemeh, Ghana; Kiyú, Uruguay; Hanko, Finland; Lemvig, Denmark; and Nome, Alaska, USA. A number of key outcomes and lessons were identified which highlights the need for a formal network of international coastal small towns to encourage and develop knowledge sharing practices going forward. A further lesson is the importance of using a range of indicators in order to establish the regional/national importance of a town. Basing this solely on population size can result in an erroneous interpretation of the significance (and therefore adaptive capacity) of a coastal small town. Finally, despite many barriers to adaptation in coastal small towns, being small offers some potential advantages, such as the possibility of being able to form a community consensus more easily, using 3D visualisations for adaptation planning, and having managed realignment as a realistic management option. It is imperative that climate change resilience in coastal small towns is increased by focussing on overcoming barriers and developing appropriate adaptation approaches by governments, non-governmental organisations, business, and researchers

Drone as a tool for coastal flood monitoring in the Volta Delta, Ghana

Abstract Background Monitoring coastal erosion and flooding in deltaic environment is a major challenge. The uncertainties associated with land based methods and remote sensing approaches affect the levels of accuracy, reliability and usability of the output maps generated. This study monitored flooding and erosion activities in a flood prone fishing community (Fuvemeh) in the Volta Delta in Ghana using Unmanned Aerial Vehicles (UAVs) or drone technology. Results The study revealed that coastal flooding and coastal erosion have destroyed sources of livelihood and increased risk to life and property in the Volta Delta communities. It was identified that between 2005 and 2017 the shoreline has moved several meters inland (over 100 m along some transects) in some areas, while in other areas about 24,057 m2 land has been gained (about 80 m along some transects) that can serve as natural fish landing site. It emerged that over 77 houses have been destroyed which resulted in the displacement of over 300 inhabitants between 2005 and 2017. The study estimated that about 37% of the total land area in Fuvemeh has been lost as a result of erosion. Conclusion Coastal erosion and flooding are major environmental challenges in the Volta delta. Coastal erosion has destroyed natural fish landing sites, which has affected the local fishing business (the main source of livelihood) and increased poverty. Coastal flooding has displaced inhabitants from their homes and increased migration from the Fuvemeh community

Spectral profiles of beached pelagic Sargassum (S. natans I, S. natans VIII, S. fluitans III)

This dataset includes the spectral reflectance of each morphotype (S. natans I, S. natans VIII, S. fluitans III) collected in situ in Ghana (Sanzule) and Barbados (Consett Bay) in 2022. It also includes reflectance data for freshly deposited (&lt;1 day) and recently deposited (&lt;3 days) mixed species/morphotypes of sargassum in Barbados. For more information on the methods of data collection, see: Fidai et al. (2023) &#39;Innovative spectral characterisation of beached pelagic sargassum towards remote estimation of biochemical and phenotypic properties&#39;, Science of the Total Environment.</span

Misperception of drivers of risk alters willingness to adapt in the case of sargassum influxes in West Africa

Since 2011, large influxes of a brown macroalgae (pelagic sargassum seaweed) have proliferated across the Tropical Atlantic basin, its dispersal and seasonality theorized to be driven by localized and large scale winds and currents, in combination with changes in the Atlantic Meridional Mode and ocean upwelling. These influxes seasonally affect coastal populations across the breadth of the Tropical Atlantic (from central America to West Africa), causing damage to: economies, marine-based and non-marine coastal livelihoods, social functioning, health, ecology, and the aesthetics of the local environment. We use the ongoing sargassum influx in West Africa as a case study of adaptation to an emergent (and compound) risk in progress that also contributes to the empirical gap in sargassum adaptation research in West Africa. The research, in four sites in the Western Region of Ghana employs data from 16 focus group discussions, six key informant interviews, and participant observation. We finds that due to a series of coincidences, participant communities perceive that sargassum influxes were seeded by and then annually driven by oil and gas exploration in Western Ghana. This is in contrast to scientific research that indicates that pelagic sargassum was initially seeded in the tropical Atlantic basin (from the Sargasso Sea) in 2010 following an anomalous weather event in winter 2009–2010. Following Rogers’ Protection Motivation Theory, we explore the sources of information and the processing of that information to understand the divergence between scientific and community perceptions of the physical drivers. We find that community perceptions of oil and gas company responsibility for causing the sargassum problem leads the communities to perceive that the oil and gas companies should be responsible for the clean-up activities. Communities are further constrained by a perceived lack of capacity to act. Solutions to address this adaptation impasse could involve the government working with communities and the oil and gas industry to clarify the actual drivers of sargassum. Such guidance may open opportunities for the government and industry to work with communities to address misperceptions of the scientific nature of the influxes. Collaborative approaches, while addressing extant tensions, may also change the narrative about the problem, support affected communities to engage with adaptive measures, including re-use opportunities, and enhance community capacity to act. As a present-day emergent risk, pelagic sargassum provides an unusual yet contemporary empirical study of real-time adaptation and the central role of perceptions in shaping proactive adaptation and seeking exploitable opportunities from new environmental risks

Remote sensing application of shore-based video and unmanned aerial vehicles (Drones) : complementary tools for beach studies

International audienceVideo camera systems have been used over nearly three decades to monitor coastal dynamics. They facilitate a high-frequency analysis of spatiotemporal shoreline mobility. Video camera usage to measure beach intertidal profile evolution has not been standardized globally and the capacity to obtain accurate results requires authentication using various techniques. Applications are mostly site specific due to differences in installation. The present study examines the accuracy of intertidal topographic data derived from a video camera system compared to data acquired with unmanned aerial vehicle (UAV, or drone) surveys of a reflective beach. Using one year of 15-min video data and one year of monthly UAV observations, the intertidal profile shows a good agreement. Underestimations of intertidal profile elevations by the camera-based method are possibly linked to the camera view angle, rectification and gaps in data. The resolution of the video-derived intertidal topographic profiles confirmed, however, the suitability of the method in providing beach mobility surveys matching those required for a quantitative analysis of nearshore changes. Beach slopes were found to vary between 0.1 and 0.7, with a steep slope in May to July 2018 and a gentle slope in December 2018. Large but short-scale beach variations occurred between August 2018 and October 2018 and corresponded to relatively high wave events. In one year, this dynamic beach lost 7 m. At this rate, and as also observed at other beaches nearby, important coastal facilities and infrastructure will be prone to erosion. The data suggest that a low-cost shore-based camera, particularly when used in a network along the coast, can produce profile data for effective coastal management in West Africa and elsewhere

Coastal Flooding Caused by Extreme Coastal Water Level at the World Heritage Historic Keta City (Ghana, West Africa)

Like low-lying sandy coasts around the world, the Ghanaian coast is experiencing increasingly frequent coastal flooding due to climate change, putting important socioeconomic infrastructure and people at risk. Our study assesses the major factors contributing to extreme coastal water levels (ECWLs) from 1994 to 2015. ECWLs are categorized into low, moderate, and severe levels corresponding to the 30th, 60th, and 98th percentiles, respectively. Using these three levels over the Pleiades satellite-derived digital elevation model topography, potential flood extent zones are mapped. ECWLs have the potential to flood more than 40% of the study area, including socioeconomically important sites such as tourist beach resorts, Cape St. Paul lighthouse, and Fort Prinzenstein. In this study, all coastal flooding events recorded by the municipality of Keta fall within the 98th percentile category. Our results show a gradual increase in the frequency of flooding over the years. Flooding events are caused by a compound effect of the tide, sea level anomaly, waves, and atmospheric conditions. Finally, while wave run-up is the major contributor to coastal flooding, the tide is the one varying most, which facilitates a simple early warning system based on waves and tide but adds uncertainty and complicates long-term predictability

Seasonal predictions of holopelagic sargassum across the Tropical Atlantic accounting for uncertainty in drivers and processes: The SARTRAC ensemble forecast system

The holopelagic macroalgae sargassum has proliferated across the tropical Atlantic since 2011, of consequence for coastal populations from West Africa to the Caribbean with limited early warning of major beaching events. As part of an interdisciplinary project, ‘Teleconnected SARgassum risks across the Atlantic: building capacity for TRansformational Adaptation in the Caribbean and West Africa’ (SARTRAC), an ensemble forecast system, SARTRAC-EFS, is providing seasonal predictions of sargassum drift. An eddy-resolving ocean model hindcast provides the winds and currents necessary to generate ensemble members. Ensemble forecasts are then obtained for different combinations of ‘windage’, the fractional influence of winds on sargassum mats, and in situ rates of growth, mortality, and sinking. Forecasts for north and south of Jamaica are evaluated with satellite-observed distributions, associated with beaching events in specific years of heavy inundation, 2015 and 2018-20. These seasonal forecasts are evaluated, on lead times of up to 180 days. Forecasts are subject to leading modes of tropical climate variability, in particular the Atlantic Meridional Mode (AMM). More accurate forecasts for a given year are obtained with ensemble members from hindcast years with a similar spring AMM-index. This is most clearly evident during negative AMM phases in spring of 2015 and 2018, when positive sea surface temperature anomalies and anomalously weak trade winds were established across the northern tropics. On this evidence, SARTRAC-EFS is potentially useful in providing early warning of high sargassum prevalence. Extended to sargassum drift off West Africa, extensive cloud cover limits availability of the satellite data needed for full application and evaluation of SARTRAC-EFS in this region, although experimental forecasts off the coast of Ghana are found highly sensitive to the windage that is associated with strong onshore winds during boreal summer. Alongside other forecast systems, SARTRAC-EFS is providing useful early warnings of sargassum inundation at seasonal timescale