Podcast mini-series: Coastal resilience in the face of climate change

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Podcast mini-series: Coastal resilience in the face of climate change

Reported by Josephine Anselin, Policy Intern, Centre for Science and Policy

Coastal areas around the UK are facing significant climate change induced risks, such as flooding and erosion. With the ongoing warming of our planet, these adverse events are likely to increase in frequency. Consequently, there is a growing necessity to implement coastal management policies that empower coastal communities to foresee and recover from these adversities, fostering increased resilience in the face of climate change.

Our CSaP policy intern, Josephine Anselin, interviewed four coastal research experts to explore different aspects of the UK’s coastal adaptation to climate change. They discussed some of the latest science on coastal resilience, the links between academic research and coastal policy, as well as the steps that academics can take to help bridge the gap between coastal science and policy action.

What is coastal resilience? And how is it measured?

Over the past decade, there has been a growing emphasis on adopting a resilience-focused approach to address coastal flooding and erosion in the UK. However, despite gaining prominence in policy documents, the notion of resilience often lacks a precise definition. This gap motivated the CoastalRes project, a NERC-funded study completed in 2020, aimed at defining and operationalising coastal resilience.

“If you’re going to use resilience in a management sense, you’ve got to be able to define it, and you’ve got to be able to measure it.” – Professor Robert Nicholls

In the first episode of this podcast mini-series, we spoke with Professor Robert Nicholls, Director of the Tyndall Centre for Climate Change Research at the University of East Anglia, and PI of the CoastalRes project. Professor Nicholls explained that traditional coastal risk management approaches were mostly aimed at avoiding damaging events such as floods. In contrast, a resilience-focused approach is about “the ability to bounce back.”. More specifically, the CoastalRes project drew on the definition of coastal resilience adopted by the US Army Corps of Engineers that emphasises “the ability of a system to prepare, resist, recover, and adapt to disturbances in order to achieve successful functioning through time”.

Based on this definition, the CoastalRes team proposed a framework to quantify the, so far predominantly qualitative, notion of coastal resilience. The model accounts for economic, environmental, and social factors, which highlights the need for a systemic, cross-disciplinary, approach when addressing resilience. Building on existing datasets, the model aggregates different indicators to generate a coastal resilience score for a particular location. Professor Nicholls emphasised that the framework is based on a multi-criteria analysis in which different weights are assigned to each factor. As a result, the coastal resilience score generated by the model can change depending on the perspective taken, emphasising the need to involve a range of different stakeholders when developing coastal adaptation strategies.

Watch episode 1 on 'what is coastal resilience' with Professor Robert Nicholls

Predicting future flood risk

Improved flood warning and forecasting systems can help enhance coastal resilience by improving the preparedness of coastal communities to flood events. In episode 2 of this mini-series, we discussed the topic of flood forecasting with Professor Jenny Brown, Coastal Oceanographer at the UK’s National Oceanography Centre and Co-Director of the new Centre for Doctoral Training for Resilient Flood Futures (FLOOD-CDT).

Coastal flooding can be caused by a combination of factors, including high tides, storm surges, wave overtopping, and increased river flow caused by heavy rainfall. Professor Brown emphasised that aside from contributing to elevated sea levels and increased storm activity, climate change can also alter flood risk through shifts in storm track position. This can change prevailing wind conditions, which in turn can influence the waves, surges, and beach response of a coastline.

Professor Brown then explained that, while AI-based flood forecasting approaches are gaining prominence, computer models are currently the primary tool used to predict future flood risk. These powerful calculators incorporate equations to represent natural processes that control flooding. When fed with specific information about ocean and weather conditions, the computer models are then able to simulate the likelihood of future flood occurrences under different emissions scenarios. Unlike short-term weather forecasts, flood risk model predictions tend to be used to develop longer-term shoreline management strategies.

While significant advances have been made in coastal flood predictions caused by tides and waves in recent years, Professor Brown highlighted the importance of improving the representation of wave overtopping in flood prediction models. Wave overtopping occurs when a wave impacts a coastal structure causing spray to go over the sea defence, which can in turn lead to flooding. The physical processes that occur when spray interacts with a structure are not well understood. Due to high-energy conditions in which wave overtopping occurs, these processes are challenging to measure in the field. Professor Brown and her team at NOC are aiming to address this challenge by developing a novel measurement system designed to collect field measurement of hazardous wave overtopping.

Watch episode 2 on 'predicting future flood risk' with Professor Jenny Brown

Nature-based solutions to enhance coastal resilience

Traditionally, coastal hazards have been mostly managed with engineered structures like concrete sea walls. While these coastal defences offer several advantages including well-established design rules and known maintenance costs, they also come with many challenges. For example, coastal protection structures are static and fixed in position, making them only a temporary solution (when considering long-term 100-year management plans) as sea levels rise. Their installation also disrupts natural processes, which can accelerate erosion downstream, potentially creating new problems further down the coast. As a result of these limitations, there has been a shift towards more sustainable management of nature’s resources, such as gravel barriers, salt marsh development and restoration of sea grass beds, to enhance the resilience of the UK’s coasts. In the third episode of this podcast mini-series, we spoke with Professor Tom Spencer, Emeritus Professor of Coastal Dynamics and Director of the Coastal Research Unit at the University of Cambridge, to learn about the advantages and challenges associated with these nature-based approaches.

Professor Spencer explained salt marshes and other nature-based schemes are very effective at reducing incoming wave energy. This helps mitigate the impact of waves on the coast, thus reducing the risk of flooding and erosion. Salt marshes also serve as natural reservoirs for floodwater storage, which can alleviate pressure on flood defences located further along the coast or further up estuaries. Professor Spencer noted that beyond reducing the risk of coastal hazards, nature-based solutions provide coastal communities with a range of additional benefits including maintenance of biodiversity, environmental conservation, carbon sequestration, and enhanced human well-being.

Despite these advantages, Professor Spencer highlighted that there are important challenges associated with the implementation of nature-based solutions. Policy initiatives promoting nature-based approaches sometimes outpace scientific understanding, making it difficult to effectively plan and execute these interventions. Moreover, coastal communities often express concerns about the effectiveness of nature-based solutions in the face of extreme storms, particularly given the time that it can take for nature-based solution to start showing tangible benefits. These uncertainties highlight the need for further research, collaboration, and engagement to effectively integrate nature-based solutions into UK coastal management strategies.

Watch episode 3 on 'nature-based solutions' with Professor Tom Spencer

Coastal adaptation policy transitions

The last episode of the series, explored policy barriers associated with transitioning to resilience-based coastal management approaches. We discussed this topic with Dr Sien van der Plank, Senior Research Fellow in the School of Geography and Environmental Science at the University of Southampton. In this episode, Dr van der Plank shared her insights from a recent paper on transitions in modes of coastal adaption, which she co-authored together with colleagues from the University of Southampton, the University of East Anglia, Middlesex University, University College London, and the National Oceanography Centre.

The paper focuses on coastal management in England and Wales, where Shoreline Management Plans (SMPs) are used to address current and future coastal adaptation strategies. The current SMP considers four policy options (hold the line, advance the line, managed realignment, no active intervention) across three different time periods: the short-term (2005–2025), the medium-term (2026–2055), and the long-term (2056–2105). For a given stretch of coast, the chosen policy option may change from one time period to the next and this will require a policy transition.

Dr van der Plank emphasised the importance of taking a holistic approach and considering a wide range of perspectives when studying coastal resilience issues. In the context of this particular study, this was addressed by combining academic literature with qualitative data gathered through workshops involving relevant stakeholders and practitioners. Dr van der Plank gave an overview of the key challenges associated with implementing coastal policy transitions, as identified in the workshops. The barriers included having to balance short-term and long-term planning priorities, limited funding options, ineffective public engagement processes, and a lack of understanding among stakeholders about the dynamic nature of coastal processes.

Referring to Figure 4 in the paper, Dr van der Plank outlined three potential solutions to address the identified challenges. The first solution emphasises the importance of improved stakeholder engagement and transparency to ensure coastal communities are prepared for future changes in policy. The second solution refers to a need for political consensus with regards to long-term coastal adaptation efforts, including funding schemes that are independent of political cycles. Finally, the third solution highlights the need for diversified public funding (i.e. at national and local scales), as well as alternative options such as insurance schemes for cases in which the criteria for public funding are not met. While challenging, these solutions offer actionable steps to facilitate policy transitions toward resilient coastal management.

Watch episode 4 on 'policy transitions' with Dr Dien van der Plank