Why nature-based coastal defence is more than replacing ‘grey with green’


11 Nov 2020173 Views

Prof Iris Möller. Image: TCD

Prof Iris Möller of TCD has helped pioneer research into how our coasts shape our world, inspired by a fishing trip with her father.

Prof Iris Möller received her PhD in Geography 1997 at the University of Cambridge. After a short spell working at HR Wallingford, she joined the university’s Coastal Research Unit as a research associate and deputy director, and then took up a full-time college lectureship in physical geography at Cambridge’s Fitzwilliam College in 2000.

From 2014 to 2019, she held a university lectureship in physical geography at the Department of Geography, while continuing her role as deputy director of the Cambridge Coastal Research Unit.

In October 2019, she joined the Department of Geography in the School of Natural Sciences at Trinity College Dublin and, in January this year, took on the role of head of department.

‘The coast has always fascinated me as it is a place that is so dynamically responsive to what happens both on the land and out at sea’
– PROF IRIS MÖLLER

What inspired you to become a researcher?

Both my parents taught arts within the secondary and tertiary education sector, but my father was one of those people who was seemingly able to understand and work with concepts from the sciences (maths, physics, biology, etc).

He used to explain them to me with a kind of fascination that made a deep impression on me. I loved maths and biology at school, but was always really aware that I wanted to contribute something to society that made people more aware of the benefits of understanding how nature operates to sustain us, as humans.

I have a memory of being invited onto a fishing boat of a friend of my father, who told me all about his experience of fishing in the ever-more polluted river, the Elbe, in Hamburg. This was the time of the rise of large-scale environmental movements in the 1970s and 1980s and I read much around acid rain and what was then still a fairly uncertain claim that humans had already altered the planet’s climate.

I was appalled by the lack of attention that was paid to an emerging body of scientific evidence that suggested that we needed to rethink how we live on this planet to allow us to continue to do so. That is what ultimately made me chose to study a subject, geography, that would give me great insights into both the physical and biological environment and human society.

Can you tell us about the research you’re currently working on?

I research how complex shallow coastal environments function. I do so with a strongly applied focus on improving coastal flood and erosion risk management, as those environments will bear the brunt of climate change impacts over the next few decades.

As sea levels rise, climatic changes are likely to lead to a rise in frequency or intensity of extreme weather events in many parts of the world. My research is highly collaborative – often in large interdisciplinary teams – and looks to provide robust, empirical science. But to do so always with a critical awareness of human subjectivity, societal relevance and context.

The coast has always fascinated me as it is a place that is so dynamically responsive to what happens both on the land and out at sea. My PhD research provided the first systematically recorded evidence of the fact that terrestrial salt-tolerant vegetation that grows below the high tide level – often in front of sea defences – actively contributes to the reduction in wave energy and thus the protection of the sea defences and of what lies behind. That was in the 1990s and the concept of nature-based coastal protection has since then become well established.

In your opinion, why is your research important?

The economic and potential human losses resulting from coastal flooding and erosion are expected to increase as a result of climate and demographic change. In England, for example, it has been estimated that by the 2080s, up to 1.5m properties and 1.1m people will be at significant risk of annual coastal flooding.

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Our research on how the vegetated marsh platform reduces wave heights, and thus the scale of artificial defences needed on the sea-facing side of artificial defences, was included as evidence within the UK Climate Change Risk Assessment and translated into between £3bn to £30bn worth of capital savings in sea wall replacement and repair.

It is fundamentally important that we find ways in which we can organise our society to be able to anticipate and live with change in an intrinsically dynamic coastal environment.

What commercial applications do you foresee for your research?

We are already working with the private sector, largely engineering companies, assisting them with the monitoring and prediction of coastal change. This means coastal management solutions can be put in place that respect and benefit from the operation of coastal processes, such as tides, waves and the organisms that thrive at the coast.

I think the next few decades will lead to many more commercial applications of our research as we are now using new methods, such as AI, to extract information from the increasing quantities of data that can now be acquired by innovative technology. Drones and [uncrewed aerial vehicles], alongside satellites and remote data logging solutions, are allowing us to acquire data at a much higher frequency and over much larger areas than ever before.

What are some of the biggest challenges you face as a researcher in your field?

It is in the very nature of world-leading research to be intellectually, technically and operationally challenging. A good example is the challenge we faced when we conducted the first ever true-to-scale controlled-environment experiment on how a salt marsh buffers waves during a storm surge.

For this, we had to excavate and transport by lorry over 200 sq m of coastal salt marsh from northern Germany to one of the world’s largest wave flumes in Hannover, the ‘Grosser Wellen Kanal’.

Fundamentally, however, there is arguably a bigger challenge that is always there and that is of course the challenge of finding someone willing and able to pay for the research.

Are there any common misconceptions about this area of research?

Yes, I still come across the view that natural coastal features cannot be as efficient as human-engineered coastal protection structures. This is really a misconception about what is meant by ‘nature-based coastal protection’.

The idea is not to replace ‘grey with green’, but is in fact much more than that. The idea around nature-based coastal protection is really to find a way of preventing the detrimental impact of flooding and erosion on humans.

That does not mean that we offer an alternative to hard structures, but that we think carefully about how we can place and design hard structures, so that they can work in synergy with the dynamic natural environment around them that we so depend on for many different reasons: not only as a wave energy buffer but also as a carbon store, fish nursery ground, water quality enhancer and a space that serves our mental and physical health and wellbeing.

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