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IHCantabria study shows the enormous benefits of beaches in dealing with climate change
A study by the Environmental Hydraulics Institute of the University of Cantabria (IHCantabria), recently published in the journal Nature Communications, and highlighted on Nature Communications’ Editor’s Highlights web page. as one of the 50 best published papers in the area of climate change impacts, demonstrates that beaches constitute dynamic natural defense systems against flooding.
This means that their disappearance -total or partial, temporary or chronic- will imply a loss of protection and an increase in risk, since the retreat of the coastline due to erosion leads to greater flooding, as has happened in the past after extreme storms. This is explained by Íñigo Losada, Professor of Hydraulic Engineering at the University of Cantabria (UC) and Director of Research at the Institute of Environmental Hydraulics (IHCantabria). In his opinion, “coasts that fail to recover from the erosion suffered during major storms end up having greater flooding problems, which affects the area they protect”. This has been the case for many beaches in the Cantabrian Sea, after the storms of 2014.
On the other hand, beaches provide an obvious recreational service and, in many countries, constitute the fundamental resource of the tourism sector. Therefore, the loss of beach has a direct economic impact on the areas where they are located. How can the combined action of erosion-flood impacts reduce protection and recreation services, and assess damages in economic terms? This is the question that was answered in the article published in Nature Communications. Of its four authors, three are linked to IHCantabria: Alexandra Toimil, Íñigo Losada and Moisés Álvarez.
“Our objective is to develop a conceptual framework and the necessary models to quantify the benefits of beaches in reducing the risk of flooding associated with storms and rising mean sea level, and to contribute to improving adaptation decision-making,” explains Alexandra Toimil, Ramón y Cajal postdoctoral researcher in the UC Department of Water and Environmental Sciences and Techniques.
The methodology applied in this study is based on obtaining the damage avoided by the protection provided by the beach against extreme events of waves and tides, as well as against the rise in mean sea level. For this purpose, the authors have calculated and compared flood damages in two different situations: considering beach erosion and assuming its maintenance; that is, assuming that the coastline remains fixed due to the implementation of adaptation measures.
A pilot case
This methodology was applied in a pilot case in Narrabeen, Australia. This beach has historical information on the evolution of the coast, for more than 40 years, and on the damage suffered by high quality protected assets; therefore, these data make it possible to validate the methodology. However, it is a methodology that can be applied anywhere in the world.
According to Toimil, this work “shows that, in 2050, the benefits of maintaining the current coastline in terms of protection and recreation could be more than 150 times higher than the cost of its maintenance, through beach regeneration”. Their results show that “the fact of not considering the dynamism of the coastline in flood studies can lead to particularly important underestimates of risk at the end of the century”, says Moisés Álvarez, a postdoctoral researcher at IHCantabria.
The results of this study are a substantial advance to know the real value of the beaches, in order to improve their management in the future. For example, considering their maintenance through the provision of sediment can be a fundamental measure for adaptation to climate change. “Having a robust and complete methodology to properly calculate the role and value -present and future- of beaches in adapting to climate change, will facilitate having a better opinion when investing in their maintenance”. This is how Íñigo Losada concludes.