Yes, Las Canteras beach could disappear

The 47 black spots on the Canary coast due to climate change. / SIGNATURE

150 kilometers of the 1,500 of the archipelago's coastal territory are at risk. Erosion and sea level rise will endanger 147 beaches by 2050

Louisa del Rosario

Of the 1,500 km of coastline that make up the Canary Islands,
47 sections are at high risk due to climate change, distributed among the seven islands, although with more affectation in the eastern ones. 29 zones between Gran Canaria (7), Fuerteventura (12) and Lanzarote (10) and 18 between Tenerife (10), La Palma (5), La Gomera (2) and El Hierro (1).
They are called 'hotspots' or alert hot spots and in which the archipelago must intervene urgently and among them are the beach of
Las Canteras, San Felipe and Puertillo de Bañaderos, Arinaga Bay, Maspalomas Lighthouse, Sotavento beach, in Jandía, or Costa Teguise and Puerto del Carmen.

This is highlighted by the
Plan to Promote the Environment Adapta Costas Canarias (PIMA) a Project coordinated by Grafcan in which the risks of the coastal environments of the islands are described. To determine these black spots, "a risk index that tries to combine the consequences on the population, the economy, the ecosystem and heritage has been taken into account, and the horizon of 2100 and the worst scenario of climate change are taken as a reference" , explains the researcher Nicolás Ferrer, from the Institute of Oceanography and Global Change (Iocag) of the University of Las Palmas de Gran Canaria (ULPGC) who participated in the study.

"Those 47 points
These are the sections with the highest risk, taking into account the horizon of 2100 and the worst climate scenario.. They constitute a comparative reference to determine the areas that have a greater risk where to focus adaptation efforts and where more detailed studies should be carried out », he explains.

  • The Gran Canarian palms
    The rise of the sea will predominantly affect the area of ​​the isthmus and Las Canteras beach.

  • From north to south
    In Gran Canaria it will also affect Bocabarranco beach, San Felipe, Ojos de Garza. Arinaga, the Tirajana ravine and the Maspalomas Lighthouse.

  • Fuerteventura
    El Cotillo, Corralejo and its dunes, La Calera, Puerto del Rosario, Caleta de Fustes, Gran Tarajal, Giniginamar, Tarajalejo, Costa Calma, Jandía and the Matorral beach.

  • Lanzarote
    Punta Mujeres and Arrieta, Costa Teguise, Las Caletas, La Bufona, Puerto del Carmen, Playa del Golfo, La Santa, Famara, Caleta de Sebo.

  • Westerners
    The topography helps the western islands, but the south of Tenerife will be particularly affected.

The study works with "return periods", that is, with the frequency with which an extreme event occurs, in this case with maritime storms. “We have worked both with situations of permanent flooding and with return periods of 5, 50, 100 and 500 years. If a flood occurs every five years there is a 25% chance of it happening, but it is a smaller event. A more destructive one occurs every 500 years, that means that each year there is a 0.2% chance of it occurring. The importance of working with these return periods is that "the data is given by magnitude and is associated with a probability".

"A natural beach does not have to be lost even if the coastline retracts, the beaches recede and recover their morphology, but for this retreat to occur they must have margin and be free of urban structures or cliffs"

However, at risk is not only those 47 areas, explains Ferrer. “There are threats to the population in many stretches of the coast. What happens is that in those points they have a greater risk and adaptation efforts must be focused ». But not even all 'hotspots' will suffer the same consequences. The study estimates that in 2050, some 147 tourist beaches in the Canary Islands will lose 10.6% of their surface due to the rise in sea level.
“On Las Canteras beach, applying the rise in mean sea level dictated by regionalized models, we have modeled the response of the beach and this model tells us that Las Canteras is going to lose 10% Of surface. If this rise in sea level occurs, 10% of the beach will be lost.

The problem with “beaches in general is that they do not have the capacity to retreat. A beach does not have to be lost naturally, even if the coastline retracts, the beaches recede and recover their morphology, but for this regression to occur they must have margin and be free of urban structures or cliffs that occlude it, "he points out. .

In the case of Las Canteras there is an obvious impediment for the beach to set back. «»In the old days we had an isthmus populated with dunes, in that old scenario with a rise in sea level the beach would have receded, but having the city behind it, what is going to happen is that any setback of the beach due to the rise in sea level sea, translates into loss of the beach.

half of the surface

The forecasts for 2100 are even worse, 153 Canarian beaches would lose 45.2% of their surface. almost half its length. The report also gives data on the possible economic losses that climate change and its effects on tourist beaches will have in the Canary Islands. The islands would stop entering 1,000 million euros per year from 2050, a figure that amounts to 4,500 million euros per year from 2100. «The economy that moves around the existence of beaches would be affected. We have pointed out the direct impact on the economic chain, which is quite important, but not the indirect ones. The direct one can affect 30-35% of GDP, the indirect one can reach 60%».

«
The loss of beaches is probably the most delicate factor in climate change in the Canary Islands. The study includes the effects on infrastructures and on the population and three solutions can be given: the first is to withdraw from the coast, to get away from the problem, but this is not always possible. We can implement protection systems such as dikes to mitigate the effects of storms and protection measures in buildings, or we can install drainage systems.
In Garachico drainage systems have been planned so that when the waves reach an area of ​​interest there are sinks through which the water is channeled and does not cause damage. But the case of beaches is very complicated or extremely sensitive because you cannot take them elsewhere. When we talk about erosion due to storms on the beach, we can mitigate it, but a rise in the average level of the sea is a huge problem. It does not seem that there is a direct adaptive measure that can be applied”, says Ferrer.

In short, he adds,
"The rise in sea level is a problem that occurs in all points of the coast at the same time and the loss of beaches is going to be difficult to face and counteract" although he is optimistic: «We will see what lies ahead and what possibilities and damage mitigation we can put into practice».

Ferrer insists on making it clear that this is not a catastrophic report. «
There are uncertainties within the climate change models themselves and we have generated average models. The spirit is to indicate the work areas to carry out detailed studies. Climate change predictions are likely to undergo changes in the coming years and will need to be updated. The most informative thing for us was to take into account the current scenario and project on it the modeling of climate change and its effects on coastal areas in 2050 and 2100”, he adds.

Now, Ferrer says,
“We have to lower the scale and focus on the 47 detected areas and carry out this same study on the risks, measure the coastal flooding and the economic value. With more reliable estimates, adaptation measures will have to be adopted based on cost-benefit.”

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