The coast of Valencia will be the third Spanish coastal area where sea level will increase the most this century, after Barcelona and Cádiz, according to NASA’s Sea Level Change Team. Estimates by scientists from the US space agency indicate that If nothing is done to reduce CO₂ emissions, the sea level in Valencia in 2030 will be 12 centimeters (cm) higher than the current one, a height that will double by the middle of the century when it reaches 28 cm and that will reach 83 cm in 2100. Of the 17 ports in Spain included in NASA projections, only Barcelona and two in the Gulf of Cádiz (Cádiz and Bonanza, in Sanlúcar de Barrameda), present a greater average increase in sea level, with 87 and 85 cm respectively for 2100.
He NASA Sea Level Change Team (N-SLCT), made up of 70 scientists, based on observations from satellites and tide gauges from ports around the world, has created a tool that allows project long-term changes in the mean sea level in the different scenarios of increase in the annual global average temperature of the Earth’s surface from 1.5 to 5 ºC foreseen by the Intergovernmental Panel on Climate Change (IPCC) depending on whether or not measures are implemented to reduce CO₂ emissions.
The N-SLCT, according to the most recent IPCC assessment, the 2021 AR6 report, also contemplates the “low probability, high impact” scenario in which high surface heating trigger a catastrophic collapse of the West Antarctic ice sheet, which would have serious implications for sea level rise, flooding coastal cities and increasing the frequency and severity of flooding.
Ice cliff in Antarctica in a file image.
Accelerated melting of Antarctica
In the AR6 report, researchers, despite deep uncertainty and limited data, analyzed the changes that under a situation of high greenhouse gas emissions could lead to “the disintegration of marine ice shelves sooner than projected”the abrupt and widespread onset of instability of marine ice sheets and sea ice cliffs around Antarctica and more rapid than expected changes in the balance of the Greenland ice mass.” That accelerated thawthe IPCC study points out, is a scenario of “low probability and high impact, since “It would mean increasing sea level by more than one meter by 2100.”
One of the N-SLCT scientists, Pat Brennan, in a recent article titled Rising seas, unknown future: How to communicate uncertainty?, calls for “the worst scenarios” to be taken into account in the urban planning of coastal areas“highly unlikely but extremely damaging sea level rise.” And in this last case NASA’s projection predicts that by 2100 the sea level in Valencia will be 91 cm higher that nowadays and 78 cm more in Alicantewhere the most favorable forecasts for 2100 involve an increase in sea level of 33 cm and 71 cm if the temperature rises 5 ºC.
Therefore, on the Valencian coast, even with the unlikely reduction to zero of CO₂ emissionsthey would be urban, tourist and port infrastructures are compromised, as well as the natural spaces close to the ground zero of the current sea level. Well, An increase of one and a half degrees in temperature is enough for sea level to rise by 21 cm in Valencia by mid-century and 15 cm in Alicante and 45 cm and 33 cm respectively by 2100.
Gandia beach flooded in January 2020 during Storm Gloria, when the sea level rose 80 cm.
And let’s not say yesi no measures against warming are implementedwell With a temperature increase of 5 ºC, by mid-century the sea level in Valencia will be 28 cm higher that now and 22 cm in Alicante, and by 2100 the increase will be 83 cm and 71 cm in each case.
The storm Gloria, a preview
You don’t need to resort to any science fiction movie to travel to the future and discover what a rise in sea level of 80 cm would mean for the coastlinewell that We Valencians already experienced it on January 19, 2020 with the storm Gloria. This storm, in which the tide gauges recorded a high tide of 80 cm in Gandia and 50 cm in Benidorm, swallowed hundreds of kilometers of beaches from Calp to Moncofa and destroyed the promenades of more than a dozen municipalities.
Benidorm’s Levante beach, flooded after the passage of Storm Gloria in January 2020
Furthermore, at the international conference Conservation and management of wetlands in the face of climate change that Valencia hosted this February on the occasion of the European Green Capital, experts warned that Up to 90% of European coastal wetlands could disappear due to rising sea levels, among them the twenty long Valencian coastal wetlands, six of them natural parks: l’Albufera, Prat de Cabanes-Torreblanca, Marjal de Pego-Oliva, Salinas de Santa Pola, Fondó d’Elx, and the Salinas de Torrevieja-La Mata.
