10 Great Mediterranean Cities on Coastal Flooding Risk

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The integrity of dozens of Mediterranean coastal towns declared World Cultural Heritage of Humanity is in danger. 

A study published in Nature Communications Journal shows that these sites, for the most part, are frightened by rising sea levels, one of the consequences of global warming. 

The research assesses how combining this factor with extreme weather events can increase erosion and flooding along the coasts. 

47 of the 49 places analyzed could suffer negative impacts from one of these two phenomena (or both). The authors consider governments to take appropriate measures at each site to guarantee their protection.

Things in the Mediterranean will not get better, as evidenced by climate change projections in the region. The main threat will be represented by coastal flooding.

Some major cities are at most risk from coastal storm flooding, and these are predicted to be extinct shortly if appropriate action is not taken soon.

1. Venice and its Lagoon, Italy

Venice and its Lagoon, Italy - Mediterranean city
Amazing Venice| Photo by Andreas M

Worldwide climate change has caused a sea-level rise in many regions of Italy. It was mainly reflected in Venice, which suffers from regular floods and is under the threat of flooding. 

Abnormal high tides have become more frequent in the city, and water has begun to flood historic buildings in the center more often.

Over the past 25 years, the water level in the Venice canals has surpassed the flood mark 163 times, while in the previous hundred years, this happened only 166 times. 

The number of floods is also increasing: since the beginning of observations in 1872, the water has risen above 140 centimeters. Most cases occur in the 21st century.

According to the European Union of Geosciences research study, the worst-case scenario suggests a sea-level rise to 120 centimeters in Venice by the end of this century.

It is almost half the United Nations forecast to increase global sea level over the same period. The most significant flood in the 21st century in Venice occurred in 2019.

More than 80 percent of the city was flooded, including the historic center, and flood damage was estimated at one billion euros.

In Venice, there is not only the sea level rising due to global warming, but also the ground which is lowering, due to the phenomenon of subsidence, and its wooden urban foundations giving way.

2. Roman city of Tarraco, Tarragona, Spain

Model of Roman city Tarraco, Tarragona, Spain - Mediterranean city
World’s second-largest Model, Coastal Taracco city on 1:500 scale| Designed by Manel R. Granell

The city of Tarraco is one of the two World Heritage Sites of the State in danger due to the rising Mediterranean. It is indicated that it is in trouble because it has a shallow risk of flooding but a very high risk of erosion.

Currently, Tarragona’s heritage already presents danger: it is in the fourth position of five possible scenarios, from least to greatest severity, without considering the safe rise in sea level. 

But even more difficult is the situation for Tarraco if the scenario of the year 2100 is taken into account. 

Tarragona’s world heritage would see its situation worsen significantly and would reach the maximum level of very high risk in terms of erosion. This impact, which now represents a real danger, multiplies as the average sea level rises. 

The baseline used by the researchers is that of the year 2000. At the time, the average distance from the places to the water was 1.1 kilometers. 

The most conservative estimates leave it at 762 meters at the end of the century and the least at just over 100 meters.

3. Gibraltar City, Gibraltar 

View of Gibraltar City, Gibraltar from tourist destination The Rock - Mediterranean city
Gibraltar coast viewed from a popular tourist destination, The Rock| Photo by Michal Mrozek

The northern area of Algeciras around the Palmones river, Los Lances beach from the Jara river to the entrance to the town of Tarifa, and much of Sotogrande to the Guadiaro river is under threat of coastal flooding. 

A study carried out by the organization Climate Central and published by the journal Nature Communications predicts that these three significant areas of Gibraltar City will be affected in 2050 by major coastal floods due to the rise in sea level due to climate change. 

These are places that are already flooded. In fact, during significant rainstorms, lagoons form in them. The investigation considers that within 31 years, they will have been definitively occupied by seawater.

In Algeciras, the entire area of the Maritime Station will be flooded, almost to the very building of the Port Authority and the two terminals of Isla Verde Exterior. 

4. Rome, Italy

bridge at the Vatican city of Rome - Mediterranean city
The heart of Rome, Vatican City| Photo by Christopher Czermak

According to the Central Apennine District Basin Authority, with approximately 300,000 people living and working in a dangerous area measuring about 11,350 sq km, Rome has the highest exposure in Europe to the risk of flooding.

Nearly 400 areas in the Rome area that are considered at risk of landslides have been identified. In particular, Monte Mario, the highest hill in the city, Viale Tiziano near the Parco della Musica concert hall, Monteverde Vecchia from the Villa Doria Pamphili park, and the Balduina district in the northwest.

Rome is further weakened by several kilometers of cavities that flow under the city, some created by man in previous centuries and others caused by subsidence.

At least 32 square kilometers of underground caves have been mapped so far, while the number of new holes opening is increasing at an alarming rate.

While the high walls protect the heart of Rome from the Tiber, the river has flooded its banks outside the historic center at least three times since 2008.

According to the report, Rome suffers the most significant number of extreme weather events, with 33 in 2018.

5. Palermo, Sicily, Italy

Coast of Palermo City, Italy - Mediterranean city
Coast of Palermo City | Photo by Henrique Ferreria

Landslides, floods, earthquakes: among the Italian municipalities at high risk in Italy, there is also Palermo. 

The data emerges from the National Council of Architects research “The state of the Italian territory, between seismic, hydrogeological risk, and land consumption” presented in Padua during the Orders of Architects’ national conference Planners, Landscape Architects, and Conservators. 

Research for the first time analyzes how the combination of the danger of landslides and floods and seismicity falls on the Italian territories. 

There are 442 high-risk municipalities inhabited by over eight million people in almost 18,000 square kilometers, 5.9% of the national area.

In the municipalities classified as high or medium-high natural risk reside about 20 million people, of which 4 million in Sicily. 

In these regions, the landslide hazard affects 189,000 and 12,500 people, and respectively, the flood hazard affects 20,800 people in Sicily.

6. Marbella, Spain

Marbella harbor coastal region, Spain -  Mediterranean city
Marbella harbor coastal region | Photo by Simon Hermans

40% of the Spanish coastal municipalities have seen how their coastline has been transformed in recent years due to large constructions, preferably for tourist uses.

In Spain, some 200,000 people would be affected by the rising oceans, which would rise to 340,000 in the year 2100 in the worst-case scenario: high emissions of the gases responsible for the climate crisis.

According to the Sustainability Observatory report, Marbella leads the ranking; it implies a high risk of flooding due to cold drops or the rise of the sea itself.

It is one of the main conclusions detailed in the report The 50 most built municipalities on the Spanish coast: urban areas most exposed to storms, published by the observatory. 

The study warns of two extensive processes in a collision on the Spanish coast. The report from the Sustainability Observatory suggests climate change and sea rise as causes, without forgetting the cold drops that have been repeated with greater frequency and intensity in recent years.

7. Malaga, Spain

Night view of Malaga city, Spain - Mediterranean city
Astounding night view of Malaga city | Photo by David Becker

The province of Malaga suffers from an increased risk of flooding due to a combination of natural and human factors and the effects derived from climate change. 

The main conclusion is drawn from the Flood Risk Study carried out by the MADECA Foundation, dependent on the Malaga Provincial Council.

In the province of Malaga, the leading causes of flooding are centered on the natural conditions of the territory, but above all on the anthropic occupation of natural floods and riverbeds in the flood zone, mainly due to urban developments and irrigated agriculture models. 

It estimates that the contribution of climate change caused by natural disasters will increase in the future due to their greater intensity and frequency.

This Flood Risk Study identifies a central-eastern zone with greater aridity and a western one with increased rainfall. Rainfall is expected to be more intense and, therefore, more erosive.

To this is added the succession of dry spells, with undoubted effects on the soil and vegetation’s applicable water content. 

It can reduce biomass and the outcrop of bare soils, which favors splashing, runoff, and erosion processes, which increase the risk of flooding.

8. Ephesus, Izmir, Turkey

Sunset at Ephesus, Izmir, Turkey - Mediterranean city
Sunset at Izmir | Photo by Furkan Kurt

Positioned on the western coast of the Aegean Sea in Turkey, the ancient city of Ephesus shows the passage of various civilizations in its amphitheaters from the Hellenic era, its libraries, and streets from the Roman period, and its architecture from the Byzantine era.

However, Ephesus and Izmir city are at threat of coastal storm flooding and could drown entirely soon. 

According to the conclusion presented by a recent scientific report published in the journal Nature Communications, the ancient city of Ephesus is among the old towns under threat.

According to the research, if the sea level rises in 2100, the historical peninsula of Istanbul is at medium risk, and Ephesus is among the high-risk areas.

In February 2021, Turkish town Izmir faced an enormous flood in 26 years. The heavy rainfall caused the flooding, which fell in the region on 2nd February 2021. 

According to the research conducted by the US-based Climate Central working on climate change, a large area between Kordon and Atatürk Stadium in Izmir is at risk of flooding. 

The region between Mavişehir and Tuzla and where the bird paradise is located is also at risk of flooding. By 2050, these places will be utterly underwater without proper action. 

9. Alexandria, Egypt

Boats and Skyline in Alexandria, Egypt - Mediterranean city
Boats and skyline at Alexandria Harbor| Photo by Flo P

The sizable Egyptian city Alexandria on the Mediterranean is home to the country’s principal port and a large industrial center. 

Alexandria, located on the coasts, is already experiencing massive flooding. The sprawling coastal metropolis, recognized as one of the oldest ports globally, is attacked by sea and land.

The ocean level rose 2.5 times faster at the beginning of the 21st century than in the 20th century and will continue to grow.

Climate change is raising sea levels in the Mediterranean. The decrease in silt build-up in the Nile Delta caused the erosion of the coastal foundations upon which Alexandria was built.

Since it originated in the 4th century BC, Alexandria has struggled with the sea. Its famous lighthouse, temples, and ancient library were swallowed up by the sea hundreds of years ago.

At the end of 2015, at least seven people died when a combination of storm surges at sea and torrential rains caused the worst flooding to hit the city in years, in which many streets and homes were submerged for several days. 

Further flooding occurred in 2017, causing a loss of millions of dollars in revenue in one of the leading industrial centers and one of the first tourist destinations in Egypt.

Another cause for concern is the relentless rise in temperatures around the world. Temperature increases have a profound impact on the seas.

When seawater heats up, it expands. Warming is also causing more frequent and intense storms. In a low-lying city like Alexandria, even the slightest rise in sea level can have serious consequences.

10. Areas near Guadalquivir River and Seville, Spain 

Areas near Guadalquivir River and Seville, Spain - Mediterranean city
Seville Gold tower near Guadalquivir River| Photo by Santiago Lacarta

The area around the end of the Guadalquivir River is the largest in the country that could be underwater. 

In this risk area, there is a large part of the Donana National Park, the village of El Rocío, and municipalities such as Isla Mayor, Isla Minima, and Marismillas. 

The floods, in this case, would not only affect the area near the coast, but they would also flood several areas near the river in the city of Seville. 

Such as the Alamillo Park, large Isla de la Cartuja, where Expo 92 developed the most notable public projects, the Maria Luisa Park surrounds the Plaza de Espana or the west of the Triana neighborhood.

Conclusion

The Mediterranean floods have been known since ancient times. But, in all countries, they are becoming an increasingly feared scourge. 

It is undoubtedly possible to underline the magnitude of the hazard and precipitation’s importance over a relatively short period.

Numerous cities listed above have gone through or recently suffered from massive flooding. These remarkable cities may sink with their cultural heritage sites without appropriate measures.

Paris Agreement 2015 and Leaders Summit 2021 has urged nations to take preventive measures against disasters, and the wealthiest countries have vowed to take appropriate actions.