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Manhattan, Venice, Cartagena de Indias. It is becoming increasingly clear to residents of these tourist centers how sea levels are swallowing parts of the bay. For Colombian resorts, the latest scientific studies record an average annual growth rate of 7 millimeters over 20 years. This is the second highest water level in the entire Caribbean, surpassed only by the southern region of Haiti. It recreates the story behind how greenhouse gas emissions accelerated the melting of polar ice sheets. Shortly after, the coasts of some of these places begin to sink due to geological processes, posing a threat and burden to neighboring countries.
But Cartagena’s case is not entirely due to climate change. There are other unavoidable realities. “41% of relative sea level rise is geological,” explains marine biologist Juan Dario Restrepo. “This is natural and there’s nothing we can do about it. For example, one of the biggest problems in this bay is that there are more than 80 underwater gas vents. When it erupts, it spits out all the mud, releases pressure, leaves empty pockets, and creates cracks. As a result, the soil of the city sinks.”
hurricane blow melissaHis Eye, formed in the waters of Jamaica, provides a good example of the impact these phenomena have had on everyday life in the Colombian Caribbean. Families in low-income areas like El Lebanon reported a state of emergency. Some hotel lobbies were flooded, as were other parking lots in wealthy buildings in the Boca Grande neighborhood.
Recent torrential rains and storm surges are another wake-up call for authorities to remind them of the city’s vulnerability. Juan Dario Restrepo explains that previously the season of strong winds and rough seas was concentrated in the first quarter. There were no more than two or three severe floods. “Currently, it occurs about 15 times a year. Not long ago, it was a phenomenon that was barely felt in the city. Today, with sea level rise of a few millimeters and high tides of more than 50 centimeters, the groundwater table rises, and so do the waves.”
Another part of the disruption is occurring within the Gulf and is related to the gradual compaction of the landscape. This geological phenomenon is called “subsidence.” This process is accelerating in other cities, such as New York, where the weight of tall buildings causes them to sink by 1 to 2 millimeters a year. Research in Cartagena, published in journal in 2022 scientific report (from the same publisher nature) A group of 10 scientists has warned that the decline will be 8 millimeters a year by 2050 unless action is taken.
In addition to the weight of the building, another factor must be added to the list of factors. That said, Cartagena de Indias’ water system uses a network of pipes, canals, and swamps that drain into the bay. These bodies of water carry sediment that has hardened over decades in areas such as the Old City. Hector Mora, a geodesy expert and co-author of the study, argues that more data is needed to definitively determine the impact of increased rainfall and groundwater and wastewater management. What solutions are available to reduce wave progression and subsidence?
Authorities in Cartagena de Indias, which has long had problems with political corruption, chose rock spurs to stop coastal erosion. But Restrepo points out that these walls are a harmless solution and “the best way to bury money,” since the majority of the bay’s subsoil is sand and mud composition. Szymon Udwinski, a geophysicist and academic at Florida International University, weighs in on the Miami case. Since the city of Miami was built on limestone, state officials chose a different option.
In their analysis, the effectiveness of these barriers is highly dependent on geological and topographic features. He points out that in highly porous soils, water always freely seeps under the walls and is filtered into the city, as if through a sponge. Juan Dario Restrepo summarizes: “They can put as many stones as they want and in four or five years the sea will crest again. This is how they are shaking up Cartagena. And it is a way to silence the communities of Boca Chica and Tierra Bomba, who have opposed the impact of these dredging works on their coastal lives.”
His testimony paints a contrasting picture of the social and environmental challenges of spas. A UNESCO World Heritage Site, the old town and part of the residential peninsula of Castillo Grande shine like an oasis of luxury and fragrance, far removed from the rest of the city, which has alarming rates of poverty and inequality.
For now, Juan Dario Restrepo suggests some actions to turn around a gray future that doesn’t seem that far away. “Cities need a basic hydraulic assessment to know how to evacuate water. Structures and canals must be designed to protect against flooding. For example, you can start with all the internal canals behind Castello San Felipe. They are all clogged with garbage and are a perfect example of the city’s environmental collapse.During the tourist season, the sewage system is overwhelmed and sewage leaves flow into the bay.Cartagena is a diamond built on top, but it’s falling apart below.
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