Sinking History: The Engineering and Ethics of Saving Venice

The Bottom Line Up Front: Venice is facing a dual existential crisis: rising sea levels and a collapsing local population. The engineering solution is MOSE, a massive system of mobile floodgates that has cost billions and was delayed by decades of corruption. It works, for now. But the greater threat might not be the water; it is the “Venexodus”—the flight of locals turning the city into a hollow theme park. Saving Venice requires more than concrete; it requires ethical tourism.

I have been booking trips to Venice for 15 years at krbooking.com, and the conversation has shifted. It used to be “Where is the best gondola ride?” Now, my clients ask, “Will it be flooded?” and “Is it ethical to go?” These are the right questions. Venice is fragile. It is a miracle that it exists at all, and visiting it requires a level of awareness that other cities don’t demand.

1. The Physics of a Sinking City: Understanding Acqua Alta

To understand why Venice needs saving, you have to understand the sheer audacity of its construction. Venice is not built on land; it is built on wood. Millions of petrified wooden stakes were driven into the mud of a lagoon 1,500 years ago. Over centuries, the lack of oxygen in the mud petrified the wood, turning it to stone. The city literally floats on a forest. But that foundation is unstable.

Venice suffers from what we call “relative sea level rise.” This means two things are happening simultaneously: the water is going up, and the land is going down. The land sinks due to natural plate tectonics and subsidence (compaction of the soil). In the 20th century, this was accelerated by industries pumping groundwater out of the aquifer, causing the city to drop by about 23 centimeters. While the pumping has stopped, the damage is done. The city is lower than it used to be.

Simultaneously, the Adriatic Sea is rising due to global climate change. This creates the phenomenon known as Acqua Alta (High Water). It is not a tsunami; it is a tide. When a high astronomical tide aligns with the Scirocco wind (a warm, strong wind blowing north from Africa), the water is pushed into the Venetian Lagoon and cannot escape back into the sea. The water piles up, and because Venice is so low, it bubbles up through the drains in St. Mark’s Square.

I was in Venice during the historic flood of November 2019. The water reached 187cm. I saw refrigerators floating out of restaurants and locals crying as their ground-floor apartments were destroyed for the third time that year. It wasn’t romantic. It was a disaster zone. The salt water corrodes the brickwork and the marble of the basilicas. Every flood ages the city by years. The famous St. Mark’s Basilica has aged more in the last 20 years than in the previous 500. This isn’t just about wet shoes; it is about the structural integrity of one of the world’s most beautiful cities dissolving into the lagoon.

For decades, Venetians lived with this by wearing stivali (rubber boots) and walking on raised wooden walkways (passerelle). But the frequency has changed. What used to happen once a decade now happens multiple times a winter. The city reached a breaking point where adaptation was no longer enough; they needed defense.

2. The MOSE Project: Engineering, Corruption, and rust

The solution is MOSE (Modulo Sperimentale Elettromeccanico). It is one of the most massive civil engineering projects in human history. The concept is simple, even if the execution is complex: it is a system of 78 mobile yellow gates installed at the three inlets (Lido, Malamocco, and Chioggia) where the Adriatic Sea enters the Lagoon.

Here is how it works: Normally, the gates lie flat on the seabed, filled with water, completely invisible. Ships can pass over them, and the tides can flush the lagoon (which is vital for the ecosystem). When a high tide of 110cm or higher is forecast, compressed air is pumped into the gates. They empty of water, become buoyant, and rise up on hinges to form a temporary dam. It takes about 30 minutes to raise the wall. I have seen the lagoon go from choppy waves to a calm lake once the barriers are up. It feels like magic.

But MOSE is also a symbol of everything wrong with Italian bureaucracy. Construction began in 2003 with a completion date of 2011. It wasn’t fully operational until October 2020. Where did the time go? Corruption. In 2014, a massive scandal revealed that nearly €1 billion (yes, billion) had been siphoned off in bribes and kickbacks to politicians and judges. The Mayor of Venice was arrested. The project became the “shame of Italy.”

Beyond the corruption, there are technical concerns. The barriers were designed in the 1980s for a certain level of sea rise. Climate models have worsened since then. Critics argue MOSE is already obsolete. If the sea rises too much, the gates will have to stay closed almost permanently. If the gates stay closed, the lagoon becomes a stagnant pond. The sewage of Venice (which flushes into the canals) won’t wash out to sea, killing the fish and creating a toxic environment. It is a paradox: to save the stones of Venice, you might kill the life of the Lagoon.

Furthermore, maintenance is a nightmare. The underwater hinges are already showing signs of rust and corrosion from the salt water and sand. It costs roughly €100 million a year just to maintain the system. It is a band-aid, a massive, expensive, technological band-aid. It works for now—St. Mark’s stays dry during storms—but for how long? 50 years? 100? In the timeline of Venice, that is a blink of an eye.

3. The Ethics of a Theme Park City: The “Venexodus”

While the water rises from below, a different flood destroys the city from above: tourists. Venice has roughly 50,000 permanent residents left in the historic center. It receives roughly 20 to 30 million visitors a year. Do the math. The ratio of tourist to local is overwhelming.

We call this “Venexodus.” Locals are leaving because they simply cannot afford to live there anymore. Every time an old bakery closes, a souvenir shop selling plastic masks made in China opens. Every time a long-term rental apartment becomes vacant, it is turned into an Airbnb for short-term profits. A city without residents is not a city; it is a theme park. It is Disneyland on the Adriatic. I have clients who ask me, “Where can I meet locals?” and I have to tell them, “In Mestre, on the mainland,” because few live on the islands anymore.

This raises the ethical question: Should you visit Venice? Some activists say no. They argue that every cruise ship and every day-tripper contributes to the destruction. Day-trippers are the worst offenders economically—they arrive by train or cruise, walk around for 4 hours, buy a bottle of water, maybe a magnet, use the public bathroom, and leave. They contribute almost nothing to the economy but crowd the narrow streets and strain the waste management systems.

However, abandoning Venice is also a death sentence. The city relies on tourism dollars to pay for the restoration of its palazzos and canals. The solution is not to boycott Venice, but to change how you visit. At krbooking.com, we preach “Slow Travel.” Stay overnight. Stay for three nights. When you stay overnight, you spend money on dinner, you pay the city tourist tax, and you see the city when the day-trippers have left. That is when the real Venice breathes.

Ethical tourism also means where you spend your money. Buy lace from Burano that is actually stitched there (it will cost €50, not €5). Buy glass from Murano that has the certification mark. Eat at restaurants that source from the Rialto market. By supporting local artisans, you make it possible for them to afford to stay. You become part of the resistance against the Venexodus. You are helping to keep the lights on in a city that is trying to turn them off.

4. Expert Frequently Asked Questions

1. Is Venice actually sinking or is the sea rising?

It is actually a combination of both, creating a “perfect storm” scenario. Scientifically, this is called Relative Sea Level Rise.

First, the sinking: Venice is built on soft mud and sediment. Over centuries, this sediment naturally compacts, causing the land to lower. This process is called subsidence. In the 20th century, this natural process was aggressively accelerated by industrial factories on the nearby mainland (Marghera) pumping fresh water out of the aquifer beneath the lagoon. This caused the ground to act like a sponge being squeezed dry, and the city sank about 23 centimeters (9 inches) in under 100 years. The pumping has stopped, but the altitude is lost forever.

Second, the rising: Global warming is causing the polar ice caps to melt and ocean waters to expand as they warm. The Adriatic Sea is rising at a rate of millimeters per year. When you add the sinking land to the rising water, the result is that the water level relative to the street is much higher than it was in 1900. This is why steps that used to be safe are now underwater during high tide.

2. Does the MOSE barrier actually work?

Yes, it works, and it has already saved the city multiple times. The system had its first fully functional deployment in October 2020. On that day, a predicted tide of 135cm (which would have flooded 50% of the city) was stopped at the inlets. St. Mark’s Square remained dry.

However, “working” is subjective. It works to stop catastrophic floods. It does not stop the lower-level flooding that affects the lowest point in the city (St. Mark’s Basilica). The barriers are only raised when the tide is forecast to hit 110cm. If the tide is 100cm, the barriers stay down to allow ships to pass and the lagoon to flush, but St. Mark’s Square (the lowest point) still floods. To solve this, a secondary, smaller glass barrier was recently installed specifically around the Basilica.

So, MOSE prevents disaster, but it does not prevent Venice from getting wet feet. It is a blunt instrument for a delicate problem.

3. Is it ethical to visit Venice right now?

This is the most common question I get at krbooking.com. The answer is yes, but it is conditional. It is ethical IF you visit responsibly.

Unethical tourism is “Hit and Run” tourism. This includes arriving on massive cruise ships that pollute the lagoon air and erode the canal foundations with their wake, or arriving by train for 4 hours just to take a selfie on the Rialto Bridge. This type of tourism treats Venice like a backdrop, not a living city. It crowds the residents out of their own streets (sometimes ambulances can’t even get through the crowds) and leaves behind trash without leaving behind money.

Ethical tourism involves investing in the city. Stay in a hotel (employing locals). Eat in sit-down restaurants. Visit museums. Hire local guides. And crucially, visit during the shoulder season (October-November or March-April) to relieve the pressure of the peak summer months. If you treat Venice with respect, your visit supports the economy required to maintain it.

4. What is “Venexodus”?

Venexodus is a play on the words “Venice” and “Exodus.” It refers to the dramatic depopulation of the historic center. In the early 1950s, the population of historic Venice was over 175,000. Today, it is just under 50,000. They are losing roughly 1,000 residents a year.

Why are they leaving? It is partly the inconvenience of living in a car-free city where groceries must be carried over bridges, but mostly it is the cost of living. The tourism industry has inflated real estate prices. Landlords prefer to rent to tourists for €200 a night rather than a local family for €800 a month. Shops that used to sell hardware, milk, or books have been converted into shops selling glass trinkets and pizza slices.

When the butcher closes and the doctor moves to the mainland, the city becomes unlivable for regular people. Venexodus is the death of the community. The remaining residents are often elderly, and there is a fear that Venice will soon become a “museum city” with no actual citizens.

5. Will Venice disappear in our lifetime?

It is highly unlikely that Venice will physically “disappear” beneath the waves in our lifetime (the next 50-80 years). The MOSE barriers are designed to protect the city from tides up to 3 meters, which is significantly higher than current projections for the next few decades.

However, the livability of Venice might disappear. As sea levels rise, the MOSE gates will need to be closed more frequently. If they are closed for weeks at a time to hold back a permanently higher sea, the lagoon ecosystem will collapse from lack of oxygen and waste flushing. The city could become a swamp.

Furthermore, the constant salt water humidity rising into the brickwork (capillary action) is crumbling the ground floors of palazzos. We might see a Venice where the ground floor is abandoned and people live only on the upper floors, moving around via high walkways. It won’t be Atlantis, but it won’t be the Venice we know today. It will be a besieged fortress against the sea.