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Will a Huge New Flood Barrier Save Venice?

Will a Huge New Flood Barrier Save Venice? 86

This story originally appeared on CityLab and is part of the Climate Desk collaboration.

On a gray, late-winter day, a converted chapel in the Arsenal, the city’s medieval boatyard, hummed with 21st-century activity. Engineers were looking at screens that displayed tables, maps, and charts on the conditions of the Venetian Lagoon.

This was the MOSE control center: the operational heart of a megaproject to protect Venice, one of the world’s most beautiful cities, from threatening waters. For nearly seven years, the engineers here have raised and lowered virtual doors, gathering a series of data to be conveyed into a sophisticated forecasting model.

Spread across dozens of islands and known as “the floating city” for its ubiquitous canals and bridges, Venice has grappled with inundation for centuries. But due to natural subsidence and the higher tides caused by global warming, the city is more vulnerable to flooding than ever before. So a flood barrier seemed like the obvious way to thwart future disasters.

MOSE (an acronym for Modulo Sperimentale Elettromeccanico, or “Experimental Electromechanical Module”) is one of the world’s largest and highest-profile civil-engineering works. It consists of a series of retractable floodgates stretching across the mouths of the lagoon’s three inlets. These gates can be raised on command to create a temporary wall against the sea in the event of a high tide.

Work on MOSE began in 2003, but after countless delays (caused by a corruption scandal and financial and structural issues), the barrier has yet to be completed. The hard part is done, however, and most of the engineers at the control center were confident that the system will become fully operational soon. Since the final leg of construction has been stalled for months, though, no one could say exactly when. Some said later this year; others said 2020 was closer to reality.

Whatever the date, it still remains unclear whether MOSE will adequately protect the city. And if so, for how long?

MOSE operates on the principle of tidal gates. In calm weather, the gates fill with water and sit on the seabed. But when a high tide threatens, the water is pushed out by compressed air that’s pumped in. This allows the gates to surface and prevent the tide from entering the lagoon. When the surge subsides, the gates again fill with water and sink back to the bottom.

“The idea is quite old,” said Paola Malanotte-Rizzoli, a physical oceanographer at the Massachusetts Institute of Technology who was among the panel of experts enlisted by the Italian government to come up with a solution. “We have evidence that Venetian engineers drafted mechanical contraptions to hold back the sea as long ago as in the 18th century.”

Nevertheless, a barrage of criticism has accompanied the project since its beginning. Environmental groups said that construction of the barrier would jeopardize the marine ecosystem beyond repair, while some politicians opposed the idea, stating that there were too many unknowns and that a cheaper solution was needed.

Many experts agree, however, that when the seas rise, there aren’t many alternatives to building a barrier to stop it—especially in a one-of-a-kind city like Venice.

“The concept behind MOSE is good,” said Jörg Imberger, an environmental engineer who teaches ocean sciences at the University of Miami. “But it all depends on what is meant by protection.”

According to Imberger, if everything goes as planned, MOSE will protect Venice from floods like the catastrophic one in 1966 for the next three decades or so. “But since the gates are raised only when the tide reaches 110 centimeters [roughly 43 inches], MOSE won’t avoid the flooding phenomenon that already takes place in low-lying sites like Saint Mark’s Square, which inundates when the tide gets above 80 centimeters [about 32 inches],” he said. “This could be potentially fixed by lifting the barrier at lower tides. But that would have some adverse effects on the health of the lagoon.”

The outlook gets foggier when it comes to the long run. Like much else in this world, MOSE’s effectiveness depends on how much carbon dioxide is pumped into the atmosphere over coming decades, and hence how fast sea levels rise during the barrier’s 50-year lifespan. Furthermore, conflicting statements on its engineering parameters do little to clarify.

According to a 2011 UNESCO report, three sea-level-rise scenarios for 2100 were considered during the planning phase: 16 centimeters (about 6 inches), 22 centimeters (about 9 inches), and 31.4 centimeters (approximately one foot). Planners suggested using the second one, labeled as “prudent.” But today, even the third scenario seems over-optimistic. With climate change, the Mediterranean Sea is projected to rise up to five feet before 2100, meaning that mean water level could reach the critical threshold of 110 centimeters. That would cause Venice to suffer flooding twice a day at high tide.

Malanotte-Rizzoli maintains that MOSE was engineered to handle about 2 feet of sea-level rise. The New Venice Consortium, the organization entrusted with building the barrier, says the same, but this reporter could find no evidence that this was an official project goal.

The question of capabilities is crucial, not only because sea-level rise makes higher storm surges more likely, but because it will require the barrier to activate more often—increasing wear and tear on a structure that has already experienced structural problems.

According to Georg Umgiesser, an oceanographer at the Italian National Research Council’s Institute of Marine Sciences, with 50 centimeters (about 20 inches) of sea-level rise, the barrier will be closed once a day, whereas with 70 centimeters (about 28 inches), the gates will be closed more often than they are open. “More frequent closing doesn’t only imply additional maintenance costs,” Umgiesser said, “but an ever-increasing dependence on the barrier to avert severe flooding. A failure could be devastating.”

Over the years, alternatives to a seawall have been proposed. Some offered tweaks to the system of mobile gates, while others involved different technologies. Still others were aimed only at making the flooding more bearable. So far, though, none has found wide support.

At any rate, it seems clear that Venice, like many other coastal cities around the world, won’t be saved by a barrier alone.

“Since the 1966 flood, the frequency of tides over 110 centimeters has doubled each decade,” said Giovanni Cecconi, head of the Venice Resilience Lab. “And this trend is not going to stop anytime soon, even if emissions were curbed.”

“It’s obvious that MOSE is not a magic wand,” he continued, “but rather something that will allow us to take time to figure out and implement new ways to cope with a crisis.”

Read More On This At Science Latest

 

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Planet Earth

Polar vortex: “wild” winter is coming in the US, Northern Europe and East Asia after the 16th of January

Polar vortex: "wild" winter is coming in the US, Northern Europe and East Asia after the 16th of January 87

In the upper atmosphere above the North Pole, experts saw a rapidly swirling vortex of cold air that could bring severe frosts to the United States, Northern Europe and East Asia. Serious cold snap and snowy weather are expected after January the 16th.

Snowfalls and a cold snap hit South Korea since the start of 2021, hitting historic snow maximums and temperatures. In the country, for the first time since 1964, television and newer communications are sending people cold snap warnings:

https://twitter.com/sonyeoljin/status/1346841272347082752?ref_src=twsrc%5Etfw

The situation is similar in Japan, where a new snow storm hit historic highs:

On January 7, the thermometer In Beijing dropped to -20 degrees Celsius, breaking the 1966 record. In other regions of China, the temperature is also not sugar, and you can only move around in special uniforms:

The cold even reached Taiwan, where the temperature in some areas dropped below freezing point, snow poured down and people realized that rice terraces can be used as a ski jump:

Even more snow went to Spain, where on January 6, 2021, a temperature of -34.1 ° C was recorded – the lowest on record. After that, a snow storm hit the country, which has not been seen for 80 years:

https://youtu.be/pHU533Krs5M

The same thing happens in Canada and in the northern states of the United States:

It seems that after a stratospheric warming, the subpolar vortex began to split:

The vortex itself is a standard phenomenon. However, this time experts were surprised at his movement. It is possible that in the near future it will be divided into two parts. 

Scientists associate the strange behavior with the changed climate in the Arctic, which has become warmer. From September to December, the amount of ice cover decreased significantly.

The polar vortex is a low-pressure region located in the stratosphere and filled with cold air. When the jet stream of air that holds the vortex weakens, the low pressure area moves south. 

As the ice shrinks, more moisture will move inland. It will turn to snow, so snowfalls are expected. Snow, in turn, reflects heat, leading to a cold snap.

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Hospital in Naples was evacuated after a new, huge sinkhole appeared

Hospital in Naples was evacuated after a new, huge sinkhole appeared 88

Eyewitnesses said they heard a loud crash at dawn when a huge hole in the ground formed outside the Ponticelli Ospedale del Mare hospital in eastern Naples.

Early in the morning of January 8, 2021, a sinkhole occurred in the parking lot of a clinic in Naples. The depth of the formed cavity is about 20 meters, the total area of ​​the hole is about 2,000 square meters.

No casualties were found at the scene; firefighters say the sinkhole “affected an area of ​​about 500 square meters” and engulfed several cars parked near the hospital.

As the press writes and as a little can be seen from the videos, rescuers and firefighters were running around the pit together with the governor of the area.  But who should be there in the forefront are Italian geologists, since Naples stands in the very center of the volcanic system known as the Phlegrean Fields.

If the surface collapsed, moreover – the surface reinforced with concrete and reinforced from below with some kind of communications, then we are talking about serious soil deformations caused by the activity of magma.

Italy has been in doubt since the summer of 2020, because swarms were observed there in very atypical places in May, and according to the forecasts of old Italian seismologists, who had witnessed many strong earthquakes, it should have boomed in the August region.

Fortunately, nothing bad happened to Italy and there was no big earthquake. But, since there are swarms, it means that something is being prepared, the magma is gathering strength. 

Following this particular sinkhole event – an obvious sign that a major earthquake in Italy is already very close.

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A new great pandemic cycle has begun (again) in China

A new great pandemic cycle has begun (again) in China 89

In the first months of 2020, the whole world with a certain fright followed the events unfolding in China, where people fell on the streets during the day and astronauts wandered, and in the evening crematoria began to smoke. And now, with the onset of December, the cycle seems to be repeating itself.

Shunyi area in Beijing, where the authorities announced “wartime status” the day before. As you can see in the videos, thousands of people are lined up in the queue for mandatory testing:

Dalian city, where “wartime” is also declared. Neighborhoods are blockaded, people are walled up in entrances, familiar characters of George Lucas roam the streets:

https://twitter.com/UndergroundSilk/status/1341741036297723905?ref_src=twsrc%5Etfw

Chinese ‘rescuers’, before performing a combat mission:

Chengdu City:

Daluo Port, Yunnan – tourists came for adventure and they received the ‘time of their life’ after leaving the ramp:

If something happens in Beijing, it does not mean that tomorrow the same will happen everywhere. However, the trend towards such dynamics is observed and, as the practice of the first wave of the pandemic has shown, all countries and people, to one degree or another, have taken into account the ‘Chinese experience’. 

Therefore, one must think that everything will now be in peace, as in spring – a new global round of the fight against the Covid has begun in China, a new great pandemic cycle!

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