ROBERT SIEGEL, host:
Time now for our series Climate Connections, which is produced in cooperation with National Geographic. As the Earth warms up, rising sea levels will increase the threat of storm surges and flooding. In some places, this will make existing problems worst.
For a glimpse of what may lie ahead, we're going to Venice, Italy, today.
MICHELE NORRIS, host:
For years, Venice has topped the list of the world's most endangered cities. Built 1,300 years ago on mudflats in the center of a lagoon, the city is sinking, and it is subject to increasingly frequent winter flooding due to high tides known there as acqua alta.
SIEGE: A major engineering project is under way to build mobile floodgates in Venice to protect the Venetian lagoon from rising sea levels. But as NPR's Sylvia Poggioli reports, most Venetians seem to take the high water in stride.
SYLVIA POGGIOLI: This has been a very lucky year for Venice. There have been only a few and very mild high-tide events, and the city has stayed dry. But it's always prepared for the worst. Wooden planks lean against walls, ready to be used for elevated walkways as soon as water washes up over the pavement. And shoe stores display the required footwear - rubber boots. From dull brown, fishermen style thigh-high, to below-the-knee in DayGlo colors. Most Venetians keep one pair at home and one at work just in case. At this sport shop, saleswoman Ana Tridisan(ph) is like all her fellow townsfolk - by necessity, an amateur meteorologist. She explains how high tides become a serious problem and cause acqua alta.
Ms. ANA TRIDISAN (Sports Shop Employee, Venice): The tide, six hour it goes up, six hour it goes down. If the wind blow up from the south, the kind of wind is a scirocco, the tide has no way to go out from the lagoon. So stay inside the lagoon, and after hour, six hours, we have a new tide over.
POGGIOLI: That's exactly what happened when I was there five years ago, when southerly winds produced a tide that reached 4 feet 2 inches.
(Soundbite of splashing water)
POGIOLLI: Walking in St. Mark Square at 10:15 a.m. on Thursday, November 21. Residents and tourists had to walk single file on the elevated wooden walkways. Acqua alta almost brings life to a halt in Venice, at least for a few hours. Big boats can't go under low-hanging bridges, water seeps into homes and shops through the sewage system, smelling both of heating oil and waste.
And in the longer term, as the city sinks, high water is corroding the porous bricks of buildings and their wooden and iron doorways. Over the last few decades, this phenomenon has been happening more and more often - on average, 100 times a year. And nobody lives on the ground floor anymore.
Everyone, residents and visitors alike, has to cope with high water. Even at luxurious hotels, it's not uncommon to see tourists walking on gangplanks above flooded marble floors. At the Bisanzio Hotel, concierge Gabriel Brunelli(ph) says a barrier is placed in the doorway.
Mr. GABRIELLE BRUNELLI (Concierge, Hotel Bisanzio): We have a pumping system. We pump the water out all the time, continuously. So the water inside, if there will be, it will be like this - a few inches maximum. Outside might be something like 50 centimeters or even more than that.
POGGIOLI: That's about two feet. But for many Venetians, rising sea levels and climate change are not the number one priority.
Professor SHAUL BASSI (English Literature, Venice University): Venice is dying as a city. I mean, socially speaking, before it is dying as a physical place. We should talk about the social climate change, which is more urgent and more relevant.
POGGIOLI: Shaul Bassi is a professor of English literature at Venice University. Venice has a population of 58,000 but receives 20 million tourists annually. With an economy solely focused on tourism, Bassi says, prices are sky-high. Venice has lost one-third of its population in the last 30 years as young people seek jobs elsewhere.
Prof. BASSI: Venice is sinking. But look around. When I see half of the houses in Venice that are closed and nobody lives in there, it is as threatening and as alarming as the acqua alta. If we solve the acqua alta problem and the city is just a beautiful empty container for tourists, I don't really care.
POGGIOLI: Many Venetians are skeptical about the huge engineering project aimed at holding back the tides. Floodgates are being built at the three inlets that link the lagoon to the Adriatic Sea at a cost of $7 billion. Francisco Orlandi(ph), who owns a newspaper kiosk near the Rialto Bridge, dismisses the project known by its Italian acronym, MOSE.
Mr. FRANCISCO ORLANDI (Newspaper Kiosk Owner): (Through translator) The MOSE doesn't serve any purpose. We are spending a boatful of money for nothing. Acqua alta is a natural phenomenon. It's the rats that bother us.
POGGIOLI: However blase Venetians may be, city authorities ensure that they are warned well in advance of high-tide events. The tides forecast office is located on the Grand Canal. Antennas cover the roof, and banks of computer screens line the walls. Real-time information arrives here from 15 monitoring stations in the lagoon and out at sea, providing wind speed and direction, wave height and air pressure.
This year, there's a novelty. City authorities have abandoned the old alarm system dating from World War II and too depressing, they say. It's been replaced by alarms with rising tones, indicating how high the tide is expected to be. This is the one for four feet, seven inches.
(Soundbite of alarm tone for tide change)
POGGIOLI: But even at this office, where the staff is required to be on constant alert for dangerous high tide, Venice's centuries-old love affair with the sea still prevails. Pablo Canestrelli(ph), a scientist by training who directs the office, says Venetians are used to acqua alta from their childhood.
Mr. PAUL CANESTRALLI (Director, Venetian Tide forecast Office): (Through translator) I remember as a kid floating on a raft in St. Mark's Square. We are not afraid of the water. Venice has always been defended by the sea. It's our friend, our defense and our economic well-being. Outside, they are scared because they don't know how high the water will get and when it will stop rising. We know it is a cycle, like a breath of the Adriatic that enters the lagoon. The breath of a good friend.
POGGIOLI: Such a good friend that still today, Venetians celebrate a festivity harking back to the times when Venice was the pearl and ruler of the Adriatic. Each spring, the mayor, as the doges did before him, set sail on a ceremonial boat, leading a colorful fleet out to sea. There, accompanied by civic, religious and military authorities, he flings a gold ring onto the waves. And renews the wedding vows of Venice's millennial marriage to the sea.
Sylvia Poggioli, NPR News.
SIEGEL: You can hear more stories in our series at npr.org/climateconnections. And while you're there, you can also find the latest climate change coverage from National Geographic magazine.