Venice, Italy, has been flooding for centuries. Once just a symptom of the city’s location on a series of islands, and its maze of canals, frequent inundation has turned Venice into a cautionary tale of environmental degradation and inevitable submersion. Climate change will assuredly bring similar risk to U.S. coastal communities. Venice offers an early warning: Some fear that the city will inevitably succumb to drowning.
Venice continued its slide toward that grim finale this year, on October 29, when the worst flooding since 1966 submerged most of the city under five feet of water. Though that cataclysm seemed to confirm fears that the city is doomed, Venice’s story is more nuanced—and hopeful. Over the past 20 years, Venice has quietly transformed itself and its surrounding lagoon into a laboratory. Technology and ecology projects still in the planning stages in the United States have been successfully realized here. American coastal cities have a lot to learn from them.
Much of climate change’s destruction is uncertain and hypothetical—more hurricanes could strike New York City, for example, or a mega-drought might overtake the desert Southwest. But Venetians have known forever that their city lies in the path of monster storms powered by offshore winds.
From its earliest days, Venetian history has been punctuated by the grim, high-water marks of such storms. The Adriatic coast is littered with the sites of communities that did not survive those events. Armed with this certainty, Venetians undertook a massive engineering project—the MOSE barriers (Modulo Sperimentale Elettromeccanico, or “Experimental Electromechanical Module”; the acronym was chosen to sound like Moses, who divided the Red Sea.) The MOSE system is intended to block the channels connecting Venice’s lagoon with the Adriatic Sea in times of exceptionally high water. They’re essentially giant water gates on a hinge, which can open and close to act as floodgates. The barriers failed to work when the October storm struck, not because they were ill-conceived but because they were incomplete. After 30 years of planning, and 15 since ground was first broken, the project, initially slated to open in 2011, is running 11 years behind.
The delays can be chalked up to political and social problems. The MOSE system was conceived in the aftermath of the 1966 floods, and its urgency waned as memory of that event faded. From its inception, the project faced bitter opposition from a wide spectrum of critics, from Greenpeace to the Communist Refoundation Party. Some opponents feared that closing off the channels might damage the lagoon’s ecology; others opposed continued large boat access to the city, which MOSE’s design permits. Still, others were dismayed by its cost, along with the financial corruption that followed. And yet the October flooding proves that without the MOSE barriers, there is no hope that Venice will survive.
But Venetian climate adaptation has many faces, and not all of them are tragic. The towering shadow of the MOSE failure stands to overshadow smaller initiatives put in place in the barrier islands; the Venetian Lagoon, which surrounds the city; and the city itself.
The Venetian climate-adaptation repertoire is staged in four settings. The barrier islands that separate the Adriatic from the lagoon are the first line of defense against high water. The three inlets that cut through the islands where the tides surge and ebb constitute the second: Here, when completed, the MOSE barriers will shut when needed. Then comes the lagoon and, finally, the city. Large-scale engineering, which tends to get more attention, is confined to the MOSE barriers. Projects on the islands and within the lagoon focus on restoring damaged landforms and the habitats they offer to indigenous plants and animals. Meanwhile, urban adaptation campaigns are focused on dredging city canals and bolstering individual buildings.
Professionals in Miami, San Diego, Boston, and other coastal U.S. cities sometimes portray local flood-control plans as groundbreaking and well ahead of the curve. They have good reason: The Fourth National Climate Assessment, just released by the U.S. Global Change Research Program, underscores the urgent need for climate-adaptation initiatives nationwide. American flooding plans draw on a common source, protocols laid down by the National Oceanic and Atmospheric Administration’s Office of Ocean and Coastal Resource Management. Multiple American cities are deep into active planning for rising waters, but enactment is years away for all of them.
Boston is one of a few cities that have studied the feasibility of fixed and movable barriers. A report released last May found that the cost and negative ecological impacts of a system of barriers to protect the Boston Harbor and waterfront far outweighed the benefits. As Venice shows, barriers can be an essential part of a complete defense, but they are only useful where natural features do most of the work.
Instead, U.S. cities rely on landform restoration. The reason for this is simple: In their natural state, coastal wetlands, dunes, and beaches limit the damage that torrential rain and storm surges cause. Island barriers block high waves; wetlands sequester stormwater. America’s coasts, however, are among the most damaged ecosystems in the nation. Natural erosion and subsidence, combined with coastal development, pollution, deforestation, energy production, and recreational abuse, are key factors identified by the NOAA as coastal stressors. These conditions hamstring coastal environments’ natural ability to counter flooding. Restoring natural features recovers and enhances their role as storage basins and defensive barriers.
Restoration projects in the Venetian barrier islands prove that the theory underlying U.S. coastal-remediation plans is sound. Seawalls take the full thrust of tidal surges—they are sure to be overwhelmed or undermined in time. But the long slopes of restored beaches absorb the impact more gradually. Replanted grasses, trees, and shrubs secure restored dunes, binding them together so that storm surges cannot beat down or break through them.
Pollution from industry, agriculture, and coastal development have compromised the Venetian Lagoon just as they have the U.S. coast. The lagoon’s topography is so unusual that its landforms—a bewildering variety of mudflats—have names only in Venetian dialect. That gives the lagoon many ways to absorb flood waters. But neglect over the past century has caused the mudflats to melt away and clog the channels that feed and drain the lagoon. Hardening the boundaries and dredging the channels have helped restore the lagoon’s flood-absorption capacity. Adding aquatic vegetation also helps absorb harmful chemicals in polluted waters and sequester atmospheric carbon effectively.
When UNESCO recognized Venice as a World Heritage site, the designation embraced not just the city but the lagoon as well. Venice is honored as a unique urban area that has partnered with an equally unique ecosystem throughout its history. Projects in the lagoon have recognized that dual designation, consistently resisting the impulse to treat the lagoon as a means to an urban end. By contrast, most coastal American cities have not restored their natural, environmental features, which over time have lost much of their identity, purpose, and integrity.
Flood-control restorations on the Venetian barrier islands have also brought back resident and transient birds, fish, and mammals that rely on the resources of the intertidal zone and the dunes for food, shelter, and reproduction. Within the lagoon, restoration has provided nesting sites for more than half of the bird species indigenous to the Italian peninsula. During fall and winter migrations, the lagoon is a reliable and rich refueling station for trans-Mediterranean wildlife. And like the shoreline that edges them, coastal fishing grounds are deeply impacted by onshore development and pollution. When coastal waters are degraded, nutrients essential to ocean dwellers are diminished, and ecosystems that fish rely on during their growth cycle are compromised.
In America, restoring coastal habitats is not a hot-button issue like climate-change adaptation is. But the NOAA argues that climate-adaptation projects go hand in hand with coastal habitat restoration. Through landform reclamation, one problem, in effect, solves the other.
In a just-released study called “Coastal Resilience Solutions for South Boston,” planners laid out a multifaceted program that parallels interventions projected in Venice. The South Boston plan also includes the development of open spaces, dunes, and a “living shoreline” that promise social benefits in addition to flood control. The Boston plan emphasizes public recreation and urban amenity rather than habitat restoration, but experience in the lagoon suggests that wildlife and water quality will be positively impacted as well.
On the other side of the country, San Diego Bay shares many of the Venetian Lagoon’s characteristics. Storm surges and El Niño events already anticipate what will happen as climate change raises sea levels in the United States. The San Diego Regional Climate Collaborative is the major coordinator of responses in the area, and like many similar organizations in America—the Chesapeake Bay Program, the Southeast Florida Regional Climate Change Compact, and others—it has been focused on collecting data, convening stakeholders, and informing the public about what to expect as waters rise.
The San Diego Bay is vulnerable to a whole host of problems—with stormwater clearance, with shoreline access, with floodplains, and with the fish and bird species that depend on the bay—that will only worsen with climate change. Here, Venice’s achievements are especially pertinent and encouraging. Successes in the lagoon are clearer and more complete than in any other part of the Venetian climate-adaptation program.
Climate adaptation in Venice’s urban center lags far behind accomplishments in the lagoon. The MOSE project, and to a lesser extent reclamation efforts in the barrier islands and lagoon, has consumed resources and occupied center stage for decades, while urban adaptation has stalled. This has created a public-relations nightmare. Condemned to wade their city in rubber boots while billions of euros evaporate in a construction ordeal with no result, Venetians are understandably enraged.
The city’s continued vulnerability to flooding, despite decades of work, underscores the importance of coordination in any climate-adaptation program—along with the material and psychological damage that follows when coordination fails. The MOSE barriers were never intended to combat the low-level flooding that constantly annoys Venetians, but to protect Venice only from catastrophic flooding. Projects in the lagoon and the city are meant to fine-tune an integrated system; MOSE cannot respond to surges higher than one meter without damaging the lagoon ecology. On October 29, the system was literally out of its depth. The barrier project not only preempted funds for urban adaptation, but its delayed completion destroyed the coordination of the climate-adaptation system.
From the start, work in Venice suffered from jurisdictional infighting. The complexities of creating an entity that was adequate to oversee multiple projects confounded politicians. Work commenced only after a region-wide authority was formed. A similar problem persists in the United States. Individual states have the primary responsibility to address climate adaptation under the Coastal Zone Management Act of 1972. When a natural area occurs at state boundaries, as in the Chesapeake Bay, for example, interstate coordination becomes essential. Even projects confined to a single state face jurisdictional conflicts. Municipal, county, and state governments have to work together to combat coastal flooding effectively, and different constituencies have contrasting views and agendas.
While most American cities have regional cooperatives only loosely coordinating climate-adaptation projects, the San Francisco Bay Area was among the first to take a Venice-like step toward the creation of a government agency with significant legal muscle. The San Francisco Bay Conservation and Development Commission, which has overseen the bay since 1965, added an important, though contested, duty in 2009: controlling land use and to coordinating initiatives that specifically target climate adaptation.
As the catastrophic October flooding in Venice shows, climate-adaptation programs only work if all the pieces mesh. Marshaling the will to act quickly, communally, and with adequate authority in the blustery American political climate is a significant challenge, but the means are there. In both positive and negative directions, Venice points the way.