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Peril, Promise, and a Watery Future For the World’s Coastal Cities

Anthony Flint / Apr 30 2010

For Release Sunday, May 2, 2010

Anthony Flint

NEW ORLEANS – Even with aggressive action on climate change, scientists agree that a global temperature rise of some kind is inevitable, triggering sea level rise, more intense storms, and an array of other chain-reaction disruptions to life as we know it. And in the typically sinister way that the climate cataclysm plays out, these impacts will hit hardest in the places most people live.

More than half of the U.S. population lives in 673 coastal counties. In China, the world’s most populous nation, 60 percent of the country’s 1.2 billion people live in coastal provinces. Worldwide, rapid urbanization in coastal and delta mega-cities includes widespread informal settlement, a recipe for disaster for the most vulnerable populations.

The good news is that planners are paying attention. Cities, as places of density and transit, can make great strides in mitigation, the reduction of greenhouse gas emissions. But coastal cities must engage in adaptation on a parallel, and in many ways integrated, track. There is no more urgent role for planners in the years ahead than to plan and help implement adaptation to climate change, says Edward Blakely, the former recovery director for New Orleans.

Coastal cities are already well aware – some painfully aware – of the breadth of the problem. Jakarta is confronting annual flooding that strains a colonial-era layout, and Dhaka in Bangladesh has struggled with stronger typhoons. At the Yantgze and Pearl river deltas in the Shanghai and Hong Kong regions, chronic flooding, coastline erosion and wetlands deterioration, storm surges, and punishing storms are wreaking havoc on areas that have been attracting the most intense in-migration and urbanization. Sewer overflow and saltwater intrusion, with impacts on drinking water, public health, and agriculture, are key areas of concern, as well as the vulnerable infrastructure, such as power plants, port and refining facilities, that will be flooded and potentially permanently underwater in the decades ahead.

The city ravaged by Hurricane Katrina five years ago, of course, has had the most vivid glimpse of the future. New Orleans’ path forward ranges from evacuation planning and relocation, “hard” solutions such as seawalls, weirs, tidal barrages, levees, and the redirection of waterways, to the restoration of natural systems to manage flooding. “The world is watching not only the city, but the planning field as well,” said EPA Administrator Lisa Jackson, who grew up in New Orleans, speaking at the American Planning Association’s National Conference in April.

The adaptation strategies detailed in the Delta Symposium symposium at the conference reflected a comprehensive approach informed by the people who know water better than anyone – the Dutch. The most promising innovations coming out of the Dutch Dialogues, with support from Waggonner & Ball Architects, the APA, TU Delft, and the Netherlands Water Partnership, are based on the concept of giving water more space – “room for the river” – in terms of spatial planning.

The approach involves lowering dikes in targeted areas to better enable flood protection in other areas with high populations or valuable infrastructure, says Tulane University’s Douglas Meffert. While this practice sounds counterintuitive, allowing certain natural habitat or in some cases, farmland areas to flood during high river stages reduces the vulnerability of nearby urban centers, he says.
A critical component is the role that nature is allowed to play. The restoration of wetlands and natural systems in coastal and delta cities has moved to the forefront. A promising model is found in the Yangtze River estuary’s wetlands and mudflats, which continue to grow due to the dynamics of riverways, tides, and sediment.

When Shanghai’s Pudong wetland was drained and developed in the 1990s to construct the Pudong International Airport, the Jiuduansha Shoals in the Yangtze Estuary were ecologically engineered to mitigate for this wetland loss and create a new habitat for the migratory shorebirds and waterfowl. The attraction of the new vegetated habitat had the added advantage of reducing bird strikes in jet engines, but the big benefit is typhoon hazard reduction for nearby
developments and infrastructure.

Other efforts in China were detailed by Lingqian Hu, senior regional planner at Southern California Association of Governments, who presented a Tsinghua University paper, “Climate Change and Urbanization in the Yangtze River Delta”; and He Canfei, professor at Peking University and associate director of the Lincoln Institute-Peking University Center for Urban Development and Land Policy in Beijing.

Future projects could not only use natural systems as flood control solutions but better use diversions for wetland restoration and creation projects, as well as improved water storage practices in population centers, such as catch basins, green roofs, gardens,
recreation parks, waters squares and pervious surfaces.

“We’re capable of doing these things,” said Robert Yaro, president of the Regional Plan Association, who was part of a team of researchers being led by Blakely, comparing adaptation scenarios in the U.S. and Australia – which share some similar characteristics. A century ago, Charles Eliot used a combination of hard infrastructure and natural systems to manage the Charles River in Boston, which was followed by the Charles River Dam project to further guide storm surges and flooding.

In the long haul, Yaro said, coastal cities will see dramatic changes – huge tidal barriers at the Golden Gate and ringing New York City, with the San Francisco Bay and Long Island Sound potentially turned into freshwater lakes. Large areas will be uninhabitable and water supplies will be a particular problem he said. “We basically can buy ourselves 300 years,” Yaro said. “We’re at the place where Amsterdam was in 1890.”

Taking adaptation seriously is a first step; paying for it will be the next. Blakely suggests that in the U.S. cities might pay into a national adaptation fund, on an insurance model. Those metropolitan regions that take the best protective measures get a break on their premiums.

Building on these innovations will require smart people who not only understand policy, urban planning and earth science, but the dynamics of deltas, sediment, and discharge. The challenge is so daunting that it’s hard to maintain hope, or to believe in much beyond the bright prospects of the seawall-building business. But adapting to climate change in coastal cities is shaping up to be the central project of planning for his century.

Anthony Flint is a Boston-based writer at the Lincoln Institute of Land Policy


  1. Bill Tirrill
    Posted May 25, 2010 at 12:49 pm | Permalink

    I hope that someone is putting some diligent effort into documenting the existing & historical shorelines, harbor facilities, flood records, storm records, wetlands, tidal patterns, water supplies, etc. The changes to come will be gradual enough to allow people to forget what they once had, or that things have changed, and ultimately to simply be unaware, or even disbelieve, that the situations in which they live were ever any different, or that natural conditions have been meaningfully affected by global human activities.

  2. azure
    Posted May 28, 2010 at 11:56 am | Permalink

    small town on OR coast: move by the city planner to have zoning (for development) revised to parallel the federal (FEMA?) coastal hazard map met by vociferous opposition by local property owners. City planner withdraws just about every proposed change, I think that perhaps, maybe, a notice on the deed that the property lies within the “red” zone (for tsuamis/earthquakes–meaning this property is eroding & will probably crumble/sink/etc., if a tsunami hits/there’s an earthquake –or it will eventually just be eroded away).

    Maybe. Why? Decreases value of the property, it will become too difficult to sell or for “too low” of a price.

    This is “green” state, with (supposedly) land use planning rules in place. Reality is in most of the coastal counties, is that land use planning is a dirty word to most of the city council & planning committee members. In my town & the county, they’ve repeatedly violated land use rules but who’s got the money & time to do all the administrative appeals & litigation? I know one woman who did pursue the issue–by the time she was done w/the repeated appeals, the house was built & no way was the city (or the court) going to tell the owner to tear the house down.

    The tax laws need to be changed–cities/towns should not derive a significant portion of their revenues from building permits. Federal income tax rules current favor “development” no matter how stupid it is–it’s no accident that we have so many useless strip malls & megamalls.

    People do not believe that tsunamis & earthquakes will happen (look at Haiti, when the earthquake occurred, there were geologists by the score saying, why the surprise? This was going to happen, we all knew there’s a huge fault there, that it’s active, etc., etc.). What the people around here “know” is that they’ve bought property & they want it to be worth as much as possible when they sell it. Land is nothing more than a form of capital in the US–don’t know what it’s like in other nations. If a disaster happens, well, that’s what FEMA’s for right? A bailout. For some people whose families bought 40 years ago before all the potential geological & climatic hazards were known, I can see it, for the others, no. Plenty of people believe climate change is a hoax anyway and even though you can see beach bluffs eroding significantly over a 3 year period–well, then it’s I should be able to put in a beach protection structure, i.e,. riprap or something else. If that results in damage to other people’s property or doesn’t really help, oh well.

    That’s how most people in the US think. It’ll be interesting to see if the US worship of large corporations survives the Gulf Oil disaster. It survived the Exxon Valdez spill & others, so it probably will survive this time too-the hundreds of millions spent on advertising (& lobbyists) by the energy industry will probably help the process along.