Thursday, July 07, 2016

Can New York Be Saved in the Era of Global Warming?

The future of America's greatest city is at risk.

Hurricane Sandy flooded huge parts of Lower Manhattan and downtown Brooklyn. (Credit: Jamal Countess/Redux) Click to Enlarge.
Next year, if all goes well, New York City will break ground on what's called the East Side Coastal Resiliency Project, an undulating 10-foot-high steel-and-concrete-reinforced berm that will run about two miles along the riverfront.  It's the first part of a bigger barrier system, known informally as "the Big U," that someday may loop around the entire bottom of Manhattan, from 42nd Street on the East Side to 57th Street on the West Side.  Daniel Zarrilli, the head of New York's Office of Resilience and Recovery, likes to underscore that the barrier will be covered with grass and trees in many places, as well as benches and bike paths – it's the East Side equivalent of the High Line, the hugely popular elevated train track on the West Side that has been transformed into an urban park.  There are plans in the works to build other walls and barriers in the Rockaways and on Staten Island, as well as in Hoboken, New Jersey, across the Hudson River.  But this project in Lower Manhattan is the headliner, not just because the city may spend $3 billion or more to construct it, but also because Lower Manhattan is some of the most valuable real estate on the planet – if it can't be protected, then New York is in deep trouble.

In Zarrilli's view, there is no time to waste.  By 2030 or so, the water in New York Harbor could be a foot higher than it is today.  That may not sound like much, but New York does not have to become Atlantis to be incapacitated.  Even with a foot or two of sea-level rise, streets will become impassable at high tide, snarling traffic.  The cost of flood insurance will skyrocket, causing home prices in risky neighborhoods to decline.  (Who wants to buy a house that will soon be underwater?)

Then the big storm will come, as it always does.  It might come this year, it might come in 2018, 2029 or 20-whatever.  It might be bigger than Sandy.  It might be smaller.  But if you add a foot or two of sea-level rise to a 14-foot storm tide, you have serious trouble.  And if it hits before the Big U is completed around Lower Manhattan, you have even more serious trouble. Water will flow over the aging sea walls at Battery Park and onto the West Side, pouring into the streets, into basements, into cars, into electrical circuits, finding its way into the subway tunnels.  New Yorkers will learn that even after the region spent $60 billion on rebuilding efforts after Sandy, the city's infrastructure is still hugely vulnerable.  In the aftermath, it's not hard to imagine how this will play out:  Businesses that don't need to be in Lower Manhattan – hedge funds, banks, law firms – will move to Midtown, others to Westchester County or the New Jersey suburbs.  The economic engine of the city will sputter.  Rents and property values will fall, eviscerating the tax base.  Throughout the city, people with money will begin moving to higher ground, leaving the poor behind in polluted swamps of abandoned buildings along the waterfront.
Almost every coastal city in the world is vulnerable to sea-level rise, but nowhere is there more at stake than in New York.  In purely economic terms, the New York metropolitan area is responsible for almost 10 percent of the U.S. gross domestic product and is the largest financial hub in the world.  The city has a symbolic value that is hard to quantify, with 8.5 million people from all over the world who live there, and millions more who are connected to it by work or family or by their dreams to come here and make it big.  "To deal with climate change, we need inspiration," says Henk Ovink, the special envoy for international water affairs for the Netherlands who was deeply involved in rebuilding New York after Sandy.  "New York City is the heart of the developed world.  If it does things right, it can radiate inspiration to other places."

In a world of rapidly rising seas, New York is better prepared than many coastal cities.  As anyone who has seen the rock outcroppings in Central Park knows, much of Manhattan is built on 500-million-year-old schist, which is impervious to saltwater.  There is plenty of high ground, not just in Upper Manhattan, in Washington Heights, but also along a ridge that runs diagonally through Queens and Brooklyn, including places like Park Slope and Jackson Heights.  Finally, the city has brains and money and attitude – New York is not going to go down without a fight.

But in other ways, New York is surprisingly vulnerable.  First, it's on an estuary.  The Hudson River, which runs along the West Side of the city, needs an exit.  So, unlike a harbor city such as Copenhagen, you can't just wall off the city from the rising ocean.  Second, there are a lot of low areas in Brooklyn, Queens and, most important, Lower Manhattan, which has been enlarged by landfill over the years.  (If you compare the map of damage from Sandy in 2012 with a map of Manhattan in 1650, you'll see they match pretty well – almost all the flooding occurred in landfill areas.)  The amount of real estate at risk in New York is mind-boggling: 71,500 buildings worth more than $100 billion stand in high-risk flood zones today, with thousands more buildings at risk with each foot of sea-level rise.  In addition, New York has a lot of industrial waterfront, where toxic materials and poor communities live in close proximity, as well as a huge amount of underground infrastructure – subways, tunnels, electrical systems.  And because of changes in ocean dynamics, as well as the fact that the ground beneath the city is sinking as the continent recovers from the last ice age, seas are now rising about 50 percent faster in the New York area than the global average. 

Perhaps the international community will take action in the next decade and dramatically cut carbon pollution, which could help slow the rising seas.  But the truth is, barring deployment of a radical geoengineering scheme that quickly cools the planet, we have already heated up the Earth's atmosphere enough to guarantee that the seas are going to rise – and they are going to keep rising for a long time.  Recent studies have shown that even if we stabilize the greenhouse-gas emissions at today's levels, the oceans will still rise by as much as 70 feet in the coming centuries and stay that high for thousands of years.  In that scenario, New York will become an archipelago on the coast, with the high ground of Upper Manhattan and parts of Brooklyn and Staten Island just above the waterline.

For anyone who thinks sea-level rise is a distant problem, the latest news from the Arctic is not encouraging. This summer, temperatures in Greenland spiked to the highest levels on record. If just one-tenth of the Greenland ice were to melt, it would raise global sea levels by two feet. The breakup of West Antarctica, which has showed signs of increasing fragility, could raise the seas 12 feet.
But dumb or not, given the amount of valuable real estate in Lower Manhattan, some kind of defensive structure is going to be erected there to keep the water out.  Building a wall is simple, quick and irresistible to politicians wanting to prove they have acted boldly.  But that doesn't mean it's always the smartest or the safest solution.
The most pernicious problem might be complacency.  Barriers, dikes and levees make people feel safe, even when they are not.  When Hurricane Katrina hit New Orleans, some people didn't evacuate because they assumed the levees would not fail; that assumption cost lives. "Barriers make people stupid," says Jorissen.  "They allow you to ignore the risk of living in dangerous places – if something goes wrong, it can be a catastrophe."
You could argue, of course, that the government's role is not just to deal with the needs of people right now, but also the needs of people in the years to come.  That's what they're doing in London, for example, where the barrier that protects the city from flooding is now being retrofit to protect it until 2100, or in Germany, where parts of the city of Hamburg have been elevated and floodproofed to withstand 25-foot-high storm surges.  But, for better or worse, thinking hard about – and preparing for – the long-term future is not the American way.

Read more at Can New York Be Saved in the Era of Global Warming?

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