Climate: Storm warning

A month after superstorm Sandy tore through the New York region, signs of the havoc it wreaked are still evident at the southern tip of Manhattan.

Around the South Street Seaport, the air is full of the sound of emergency generators, many of them powering Wall Street financial companies. South Ferry subway station, the city’s newest, was flooded by the 14-foot storm surge and remains boarded up. It is expected to cost $600m to repair.

Hurricane map

Beneath the East River, the tunnel carrying the R Train to Brooklyn remains closed. Across the water, some of the 8,000 residents of the Red Hook housing project are still without heat and power.

Sandy killed more than 100 people in the US. In New York state alone, it cost an estimated $32.8bn in damage and lost income, and affected more than 265,000 businesses. In total more than 8.2m customers lost power, some of them for weeks. The Metropolitan Transportation Authority, which runs the New York subway, has estimated it needs to spend $5bn to repair stations and tunnels.

The region’s vulnerability to hurricanes and storm surges has been known for decades. A 2007 study from the Organisation for Economic Co-operation and Development found New York was the city with the world’s second-highest value of assets at risk from flooding after Miami.

City and state authorities have been worrying for years about what would happen if a great storm hit, without doing very much about it. Now they do not have to wonder any longer. The question of how to protect New York and the surrounding area from future storms has become urgent.

“It’s common sense,” said Andrew Cuomo, governor of New York state, this week. “Rather than sustain another $30bn of damage, why don’t you spend some money now to save money in the future?”

Christine Quinn, the speaker of New York City council who is expected to run for mayor next year, has gone further, calling for up to $20bn to be spent on flood defences.

Sandy’s impact has been a dramatic demonstration of a much wider problem: the weakness of vital parts of US infrastructure.

Engineers have put forward plenty of ideas to reduce the damage done by future storms, from a five-mile barrier across the lower bay of New York, to putting back-up generators high up in buildings rather than in basements. There is much that could be done. The question is: will it?

Roger Pielke of the University of Colorado-Boulder, who studies the damage done by hurricanes, argues that although much of the talk since Sandy has been about the possible influence of climate change on the storm, the level of uncertainty in projections of hurricane activity makes it hard to use them as a guide to decision-making.

“The next storm could hit next year or in 20 years,” he says. “The real question for New Yorkers is, given that there will be another storm, what do they want it to look like? And if they don’t want it to look like Sandy, they are going to have to spend some money.”

Not every precaution is expensive. The most important factor in limiting the death toll and damage done by Sandy was effective disaster planning, helped by the early warning of the storm’s approach given by highly accurate weather forecasting using satellite data.

Knowledge that the storm was coming several days in advance enabled governments, businesses and individuals to take precautions ranging from evacuating some areas to moving televisions and stereos out of basements.

“The cost of Sandy was very high but it would have been very much higher without good forecasts,” says Stephane Hallegatte, an economist at the World Bank.

Early warnings made it possible for the MTA to avoid some damage, according to Richard Barone, director of transportation programmes for the Regional Plan Association.

Learning lessons from recent severe weather, the MTA shut services down well before the storm hit, to ensure equipment was kept safe and dry for a quick resumption of service.

Other measures to improve resilience are more expensive. Mr Cuomo has put a price tag of $9bn on what he calls “common sense” actions, such as flood protection for the World Trade Center site and back-up power for the fuel supply system, which suffered disruption for over a week.

Storm gates can be fitted to subway stations, and other defences strengthened. Lower Manhattan suffered a blackout caused by flooding at the electricity substation on the East River at 14th Street, which had a flood wall to protect against a 12-foot storm surge but was overwhelmed by the 14-foot surge caused by Sandy. That flood wall is likely to be raised.

However, many of the changes needed to safeguard New York’s infrastructure would be very expensive. Electricity substations and back-up generators in Manhattan are often located in basements, leaving them vulnerable to flooding. (Goldman Sachs, for example, had the foresight to place its generators on the roof of its headquarters, enabling the firm to keep its lights on when most of the buildings around it went dark.) But moving every piece of electrical infrastructure to a higher elevation would be difficult.

Jeroen Aerts of the Free University of Amsterdam, who is preparing a report on flood defence options for New York City, believes a comprehensive package of reinforcements, including protection for subway stations, airports and Wall Street, could cost about $20bn.

Mr Aerts argues that for about the same price, New York could have a system of flood barriers similar to those that protect London or Rotterdam.

Taking estimates from various engineering companies, he suggests a system of two barriers – the larger spanning five miles from New Jersey to Long Island across the lower bay of New York, with associated reinforcements to beaches at the end of the barriers – would cost $15bn. A more complex system with four barriers would cost $22bn.

With Sandy having cost New York City an estimated $19bn, that might seem like money worth spending, even if the lack of understanding of hurricane activity makes the cost-benefit analysis uncertain.

“If you look only five or 10 years into the future, then it’s probably not worth it,” says Malcolm Bowman, a professor of oceanography at the State University of New York at Stony Brook. “But if you look 50 or 100 years ahead, then maybe it is.”

The problem, though, is that even if politicians decide investment in barriers makes sense, financing that scale of infrastructure investment in the US is extremely difficult. For all New York’s wealth and economic importance, there are many cities in Europe, and some in emerging economies such as St Petersburg and Shanghai, with stronger flood defences. The same unflattering comparisons can be applied to rail systems, airports and highways.

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The problem is not so much the lack of money as the way infrastructure is financed in the US.

“In the US, localities bear the brunt of the expense for infrastructure. It’s unique among developed countries in being so decentralised,” says Anand Kesavan, senior vice-president for public finance at Siebert Brandford Shank, an investment bank. “When there’s been a recession, that’s often the best time to build infrastructure, because costs are lower. But localities often can’t afford it.”

Ms Quinn’s proposed solution is that the federal government should pay. There is a precedent, in the money spent to strengthen flood defences around New Orleans in the wake of hurricane Katrina in 2005.

The difference then was that the maintenance of those defences, which failed during the storm, was clearly a federal responsibility. In today’s acrimonious climate in Washington, with enormous pressure to cut public spending, it is hard to see Congress committing tens of billions of dollars to help New York.

Even Michael Bloomberg, the city’s mayor, who has been vocal in warning of the threats posed by a warming planet, has sounded pessimistic about the prospect of committing large sums to ambitious flood defences.

Mr Aerts fears that as time passes, the pressure for greater storm protection will fade. “Now it’s quite fresh. But in half a year’s time, there will be other debates, other priorities,” he says. “If you look at the Thames barrier, or the barriers in the Netherlands, they were built after major disasters. When you have 2,000 fatalities, then the urgency is there.”

How other cities fare

Buenos Aires: Roads turned into rivers this month, cars piled on top of one another and one woman was stranded waist-deep in a busy area, writes Jude Webber.

Daniel Capdevila, the city government’s infrastructure chief, laments a “lack of infrastructure investment for 70 years”. He says the Argentine capital has studied the problem since 1998 and a $250m World Bank loan helped build nearly 15km of drainage tunnels so people would never again have to cross one main intersection by clinging to a rope.

That first phase, completed in July, covers an area that is home to a third of the city’s population. The second phase, in the area where the woman was stranded, needs a $120m loan and approval. Overall, the project will cost $800m.

London: The Thames Barrier, one of the world’s largest moveable flood barriers, was built across the river downstream of the British capital, principally to protect the capital from a storm surge, writes Clive Cookson.

Since its completion in 1982 at a cost of £535m (about £1.6bn at today’s prices) the barrier has been closed 120 times. Although the biggest threat is a storm surge from the North Sea, the barrier has also prevented flooding from the opposite direction, following intense rainfall west of London.

The barrier was designed to withstand many decades of rising sea levels. The UK Environment Agency, its operator, says that a new barrier closer to the mouth of the estuary – which would cost billions of pounds – is unlikely to be needed before 2070, though extensive fortification of secondary flood defences might be required after 2035.

Shanghai: Researchers have rated the Chinese business hub the most vulnerable to serious flooding of nine coastal cities around the world. They took account of not only the possibility of storm surges there but also the economic consequences of flooding, writes Patti Waldmeir.

Although many people live in flood-prone areas, the city is poorly prepared, with insufficient flood shelters, the researchers from the Netherlands and the University of Leeds found.

But Hu Xin, deputy director of the Shanghai Flood Control Headquarters, told television news: “We’ve built 523km of coastal levee and the city’s flood resistance standard can withstand a once-in-200-years high tide level and cope with gales of up to 133km per hour.” During a recent typhoon, the city evacuated 374,000 people within a day and a half, the government said.

Venice: “Acqua alta”, or high tide, has been a feature of life in Venice for centuries but is now a state priority, writes Rachel Sanderson.

The Mose project, giant barriers that will protect the Italian city, is due to be completed in 2016.

Ten years in the making, Mose is Italy’s biggest public works project with a cost of about €5.5bn. An allusion to the story of Moses parting the Red Sea, it will put 78 gates across three inlets that feed into the lagoon.

The project is contentious due to the cost and its potential impact on the lagoon ecosystem.

Some local groups argue that the city’s inhabitants would be better served coping with high tides as they have done for centuries – by carrying on their daily business helped by a pair of waterproof shoes.