THE impact of hurricane Katrina has been truly dreadful. Even with the full toll not yet known, it is clear that thousands of people have lost their lives. Hundreds of thousands have been left homeless and jobless, and the clean-up bill could top $50 billion. The realisation that an iconic American city can be destroyed at a stroke is utterly shocking.
As New Orleans police continue the grim task of collecting corpses and the Army Corps of Engineers pumps out the flood water, it is easy to forget that the devastation was predictable and to a certain extent preventable. Powerful hurricanes will hit New Orleans as surely as earthquakes will strike Tokyo or San Francisco. Terrorist attacks may or may not take place, but some natural disasters are inevitable. We don’t know when they will happen, but happen they will.
Scientists have long warned that New Orleans’s natural protection had eroded. The barrier islands and coastal marshes that might have blunted Katrina’s ferocity have not been replenished with silt from the Mississippi, so have settled beneath the sea (see “The day their luck ran out”). Numerous researchers and groups have warned over the years that the city’s levees would not withstand more than a category 3 storm. It was this knowledge that convinced the mayor of New Orleans, Ray Nagin, to evacuate the city as Katrina approached. So why wasn’t more done to protect the city?
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There is a clear mismatch between forecasting natural disasters at some indeterminate time in the future and the short lifetime of local and national governments in modern democracies. And there are few, if any, votes to be had in raising levees or creating new building codes for earthquake-prone cities.
There are so many more urgent things to spend tax money on, and so long as a disaster doesn’t strike while an administration is in office, it can justify its spending priorities. When it does happen, the blame is shared. The US Department of Homeland Security, for example, may have cut the budget for maintaining New Orleans’s levees, but neglect of the flood defences began years before the department even existed.
And the world can always be made safer. The tough part is deciding what level of safety is acceptable and at what cost. What is certain is that the way such decisions are made needs a total rethink. The Asian tsunami and the disaster in New Orleans show clearly that the political processes for handling disaster prevention are failing badly.
One option is to measure the success of disaster prevention. How many times has the Netherlands’ system of dykes protected it from disastrous flooding? How many lives have they saved, and how much money? In November 2002, when a magnitude 7.9 earthquake struck Alaska close to the trans-Alaska oil pipeline, there was no leak and no environmental disaster because the pipeline was built to withstand quakes. What value should we put on such a design?
“The world can always be made safer. The tough part is striking the right balance between safety and cost”
Such figures can be calculated. The Thames barrier has been raised 80 times in 23 years to prevent surge tides inundating London. The cost of a serious flood has been put at £30 billion. If success is measured by what does not happen during a quake, eruption, flood, fire or storm, then perhaps taxpayers and politicians will find the price of disaster prevention worth paying.
Those with the job of redesigning the defences of New Orleans now face an extraordinary task. The city is largely below sea level and in some parts is sinking by 5 millimetres a year. It is hemmed in by the Mississippi and Lake Pontchartrain, which like the sea beyond is rising by 2 millimetres a year. And it sits on a coastline frequently pummelled by hurricane storm surges.
And there is a further factor in the equation. Our best estimates suggest that climate change will increase the rate of sea-level rise to as much as 8 millimetres a year. There is also strong evidence that as global warming heats the oceans, hurricanes will grow more severe.
This is a great opportunity to try a new way of discussing disaster prevention and reaching a consensus on what constitutes an acceptable level of risk. After what they have endured in the past week, the citizens of New Orleans are likely to vote for the highest level of protection possible. The price tag could top $20 billion, but the cost of opting for less will undoubtedly be greater. Katrina may have gone, but the arrival of another powerful hurricane is inevitable.
