Surging storms: Can the US adapt in time to avert coastal damage?
Damage from severe storms such as Sandy is likely to escalate by the end of the century as the population grows and people continue to build along the Eastern Seaboard.
An afternoon breeze tousles the waters of a tiny harbor here at the mouth of Narragansett Bay – nothing like the heavy winds, rain, and storm surge superstorm Sandy brought to the East Coast as October ended.Skip to next paragraph
In Pictures Sandy: Chronicle of an unrelenting storm
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Armed with a cordless drill, Andrew Waite, a US Geological Survey (USGS) hydrologist, drops onto his stomach and scooches far enough over the edge of a weathered wooden pier to allow him to remove a length of narrow PVC pipe from a piling. It's not a task for the squeamish: The pier's deck looks as though seabirds have used it to practice carpet bombing.
Mr. Waite and a co-worker are retrieving storm-surge gauges deployed in advance of Sandy – a scene being repeated up and down the East Coast. The USGS will use the readings (six feet at this particular site) to update flood maps, and also to check the accuracy of surge forecasts, with an eye to improving them.
IN PICTURES: Sandy – chronicle of an unrelenting storm
Both goals could hardly be more important, as global warming raises sea levels and severe-storm activity intensifies off the Eastern Seaboard and elsewhere. Assessing the risk that storm surges pose to future coastal homes and businesses goes hand in glove with efforts to reduce vulnerability to such events.
"You think about it, and putting factors like sea level [rise] and all that aside, you're building where you're going to get flooded," Waite says. "It's just a matter of time."
Indeed, damage from tropical systems such as Sandy are projected to multiply by the end of the century as the population grows and people put more assets in harm's way. That's true whether or not global warming, which many researchers say is feeding extreme-weather events, is factored in.
Tropical-cyclone damage now runs about $26 billion a year globally, according to a study published in January in the journal Nature Climate Change. By 2100, increases in population and wealth as economies grow could push that number to $56 billion a year, assuming little or no effort to adapt to the hazard.
Throw global warming into the mix and the number grows to $109 billion a year, the researchers calculate. Most of that added burden falls on North America, where, absent efforts to adapt to the changes, damage could range from $60 billion to $70 billion a year – roughly double the rate by 2100 that assumes today's climate.
Along the US East Coast, where Sandy and last year's hurricane Irene left chaos in their wakes, a perfect storm of rising sea levels and coastal development is brewing. Forty-two percent of the dry land up to one meter above sea level is already developed, and another 15 percent is slated for partial or complete development, according to a survey of state and local coastal development agencies in the region conducted three years ago by the US Environmental Protection Agency.
If communities and developers follow through on those plans, that would bring to nearly 60 percent the proportion of dry-land coast below one meter above sea level with more people and high-priced assets in harm's way. In the process, wetlands seaward of these developed areas would have no place to migrate as the sea level rises, leaving engineered barriers as the only protection from surge flooding.