Climate Change Meets the Little Mermaid

Copenhagen—Denmark’s famed "Little Harbor Lady," or in English, "Little Mermaid," has had her share of antics and perils. She’s been photographed by millions in Copenhagen’s harbor, carted off and shown at the 2010 World Fair in Shanghai, beheaded (several times), dynamited, splashed with pink paint, and enveloped in a Burqua. An environmental nerd for all occasions, I look at her longing face and wonder, How long before the rising sea swallows her up? Bolted to that rock in the sea, a shaft a concrete now inserted into her neck, what will she do? Or, for that, matter, the thousands of others who call coastal Copenhagen home. Is anyone thinking about this?

Many experts expect the world’s seas to rise somewhere between 1 to 1.5 meters this century, depending on location (and, of course, it could be more). Add to this a potential for stronger storms and much higher storm surges and you see why cities like Copenhagen, London, New York, and Miami are all in the crosshairs.

Danish experts have begun using computer-enhanced mapping techniques to predict what a high-tide of 2.26 meters—what they believe a "20-year event" might look like in 2110—would do to the city. The result leaves an inner city map covered in blue, including the Danish Stock Exchange, the Royal Library, and the city’s stunning Opera House. For this reason, the country is developing a proposal for a dike along Copenhagen’s North Harbor and an area called Kalveboderne to protect some of the city’s most treasured assets. For areas lying outside the protected region, which includes the Opera House, engineers are considering elevating roads and introducing architectural adjustments.

Back in New Orleans, where I live, we are also strengthening our fortress walls. At the opening of hurricane season this month, city residents took comfort (perhaps) in the strongest flood-control system ever constructed for the region. My favorite part is the Lake Borgne Barrier, a 1.8-mile-long castle-toothed wall, anchored by 66-inch-wide, 144-foot-deep concrete columns. The structure, which cost $1.1 billion and was built in just two years, is designed to block the kind of crashing hurricane surge brought by Hurricane Katrina, which in 2005 swept through the Gulf Intracoastal Waterway and Industrial Canal into the heart of New Orleans.

As I continually remind my students, resistance, while expensive and complicated, is not always futile. But it must be done with full knowledge and disclosure of what residual risk remains. And it must incorporate a strategic use of natural barriers and other natural systems to amplify the protection value. That means restoring and preserving natural buffers like beaches, wetlands, and flood plains.

The importance of natural shields, what coastal engineers call “soft-armoring,” is gaining attention all over the world. Indeed, the Obama administration has proposed a draft of revised standards for flood-control and other water resources projects that would require the “wise use of floodplains” and maintain a presumption in favor of nonstructural solutions to flood management. That would be a terrific start. But other policy innovations must follow. As legal researchers at Georgetown’s Climate Center are learning, many federal permitting systems that apply to coastal structures are designed to favor “hard armoring” proposals, often fast-tracked through general permits, over less familiar “soft armoring” techniques.

And what of Copenhagen’s Little Harbor Lady? Standing next to her, assuming my straightest posture, I estimate that a high-tide of 2.26 meters would at least encircle the waist of this pensive lass, though I like to imagine those finned ankles would do her some good. Staying afloat, you know, is mostly about preparation.