Sea Walls, Dikes, Evacuation: US Cities Must Cope With Rising Sea Levels


Photo: Martin Burns via Flickr/CC BY

Whether or not the anti-science crowd wants to believe it or not, global warming is happening. This year is shaping up to be the hottest in the global temperature record, and weather events in line with scientists' climate models have wracked the globe. And, yes, sea levels are rising. And when you can actually mark sea levels in coastal areas and notice that, yup, they're getting higher, it's hard to say it's part of a hoax concocted by Al Gore -- sea level rise is a reality. And coastal cities are coming face to face with that reality. Here's what they're doing in response. Not much. As sea levels are rising, the planning has been poor and inconsistent, especially in coastal cities that stand to be impacted the most. But something needs to be done. Steve Nash writes in the New Republic:

There are three broad options for dealing with sea-level rise. We can build walls to ward off the sea. We can put our coastal buildings and infrastructure up on stilts. Or we can plan a slow retreat and move our built environment farther inland. All of these options would take a long time to implement, and many of them would be absurdly expensive. Jim Titus, chief sea-level-rise expert at the Environmental Protection Agency (EPA), estimates that shore protection for the lower 48 states could cost around $1 trillion.
Yes, $1 trillion. That is far more expensive than any proposed policy for dealing with climate change -- further evidence that mitigation is the cheapest and most effective strategy for dealing with it. Adaptation is going to be, put simply, a bitch. And the solutions often create as many problems as they address:
And seawalls--a necessity to protect places like Manhattan--could create as many problems as they solve. Dikes, levees, and bulkheads will destroy many coastal wetlands by preventing them from migrating inland as the seas advance. Most of the coastal wetlands in the mid-Atlantic could disappear by the end of the century if they have no place to go and the seas rise three feet or more. These wetlands are highly valuable, reducing the impact of floods, protecting against storms, and shielding freshwater supplies from the ocean. They're also key nurseries for fish: About two-thirds of the commercial fisheries off the Atlantic depend on wetlands, where invertebrates and small fish that feed on decomposing matter support rockfish, menhaden, blue crab, and other large species.
In other words, seeing as how our nation has decided not to participate in the effort to head off the worst of climate change, we need to get cracking on how we're going to deal with its effects on a practical level. It's not going to be easy. Or cheap.

More on Sea Level Rise
Sea Level Rise Best Case Scenario: 50cm Rise, 10% of World Population Hit
See For Yourself: Interactive Sea Level Rise Explorer
Two Meter Sea Level Rise Now Inevitable - But How Fast Will It Come?

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