The problem with reports about rising sea levels is that the damn thing—the world’s ocean—seems to creep up very, very slowly. In the past 21 centuries it’s raised an average of .07874 an inch every year, about the thickness of a nickel.
That doesn’t sound like much, right? Nothing to worry about! But what makes rising sea levels a deadly serious problem is that the ocean just keeps creeping up, up, up. And the average in recent decades is more like an inch a year.
In fact a new report from the National Academy of Sciences says the rate of increase along the U.S.’s Atlantic seaboard is now the greatest in the past 2,000 years.
What separates this study from all those that have preceded it is that researchers were able to construct a model illustrating the first continuous sea level rise over the past 2,000 years, and link it to global temperature changes during the same period.
According to the new report, backed by NOAA, the most at-risk state in the U.S. is now North Carolina. It predicts the Tar and Turpentine State will experience a three-foot rise along its coastline by 2200, meaning more flooding, more loss of land, and more saltwater infiltrating freshwater rivers and marshes.
The NAS study is supported by another new report, issued in May by the Oslo-based Arctic Monitoring and Assessment Programme, which suggests coastal communities worldwide should plan on similar increases of three to five feet by 2200.
What’s at risk? Two-thirds of the world’s largest cities and 634 million people currently living in “threatened coastal areas,” defined as those lying less than 33 feet above sea level.
Globally the places most at-risk of rising sea levels are island nations like the Maldives in the Indian Ocean and Tuvalu in the South Pacific, which rise just a few feet above the ocean’s surface. Mumbai, Guangzhou, Ho Chi Minh City, Osaka-Kobe, and Alexandria top the list of major international cities at risk. Calcutta and Dhaka. Places like London, New York, and Shanghai are already making plans to spend billions to keep raising waters at bay. Others are actively discouraging new populations from growing along water’s edge.
In the U.S., after the coast of North Carolina, the 5 most at-risk places, considering both populations and economies, are:
- Miami. A combination of factors—a sprawling, low-lying city that grows bigger every day, thanks to immigration and migration, combined with an increase in tropical storms and hurricanes, thanks to a slowly warming Atlantic Ocean—make Miami uniquely vulnerable to rising sea levels.
- New York City/Newark. Unlike Southern Florida, the New York City/Newark area doesn’t often get hit by hurricanes or floods, but the densely populated region—home to nearly 20 million people—is built on little more than swamps, islands, and landfills, which gives it few natural defenses against rising seas. That its subways and trains, telecommunications cables, fiber-optic networks, plumbing, and power mains are all underground make it a disaster-in-waiting.
- New Orleans. Two words—Hurricane Katrina—should define New Orleans' future. The city was built below sea level from the get-go, on one of the world’s largest deltas. Thanks to the combo of coastal erosion, increasingly intense storms, and sea level rise, it is nearly impossible today to get a 30-year home mortgage south of I-10, which cuts the state in thirds, because Louisiana bankers don’t believe the region will be livable in 2041.
- Tampa. On Florida’s Gulf Coast, Tampa boasts both a growing population and the state’s largest port, and is susceptible to the same boom in Gulf storms as New Orleans.
- Virginia Beach. The 38 miles of coast stretching north and south from Virginia Beach—home to military bases, manufacturing, and hundreds of hotels and resorts—are wide open to storms and rising sea levels coming off junction of the Atlantic and Chesapeake Bay.
Rounding out the Top 10? Boston, Philadelphia, San Francisco/Oakland, Baltimore, and Los Angeles/Long Beach.
Want to feel truly safe from rising sea levels and an angry ocean, and stay in North America? I’d start thinking about the Canadian Rockies.