Old Rocks
Diamond Member
Rising Seas Imperiled Cities Harvard University Center for the Environment
Cities at Risk
Getting ready for sea-level rise is every city’s problem. Without action, in fact, rising seas will sooner or later alter most of civilization’s urban footprint. Coastal floodplains worldwide are crowded with cities often built no more than 3 feet above sea level. More than 2 billion people—an estimated 37 percent of the world’s population—live within 60 miles of the coast and would be affected, directly or indirectly, by incursions of the sea.
In sheer economic terms, the stakes of sea-level rise in urban areas are particularly high. An added 0.5 meters (20 inches) of ocean water by the year 2050 would put $28 trillion in assets at risk in the world’s 136 port megacities, according to a 2009 report of scientists and insurance experts assembled by World Wide Fund/Allianz, a global investment and insurance company. On the Northeastern coast of the United States, the expected maximum rise in sea level of 26 inches by 2050 would threaten in five cities alone—Baltimore, Boston, New York, Philadelphia, and Providence—assets worth about $7.4 trillion. In Boston, losses could reach $460 billion, or the equivalent of 20 Big Digs.
To understand what is at risk, one cannot just look at the current coastline; it’s the highest tide during a storm surge that you worry about. In Boston, storm surges can temporarily raise sea levels as much as 8 feet, depending on tides, wave action, and the duration and speed of winds. History testifies to the city’s vulnerability: in 1978, Boston’s then brand new Charles River dam was barely in place when a three-day blizzard struck on Feb. 5. The resulting storm tide rise came within 0.4 meters (16 inches) of overtopping the dam. (The Charles River dam was designed to protect against a storm surge of 3.8 meters — about 12 and a half feet — above mean sea level.) What is more, said Wilson in his thesis, the dramatic floods of March and April 2010, which inundated parts of Rhode Island, could also have been catastrophic. Boston’s salvation was the Charles River dam’s six 2,700-hp diesel pumps, which ran 24 hours a day for several days.
This is a short article, the definatively outlines what the world's port cities are facing in this century.
Cities at Risk
Getting ready for sea-level rise is every city’s problem. Without action, in fact, rising seas will sooner or later alter most of civilization’s urban footprint. Coastal floodplains worldwide are crowded with cities often built no more than 3 feet above sea level. More than 2 billion people—an estimated 37 percent of the world’s population—live within 60 miles of the coast and would be affected, directly or indirectly, by incursions of the sea.
In sheer economic terms, the stakes of sea-level rise in urban areas are particularly high. An added 0.5 meters (20 inches) of ocean water by the year 2050 would put $28 trillion in assets at risk in the world’s 136 port megacities, according to a 2009 report of scientists and insurance experts assembled by World Wide Fund/Allianz, a global investment and insurance company. On the Northeastern coast of the United States, the expected maximum rise in sea level of 26 inches by 2050 would threaten in five cities alone—Baltimore, Boston, New York, Philadelphia, and Providence—assets worth about $7.4 trillion. In Boston, losses could reach $460 billion, or the equivalent of 20 Big Digs.
To understand what is at risk, one cannot just look at the current coastline; it’s the highest tide during a storm surge that you worry about. In Boston, storm surges can temporarily raise sea levels as much as 8 feet, depending on tides, wave action, and the duration and speed of winds. History testifies to the city’s vulnerability: in 1978, Boston’s then brand new Charles River dam was barely in place when a three-day blizzard struck on Feb. 5. The resulting storm tide rise came within 0.4 meters (16 inches) of overtopping the dam. (The Charles River dam was designed to protect against a storm surge of 3.8 meters — about 12 and a half feet — above mean sea level.) What is more, said Wilson in his thesis, the dramatic floods of March and April 2010, which inundated parts of Rhode Island, could also have been catastrophic. Boston’s salvation was the Charles River dam’s six 2,700-hp diesel pumps, which ran 24 hours a day for several days.
This is a short article, the definatively outlines what the world's port cities are facing in this century.
