|Delray Beach, Florida|
National Geographic Magazine has written in "Sea Level Rise" (an internet document) that samples, tide gauge readings, and satellite measurements tell us the sea level has risen eight inches in the last 100 years.
There can no longer be any doubt that fossil-fuel burning and human and natural activities have released enormous heat-trapping gases into our atmosphere. The earth saw its third straight year of record-high temperatures in 2016 (hottest ever recorded), and its surface temperature has risen by more than a full degree Fahrenheit over the last 100 years. Oceans absorb 80% of this additional heat. In May, '16, the concentration of CO2 in the atmosphere reached 400 parts/million, the highest since 3,000,000 years ago ("Rising Seas" by Tim Folger, National Geographic Magazine internet document).
What does this mean for us humans? First, warmer oceans occupy more space. Thus, a rise in sea level.
Second, melting glaciers and melting polar ice caps produce a rise in sea level. Greenland's and West Antarctica's massive ice sheets are diminishing at an accelerated pace, having lost on average 50 cubic miles of ice/year since 1992 ("Rising Seas," Tim Folger). At Palmer Station, Antarctica, local island census-taking over the last 43 years has recorded an 85% decline in penguins due to a lack of sea ice, where the penguins find nourishment (CBS News internet "Climate Diaries" by Mark Phillips, Feb. 15, 2017).
|African Penguins near Cape of Good Hope|
Radley Horton, a research scientist at Columbia University stated, "If acceleration continues, by the end of the 21st century the sea level could rise as much as six feet globally." The U.S. Army Corps of Engineers recommends planners consider a conservative "high-rise" scenario of five feet by the end of the 21st century.
The result would not only be destructive coastal erosion and wetland flooding, but soil contamination and lost habitat for fish, birds, and plants.
In addition, bigger, more powerful storm surges (like Hurricane Sandy) might occur every decade or less by 2100. The Organization for Economic Co-operation and Development estimates that by 2070, 150 million people in the world's port cities will risk coastal flooding, along with $35 trillion worth of property being jeopardized ("Rising Seas," Tim Folger).
New York City is essentially defenseless to hurricanes and floods. London, Rotterdam, New Orleans (where a levee was breached in 2005 during Hurricane Katrina), St. Petersburg, and Shanghai have all built levees and storm barriers in the last decades. In New Orleans, eleven diesel pumps in a new storm-surge barrier south of the city, built in 2011, can discharge 150,000 gallons of flood water/second.
|Statue of Liberty and Ellis Island, New York City|
"Twenty-five percent of New York harbor used to be oyster beds," according to Kate Orff, NYC landscape architect ("Rising Seas," Tim Folger). The reefs of oysters and other shellfish grew as sea levels rose, buffering storm waves. The shellfish, filter feeders, cleaned the harbor.
Last June, Mayor Bloomberg outlined a $19.5 billion plan to defend NYC against rising tides: levees, storm-surge barriers, dunes, oyster reefs, etc. Meanwhile, development in the city's flood zone continues.
|Amsterdam Harbor, with railroad station in foreground and white Museum of Film across Amstel River|
The prospect for low-lying cities is dire. Among the most vulnerable is Miami. Han Wanless, Chairman of the Department of Geological Sciences, University of Miami, stated, "I cannot envision southeastern Florida having many people at the end of this century." ("Rising Seas" by Tim Folger, National Geographic Magazine on-line) With a minimal projected four-foot rise in seas possible by 2100, two-thirds of southeast Florida would be inundated and Miami would be an island ("Rising Seas," Tim Folger).
|Key West, Florida|
Miami and most of Florida sit on a foundation of highly porous limestone. A barrier would be pointless, since water would flow through the limestone.
Another problem is salinity control. There are about thirty salinity-control structures in South Florida at present. At times, however, the sea level is higher than the fresh water level in canals. This accelerates the saltwater intrusion and prevents discharge of flood waters. Already during unusual high tides, seawater spouts from sewers in Miami Beach, Ft. Lauderdale, and other cities, flooding streets.
|Typical canal scene, Amsterdam|
During a three-day tour of South Florida, Ovink (a senior advisor to Obama's Hurricane Sandy Recovery Task Force) inspected Miami's incremental approach to save itself: raising streets (starting with Dade Boulevard) and sidewalks, installing pumps, rewriting building and zoning codes. Ovink declared Miami's attempt, "Exemplary...but not enough."
"Never stop thinking about living with water," Ovink advised ("Miami Beach Receives Advice on Sea Level Rise," The Palm Beach Post, February 12, 2017, pg. B2).
Assistant City of Miami Engineer Roger Buell stated, "Miami is buying twenty years, possibly thirty."
"Building as usual in South Florida won't cut it," Ovink stated. "Miami is at the edge." ("Miami Beach Receives Advice on Sea Level Rise, The Palm Beach Post, February 12, 2017, B2)