July 31, 2013
Coastal American Cities Threatened By Sea-Level Rise
Michael Harper for redOrbit.com - Your Universe Online
Boston, Miami, New York and more than 1,700 other coastal American cities are facing a greater risk from rising sea levels than had previously been estimated.
A new study published in the Proceedings of the National Academy of Sciences (PNAS) claims at least 316 American cities will one day be overtaken by the sea if pollution continues to grow as it has been. More than 1,400 other cities will be "locked-in" by rising sea temperatures. The report doesn't give an estimated date when these cities will see oceans and gulfs begin lapping at more of their shorelines, but it does claim large portions of California, Florida, Louisiana, New York, North Carolina and Texas will have 25 percent of their land mass threatened by the rising sea, should pollution continue on its current track. With "deep cuts" in air pollution, this number could shrink dramatically from a 23-foot rise in sea level in 2100 to seven feet.
The paper uses the term "lock-in" to describe the amount of sea-level rise which has yet to happen and cannot be avoided. If reductions in pollution are made, the rising sea could be slowed some. The locked-in rate, however, is the amount the sea will rise despite these actions, and according to the published paper, the sea will rise another four feet in areas like Boston, Miami and New York.
The study, conducted by an international team of scientists led by Benjamin Strauss of Climate Central concluded the sea will rise by 4.2 feet for every degree Fahrenheit increase in global warming due of carbon pollution. The team now say the level at which this pollution is being spewed into the air will cause the sea to rise about a foot per decade for many decades into the future. Using this math, Miami, Virginia Beach, Sacramento, Jacksonville and other threatened cities could have sea levels increase by four feet by 2053.
"Even if we could just stop global emissions tomorrow on a dime, Fort Lauderdale, Miami Gardens, Hoboken, New Jersey will be under sea level," explained Strauss to The Guardian.
"Hundreds of American cities are already locked into watery futures and we are growing that group very rapidly. We are locking in hundreds more as we continue to emit carbon into the atmosphere."
Though countries are looking to make deep cuts to pollution levels in the coming years, Strauss says these may not be enough to stop the rising sea, noting lock-in levels may already be too high. After all, he notes, just because pollution is reduced the existing emissions continue to harm the environment. Even if emissions came to a full stop, the amount of greenhouse gases in the atmosphere will continue to affect sea levels. These gases trap more heat in the Earth's atmosphere which lead to ice sheet melting in Antarctica and Greenland, which, in turn, leads to an increase in sea levels.
This is the second study published in PNAS in July detailing the effects of pollution on sea level. In the previous study, researchers used computer models to combine the Earth's early history with new data from four major contributors to sea level rise. These contributors include the expansion of the ocean due to warmer temperatures, melting glaciers and the melting of both the Antarctic and Greenland ice sheets. Here researchers found today's greenhouse emissions will drive sea levels to climb higher for centuries to come.