Rising Sea Levels May Significantly Increase Coastal Flood Risk in the U.S. by 2050

by Anne Englebert on June 14, 2012

flood risk rising sea levels

“All low elevation places in the many urban areas along the coast will become more vulnerable, like Boston, New York City, Norfolk (Va.), New Orleans, Charleston (S.C.), Miami, Washington, D.C./Alexandria (Va.),” said S. Jeffress Williams, scientist for the U.S. Geological Survey, Flickr User: lindenbaum

It is not only small island nations that must face the effects of rising sea levels; soon the United States will have to as well. Global warming has raised sea level about eight inches since 1880, and the rate of rise is accelerating. According to a new study from Surging Seas by Climate Centrale, rising seas are dramatically increasing coastal flood risk in the U.S. from storm surges. More than 3 million people from 544 U.S. cities may be affected by extreme coastal floods over the next few decades.

Sea Level Rise:
Currently, sea levels around the world are rising. The main factor contributing to the rising ocean level is global warming. The major store of water on land is found in glaciers and ice sheet, and as the atmosphere and ocean water warm due to greenhouse gas emissions, large quantities of ice are melting, contributing to sea level rise. Rising seas dramatically increase the odds of damaging floods. It will force every inhabitant living in a coastal area to confront the risks and the realities of flooding.

The impact of sea level rise on the U.S. coastline:
The coastline of United States is highly populated — of the 25 most densely populated U.S. counties, 23 are along a coast. The impacts of sea level rise on those particular locations are likely to be severe. According to a new report from Climate Central, the rising ocean level may affect 3.7 million people in 544 U.S. cities. This study makes mid-range projections of 1 to 8 inches by 2030, and 4 to 19 inches by 2050, depending on the location across the contiguous 48 states. These increases are likely to cause enormous damages, mainly in cities located in Florida, Louisiana and New York where most people are living within three feet of high tide (the projected sea level rise by the year of 2100).

coastal floods

In the New York City area, the researchers’ model projects that water will inundate the coast. Statistics accompanying the map explain that over 64,000 people live within 1 foot of the tide line. There is over a one in six chance that rising sea levels in combination with a storm surge and high tide will be 1 foot by 2020 at the New York Harbor (the nearest flood risk indicator site).

“Southeast Florida is definitely the highest density of population that’s really on low coastal land that’s really most at risk,” said lead author Ben Strauss, a scientist at Climate Central. Coastal flooding promises to cause billions of dollars of damages over the coming decades. If the rising sea level reaches four feet, it would impact millions of acres of roads, bridges, commercial buildings, agricultural lands, toxic waste, schools, hospitals and many problems that other coastal areas already face such as shoreline erosion. The situation of small island nations around the world should serve as a warning for the U.S.

During the 20th century, the global sea level rose by roughly seven inches due to warmer waters and it is not expected to slow down. For that matter, the U.S. government is working to diminish remaining dangers by preparing programs for higher oceans in coastal counties. Climate Central has also put together a list of plans and resources to help prepare the sea level rise in concerned areas. Some states have already taken actions to adapt to the impacts of climate change on coastal areas:

  • Restoring natural storm surge buffers and incorporating climate change into coastal habitat restoration plans
  • Building or repairing dikes, seawalls, and other structures that protect cities from erosion and storms
  • Modifying building codes to enable structures to withstand higher water levels
  • Expanding setbacks (the distance between a structure and the shoreline) and instituting other land-use arrangements to enable wetlands and beaches to migrate inland
  • Upgrading and redesigning infrastructure such as bridges, roads, culverts and stormwater systems
  • Evaluating drinking water supplies with respect to climate change
  • Mapping coastal hazards and developing emergency response plans with regard to sea level rise

 

coastal hazards

Marylandand Virginia’s Coastal Programs have developed a “Living Shorelines” initiative. The initiative promotes alternatives to armoring shorelines with hard structures such as bulkheads and stone revetments, which eliminate wetlands and beaches. Flickr User: ChesapeakeBayFoundation

For more information on recent and future sea level rise and coastal flood risks in your area, please visit Surging Seas Maps (sea level rise analysis by Climate Central).


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