The Natural Resources Defense Council (NRDC) dropped a report this week (following this fairly damning one) outlining the potential (and likely) effects of rising sea levels on several U.S. cities. New Orleans of course is on the list — the NRDC says its one of "the most vulnerable cities in the United States to the impacts of climate change, due to its low elevation, land subsidence rates, sea level rise, and prediction of more intense hurricanes." (Read the full breakdown of New Orleans here.)
The NRDC predicts sea levels in the area to rise by 1 to 4.6 feet by 2100, one of the highest rates in the the nation. The effects include wiping out significant chunks of wetlands, exposing the city directly to the Gulf of Mexico.
Rising seas will likely wipe out a significant portion of the coastal wetlands in the Mississippi River Deltaic Plain, where wetland loss rates are already among the highest in the world. Without inputs of sediment, an additional 3,900 to 5,200 square miles of wetlands will be under water by the end of the 21st century. If the impacts of relative sea level rise on wetlands are not checked, metropolitan New Orleans could eventually sit on land almost completely surrounded by the open waters of the Gulf of Mexico.
Loss of Louisiana’s coastal wetlands would not only represent a loss of natural flood protection, but it would impact the vast array of plants and animals that the wetlands support, many of which are tied to economic activity including fishing, timber, agriculture, tourism, and recreation. The combined value of infrastructure and biological productivity associated with Louisiana’s wetlands exceeds $100 billion.
Earlier this year, the University of Arizona produced a similar report showing that by 2100, New Orleans could face 10 percent land loss. The report's maps show much of the city lying at or below 1 meter of elevation, with areas immediately along the Mississippi River (read: levee protection and higher ground) lying at or below 6 meters of elevation.
But while the UA report didn't specify any call to action, NRDC seems confident in post-Katrina reconstruction — raising homes, 500-year storm protection, flood mitigation — to combat the rising tide.