Top 20 Cities with Billions at Risk from Climate Change

By Eric Roston - 2012-07-06T03:32:54Z

Photograph by Tyrone Turner/National Geographic Stock

Company Symbol % Change
JPMorgan Chase & Co JPM:US -0.59
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#12 New Orleans, Louisiana, U.S.

<strong>2005 assets at risk:</strong> $233.7 billion
<strong>2070 est. assets at risk:</strong> $1.0 trillion
<strong>2005 population at risk:</strong> 1.1 million
<strong>2070 est. population at risk: </strong>1.4 million

Threats to New Orleans are legend. Subsidence lowers an elevation that is already at or close to sea level. The U.S. Army Corps of Engineers has levied the Mississippi river since the 1930s, pushing its silt into the Gulf of Mexico, where it can't accrete into hurricane-blocking marsh that the city needs. The existing Louisiana marsh was carved up and weakened by generations of industrial canals. Warming waters, rising seas and historical canal-building through marsh has brought a terrible net result: The Gulf swallows southern Louisiana land at a rate of approximately a football field every hour.

Louisiana has spent at least three decades developing plans to protect its southern flank against the Gulf of Mexico. The critical nature of these defenses was brought home by one of the most terrible American tragedies in modern history, Hurricane Katrina in August 2005. Despite advances since then, federal and state authorities still face years of work girding levees and deploying "<a href="">multiple lines of defense</a>" along the coast.

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