Warmer Oceans, Stronger Storms

There is perhaps no better example of the potential for devastating global warming impact than the Gulf Coast and Hurricane Katrina. While scientists are clear that no one storm can be attributed to global warming, they have unearthed a trend towards larger, more intense storms as oceans around the world warm. After Katrina, the response from the American public was to help New Orleans any way we can. In order to protect the Gulf Coast over the long term, America should adopt policies that cut global warming pollution to reduce warming of the oceans.

Stronger Hurricanes

Hurricane formation is complex, but warm water is a necessity and also influences the strength of the storm. In a chilling instance of scientific soothsaying, scientists from MIT published a groundbreaking study on the link between increasing sea surface temperatures and hurricane intensity just one month before Katrina hit. A few weeks later, a similar study was released by Georgia Tech researchers. The professors at these respected institutions found that hurricane intensity—a measure of the strength and duration of a storm—had increased since the 1970s. Ocean temperatures had risen by about one degree Fahrenheit over this time, showing how a small difference in temperatures can have profound impacts on our planet.

In the North Atlantic where the most detailed records exist, the number and intensity of recorded tropical storms and major hurricanes appears to be increasing.  In the period from 1850-1990, there was an average of about 10 tropical storms per year, including approximately 5 hurricanes. Since 1995, the 10-year running average has risen dramatically, with the 1997-2006 average at about 14 tropical storms, including 8 hurricanes. Since 1996, tropical storm frequency has exceeded by 40 percent the previous maximum from the mid-1950s.

Protecting New Orleans

Compounding the challenges of stronger storms is the loss of New Orleans’ natural protection. Within this century, at least 70 percent of the coastal salt marshes that protect New Orleans from the brunt of storms may be buried by rising sea levels. Some parts of New Orleans are already 8 feet below sea level. While its levees are designed to protect against flooding from the Mississippi River and Lake Pontchartrain, they do not adequately protect the city from sea level rise and more intense storms.

Congress has mandated that the Army Corps of Engineers protect the New Orleans area from a 100-year hurricane by the beginning of the 2011 hurricane season. To reach the 100-year hurricane protection level, the Corps is expected to raise levees as high as 27 feet above sea level in some areas. In order to account for sea level rise, continued loss of wetlands and increased risk of storms from global warming that is expected to occur in the next 50 years, the Corps may need to add one to two feet to the design heights in the future.

To protect New Orleans, building larger levees will not be enough. Strategies to reduce coastal vulnerability – from more rigorous building codes to improved emergency response – should be implemented.  Restoring natural coastal protections and addressing global warming can ensure long term protection.
 

You Can Still Help the Gulf Coast Rebuild Today!

Habitat For Humanity

American Red Cross

 

  

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