Can Louisiana's 'master plan' reverse coastal land loss? 'We don't believe that anymore,' official says _lowres

Photo provided by USDA Natural Resources Conservation Service -- This is one of three shoreline protection products being tested along Louisiana's coastline in the area of Vermilion Bay and Weeks Bay. State and federal coastal restoration agencies will test the effectiveness of these measures over the next three years in order to find alternatives to rock placement along the shore.

Jeff Sadow's column (The Advocate, Jan. 29) has one valid point: the highest scenario of sea-level rise of 200 cm used in the Louisiana’s 2017 Coastal Master Plan is rather unlikely, at least during this century, based on my appraisal of the latest science. I admit that even though I am the lead author of the 2013 Maryland report, “the conclusions of which are not supported by the data,” according to Sadow. 

As a native Louisianan and an ocean, rather than political, scientist, I follow both coastal protection and restoration and climate science closely. The consideration of this high sea-level rise scenario, which is unlikely but could happen if there is a catastrophic collapse of Antarctic ice shelves, is in no way a reason to reject the Coastal Master Plan. The more likely low (100 centimeters) and medium (150 centimeters) sea-level rise scenarios are challenging enough to require the urgent and systemic measures that comprise the plan. 

Looking past Sadow’s allegations of political conspiracy, offensive dismissal of serious science as “tossing darts while blindfolded,” and reference to the wacko Nongovernmental International Panel on Climate Change (really!), it is refreshing that he argues that scenarios of 50, 100, and 150 centimeter sea-level rise should be used because they are “more realistic.” Fair enough; at least he’s not denying accelerated sea-level rise! 

The difference between a 100- to 150-centimeter rise by the end of the century (1.4-2.1 feet within the 2065 planning horizon in addition to land subsidence) and a 50-centimeter rise is a matter of moving or staying for much of coastal Louisiana. The only chance that Louisianans will have to contend with anything less than the master plan’s low sea-level rise scenario depends on quickly reducing the world’s greenhouse gas emissions to levels that meet the goals of the Paris Agreement endorsed by virtually all nations. It’s that straightforward scientifically.

Donald F. Boesch

president, University of Maryland Center for Environmental Science

Cambridge, Maryland