Significant sea level rise is a very real threat to the near future for Miami-Dade County. BACKGROUND: Over the past 2,500 years south Florida has experienced an average rate of relative sea level rise1 of about 1.5 inches per century. Over this time our sandy, mangrove and muddy coastlines were mostly stable or expanding seawards. The broad coastal wetlands and historically stable sandy coastlines of south Florida are a product of this prolonged period of very gradual sea level rise. Since 1932, south Florida has had about a 9 inch relative rise of sea level. This is a rate of one foot per century and is about 8 times the average rate over the past 2,500 years. Much of this accelerated rise is the result of warming (and expansion) of water in the western North Atlantic Ocean in response to global warming. Our coastal and shallow-marine environments are now evolving in response to the stresses of this rising sea level.