sea level rise

How can sea level rise cause coastal flooding when the sea level has only risen by an inch or less?

Jennifer Jurado, chief resilience officer for Broward County, Florida, said global average sea level has risen between 6 and 8 inches since 1880, with regional variations.

“In Southeast Florida, the amount of measured rise is closer to 9 inches, with 3 inches just since 1992,” she said. “Perhaps small rates of rise don’t produce dramatic effects for communities at higher elevations, but many coastal areas are flat and low-lying (sitting just a foot above sea level, or less) so that even gradual changes over time have pronounced effects and can result in significant inland movement of tidal water.”

Existing drainage systems and seawalls are already being swamped by tides that are 12 inches higher now than they were when the structures were designed and built 50 years ago, she said.

She added, “Without higher seawalls and redesigned stormwater systems, the flooding will become permanent. In our region, the impacts have become so severe, there is no longer debate about the need to upgrade and to plan for future conditions.” In Southeast Florida, a projected sea level rise of 40 additional inches by 2060 is the basis for planning and designing all new infrastructure.

More information on sea level rise is available in this Q&A with an expert from the National Oceanic and Atmospheric Administration. 

Bob Berwyn

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