RISING THREATS

Seas are rising faster as heat-trapping pollution is released from fossil fuels, farming and forest losses. While governments worldwide are taking steps to slow warming and help communities adapt, elected leaders in Florida and the federal government have been dismissive of the problem. As McPeak’s neighbors installed seawalls to protect their own yards, they made her problems worse. When waves pound against seawalls and bulkheads, wave energy can bounce back into neighboring properties. And it can cause erosion at the base of the infrastructure, which can lead to collapse. “The erosion is happening,” said Bret Webb, a coastal engineer at the University of South Alabama. He also co-owns a coastal engineering firm specializing in natural protections. “It’s just being transferred.” Living shorelines are best suited for calmer waterways. They do less to keep floodwaters at bay, but they’re more likely to withstand serious flooding. When a storm surge overtops a seawall or bulkhead, it can scour the earth from behind the infrastructure and cause it to fall over. Scientists combined insurance industry information, storm data and climate and development scenarios along the Gulf Coast, then assessed the cost-effectiveness of different types of approaches to reduce future damage from flooding. They reported in the journal PLOS ONE that nature-based shoreline protections could halve the costs associated with future flooding along the Gulf Coast, potentially saving tens of billions of dollars. “Nature-based solutions” were found during the study to be “particularly cost-effective,” said Borja Reguero, a coastal engineer at the Nature Conservancy and the University of California, Santa Cruz who worked on it. “In terms of a pure benefit-to-cost ratio, they were ranking pretty high.” Benefits can extend beyond property lines. Nitrogen pollution from lawns and farms that washes into waterways during storms, feeding harmful algae, can be reduced using oyster reefs and other shoreline ecosystems. Marsh growth can support fisheries and clean water, which support Florida’s economy. And coastal vegetation slows climate change by absorbing carbon more effectively in some cases than forests. Still, seawalls and bulkheads remain more common and popular than natural alternatives. Research published in 2016 by two of Reguero’s colleagues showed that a tiny fraction of spending on coastal protections goes toward natural solutions. While living shorelines have become popular “as an idea,” Webb said, “what we have not seen is this translate into widespread adoption at the homeowner level.”

 

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