Southern California environment news and trends

Doing the math on sea level rise & coastal erosion in Malibu, Venice, and locally

The fun part of covering an economic study of sea rise’s coastal impacts is seeing what the math looks like without politics to distort it.

And sea walls at Zuma and Broad beach don’t math out, San Francisco State University economist Philip King and his fellow researchers say in the new study we reported on. “[A]n overwhelming majority of benefits are directly tied to protecting residential structures at the back of Broad Beach.” Those high-value homeowners were instrumental in getting a 4100 foot emergency seawall up at Broad Beach in 2010. King’s report says that if it’s maintained, “nearly all of the recreational and habitat benefits associated with this stretch of shoreline will be lost in the near future as water levels rise.”

Venice has its challenges, too. At that beach, they’ve already started nourishment projects: shoveling more sand into the maw that the sea leaves behind just doing what it do. King’s team says more shovelfuls would be good in the future (though they note potential ecological consequences). “Additional nourishment projects could help minimize recreational losses due to sea level rise; the placement of winter berms could also help reduce the impacts of flooding following large winter storms.”

San Francisco State released key findings of the report on its website. You can read the entire report here

California’s efforts at adapting to climate change and undertaking planned costs have lost the high profile that a more-active Governator press office occasionally achieved for the subject. State officials on climate issues are still updating their website and it’s pretty, but the matter of how to solve the adaptation puzzle is left for now to the locals to sort out. Malibu, Venice, and even Newport Beach all face different local political challenges as they decide among the three main choices, to spend money to nourish beaches with sands, to build sea walls, or to cede territory to the ocean. 

Environmentalists and economists raise questions about sea walls. They curtail (sometimes severely) recreational and habitat benefits associated with shorelines. Malibu’s seeing this already at Broad Beach, along which the Trancas Property Owners Association has funded a rock revetment (that’s a hardening of coastal defenses, but not a concrete wall; it’s also known as riprap). That’s already creating a lively debate about adaptation measures in the long run. 

I moved to New Orleans after Hurricane Katrina to cover New Orleans rebuilding, and one of my least favorite parts of the public rebuilding debate was the way people dug in on their positions in the political arena. “Why should a city be built there? We should just let it go?” went toe-to-toe with “Put walls around the whole thing and give us bigger protection.” In that case as in this one, the truth lies somewhere in the middle. 

 

(Photo by Surfrider West LA/Malibu chapter via Flickr..)

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