Speaker 1: Welcome to brain Stuff from How Stuff Works, Hey, brain Stuff,
Speaker 1: Lauren Vogel bomb Here in summer, there's nothing like feeling
Speaker 1: the sun on your face and the sand between your toes.
Speaker 1: But the rising sea levels and stronger coastal storms associated
Speaker 1: with climate change pose a threat to the sands that
Speaker 1: make up our beaches. A common approach to combating erosion
Speaker 1: at u S coastlines is beach nourishment, which is literally
Speaker 1: taking sand from one place off and off shore and
Speaker 1: pumping it onto a sand depleted beach. The question is,
Speaker 1: can beach nourishment keep up with the ever increasing forces
Speaker 1: of climate change, or, like Sisyphus forever pushing his boulder
Speaker 1: up the hill, is adding sand to beaches an expensive,
Speaker 1: temporary fix to a long term problem. We spoke with
Speaker 1: Bonnie Lutka, a post doc at Scripps Institution of Oceanography
Speaker 1: at the University of California in San Diego. She said,
Speaker 1: I think there's reason to be concerned, but I also
Speaker 1: think there's still a lot we don't know about how
Speaker 1: long the sand stays where it goes, and how much
Speaker 1: sand you need to place on a beach to be effective,
Speaker 1: or learning as we go. A study published by Luca
Speaker 1: in the June issue of the journal Coastal Engineering examines
Speaker 1: exactly what happened to sand deposited on four beaches in
Speaker 1: San Diego County in California. She and her colleagues used
Speaker 1: jet skis, a t v s, and other tools to
Speaker 1: continuously monitor sand levels and sand movement at the beaches
Speaker 1: over a period of about ten years. The research received
Speaker 1: funding from the U. S. Army Corps of Engineers, the
Speaker 1: California Department of Parks and Recreation, the National Science Foundation,
Speaker 1: and the California Sea Grant. Among their findings, the team
Speaker 1: learned that the entire amount of sand added to San
Speaker 1: Diego's Tory Pines in two thousand one was washed away
Speaker 1: during a single storm. At another beach, the addition of
Speaker 1: a hundred and thirty eight Olympic swimming pools worth of
Speaker 1: sand contributed to the clogging and eventual closure of a
Speaker 1: nearby estuary. Among the team's more positive findings was that
Speaker 1: larger grained sand appeared to have better staying power than
Speaker 1: fine grained sand, and in some cases, the amount of
Speaker 1: sand deposited to a beach by natural forces was comparable
Speaker 1: to any mechanically added sand Luca said, there is quite
Speaker 1: a bit of natural variability, so it's hard to pick
Speaker 1: out trends, but at our longest recorded site, we did
Speaker 1: see an overall pattern of erosion. The pattern of erosion
Speaker 1: that Luca's team observed at ground level is what's alarming
Speaker 1: to researchers assessing the long term future of US beaches.
Speaker 1: With climate change, sea level has risen by about eight
Speaker 1: inches that's twenty since nine, according to the Intergovernmental Panel
Speaker 1: on Climate Change, and could rise three to five feet
Speaker 1: higher that's point nine to one point five meters by
Speaker 1: the end of this century. More frequent coastal storms, also
Speaker 1: associated with climate change, take a further toll on beaches
Speaker 1: by unleashing rough waves that eat away at the shore.
Speaker 1: We also spoke with Michael or Back, Professor Emeritus of
Speaker 1: Marine Affairs and Policy at Duke University. He said, any
Speaker 1: beach nourishment is forever. It's like painting house. Once you
Speaker 1: start it, you have to keep doing it forever to maintain.
Speaker 1: The problem is with climate change, in rising sea levels,
Speaker 1: there's going to be even more demand by orders of
Speaker 1: magnitude because the beaches are going to erode more and faster.
Speaker 1: Western Carolina University's Program for the Study of Developed Shorelines
Speaker 1: hosts an interactive database of beach nourishment projects across the
Speaker 1: US and their costs. As the data show, beach nourishment
Speaker 1: today is not cheap. Or Bach estimates the average cost
Speaker 1: of supplementing sand at beaches comes out between one and
Speaker 1: two million dollars per mile of sand. As the demand
Speaker 1: for sand four beach nourishment increases, the cost will rise
Speaker 1: even higher. Or Bach predicts. He said, in the end,
Speaker 1: there may not be enough sand that's economically recoverable to
Speaker 1: nourish every beach that people want to nourish. There's also
Speaker 1: an ecological cost. Studies have shown that dredging and depositing
Speaker 1: sand is disruptive to creatures living in the sand and
Speaker 1: the animals that eat them. While the research suggests those
Speaker 1: animals tend to recover after eighteen months to two years,
Speaker 1: beaches that undergo repeated nourishment to see significant declines in
Speaker 1: animal life. Despite the economic and ecological costs of beach nourishment,
Speaker 1: it may be among the few available options for preserving
Speaker 1: beaches in the future. Sean Vita, sec and engineer specializing
Speaker 1: in ocean modeling at the University of Illinois and Chicago
Speaker 1: points out that natural sources of beach sand, including rivers
Speaker 1: and eroding cliffs, have been suppressed by human built dams
Speaker 1: and protective coverings. Vita Sex served as lead author of
Speaker 1: a March seventeen modeling analysis from the U S Geological
Speaker 1: Survey that concluded that if no measures are taken, up
Speaker 1: to sixty seven percent of California's beaches could be completely
Speaker 1: eroded back to sea, cliffs or coastal infrastructure by the
Speaker 1: year twenty one hundred. The U S Geological Survey models
Speaker 1: showed that beach nourishment could protect some larger beaches that
Speaker 1: have undergone nourishment for decades, but that overall beach nourishment
Speaker 1: will have to be stepped up to a much faster
Speaker 1: pace to continue to be at all effective. Vita Sex said,
Speaker 1: if you dump sand on a beach, that sand is
Speaker 1: not going to stay there forever, the current methodical rate
Speaker 1: of beach nourishment is insufficient against the coming sea level rise.
Speaker 1: Ludca said there is quite some debate about how climate
Speaker 1: change will influence the frequency and intensity of storms, and
Speaker 1: these storms will be more responsible for beach evolution than
Speaker 1: sea level rise in the next few decades. It may become,
Speaker 1: she says, a matter of choosing between investing in ever
Speaker 1: pricier efforts to preserve beaches or standing back and allowing
Speaker 1: nature's forces to redraw the lines of where the ocean
Speaker 1: meets the land. Today's episode was written by Amanda Onion
Speaker 1: and produced by Tyler Clang. For more on this and
Speaker 1: lots of other alarming but important topics, visit our home planet,
Speaker 1: how stuff Works dot com.