Last year's crazy El Niño resulted in unprecedented beach erosion (USA)
Author: 系统管理员Source: Updated: 2017-02-22

El Niño may be behind us, but it turns out the weather phenomenon left a lasting impact on the California coastline. According to a scientific study published this week, last year’s El Niño system caused unprecedented levels of erosion and it could be a long time before the beach ecosystems recover from the blow. 

When we talk about El Niño, often the first thing that comes to mind is rain—but that’s only one of several factors. Another component of the system is powerful ocean waves that can batter delicate coastlines. The strong waves of an El Niño season slam into the beach and scoop up sand and carry it back out to sea faster than it can be replenished. 

That’s tough on a beach any time, but this go-round was particularly intense. The most powerful waves of the 2015 to 2016 El Niño cycle clocked in at 50 percent larger than even the 1997 to 1998 El Niño. All told, the erosion along the coastline was 76 percent greater than what occurs in a standard year, the L.A. Times reports.

The fact that California’s beaches are eroding can’t entirely be blamed on a freakishly strong El Niño, though. Some of the responsibility falls to human development.

“Our beaches are sand-starved, partially because we’re starving them,” said Robert Guza, a physical oceanographer at U.C. San Diego’s Scripps Institution of Oceanography.

What he means by that is this: In nature, there’s a system that connects the sand deposits of the ocean, rivers and other bodies of water. Over time in Southern California, building developments have sprung up in what were once river floodplains, and once the rivers are controlled with dams, the flow of sand deposits gets cut off. Guza estimates that half of the sediment that would otherwise be replenishing beaches is currently being trapped in these dam systems.

The implications of this level of erosion are pretty big. In the short term, we can expect to see problems for property owners along the beaches and habitat destruction for beach-dwelling plants and animals. Longer term, it’s also a troubling preview of what might be to come as climate change and sea level rises continue and monster El Niños become the norm.


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