Thanks to rising seas, 95 percent of the city's marsh area could become mudflats by 2100.

By now, we're used to hearing about the threats sea level rise poses to human society: It can wash away urban areas, give a boost to storms, and swallow island nations. But new research from a team at the US Geological Survey shows that rising seas can also devastate fragile ecosystems.

Wikimedia Commons

Using a custom-built sea level modeling tool, USGS's Western Ecological Research Center forecast the future for a dozen salt marshes in the San Francisco Bay Area, home to several species of federally protected birds and other animals. The predictions are grim: 95 percent of the marsh area could become mudflats by 2100, the effect of four feet of sea level rise (a level projected by previous studies).

That's a problem for marsh-loving endangered species like the salt marsh harvest mouse (left) and the California black rail bird, both found only in the Bay Area, and for other beach-dwelling birds that count on solid ground to lay their nests.

Take a look at the video below, which shows the projection for a marsh in San Pablo Bay; yellow is land, light blue is average sea level, and dark blue is high water level: 

By the end, no more marsh (have a favorite Bay Area marsh? You can see projections for it here). Here's that same story, told a different way, as the marsh goes from a healthy green to muddy brown:

san pablo marsh

The study points out that marshes have historically been able to keep pace with sea level rise, by continually accumulating sediment and plant life. They can also escape rising seas by retreating inland. But in the Bay Area many marshes are hemmed in by development, and the rate of sea level rise projected for the remainder of this century could outpace their ability to keep up. By century's end, the study predicts, the unique "high" marsh habitat—marked by infrequent flooding, relatively solid ground, and hardier plants—could be lost completely, replaced by watery expanses of mud interspersed with a few "low" marshes, bathed in warm salty water and suitable only for algae. This isn't a problem only for the flora and fauna there: Marshes serve as an important buffer zone between the sea and urban areas; in San Francisco, a lot of important infrastructure (highways, airports, etc.) are only a few feet above sea level.

John Takekawa, who led the study, said the findings make an important statement about the damage sea level rise can bring even when it doesn't cover the coast. "Even when it's not that entire areas will be washed away, per se," he said, "the vegetation is changing, and then the habitat."

Top image courtesy of Ingrid Taylor/Flickr.

About the Author

Most Popular

  1. Life

    The Cities Americans Want to Flee, and Where They Want to Go

    An Apartment List report reveals the cities apartment-hunters are targeting for their next move—and shows that tales of a California exodus may be overstated.

  2. photo: A Lyft scooter on the streets of Oakland in July.
    Transportation

    4 Predictions for the Electric Scooter Industry

    Dockless e-scooters swept cities worldwide in 2018 and 2019. In 2020, expect the battery-powered micromobility revolution to take a new direction.

  3. photo: Dominque Walker, founder of Moms 4 Housing, n the kitchen of the vacant house in West Oakland that the group occupied to draw attention to fair housing issues.
    Equity

    A Group of Mothers, a Vacant Home, and a Win for Fair Housing

    The activist group Moms 4 Housing occupied a vacant home in Oakland to draw attention to the city’s affordability crisis. They ended up launching a movement.

  4. photo: a pair of homes in Pittsburgh
    Equity

    The House Flippers of Pittsburgh Try a New Tactic

    As the city’s real estate market heats up, neighborhood groups say that cash investors use building code violations to encourage homeowners to sell.  

  5. photo: Toxic lead paint peels from a window frame on a rowhouse in Baltimore, Maryland.
    Environment

    The Unequal Burden of Urban Lead

    Decades after federal regulations banned the use of the deadly metal in paint, gasoline, and plumbing, the effects of lead continue to be felt across America’s cities.

×