Bye-Bye, Beaches

Californians love the ocean. In fact, 39 percent of us live near the Pacific Ocean, the vast, endlessly complex ecosystem that hugs our state's 840 miles of shoreline. The other 61 percent would probably live there too, if we could afford it.

Those beaches, as we know them today at least, almost certainly will not last. By the end of the 21^st century, more than $150 billion in property along our coast could be under water. That's because the level of the sea is rising at an alarming rate, putting these areas at risk for devastating floods.​​​

“The California coast contains some of the most valuable property on the planet," says Ross Clark, coastal ecologist and director of Central Coast Wetlands Group (CCWG) at Moss Landing Marine Laboratories (MLML), which is administered by San José State University. “Much of that development is vulnerable to flooding and storm impacts because we didn't develop our lands with a consideration for the fact that ocean levels and the edge of the coast will change over time."

That change is happening now.

So What Is Sea Level Rise, Exactly?

You probably already know that climate change makes both land and water warmer. As seawater heats, it expands, which causes oceans to swell. In addition, rising global temperatures are causing ice to melt in Greenland and Antarctica. “It's flowing down into the ocean and there's so much water that it's having an effect on our current ocean levels," Clark explains.

What Does This Mean for California?

Sea level rise brings powerful waves ashore. That means extensive damage to natural habitats (beaches, wetlands, sand dunes), homes, schools, infrastructure (airports, roads, bridges, train tracks, water treatment plants, electric generation plants) and agriculture (crop land).

By 2100, as much as two-thirds of Southern California's beaches may experience complete erosion up to their sea cliffs. Coupled with the increase of unpredictable storms brought on by climate change, the result will be catastrophic. Most at risk are cities in lower-lying areas, such as San Francisco and Long Beach, the site of the country's second-busiest port, which moves more than $194 billion worth of goods annually. If the port were shut down due to flooding, the economic repercussions would reverberate throughout the U.S.

Some coastal communities are already "armoring" their shoreline, meaning they're adding physical barriers from sandbags to seawalls to off-shore breakwaters to stave off erosion. But these efforts might be shortsighted.

“We're putting rock and concrete on top of our beaches and our dunes to protect what's inland of them," says Clark, but “armoring is constructed to the detriment of our natural environment." The artificial barriers can cause erosion down the coast, limit beach access, change the coastline's natural beauty and affect birds and other species that rely on the beach for food and nesting.

Also in danger is the state's fishing industry. “Sea level rise is going to impact our estuaries, creeks and rivers, which are breeding grounds for many of our commercial fish species," Clark adds. “We may lose some of those nurseries. And much of the fishing industry is located in our coastal harbors, which are vulnerable in many ways."

How Is the CSU Helping?

A lot of the current work by CSU faculty researchers and their students is focused on assessing the impact of sea level rise so we can predict, and protect, the most vulnerable places along California's coast.

For example, Clark works with a team of four MLML biologists and students to restore and enhance living shorelines such as sand dunes and wetlands. These will help protect property and beaches against sea level rise and provide habitats for natural species.

“Dunes can help buffer wave impacts to low-lying areas," he explains. “Our restoration activities are focused on making sure the dunes are able to withstand predicted waves and be high enough to resist that wave overtopping." The CSU is also working to remove invasive species such as ice plant, which restricts sand movement, so sand can adjust to changing ocean levels.

Wetlands can mitigate flooding by reducing the strength of waves and restricting how far a wave can move inland by acting as a storage space for seawater. “We're working with farmers to transition some low-lying areas that are no longer viable for farming due to sea level rise back into wetlands," Clark says. “Our students do a lot of the actual field restoration, species eradication, watering and collecting of data to document the success [of this work]."

Restoration of oyster reefs and seagrasses may also be a key to assisting with sea level rise. An experimental project in San Francisco Bay in collaboration with San Francisco State University's Estuary & Ocean Science Center showed that oyster reefs can reduce wave energy by 30 percent. The local seagrass, known as eelgrass, is being used in combination with oyster reefs to provide habitat and other ecosystem services. 

“Eelgrass beds slow the flow of water, allowing fine particles to drop out, which aids in clearing the water as well as accumulating sediment," says Katharyn Boyer, Ph.D., professor of biology at San Francisco State. “The latter can help an eelgrass bed keep pace with sea level rise. We are evaluating whether planting eelgrass on the shoreward side of oyster reefs can protect the eelgrass and thus how the two habitats together can reduce erosion and protect shores while also maximizing wildlife habitat."

Dr. Boyer was awarded funding to develop and test new designs for oyster reefs in an effort to simplify their construction, which is very difficult in shallow marine environments. That project includes the design of panels that can be added to seawalls to increase their habitat value. She and graduate student Kelly Santos are also testing methods to raise the height of wetland plant canopies to provide refuge for endangered birds and mammals during flooding. Such innovations in what are called “living shorelines" offer greener alternatives as the water rises along our coasts.

Multiple CSU campuses are researching sea level rise with funding from the CSU Council on Ocean Affairs, Science & Technology (COAST) and working to mitigate its effects, including Cal State Long Beach, CSU Channel Islands and Humboldt State.