Five sea level rise studies that could help cities plan for climate change

A slew of research points to rapidly rising oceans. How will the West Coast adapt?


A set of standard apartment buildings line Esplanade Avenue in Pacifica, California, a small beach town just south of San Francisco. They’re not much to look at: two stories high, with chipping taupe paint and rickety staircases. Inside are cookie-cutter units with shaggy carpet and outdated kitchens. But residents refuse to move out of this place. And it’s hard to blame them: Just beyond each apartment’s sliding glass doors are cliffs that drop to the Pacific Ocean. Residents’ balconies overlook miles of sea, providing a serene backdrop and sunset view.

At least it was serene until January, when a strong El Niño storm surge suddenly caused a giant chunk of the cliffs to crumble into the ocean, leaving a section of apartments teetering over the edge. Pacifica declared a state of emergency and 20 families were ordered to evacuate. This month, the building was demolished and tenants in the neighboring dwellings were told to search for new homes. Even so, some are fighting to stay put.

Waves crash the coast in Pacifica, California.

Pacifica is a prime example of what many coastal communities on the West Coast will face as sea levels continue to rise. Inevitably, more bluffs will erode, more shoreline will disappear, and people will have to either adjust current buildings and infrastructure, or evacuate. “We can say that kind of thing is going to be happening more frequently and with more severity in the future,” says Matthew Heberger, a researcher at the Pacific Institute in California.

Scientists have warned about this for decades, and sea level rise research has been ramping up in recent years to provide policymakers and developers with the information they need to create plans and help coastal communities adapt. Here’s a look at five influential studies:

The study: “Millions projected to be at risk from sea level rise in the continental U.S.” Nature Climate Change, March 2016

Takeaway: By 2100, up to 13 million people in the U.S. will be at risk of flooding from sea level rise averaging nearly six feet.

More: Forty-seven of the 319 counties studied are on the West Coast, including San Mateo County, California, the home of Pacifica where up to 16 percent of the population is in the path of coastal flooding, and Clatsop County, Oregon, where 12 percent will be affected. Some other vulnerable areas are low-lying estuaries in San Francisco Bay and Humboldt Bay, coastal wetlands in southern California, and 30 counties along the Washington coast, Puget Sound, and the Columbia River. On the bright side, research from the U.S. Geological Survey found that about 70 percent of coastal cities can respond and adapt to this sea level rise.  

The study: “Temperature-driven global sea-level variability in the Common Era,” Proceedings of the National Academy of Sciences, January 2016

Takeaway: Seas are rising faster than they have in 2,800 years. Until the 1880s, they rose 1 to 1.5 inches a century. In the 20th century, they rose 5.5 inches.

More: Climate Central published a report in conjunction with this study, where researchers looked at three West Coast cities: Seattle, Washington, San Francisco, California, and La Jolla, California, to show the human impact on coastal flooding since 1950. In Seattle, for example, there were 24 days of natural coastal flooding, compared to 77 days of human-induced flooding, which often means flooding caused the removal of wetlands and flood plains for development.

The study: “PDO and ENSO modulations intensified decadal sea level variability in the tropical Pacific,” Journal of Geophysical Research: Oceans, 2015

Takeaway: From 1980 to 2010, the West Coast experienced a slight drop in sea level rise due to a weather pattern called Pacific Decadal Oscillation, according to NASA. Now, West Coast sea levels are expected to catch up to the global mean.

More: Die-offs in California sea lions, seabirds in Oregon and Washington, and salmon in Alaska were prime indicators of these types of shifts in large-scale climate patterns that make the Pacific Ocean warmer and less productive, according to a 2015 NOAA study

The study: “Expert assessment of sea-level rise by AD 2100 and AD 2300,” Quaternary Science Reviews, 2014

Takeaway: Ninety experts from 18 countries concluded the Intergovernmental Panel on Climate Change had underestimated sea level rise predictions in its reports. They said oceans could rise anywhere from one to 10 feet by 2300, depending on how quickly we cut greenhouse gas emissions.

More: This report called the IPCC’s outlooks into question by providing scientific evidence that sea level rise consequences are far more serious than the IPCC reported. Researchers also looked farther into the future, to 2300 and beyond. These days, more researchers are tying sea level rise research more directly to policy decisions that will affect ecosystems in future millennia.

The study: “Sea-Level Rise for the Coasts of California, Oregon, and Washington: Past, Present, and Future,” National Research Council, 2012 

Takeaway: Major factors that influence sea level rise on the West Coast are: climate patterns like El Niño, the rising and sinking of coastal land due to plate tectonics, and the proximity of the rapidly melting Alaskan glaciers.

More: In 2008, after Gov. Arnold Schwarzenegger issued an executive order for California agencies to plan for sea level rise, California, Oregon, and Washington had major science organizations project possible futures for 2030, 2050 and 2100. It laid important groundwork: The California Coastal Commission has since implemented a sea level rise guidance policy, and Oregon Coastal Management program developed an adaptation toolkit with NOAA.

Lyndsey Gilpin is an editorial intern at High Country News. She tweets 

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