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Beware the Rising Tide

King tides and storm surge give us a glimpse into the future

By Charlotte Stevenson, USC Sea Grant

Climate change? How about climate changed. There is no need to argue over models anymore. You can see the future right in front of you today. Storm frequency has increased. Droughts are more severe. Shellfish growers see thinner shells due to ocean acidification. The Great Barrier Reef is dying. Some crops are failing. Other crops are thriving. In May 2014, the National Climate Assessment was published, documenting these and numerous other cases of climate change happening now.

Here in California, one effect of climate change—sea level rise—generates great concern for coastal cities. And the sea is already rising. NOAA reports a 0.04-0.1[1] inch rise in sea level over the last one hundred years, and a recent NOAA report[2] on “nuisance flooding” shows increases of 300-900% on all three U.S. coastlines since 1960. 

However, California residents are getting a real looking-glass view into the future by watching what happens during the annual king tides and storm surges. King tides are simply the highest tides of the year, occurring when there is an alignment of the gravitational pull between moon and sun. During these extreme high tide events, Californians get an idea of what future sea level may look like in their coastal communities. Instead of only relying on a computer model, Californians are watching in real-time where the rising tide goes.

USC Sea Grant has had the privilege to be part of several collaborative projects that are tracking, recording and analyzing these high tides events in order to predict future sea level rise. One such project—The California King Tides Initiative—is organized by a partnership among non-profit organizations and several state and federal agencies, including the San Francisco Bay National Estuarine Research Reserve and the Gulf of the Farallones National Marine Sanctuary. The project focuses on collecting public images of king tides taken with smart phones or cameras and creating a public database and historical record.

As the California King Tides Project Slogan reads—“snap the shore, see the future”—these temporary rises in sea level have already indicated to Californians where there may be permanent future problems, including: loss of beaches, loss of low lying wetland habitats, loss of agricultural lands near the shore, flooding and loss of vital public infrastructure (roads, wastewater treatment facilities, energy facilities, stormwater infrastructure, potable water systems, etc), damage to ports, and saltwater intrusion into valuable groundwater supplies.

FEMA (Federal Emergency Management Agency) plans to use these images as part of the data gathered for a Beach Profile Data Collection project, which will document beach change and high water marks for extreme events in 2014 and 2015. USC Sea Grant will help to coordinate the data collection and provide outreach to constituents on project results. Through AdaptLA—a USC Sea Grant-led project that provides scientific, technical assistance and adaptation planning capacity-building to L.A. regional coastal communities—coastal municipal leaders will participate in a pilot project to use these images to ground truth sea level rise models under development.

One such model[3] is the Coastal Storm Modeling System (CoSMoS), which is a numerical modeling system that will project coastal flooding and erosion driven by climate change, not only from sea level rise but also from future storms, throughout the Southern California Bight. USC Sea Grant will lead outreach, communication, and training throughout the Southern California region to ensure the model meets user needs and effectively supports policy and planning decisions and to ensure CoSMoS results and training will be free of charge. Local governments and communities will be able to use CoSMoS to support coastal hazard and sea level rise vulnerability assessments. The inclusion of current storm data is unique and important because, like the waves from Hurricane Marie that arrived in Southern California in late August 2014, storm surge gives a glimpse into the vulnerability of coastal infrastructure and ability of the coast to deal with large volumes of flooding water.

Just as it is necessary to educate the public and decision-makers about these impacts, it is also necessary to educate teachers and our children about sea level rise, storms and tides. USC Sea Grant has helped to develop a pilot curriculum that is currently being tested by teachers throughout California. Students learn about climate change induced sea level rise, its potential impacts on the coastline, and how they can become leaders in citizen-science-based projects like the California King Tides Projects. While we already experience climate change impacts today, these students represent the generation that will face the full impacts of climate change-induced sea level rise, so there is no better group of people to learn lessons from today’s rising tides in order to adapt for the future.


For more information:

[3] Funding for CoSMoS in Southern California is funded by the California State Coastal Conservancy, the Tijuana River National Estuarine Research Reserve and the California Department of Fish & Wildlife. The USC SG-led outreach is funded by USC Sea Grant and the California State Coastal Conservancy.
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