CityAdapt Blog – Rising Seas in California: How Are Coastal Communities Adapting?

Our climate is changing in unprecedented ways. Here in California, one effect of climate change—sea level rise—generates great concern for coastal cities. And the sea is already rising. Over the next century, sea level rise in the Los Angeles region is expected to match global projections with and increase of 0.1 – 0.6 m (5-24 inches) from 2000 to 2050 and 0.4 – 1.7 m (17-66 inches) from 2000 to 2100[1]. Rising seas, combined with the threat of other coastal impacts such coastal erosion, high tides and severe storms are driving coastal communities to begin planning for these challenges and identifying strategies to adapt.

Planning for an uncertain future is no easy feat. The International Panel on Climate Change pointed out in the most recent assessment that “responding to climate-related risks involves decision making in a changing world, with continuing uncertainty about the severity and timing of climate-change impacts.”[2] This challenge is faced by communities and decision-makers at all levels. Without a crystal ball to tell us exactly what our future holds, we rely on predictive models to help identify vulnerabilities, set priorities and steer planning in the right direction.

Sea level rise and coastal storm models are advancing quickly; we’ve moved beyond “bathtub” or stationary models to more dynamic models that downscale global climate models to the local level and integrate the physical processes such as tides, surge and waves that affect water levels. For Southern California, the US Geological Survey’s Coastal Storms Modeling System, CoSMoS 3.0, is being developed to project shoreline change, erosion, and flooding resulting from increased sea level rise, storms, and river discharge. Local governments and communities will be able to access this information to support coastal hazard and sea level rise vulnerability assessments beginning this fall.

While scientists are working diligently to develop sophisticated sea level rise models for Southern California, the University of Southern California (USC) Sea Grant program is laying the groundwork for successful adaptation planning by working directly with coastal managers, planners, and leaders throughout Southern California. As stakeholders have expressed repeatedly, it is not enough to just hand over the science when it is ready. USC Sea Grant plays an important role as a boundary organization, providing the technical assistance, training and outreach needed to help build capacity in coastal communities as they begin to plan for impacts from sea level rise.

USC Sea Grant is leading two major capacity building projects – Regional AdaptLA (which includes L.A.’s 11 coastal municipalities and L.A. County), and the Southern California Coastal Impacts Project (SCCIP), which focuses on capacity building and technical assistance for the Coastal Storm Modeling System (CoSMoS 3.0) for coastal communities. USC Sea Grant is leading the outreach, communication, and training on CoSMoS 3.0 to ensure the model meets user needs and effectively supports policy and planning decisions. Sea Grant hosts ongoing free professional development workshops and webinars to provide subject-specific information and training to advance sea level rise and coastal impacts planning in L.A. and Southern California.

In both of these programs, we encourage stakeholders and partners to consider an “adaptive” approach to adaptation as they plan and respond to sea level rise and other coastal impacts. Adaptive management, a concept familiar in resource management, is characterized as “learning by doing, a formal iterative process that acknowledges uncertainty and achieves management objectives by increasing system knowledge through a structured feedback process.”[3] We cannot wait for “perfect” information to begin planning for potential impacts — the science will continue to evolve and advance. Local and regional adaptation processes and plans need to be flexible to integrate new information, iterative to respond to change, and account for a range of potential scenarios.

 USC Sea Grant is pleased to work directly with coastal communities to embrace this approach, having completed a Sea Level Rise Vulnerability Assessment with the City of Los Angeles, assisting the City of Imperial Beach as they undergo a vulnerability and adaptation planning process, and providing technical assistance across Southern California. Improved communications, and sharing of management plans and lessons learned among jurisdictions will help support decision-making and ensure not only the use of the best available science, but that it is understood and utilized for proactive and effective planning.

UnknownAbout the author: Alyssa Newton Mann is a Regional Research and Planning Specialist at USC Sea Grant, focusing on planning for climate change impacts and building disaster resilience.  Her background is in emergency management and international affairs, having worked at multiple federal and state government agencies, including FEMA, the U.S. Department of State and the State of California.



[1] National Research Council. “Sea-Level Rise for the Coasts of California, Oregon, and Washington: Past, Present Future,” 2012.

[2] International Panel on Climate Change. Fifth Assessment Report, 2014.

[3] Allen, Craig R.; Fontaine, Joseph J.; and Garmestani, Ahjond S., “Ecosystems, Adaptive Management,” 2013. Nebraska Cooperative Fish & Wildlife Research Unit — Staff Publications. Paper 128.