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Adapting to Sea Level Rise in a Coastal Megacity

Los Angeles adapts to sea level rise

By Alyssa Newton Mann, USC Sea Grant and Henry Hodde, Sea Grant Knauss Fellow with the National Sea Grant Office

Can you imagine Los Angeles without its iconic wide sandy beaches, coastal boardwalks, and flocks of tourists? All of these are jeopardized by sea level rise due to global climate change.

The L.A. economy is highly reliant on its coasts. The bustling tourist industry is centered on pristine beaches, and a sprawling boardwalk. The Port of L.A. is one of the busiest in the United States, responsible for over $400 billion in trade. To keep a city this size running, the city maintains two power plants and two wastewater treatment plants, all of which sit approximately 10 feet above sea level. Some of these and other invaluable coastal assets are already vulnerable to flooding during high tides and severe storms. This flooding is expected to worsen, as higher sea levels exacerbate impacts from storm surge and wave run-up. 


In an effort to safeguard valuable areas along the coastline, the City of L.A. engaged the University of Southern California (USC) Sea Grant Program to develop AdaptLA, a city-led science-based and stakeholder-supported adaptation planning process and vulnerability assessment. AdaptLA helps the City first to identify vulnerable assets, resources and communities, and then provides guidance for adaptation strategies.

The strength of AdaptLA comes from the unprecedented degree of stakeholder collaboration and interagency coordination. USC Sea Grant assembled a team of experts to help evaluate the extent of risk, examining physical, social, ecological and economic vulnerabilities to sea level rise. “USC Sea Grant assembled the strongest possible science team. With information being continually updated and improved, especially in the field of climate science, it is critical to connect decision-makers with the scientists working on these issues,” said USC Sea Grant Associate Director Phyllis Grifman.


USC partnered with the Los Angeles Regional Collaborative for Climate Action and Sustainability (LARC), a network that is a catalyst for climate action in the region, and ICLEI – Local Governments for Sustainability, California Region, to engage local businesses, industry experts, L.A. representatives, public utilities, and environmental organizations.

The process began through a coastal impact model developed by the U.S. Geological Survey, which incorporated impacts of rising seas with wave and storm surge. This assessment was used to look at the direct impact of sea level rise in the L.A. region.

Based on the findings from the coastal impact model, the study identified physical vulnerabilities in critical infrastructure and communities. These areas were further broken down into identifiable sections including: the stormwater management system, potable water system, roadways, museum and cultural centers, parks, ports, and energy facilities. Based on the assessments, City officials were able to prioritize improvements that would lessen impacts and increase overall resiliency to sea level rise.


AdaptLA also examined the social vulnerability of L.A.’s coastal communities. U.S. Census data was used to screen for socioeconomic characteristics of communities that, when faced with the threats of climate change, had higher sensitivity and lower adaptive capacity. This examination was particularly powerful, allowing city official to pinpoint communities that most vulnerable to sea level rise impacts. This knowledge can prove vital to city officials, in the creation and adoption of a climate adaptation plan.

“Identifying vulnerable communities within the potential inundation zone is extremely valuable to disaster planning authorities,” said USC Sea Grant Planning & Research Specialist Alyssa Newton, formerly of FEMA. “The impacts of climate change will be felt more strongly by populations less able to prepare or recover from extreme events. Knowing where these populations reside, and developing strategies to enhance preparedness and building resilience in these communities are essential.”

USC Sea Grant continues to work with the City as it develops adaptation strategies for other climate-driven hazards and vulnerabilities. Moreover, USC Sea Grant will continue its work with LARC to develop a multisectoral sea level rise planning process for the entire L.A. region.


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