First statewide high-resolution assessment of recent coastal cliff erosion and retreat

Coastal cliff erosion in California threatens structures, beaches, parks, public safety, and major transportation corridors. Erosion will worsen as sea levels continue to rise. University of Southern California (USC) Sea Grant funded a study to use the most recent data to update cliff retreat rates statewide. Understanding the processes that drive cliff erosion and quantifying the rates at which they operate are essential for coastal managers and for building resilient communities.

Key Results:

  • Provided the first modern, high-resolution erosion rates for about half of California
  • Identified hot spots, detected regional and local trends, and validated an experimental cliff top hazard index designed to better direct management efforts
  • Journal publications in Geomorphology and Geoscientific Model Development


Project Impacts & Application:

  • Presentations: American Geophysical Union Conference, Scripps Directors Council, AGU Ocean Sciences, Office of Management and Budget – Executive Office of the President, Osher Lifelong Learning Institute
  • Briefings: CA Assemblymember Davies; Staff of US Senator Padilla; Marine Corp Air Station Miramar; City of San Diego Chief Sustainability Officer Shelby Rust Busó
  • Webinars for staff from California State Parks and California Coastal Commission
  • Media attention: front-page articles on the LA Times, San Francisco Chronicle, and San Diego Union-Tribune; features on KQED, KPCC, KPBS, The Weather Channel, The Coast News, Lost Coast Outpost, Pacifica Tribune, and The San Diego Reader


Principal Investigators:

  • Adam Young, Ph.D., University of California San Diego 
  • Mark Merrifield, Ph.D., University of California San Diego 



California Ocean Protection Council, 2018-2021


Additional Info and Publications


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