In the past century, global mean sea level has increased by 7 to 8 inches with human influence the dominant cause of observed atmospheric and oceanic warming. Given current trends in greenhouse gas emissions and increasing global temperatures, sea level rise is expected to accelerate in the coming decades, according to the most recent available science, by the year 2100, sea levels may rise by 1 to 6.6 feet (0.3 to 2.0 meters) (OPC 2024). While over the next few decades, the most damaging events are likely to be dominated by large El Niño - driven storm events in combination with high tides and large waves, impacts will generally become more frequent and more severe in the latter half of this century.
The impacts of sea level rise in California will affect almost every facet of our natural and built environments. Natural flooding, erosion, and storm event patterns are likely to be exacerbated by sea level rise, leading to significant social, environmental, and economic impacts. Through its Sea Level Rise Policy Guidance and ancillary efforts, the Coastal Commission advances, supports, and helps to fund California's preparation for these critical challenges to ensure a resilient coast for present and future generations.
2024 Update to SLR Guidance: The Coastal Commission has released a public review draft of the latest update to its Sea Level Rise Policy Guidance. Updates address three main topic areas: 1) evolving best available science; 2) integration of environmental justice principles and planning considerations related to sea level rise; and 3) guidelines regarding Local Coastal Program updates consistent with Senate Bill 272. More information and the draft document can be found on the SLR Policy Guidance webpage. The Draft Update will be introduced at the August Commission meeting, focusing on science and Senate Bill 272 updates. The environmental justice updates will be described at the September Commission meeting. Commission action to adopt the Update is anticipated later in 2024. The public review period will close on Monday, September 23, 2024. Comments can be sent to StatewidePlanning@coastal.ca.gov.
SF Bay Area SLR Adaptation Funding & Investment Framework: In July 2023, BCDC, in coordination with the Metropolitan Transportation Commission and Association of Bay Area Governments, released a Sea Level Rise Adaptation Funding and Investment Framework which quantifies the magnitude of the funding required to protect the San Francisco Bay’s shoreline from flooding due to sea level rise and storms by 2050. Among a variety of recommendations, the report identifies that the cost to protect the SF Bay shoreline to hazards in 2050 will be $110 billion. The BCDC Chair and Executive Director also joined the CCC’s July 12 hearing to discuss the report and BCDC’s SLR planning efforts (Item 6e).
Sea Level Rise Guidance for Critical Infrastructure Adopted by Commission: At its November hearing, the California Coastal Commission adopted a guidance document for critical infrastructure adaptation planning, titled: Critical Infrastructure at Risk: Sea Level Rise Planning Guidance for California’s Coastal Zone. With a focus on water and transportation infrastructure, the goal of the Guidance is to promote resilient coastal infrastructure and protection of coastal resources by providing local governments, asset managers, and other stakeholders with policy and planning information to help inform sea level rise adaptation decisions that are consistent with the Coastal Act.
SLR and Rising Groundwater Briefing: On September 8, 2021 the Coastal Commission heard an informational briefing by a team of scientists from USGS and the University of Arkansas on a new statewide model that shows how sea level rise could cause coastal groundwater tables to rise and the implications that could have for adaptation planning. Click here to view a video of the briefing and here to view the slide presentation. The model can be accessed at https://ourcoastourfuture.org/ and a video demonstration of how to use the website can be viewed here.
The Coastal Act mandates the California Coastal Commission to "protect, conserve, restore, and enhance" the state's coastal resources. Policies on hazard avoidance and coastal resource protection provide the basis for the Commission to consider the impacts of sea level rise. The Commission has long considered sea level rise, erosion rates, and other effects of a dynamic climate in its analysis of permits and LCPs, staff recommendations, and Commission decisions. When Section 30006.5 was added to the Coastal Act in 1992, it directed the Commission to both develop its own expertise and interact with the scientific community on various technical issues, including coastal erosion and sea level rise, specifically.
