Saving Tomorrow’s Coast

Can California protect its iconic coastline as sea levels rise?

In the face of climate change and rising sea levels, the California coast we know today will not be the coastline of the future.

Including estuaries like San Francisco Bay, California’s coastline measures over 3,400 miles (5,472km) and encompasses a range of physical settings that support a great diversity of habitats, some of which are found nowhere else in the world. California’s beaches, tide pools, wetlands, estuaries, and coastal uplands also provide important services to people in the form of storm buffering, water filtration, fisheries production, and recreation – all of which fuel the state’s economy.

As waters rise and coastal margins erode, investments that have been made in coastal conservation to protect important habitats and species are at risk. How the State anticipates and adapts to changes from sea level rise will determine what the future coastline will look like, how well conserved and protected its coastal ecosystems will be, and what benefits the coast will offer future generations. To make informed decisions, we need to understand where coastal ecosystems are vulnerable to sea level rise, and where there are opportunities to conserve the coastline of the future.

Applying our Science

To provide answers to these questions, Conservancy scientists are working in partnership with the California Coastal Conservancy to quantify the vulnerability of coastal habitats to sea level rise, and map and quantify where there are opportunities to conserve or enhance coastal habitats into the future. Our study area spans the entire California coast and extends inland 8 km beyond the projected footprint of 1.5 meters of sea level rise. Using best available spatial data, we characterized the landscape into 35 wetland and upland habitat types and 17 developed or agricultural land uses.  We spatially quantified the vulnerability of coastal habitats as the relationship between the potential impact from sea level rise exposure and the habitat’s adaptive capacity or ability to transgress inland over time in response to sea level rise. We also identified the biggest impediments to adaptive capacity, the anticipated “loss” given no action, and where the best opportunities are to enhance and maintain habitat area and mitigate habitat losses.

This state-of-the-science assessment can be used to guide conservation strategies such as land conservation, management in place for resilience, and the reclamation of habitat from the built environment. By making the analyses standardized and modular, the assessment is scalable to other geographies and may be updated as data are improved, such as when new sea level rise projections, become available.

California’s iconic coast provides not only invaluable habitat for native species – but also incalculable benefits for people. Science can help ensure those values persist, even in a rapidly changing world.

One way estuarine marshes could adapt to rising sea levels is by collecting sediments – and migrating vertically. Unfortunately, the sediments estuarine marshes need are often locked behind human-made structures, therefore, marshes will need to adapt by slowly moving inland in response to rising sea levels. However, the built environment may preclude that natural inland transgression. © Walter Heady/TNC

Beaches will move upwards and inland in response to sea level rise. Dunes along beaches provide sand to “feed” and maintain beaches, helping them move vertically in response to sea level rise, as well as providing space for beaches to move inland in to. Photo: © Walter Heady/TNC

Related Products

2019 | Freshwater | Marine | Planning | Technology | Science | Publications & Reports

Insights into estuary habitat loss in the western United States using a new method for mapping maximum extent of tidal wetlands

Laura S. Brophy, Correigh M. Greene, Van C. Hare, Brett Holycross, Andy Lanier, Walter N. Heady, Kevin O’Connor, Hiroo Imaki, Tanya Haddad, Randy Dana

The authors of this study generated new maps of current and historical tidal wetlands in 450 estuaries throughout Washington, Oregon, and California. Using laser-mapping technology known as LIDAR combined with water elevation models, the team estimated that West Coast estuaries historically covered nearly 2 million acres.…

2018 | Freshwater | Terrestrial | Marine | Planning | Science | Publications & Reports

Conserving California's Coastal Habitats: A Legacy and a Future with Sea Level Rise

Walter N. Heady, Brian S. Cohen, Mary G. Gleason, Joshua N. Morris, Sarah G. Newkirk, Kirk R. Klausmeyer, Hilary R. Walecka, Elizabeth Gagneron

Sea level rise presents a new challenge to coastal conservation. The authors quantified and mapped the vulnerability of habitats, imperiled species, and conservation lands to sea level rise throughout the entire California coast, where high biodiversity, high endemism, and 26.5 million people coincide. Combining habitat…

2016 | Marine | Publications & Reports

Marine and Coastal Impacts of Ocean Desalination in California

Szeptycki, L., E. Hartge, N. Ajami, A. Erickson, W. N. Heady, L. LaFeir, B. Meister, L. Verdone, J.R. Koseff

The drought in California rekindled interest in ocean desalination as a new and reliable water supply option; yet desalination is expensive, energy intensive, potentially emits greenhouse gases, and has adverse impacts on coastal and marine ecosystems. This report is a synthesis of an Uncommon…

2015 | Marine | Planning | Maps & Webmaps

Coastal Resilience Monterey webmap

Brian Cohen

The Coastal Resilience Network supports a community of practitioners who are applying nature-based solutions to coastal hazard and climate adaptation issues. As a member of this Network, the Conservancy is working with scientists, geomorphologists, urban and environmental economists, regional conservation partners, and local stakeholders…

2015 | Marine | Planning | Maps & Webmaps

Coastal Resilience Ventura Web Map

Brian Cohen

As a member of the Coastal Resilience Network, the Conservancy is leading Coastal Resilience Ventura. Coast Resilience Ventura is a partnership that provides science and decision-support tools to help conservation practitioners, planners and policymakers address the impact of climate change. Through this effort, the…

2014 | Freshwater | Marine | Planning | Publications & Reports

An Inventory and Classification of U.S. West Coast Estuaries

Walter N. Heady, Kevin O'Connor, Jennifer Kassakian , Kate Doiron, Charles Endris, Daniel Hudgens, Ross P. Clark , Jena Carter , Mary G. Gleason

Estuaries are some of the most productive ecosystems on the planet. This inventory classifies more than 600 coastal confluences on the West Coast of the United States. Each estuary was classified using the federal Coastal and Marine Ecological Classification Standard (CMECS). A spatial database of…

2014 | Freshwater | Marine | Science | Publications & Reports

Nursery Functions of U.S. West Coast Estuaries: The State of Knowledge for Juveniles of Focal Invertebrate and Fish Species

Brent B. Hughes, Matthew D. Levey, Jennifer A. Brown, Monique C. Fountain, Aaron B. Carlisle, Steven Y. Litvin, Correigh M. Greene, Walter N. Heady, Mary G. Gleason

Estuaries support significant biodiversity and important ecosystem functions such as providing rearing habitat for juvenile fish and invertebrates. This report synthesizes the scientific literature and geospatial data on the nursery requirements of fifteen species of commercial, cultural, and conservation concern and highlights the potential nursery role…

2012 | Marine | Planning | Science | Maps & Webmaps

California Coastal and Marine Program: Protecting Fish Stocks and Livelihoods

Matt Merrifield, Megan Webb, Katie Andrews

Since 2007, The Nature Conservancy has pioneered a first-of-its-kind fishery reform approach that aligns communities, the fishing industry, and conservation interests to drive strategic changes in fishery management and harvest practices. We have provided science and planning expertise and applied technology to increase efficiency and…

2011 | Freshwater | Marine | Planning | Publications & Reports

Conservation Assessment of U.S. West Coast Estuaries

Mary Gleason, Sarah Newkirk, Matt Merrifield, Jeanette Howard, Robin Cox, Megan Webb, Jennifer Koepcke, Brian Stranko, Bethany Taylor, Mike Beck, Roger Fuller, Dick VanderSchaaf, Jena Carter

While significant progress has been made over the past few decades in improving estuarine water quality, restoring wetland habitats, and incorporating estuarine habitats into managed areas, estuarine conservation efforts along the U.S. West Coast—including Washington, Oregon, and California—have generally proceeded on a bay-by-bay basis, with…