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


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