San Diego County Coastal Habitats and Sea Level Rise
San Diego County has roughly 70 miles of coastline that form the backbone of our culture, economy and critical wildlife habitat. Sea level rise resulting from global climate change has the potential to alter the form and function of our coastline habitats. Gauges along the California coast have recorded an increase during most of the 20th century. By 2050, models predict sea level increases of 12 to18 inches in San Diego. The combination of higher sea level, waves, tides and weather conditions may put coastal habitat in San Diego County at risk for habitat loss.
As sea levels continue to rise, new challenges for planning, managing and protecting our natural resources and communities will face decision makers. To help reduce some of the associated uncertainty, we will need local data to guide management decisions. To this end, Dr. Rick Gersberg at San Diego State University and San Diego Coastkeeper partnered to disseminate information about one key aspect of global climate change - how sea level rise might change San Diego's coastal landscapes.
The generous support of the Environment Blasker Grant of the San Diego Foundation made this project possible.
Dr. Gersberg’s lab integrated data specific to the San Diego coast into an EPA model, Sea Level Affects Marshes Model (SLAMM), to predict how San Diego’s coastal habitats might shift as sea levels change. Using different sea level rise scenarios (essentially low, moderate, high sea level rise), the model predicts that San Diego’s coastal habitats may look very different over the next 100 years. To view the predictions for three key San Diego coastal areas (Mission Bay, San Diego Bay, and the Tijuana Estuary), see the map below. To learn more about the SLAMM model and its predictions for the rest of San Diego's coastline, download the full report and check our climate change and sea level rise resource page for additional information.
Coastkeeper’s Priorities for Sea Level Rise Adaptation Planning:
Planning for adapting to sea level rise is different than mitigation planning.
- Plan holistically
- Prioritize protecting and adding buffer areas to allow habitats to shift as needed
- Prioritize ‘soft strategies’ (natural shorelines, wetland restoration, etc)
- Incorporate low impact development stormwater planning with climate change planning
Key Findings from the SLAMM model
For the whole San Diego coastline, the SLAMM model predicts that sea level rise may result in:
- the loss of approximately 23% of our freshwater marshes when sea level rise by 2100 exceeds 1 meter;
- a slight gain of salt marshes under all scenarios because freshwater marshes and swamplands convert to salt marshes when inundated; and
- a loss of 35% - 43% of ocean beaches by 2100. This does not account for anthropogenic beach nourishment, however, nor does it account for increased sedimentation rates caused by increased upslope erosion.