Bay Area Resilience Challenges

Flooding and Sea Level Rise

Resilient by Design

Over the last century, mean sea level in the Bay Area has risen more than 8 inches (20 cm).

Recent projections show a likelihood of an addition 1.1ft (0.33m) by 2050, and between 2.5 and 3.5 ft (0.74 to 1.37 m) by 2100. When projections for ice melt from a major Antarctic ice sheet are factored into the calculations, sea level could rise up to 10.2 ft (3.1 m) by 2100. Flood risks from extraordinary events like king tides or major storms pose additional threats on top of these figures and threaten people, property and infrastructure onshore. Even if emissions levels are significantly reduced, recent studies indicate that a minimum of 6.54 ft (2 m) of sea level rise over the next several centuries is effectively inevitable.

Without any additional protections in place, 3 ft (0.91 m) of sea level rise would likely pose serious flood risks to vulnerable areas in and around the city of San Francisco, including parts of the Embarcadero, most of San Francisco and Oakland international airports, and parts of Corte Madera and San Rafael along Highway 101. In response, many municipalities are planning to implement measures to mitigate or protect against these threats. A recent ballot measure was approved to fund reinforcements to the Embarcadero seawall, which protects the eastern shoreline of San Francisco. Studies on sea level rise scenarios have been completed for several neighborhoods in the city of Oakland, and the municipality is also developing a new 2030 Equitable Climate Action Plan that is being discussed within the City Council.

Read more in the San Francisco Bay Area Summary Report

Learn more about the Oakland 2030 Equitable Climate Action Plan

Water Scarcity and Drought

Resilient by Design

Between 2012 and 2016, California experienced the most severe drought of the last 1,200 years, which coincided with a 1-in-500-year low in snowpack in the Sierra Nevada mountains.

The record low snowpack caused $2.1 billion in economic losses, and approximately 21,000 jobs within the agriculture and recreation sectors were lost statewide. The lack of surface water supplies necessitated the overdraft of groundwater, exacerbating an ongoing and unsustainable trend of relying on dwindling aquifer supplies. By the end of the 21st century, average snowpack in the Sierra Nevada mountains is projected to decline by over 80 percent, a worrying phenomenon for the future of freshwater supplies in the region.

As global temperature increases due to climate change, longer and more profound droughts are projected to occur in California – regardless of whether total annual precipitation increases or decreases. This is of major concern for the provision of drinking water and food supplies, as well as for the integrity of natural ecosystems in the area.

Read more in the San Francisco Bay Area Summary Report

Extreme Heat

Resilient by Design

Projections show that the Bay Area will likely experience significantly higher temperatures by 2050, even if serious efforts to curb greenhouse gas emissions are implemented.

The Bay Area currently has a relatively mild climate, moderated by Pacific air and its proximity to the coast. However, as temperatures continue to rise, heat waves will become more frequent and intense, posing increasing risks to public health and requiring the adoption of cooling infrastructure. As summers warm, energy demand will increase across the area, especially in coastal cities that have not required air conditioning in the past. Low-income communities, with limited resources to adapt, will be subject to compounded risks from rising temperatures.

Whether the global community invests in measures that result in the low- vs. high-emissions scenario will make a grave difference in how much temperatures rise in the Bay area by the end of the century.

Read more in the San Francisco Bay Area Summary Report

Coastal Ecosystems and Urbanization

Resilient by Design

The ecosystems that are part of the San Francisco Bay-Delta estuary are some of the most productive and valuable across the state of California.

Services provided to local communities by these ecosystems include fresh water supplies, shoreline protection, maintenance of water quality, carbon sequestration, and opportunities for recreation. Heavy urbanization around the Bay Area and Delta has occurred based on the geography of the estuary, which highlights the importance of these ecosystems and the relevance of climate change impacts on the Bay-Delta tidal wetlands to the human societies which rely upon them.

Estuaries are naturally resilient and adaptable but are facing multiple stressors as a result of climate change, sea level rise, and urbanization that interrupts natural processes. Billions of dollars’ worth of infrastructure has been built upon tidal wetlands in San Francisco Bay (Heberger et al. 2012). Another significantly modified area is The Golden Gate watershed, which comprises approximately 40% of California’s land area. As a result, the timing and magnitude of flows of sediment and water to the estuary are starkly different from their natural patterns. Rising seas as a result of climate change will increase erosion on coastal cliffs, dunes and beaches, which may require the installation of infrastructure that could limit or prohibit recreation in these culturally important areas (California Legislative Analyst’s Office). Ultimately, what once was a dynamic and resilient estuarine ecosystem in the Bay Area has been modified extensively into a rigid landscape that must be protected from the dire impacts of climate change.

In contrast to purely hard infrastructural interventions, new approaches that rely on the resilience value of natural infrastructure can create shorelines that can more readily adapt to changing conditions and provide co-benefits to people and nature. Adopting adaptive management practices, such as planned flooding, can also increase overall resilience of the Bay Area shoreline (Newkirk et al. 2018).

Read more in the San Francisco Bay Area Summary Report

California’s Fourth Climate Change Assessment: San Francisco Bay Area Region Report

Resilient by Design

As stated in the Report: “This report examines the potential impacts of 21st century climate change on the physical climate, social systems and built environment, and natural and agricultural systems of the Bay Area.”

“The geography of the region sets the stage for understanding how rising temperatures, changes in precipitation and fog, and rising sea levels will impact the region. Projected impacts on social systems and infrastructure are examined, from coastal flooding to wildfire and public health, with attention to the effects of social inequity on the vulnerability and resilience of local communities. Finally, the impacts of climate change on biodiversity and open space conservation are examined, as are the effects on agriculture, with a focus on vineyards and rangelands. Where possible, proposed climate mitigation and adaptation strategies are summarized in a regional context to highlight potential actions and solutions necessary to meet these diverse challenges.”

Source: Ackerly, David, Andrew Jones, Mark Stacey, Bruce Riordan. (University of California, Berkeley). 2018. San Francisco Bay Area Summary Report. California’s Fourth Climate Change Assessment. Publication number: CCCA4-SUM-2018-005.

Regional Collaboration to Address Climate Adaptation

Resilient by Design

In July 2017, Plan Bay Area 2040 was adopted and included new commitments to resilience-building actions.

Authors recognized that the Bay Area region is at an important crossroads in consideration of ongoing and interrelated activities in the research, planning, design and management sectors. Efforts to increase climate resilience across the region have been immeasurably benefitted by cross-sector collaboration resulting in policy and on-the-ground projects.

The Bay Area 2040 plan reflects on how far the Bay Area has come in recognizing and addressing resilience challenges, and importantly, highlights opportunities to further increase resilience, particularly by focusing on the region’s transportation systems and other critical infrastructure, heavily urbanized areas, and ecosystems.

Within the U.S., California is considered a leader in reducing greenhouse gas emissions to mitigate the effects of climate change. However, according to the 2018 Fourth Climate Change Assessment ed by UC Berkeley, “dedicated funding and clear guidance to help the cities and counties adapt to rising sea levels, hotter temperatures, unpredictable rainfall and drought and year-round wildfires are still lagging.”

Read more in the San Francisco Bay Area Summary Report from California’s Fourth Climate Change Assessment.

View the Plan Bay Area 2040.