OAAC workshop looks at climate change’s effects and tools to counter it
When you live on an island in the Bay Area, you’re bound to hear the term “sea level rise,” but how much do we really know about it? The Oakland Alameda Adaptation Committee (OAAC) hosted a Zoom workshop on Monday, May 20, to discuss what sea level rise means for us and our neighbors in Oakland, and to talk about tools to make our communities more resilient to the inevitable changes it is likely to bring.
Simply stated, sea level rise refers to the total volume of ocean water as it steadily increases. As temperatures increase, water expands, raising the surface of the ocean and bay. Melting glaciers and polar ice sheets also increase the volume of ocean water. What might that mean for us, and what can we do about it?
OAAC is “a coalition of shoreline communities and stakeholders working to co-create a coordinated and inclusive future-looking action plan and sub-regional organizational structure to accelerate sea level rise adaptation, protect and restore water quality, recreation and habitat, and promote community resilience,” according to the OAAC website.
One of OAAC’s consultants, CMG Landscape Architecture Principal Jamie Phillips, outlined OAAC’s goals:
- Protect Oakland-Alameda sub-region from the negative effects of expected sea level rise, inland flooding, and groundwater rise and liquefaction.
- Identify and develop opportunities for multi-benefit adaptations strategies.
- Avoid negatively affecting neighboring subregions through protection and adaptation measures.
- Utilize an adaptation pathways approach to address different sea level rise thresholds and time horizons. Identify near, mid-, and long-term adaptation strategies.
- Enhance transportation, recreation corridors, bay access, and the San Francisco Bay Trail.
- Preserve and increase open space where possible.
- Improve subtidal, intertidal, transitional, and upland habitat with nature-based solutions.
- Improve air quality.
One of the projects OAAC is currently working on is the Subregional Long-term Adaptation Project, which addresses the subregion from the Bay Bridge along the Oakland shoreline, around the shoreline of Alameda, through San Leandro Bay, and around the Oakland airport and Bay Farm Island.
The second funded project is the Bay Farm Island Project, which addresses “risk to sea level rise today that is located at Veterans Court at the bridge and at the lagoon outfall and pump station on the northern edge of Bay Farm Island,” said Phillips. “This project will look at near-term solutions for these areas because they’re at risk of flooding with today’s king tides. And this project will also develop a long-range adaptation plan for Bay Farm Island.”
The third project is the Oakland-Alameda Estuary Project, which focuses on the parallel shorelines along the estuary.
Dr. Kris May of Pathways Climate Institute touched on climate science, coastal flooding, rising groundwater, inland flooding, and compound flooding. “Despite being in a cool bubble in the Bay Area, 2023 was the hottest year on record,” May said. “And the last 10 years are the 10 hottest years on record. It’s just steadily gotten hotter, which is frightening.”
In regard to flooding, May encourages people to consider the entire water cycle. “We have to look at more than sea level rise and coastal flooding,” she said. “I want to talk about increased precipitation. I want to talk about rising groundwater, increasing coastal flooding from the bay. Think about those winter rain storms that hit us in 2023. Those storms are getting bigger and that groundwater table is rising right beneath our feet.”
When discussing sea level rise, scientists look at a range of possible scenarios from low-trend to high-trend over the next 100 years. “We don’t know exactly where we’re going to fall in these projections,” said May. There are two variables that provide the greatest areas of uncertainty—humans and the ice sheets.
“Humans are the ones that have caused this change, and global human behavior is what is going to reduce greenhouse gas emissions and mitigate climate change and help us get to one of these lower ends of the curb,” she said. “So it’s really up to us whether we stay on the intermediate path or whether we can reduce emissions and reduce that rate of sea level rise.” She added that the other source of uncertainty is what is going to happen to the ice sheets and that marine ice sheet melting.
May then spoke about the importance of assessing the intensity of rainfall when designing sea level rise adaptation. “We need to consider the amount of rainfall that’s going to fall on our cities and how we get that water out of our communities through our stormwater systems,” she said.
Locally, we use gravity and pumps to capture rainfall runoff and funnel it into the bay. “But flooding can take a pump station out of service and then it can’t do its job so the flooding gets worse,” May said. “So these systems can’t drain out to the bay. Or the storms are just too big. Figuring out where we can store this stormwater is a really big part of planning for overall resilience.”
Rainfall is also raising the groundwater table, May said. “This groundwater flows very, very slowly through the soil. So when we get tons of rain the groundwater table can stay elevated in the low areas near the shoreline for many months, and when there’s the second storm, or the third storm, or the thirteenth storm, as we saw in 2023, the ground was totally saturated and had no capacity to take anymore groundwater. There’s no more infiltration. It just causes direct runoff and flooding. So we have to consider the groundwater table, how much it can absorb in relation to precipitation.”
Possible ways to address flooding include flood-proofing and relocating structures, along with adding additional pump stations. Phillips added that seawalls and levees, as seen in Jack London Square and Foster City, are also being utilized locally to protect against sea level rise.
Phillips and May closed their presentation with a slide detailing OAAC’s long-term adaptation planning framework:
- Support planning under uncertainty. How much our climate will warm over the next 100 years is uncertain, which makes planning hard.
- The biggest part of that uncertainty is humans, and how quickly we act to reduce greenhouse gas emissions.
- Adaptation pathways allow us to make incremental adaptation decisions and actions over time:
- Developing a long-term plan that considers the higher end projections of what is plausible in the future.
- Identifying near-term actions that address both existing risks and likely projections of the future.
- Identifying triggers and/or thresholds for additional actions over time.
- Identifying decision points, or actions that change the adaptation trajectory.
Perhaps the most important thing to recognize is simply that we cannot sit and wait to achieve greater certainty of the future.
Kelsey Goeres is a contributing writer for the Alameda Post. Contact her via [email protected]. Her writing is collected at AlamedaPost.com/Kelsey-Goeres.
