Sea Level Rise

Climate change is causing the seas to rise, a reality that could cause severe flooding in Hayward if left unaddressed.

Local, state, and global actions are necessary to curb climate change, and the City of Hayward already has a number of initiatives in place to address its effects -- but even if the entire world were to stop all GHG emissions today, there would still be a 1-3 foot rise in sea levels across the globe. As a community adjacent to the San Francisco Bay, Hayward is particularly vulnerable to this threat.  

The Hayward Area Shoreline Planning Agency (HASPA) is preparing a Shoreline Master Plan to determine the policies and projects necessary to prepare for sea level rise along the Hayward Shoreline. 

Click here to Learn About the Shoreline Master Plan

Causes of Sea Level Rise

As depicted above, sea level rise is caused by two main factors:

Melting glaciers and ice sheets: Increased global temperatures cause glaciers and ice caps to melt faster, causing sea levels to rise. West Antarctic ice sheets are predicted to have the greatest impact on California and its sea levels.

Thermal expansion: The increase of greenhouse gases in the atmosphere causes ocean temperatures to rise. Rising water temperatures result in rising water levels, something you’ve likely seen first-hand if you’ve boiled a pot of water. 

While thermal expansion has historically been the largest cause of sea level rise, melted glaciers and ice sheets are anticipated to be the largest contributor after 2050.

King Tides: “Today’s High Tide is Tomorrow’s Tide”

King tides are the exceptionally high tides that typically occur in December and January, when the moon is closest to the Earth. As climate change continues to progress, these tides will eventually become the normal high tide experienced in the Bay. This poses a particular threat to bayfront facilities and infrastructure, including the Hayward Shoreline Interpretive Center and the State Route 92 Hayward-San Mateo Bridge.

While marshes along the Hayward shoreline are currently protected by a system of levees, including the San Francisco Bay Trail, they will not be safe in the long term. The levee system was created for salt production, not flood prevention, and today’s king tides can already overtake them, as evidenced by the king tide that flooded the Bay Trail in 2017.

Check out this story map to get more info about sea level rise, king tides, and some of the direct impacts they will have on Hayward. 

Frequently Asked Questions

1. Why should I care about sea level rise?

Sea level rise could result in the flooding of areas you work or frequent. Do you enjoy riding your bike along the Bay Trail? Do you work near the shoreline? Do you enjoy visiting the Hayward Shoreline Interpretive Center (HSIC) and learning about the marshes? If you answer yes to any of the questions above, YOU will be impacted by sea level rise.

2. How can I learn more about how sea level rise will impact me?

Use the sea level layer in our GIS web map to see what areas will be flooded if there is a 12” rise in sea levels. To do this, zoom into the map using the plus sign and click the “12inch Sea Level Rise - Inundation Areas” layer in the upper right corner. You can navigate around the map to see how much flooding will occur. The shade of blue indicates the depth of the water at a high tide. Scientists predict that California will experience 12” of sea level rise by 2100 and maybe even as early as 2050, depending on rates of ice melt in the West Antarctic.  You can also check out this Sea Level Rise Map to see what 16” and 55” of sea level rise would look like. 

3. How can sea level rise impact me now?

When there is an extreme weather event or a king tide, vulnerable areas will flood with even a small amount of sea level rise. This can and will happen before 2050 --  the Bay Trail already floods during king tides. Though sea level rise is a slow-moving impact, we will continue to experience flooding in the short-term and need to start planning for the larger tides that will inevitably impact our community.

4. How can I adapt to, prepare, and mitigate against sea level rise as a Hayward resident?

Check out actions you can take to reduce your carbon footprint. Educate others about sea level rise and attend workshops at the Hayward Shoreline Interpretive Center to learn more about the importance of marshes and the natural flood protection they provide.

5. How can I adapt to, prepare, and mitigate against sea level rise as a developer?

Work with City Planners to evaluate how your project site will be impacted by sea level rise. Think about adaptation measures that can be taken to decrease that impact. Get involved in helping to shape the Shoreline Master Plan by providing feedback through a quick survey (coming soon).

6. What are king tides and what impact will they have on bayfront structures like the Interpretive Center?

King tides are extremely high tides that occur when the moon is closest to the Earth in December and January. If nothing is done to protect the Interpretive Center, the building will flood when there is 12’’ of sea level rise and an event such as a king tide (more information can be found here). The Interpretive Center is currently brainstorming ways to prevent future flooding.