Bay Crossings Article

Preparing for Climate Change in the Bay

Sejal Choksi
From the August 2009 edition of Bay Crossings

In the last 200 years, San Francisco Bay has undergone profound changes, and the health of the Bay has varied dramatically. Before the wave of gold rush settlers, for example, the Bay was a vibrant ecosystem teeming with marine life, to the extent that oysters, shrimp and several species of fish were commercially harvested. By the 1970s, however, the Bay had become a severely polluted waterbody that suffered from frequent waves of fish dying off and a notorious foul stench.

Since the enactment of the Clean Water Act in the 1970s, there have been some significant improvements to the health of the Bay. Our wastewater treatment plants release far less pollution into the Bay, the trend of filling in the Bay has been reversed, and, some of our vital wetland areas and critical eelgrass and oyster beds are being restored.

This progress is threatened, however, by an environmental problem of unprecedented magnitude: human-induced climate change. The future of the San Francisco Bay and surrounding communities will be shaped by how we adapt to the consequences of climate change. Projected sea level rise, more intense and frequent storms, and decreases in the availability of fresh water in the Bay Area will all have profound implications for the communities and wildlife that depend on the Bay.

According to estimates by oceanographers at the National Oceanic and Atmospheric Administration, Bay waters have already risen nearly 8 inches at the Golden Gate during the past 100 years. With freeways, airports, and wastewater treatment facilities built along the water’s edge, the Bay Area is particularly vulnerable to flooding and property damage caused by sea level rise. The Bay Conservation and Development Commission recently released data that forecasts a 16-inch rise in Bay waters by mid-century and a 55-inch rise by 2100. The projected sea level rise for the Bay Area by 2100 would damage an estimated $48 billion worth of property if no action is taken to adapt to the changes.

But the consequences of climate change won’t only be felt on land. There will be significant impacts to the Bay’s water quality, wetlands and wildlife. As the sea level rises and more intense storms flood shorelines and damage coastal infrastructure, Bay waters will be exposed to pollutants from landfills, water treatment plants and other sources of toxic waste that are at, or below, sea level. There are 235 Superfund sites, hazardous waste generators, and other properties in the Bay Area that contain hazardous materials and are at risk of inundation from sea level rise. Climate change will also worsen the Bay Area’s already-pressing sewage spill problem. There are 20 wastewater treatment plants along the Bay margin that are at risk of inundation, and our already-crumbling sewer infrastructure will be unable to withstand projected flooding and intense storms.

As the sea level rises, Bay waters will also flood many of the natural wetlands in the Bay Area, drastically limiting the Bay ecosystem’s ability to filter pollutants and prevent contaminants from entering waterways. Tidal wetlands create natural land features that act as storm buffers, protecting people and property from flood damage. Without these wetland buffers, Bay Area residents can expect increased contamination and more severe shoreline property damage.

The history of the Bay has been shaped by how people have used this area’s natural resources. Humans have altered the San Francisco Bay-Delta though gold mining practices, with the construction of dams, reservoirs and canals to divert the Delta’s freshwater, and by filling in and paving over Bay wetlands to make room for development. Once again, the fate of San Francisco Bay is in our hands.

The Bay’s future depends on our ability to confront the new challenges created by climate change. The communities of the Bay Area must take swift action to adapt to seal level rise, protect key infrastructure, and protect the integrity of our Bay wetlands and other habitat. And, we must ensure that all future land use planning and development is climate-change aware, meeting both emissions reductions goals and adaptation needs.

San Francisco Baykeeper has worked for twenty years to protect the Bay from the most pressing pollution problems—from sewage spills to storm water pollution to toxic industrial chemicals. We will continue to address these ongoing sources of pollution while tackling the additional challenges posed by climate change. To keep informed about this and other issues that impact the health of the Bay, visit us at and sign up to receive our monthly electronic newsletter.