San Francisco and several other parts of Northern California are sinking at an alarming rate, compounding the region’s existing geological and environmental challenges. According to a recent NASA study, land subsidence—caused by sediment compaction, erosion, and past industrial activity—is amplifying the threat of rising sea levels, putting thousands of residents and billions of dollars in infrastructure at risk.
Bay Area Land Sinking At A Concerning Pace
NASA’s report, published on February 10, 2025, highlights several regions where the ground is sinking at a rate exceeding 0.4 inches per year. Some of the most affected areas include:
- San Rafael, Corte Madera, and Bay Farm Island, where land subsidence is accelerating,
- Foster City, which has mitigated some of the risk with a $90 million levee improvement project completed in 2024,
- The Big Sur coast, where slow-moving landslides are contributing to sinking terrain.
What Lies Beneath San Francisco?
One of the most significant drivers of subsidence in San Francisco is its reclaimed land, areas that were once natural wetlands or marshes but were developed for urban use. According to Marin Govorcin, a remote sensing scientist at NASA’s Jet Propulsion Laboratory, some of these lands are sinking faster than sea levels are rising.
Historical data from the United States Geological Survey (USGS) shows that before 1850, the Bay Area had over 2,000 square kilometers of wetlands. However, extensive hydraulic mining and industrial expansion wiped out nearly 95% of these habitats, raising long-term concerns about ground stability.
Rising Sea Levels And The Race Against Time
While land subsidence is worsening, California is also grappling with the impact of climate change-driven sea level rise. The NASA study warns that by 2050, sea levels along California’s coast could increase between 6 and 14.5 inches compared to the year 2000. Some low-lying areas could see water levels rise by over 17 inches, exacerbating flood risks.
By 2100, approximately 700,000 Californians and $250 billion worth of property could be in danger. This poses a major threat to California’s coastal economy, which generates $45 billion annually and supports millions of residents.
California’s Urgent Call For Action
Recognizing the increasing risks, California’s 2024 state sea level guidance plan stresses the need for bold and immediate action to protect communities. The report highlights the urgent need to safeguard public infrastructure, private properties, and natural ecosystems from the effects of both subsidence and sea level rise.
“To ensure that people, the environment, and the economy can continue to thrive, California must take bold and swift action to help prepare communities for the impacts we are starting to see now and that are projected to worsen in the years ahead,” the report states.
What’s Next?
As subsidence and rising waters converge, experts say that mitigation efforts, such as levee reinforcements, marshland restoration, and strategic urban planning, will be essential. However, without comprehensive and sustained intervention, the fate of many coastal communities—including parts of San Francisco—remains uncertain.
