A groundbreaking new map created by NASA scientists has unveiled concerning patterns of land subsidence across California, adding complexity to future sea level rise predictions.
The research, led by Marin Govorcin from NASA's Jet Propulsion Laboratory, combines satellite radar measurements with ground-based data to track vertical land movements along thousands of miles of California coastline between 2015-2023.
The findings paint a troubling picture for several coastal regions. The San Francisco Bay Area shows notable subsidence, with areas like Bay Farm Island and Foster City sinking more than 0.4 inches annually due to sediment compaction. This local sinking, combined with projected sea level rise, could result in over 17 inches of relative sea level increase by 2050 - more than double previous estimates.
Other concerning hotspots include the Big Sur mountains and Los Angeles' Palos Verdes Peninsula, where downward motion links to slow-moving landslides. Northern California's marshlands and lagoons around San Francisco and Monterey bays display subsidence likely tied to erosion.
Human activities also play a major role. Oil and gas production coupled with groundwater extraction introduce substantial uncertainties in future projections, particularly in Los Angeles and San Diego counties. Parts of California's Central Valley experience dramatic subsidence of up to 8 inches yearly due to groundwater fluctuations.
However, the news isn't all negative. Some areas show upward movement, including Santa Barbara, where groundwater basin replenishment since 2018 has led to measurable uplift. Long Beach also demonstrates uplift patterns related to fluid dynamics from gas and oil recovery operations.
The research highlights how land subsidence can accelerate the impacts of climate change-driven sea level rise. By 2050, California sea levels are projected to rise 6 to 14.5 inches above 2000 levels. This new mapping data is now helping inform California state guidance on managing future sea level changes.