A recent analysis by researchers at NASA’s Jet Propulsion Laboratory has revealed that the rising and sinking of land across California could significantly impact sea levels in the state over the coming decades.

By utilizing satellite radar data, the researchers were able to capture the vertical movement of land across over 1,000 miles of California’s coastline. When compared to historical observations of the same locations, the team discovered that the land was subsiding and rising at rates significantly higher than regional estimates.

The research, which was published last month in Science Advances, employed data from the European Space Agency’s Sentinel-1 satellites and ground-based receiving stations that are part of the Global Navigation Satellite System to determine the amount of surface motion on the ground. The data, collected between 2015 and 2023, illustrates how different areas across the state are rising and sinking. In the image below, areas in blue indicate subsidence, while areas in red indicate rising land (with darker red indicating a faster rate of rise).

According to a release from NASA JPL, the San Francisco Bay Area is experiencing subsidence at a rate of more than 0.4 inches per year, primarily due to sediment compaction. The team’s study suggests that local sea levels could rise by more than 17 inches by 2050 due to subsidence, particularly in low-lying areas such as San Rafael, Corte Madera, Foster City, and Bay Farm Island.

As stated by Marin Govorcin, a scientist at NASA JPL and the lead author of the study, in an agency release, “In many parts of the world, like the reclaimed ground beneath San Francisco, the land is moving down faster than the sea itself is going up.”

The researchers also identified areas of significant uplift, with rates of several millimeters per year, in the Santa Barbara groundwater basin and Long Beach.

In parts of Los Angeles and San Diego counties, the team found evidence that human-driven land motion increases uncertainties in sea level projections by up to 15 inches. Human activities, including groundwater extraction and hydrocarbon production, contribute to this uncertainty by making it more challenging to predict land motion.

The team observed downward motion in areas prone to landslides, such as the Palos Verdes Peninsula south of Los Angeles.

Future observations of elevation changes across North America will be facilitated by the JPL’s OPERA project, which will work in conjunction with the NISAR mission, a joint effort between NASA and the Indian space agency ISRO. The OPERA project will collect data on the elevation of North America, enabling careful monitoring of the continent’s ever-changing surface.