The NASA-led study (Science Advances, Jan.) used 2015–2023 satellite data to map coastal vertical land motion in Los Angeles and San Francisco. It finds that subsidence — driven in large part by groundwater extraction — can combine with rising seas to produce more than double the previously forecast relative sea level rise in some areas by 2050. The authors urge updated assessment criteria and stronger coastal adaptation to protect people and infrastructure.
NASA-led Study: Los Angeles and San Francisco Are Sinking Faster Than Expected — Risks to People and Infrastructure
The NASA-led study (Science Advances, Jan.) used 2015–2023 satellite data to map coastal vertical land motion in Los Angeles and San Francisco. It finds that subsidence — driven in large part by groundwater extraction — can combine with rising seas to produce more than double the previously forecast relative sea level rise in some areas by 2050. The authors urge updated assessment criteria and stronger coastal adaptation to protect people and infrastructure.
06:36 AM, 11/21/2025Environment
A NASA-led study published in the peer-reviewed journal Science Advances in January warns that parts of Los Angeles and San Francisco are sinking at rates that could dramatically amplify the local effects of global sea level rise. Using nearly a decade of high-resolution satellite observations (2015–2023), researchers measured coastal vertical land motion — including both uplift and subsidence — and projected relative sea level changes through mid-century.
The study identifies subsidence (the gradual sinking of land) as a key driver of increased local sea level risk. According to the researchers and state water authorities, groundwater extraction is a major, human-driven contributor to subsidence in many coastal areas. When subsidence is combined with rising oceans, the result is a larger-than-expected increase in local or "relative" sea level.
Key findings
Researchers found that some parts of Los Angeles and San Francisco could experience more than double the relative sea level rise previously forecast by 2050. These projections incorporate both past groundwater pumping and likely future extraction patterns, along with satellite-derived ground motion trends.
Nearly 70% of Californians live in coastal counties, which makes these localized increases in relative sea level especially consequential for communities, transportation corridors, utilities, and other critical infrastructure.
"In effect, we're seeing that the footprint of land experiencing significant impacts has expanded, and the speed is more than enough to put human life and infrastructure at risk," said Alexander Handwerger, a landslide expert quoted in a NASA Jet Propulsion Laboratory press release.
Implications and recommendations
The authors call for an urgent reassessment of how sea level rise and subsidence are evaluated in coastal planning models. Because many contributing factors are human-controlled, the study highlights opportunities for mitigation — for example, managed groundwater use, improved monitoring, and updated resilience standards for coastal development and infrastructure.
The study underscores the need for policymakers, planners, and utilities to incorporate localized subsidence measurements into sea level rise planning and adaptation strategies to better protect people and assets over the coming decades.
Sources: Study published in Science Advances; NASA Jet Propulsion Laboratory; California Department of Water Resources.