GabyRecently, scientists have frequently created and published visualizations of potential flooding in coastal areas around the world, including cities that have already sunk beneath the waves. Unfortunately, these grim forecasts are gradually becoming a reality. The cause is well-known: global warming driven by human activities. A new study focusing on two California megacities—Los Angeles and San Francisco—has highlighted a troubling trend. Coastal areas around these cities are increasingly sinking underwater, and sea levels in these regions could rise more than double the predicted levels.
This alarming information comes from researchers at the National Aeronautics and Space Administration (NASA) and the National Oceanic and Atmospheric Administration (NOAA). The scientists reached this conclusion by examining the dynamics of coastal subsidence using satellite radar. What did they discover? It turns out that in the most critical areas, such as San Rafael and Foster City (in the San Francisco Bay area), the land is sinking by more than 10 millimeters each year. This process indicates that over the next 25 years, sea levels here could rise by 45 centimeters or more—twice the expected expert estimate of 19 centimeters. Meanwhile, coastal areas of Los Angeles are projected to sink 15 centimeters below the anticipated level, as reported by Live Science.
“In many parts of the world, such as the coastal areas around San Francisco, the land is sinking faster than sea levels are rising,” stated lead author Marin Govorchin, a remote sensing specialist at NASA’s Jet Propulsion Laboratory.
According to the study, the rise and fall of land, which scientists refer to as “vertical land movement,” is caused not only by natural processes like tectonic plate movement but also by human factors such as groundwater extraction. Of course, in California, as in many places around the globe, sea levels are rising due to climate change. The additional heat from a warming planet melts glaciers and ice sheets, raising water levels and ultimately pushing coastlines further inland. The release of large volumes of water poses a threat to coastal communities worldwide.
To understand how vertical land movement affects this process, researchers analyzed radar data collected by the European Space Agency’s Sentinel-1 satellites, as well as land movement data obtained from the Global Navigation Satellite System. The most extreme land subsidence was observed in central California, where aggressive groundwater extraction causes parts of the Central Valley to sink by as much as 20 centimeters each year. Scientists are concerned that vertical land movement is difficult to predict. However, as the study has shown, this crucial factor must be considered when forecasting the inundation of coastal areas.
The findings of this research were published in the journal Science Advances.
