A recent study by NASA and NOAA has found that parts of California’s coastline, including San Francisco and Los Angeles, are sinking at an alarming rate. This means that sea levels in these areas could rise even more than predicted, posing a significant threat to coastal communities.
Satellite radar data collected by the European Space Agency’s Sentinel-1 satellites revealed that ground elevation along the California coast is dropping by over 0.4 inches per year in some areas. In San Rafael and Foster City, which were partially built on landfill, this sinking has led to predictions of a local sea level rise of over 17 inches in the next 25 years.
Near Los Angeles, similar reclaimed areas like Newport Beach are also experiencing subsidence due to groundwater pumping, with an additional 6 inches of predicted sea level rise for 2050. This is on top of the already predicted 6.7 inches of rise, making the total estimate nearly double.
According to study lead author Marin Govorcin, “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 attribute this phenomenon to natural processes such as tectonic plate movement and human factors like groundwater pumping.
While globally, sea levels are rising due to climate change, local variations in vertical land motion can significantly impact predictions of coastal flooding. This study highlights the importance of considering these regional changes when predicting future ocean rise.
The research used radar data collected by multiple satellite systems and land movement data from global navigation satellites. The Central Valley is experiencing significant subsidence due to groundwater pumping, while some areas like Santa Barbara are rising due to replenishment of groundwater supplies.
Source: https://www.livescience.com/planet-earth/parts-of-san-francisco-and-los-angeles-are-sinking-into-the-sea-meaning-sea-level-rise-will-be-even-worse