Foster City, many areas of which could be flooded in 2100 because of rising sea levels (SLR, yellow), will be even more at risk because of local land subsidence (SLR+LLS, red).

(ASU/Manoochehr Shirzaei)

At a Glance

Researchers determined that more land than previously thought is sinking around the Bay Area, which could exacerbate flooding issues by 2100.The team determined that the Bay areas of Foster City and Treasure Island, both areas created by landfill, are most at risk.Much of the San Francisco Airport will be flooded, the researchers found.

The amount of land that could be flooded in the San Fransisco Bay Area by the turn of the century as a result of rising seas could be underestimatedby as much as90 percent, a new study said.

Geologists from the University of California, Berkeley and Arizona State University used high-resolution satellite and aircraft data to determine that more land than previously thought is sinking around the Bay Area and, according to the study published Wednesday in Science Advances.

They found that, depending on how fast seas rise, the "areas at risk of inundation could be twice what had been estimated from sea level rise only."

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The researchers say San Francisco International Airport’s runways will be flooded by 2100 because of sea level rise (yellow) and subsidence of landfill used to construct the airport (red).

(ASU/Manoochehr Shirzaei)

Previous studies did not take subsidence into account and estimated a 20- to 160-square-mile loss of San Francisco Bay shoreline to future flooding. This new study estimates that flooding will cover between 48 and 166 square miles if subsidence is taken into account.

"We are only looking at a scenario where we raise the bathtub water a little bit higher and look ," senior author Roland Bürgmann, a UC Berkeley professor of earth and planetary science, said in a press release. "But what if we have a 100-year storm, or king tides or other scenarios of peak water-level change? We are providing an average; the actual area that would be flooded by peak rainfall and runoff and storm surges is much larger."

The team determined that the Bay areas of Foster City and Treasure Island, both areas created by landfill, are most at risk and noted that city planners should take this data into account when making plans for the future.

"This work is an important step forward in providing coastal managers with increasingly more detailed information on the impacts of climate change, and therefore directly supports informed decision-making that can mitigate future impacts," saidPatrick Barnard, a research geologist with the U.S. Geological Survey in Menlo Park.

The work conducted by the team is importantnot only for the Bay Area but for communities worldwide.

"Flooding from sea level rise is clearly an issue in many coastal urban areas," said Bürgmann. "This kind of analysis is probably going to be relevant around the world, and could be expanded to a much, much larger scale."