Silicon Valley, the US capital of new technologies located near San Francisco, is threatened by soil subsidence that could worsen floods in the future, according to a study released on Wednesday.
This subsidence, in 'adding to the rising sea levels due to climate change doubles the risk of flooding in this region by 2100, according to the report of the work published by Science Advances.
'the ocean level is rising and the floods are more inland than any of the phenomena,' commented Manoochehr Shirzaei, a professor at the Earth and Space University of Arizona.
The majority of the coastline of San Francisco Bay sinks a little less than two millimeters a year but "in several areas we discovered a subsidence of ten millimeters per year or even dava
The most exposed infrastructure is that built on areas of the sea that are squeezed together, such as the San Francisco International Airport.
"When the subsidence of the land is added to predictions of rising sea levels, the water will cover nearly half of the runways and tarmac of the airport by 2100 ", noted the study.
Other areas at risk: Foster City, polder between San Francisco and San Jose, which rises two meters above the ocean, or Treasure Island, between San Francisco and Oakland, sinking 12 to 20 millimeters a year.
Previous studies , which did not take into account subsidence, estimated that at least 50 square kilometers of the San Francisco Bay coast were at risk of flooding by the end of the century because of rising sea levels
Adding the consequences of the affair the risk area increases to at least 125 km2. In the worst-case scenario, which includes an acceleration of ice melt and thus rising sea levels, it climbs to 413 km2 at the same horizon.
These new estimates are based on data collected between 2007 and 2011 with InSAR radar installed on board a satellite
"There are many predictions and models of rising sea levels, but they are all wrong because they do not take into account the evolution of the ocean. the elevation of land, "said Shirzaei.