Virginia Tech researchers have conducted the most comprehensive study to date on subsidence, the gradual sinking of an area of land.

The study involved observing cities, farms, forests, infrastructures, pipelines, roads, railways and more along the East Coast.

“Almost every city along the East Coast is subsiding, some of them are faster than others,” said Virginia Tech Associate Professor Manoochehr Shirzaei.

The study finds subsidence rates of 2 millimeters per year affects a maximum of 2.1 million people and 867,000 properties. This hazard is a major threat to cities such as New York, Baltimore and Norfolk, Virginia.

“The good thing about this study is that you can see it as an early warning. Nothing is in a critical situation. But if we don’t do anything, this gradual shrinking of land, in the long run, will result in significant cost and damage,” Shirzaei said.

Subsidence happens naturally, but the use of groundwater is making it worse and could lead to more severe flooding.

“This data can be used as a guideline or guidance to where we need the most investment,” Shirzaei said. “We can avoid the catastrophic outcomes.”

Shirzaei said we should act now. She cited examples that city and local governments could work on now, such as building sea walls to keep the water out, elevating infrastructure and reducing our reliance on groundwater.