Chances That NYC Will Flood Have Increased 20-Fold

New York City's chances of flooding have increased by 20 times compared with the mid-1800s as maximum sea levels rise.

Because water in the New York Harbor is about 2.5 feet higher than it was 170 years ago, scientists estimate that the chances that water will overtake the Manhattan seawall and the city will flood have increased 20-fold, National Geographic reported.

According to the new study, which will be published soon in Geophysical Research Letters, the maximum height of New York Harbor's storm tide has increased by about a foot since the mid-1800s.

"Knowing that there has been an increase in storm tides and figuring out why the increase occurred could help scientists better predict what will happen in the coming decades and help cities mitigate future problems," said lead study author Stefan Talke, who is a professor in the civil and environmental engineering department of Portland State University, as quoted by National Geographic.

Experts fear that the rising harbor combined with climate change will only further increase the city's chance of being flooded.

 "Historic sea-level rise has clearly increased the odds of flooding in New York Harbor. Climate change will only accelerate that impact," Daniel Zarrilli, director of the newly launched Office of Recovery and Resiliency for New York City Mayor Bill de Blasio, said in response to the study, as quoted by National Geographic.

The mayor's administration plans to "build a stronger, more resilient New York," Zarrilli said.

Updating efforts from former Mayor Michael Bloomberg's administration, work under Mayor de Blasio has included reinforcing the beaches with more sand, strengthening building codes in more vulnerable areas and rebuilding after damage from Hurricane Sandy in October 2012.

Researchers will work to make computer models of New York Harbor during the 1800s and the present day as well as during major storm events to find ways to keep the water at bay. 

"My hope is that if we can figure out the local contribution, then maybe there is a chance for local solutions," said Talke, as quoted by National Geographic. "It's not practical to go back to a 23-foot-deep shipping channel, but there are some things we could do."