A considerable rise in sea level and storm surges during cyclones put New York City at a greater risk of flooding, according to a new study.
According to a paper published in the Proceedings of the National Academy of Sciences (PNAS) on Sept. 28, the risk of New York City experiencing flooding driven by a major hurricane or storm has grown significantly higher as compared 1,000 years ago, due to both human-caused sea level rise and “more intense storms with greater ability to produce high storm surges.”
The team is composed of researchers that include Andra Reed and Michael Mann of Penn State University, Kerry Emanuel of Massachusetts Institute of Technology (MIT), and Ning Lin of Princeton University. Emanuel and Lin’s separate paper published this month suggests that a major hurricane flooding risk is threatening Tampa, Florida.
The researchers evaluated sediment at various points along the New Jersey shore to compare sea levels between 1970 and 2005 and between 850 and 1800. A flood that was 7.4 feet above sea level before 1800 took place once every 500 years, compared to a storm of the same size occurring about every 24 years since 1970.
They found that the average storm surge during the anthropogenic era was 4.1 feet higher than during the previous – and much longer – period in history.
The average flood height also increased by about 4 feet between the two periods, and given continued warming and more extreme storms, considerably higher sea level will likely cause more frequent, intense flooding.
“We found that the biggest tropical cyclones tend to be larger, with a larger radius and maximum winds of these storms in the later anthropogenic time period. We also found that the most intense storms are even more intense in the later time period,” said Reed.
According to the researchers, the study findings indicate the impacts of climate change on coastal inundation and “call for advanced risk management strategies.”
Other experts echo the researchers’ findings.
“The study is the preamble for what we have to be concerned about. Areas like the Rockaways, Staten Island, are just not sustainable. They cannot exist in 100 or 150 years as they exist now,” said Klaus Jacob, special research scientist at Lamont-Doherty Earth Observatory of Columbia University.
As global sea level has already increased by about one foot since 1900 and is estimated to rise as much as 29 inches by century’s end, hurricanes are expected to be stronger and happen more frequently. This could mean more Sandy-like storms for New York.
“Climate change is already costing us dearly, but it’ll be a whole lot worse if we do nothing about it,” warned Reed.
Photo: Anthony Quintano | Flickr