When Hurricane Sandy first reached New York City four years ago, the city saw some of the worst flooding in its history. The hurricane also caused massive financial damage, with damages reaching up to more than $71 billion. This number is second only to Hurricane Katrina in natural disaster damage in the United States. And while Hurricane Sandy was bad, this could be even worse: Researchers are now reporting that New York City is very likely to get hit by many more floods in the future, and many of them could be as bad.

Hurricane Sandy
NYC Flooding by Ruanon, Flickr

“[T]he frequency of Hurricane Sandy-like extreme flood events increased significantly over the past two centuries and is very likely to increase more sharply over the 21st century, due to compound effects of sea level rise and storm climatology change,” wrote Ning Lin, an assistant professor of civil and environmental engineering at Princeton University, today in Proceedings of the National Academy of Sciences.

Study shows more Hurricane Sandy-like flooding on the way

The study, led by Lin and a team of scientists from Princeton University, floods are up to 17 times more likely to happen between 2000 and 2100 in the worst possible way, i.e. Hurricane Sandy.

For the study, scientists put together historical weather data from New York City all the way back to 1856. With the data found, the researchers were able to create computer-based projections to predict how frequent floods will be in the area in the future.

Using the historical data, researchers found out that Sandy-level flooding jumped 3 times between 1800 and 2000. The frequency of New York City encountering some kind of severe flood has increased to one Sandy-like event every 400 years in the year 2000 when a Sandy-level event occurred once every 1,200 years back in 1800. By 2100, these types of floods could potentially happen every 19 years.

Natural effects has been the main cause of the rising sea levels, including the sinking of the Mid-Atlantic region. However, during the 20th century, climate change caused by humans largely influenced this weather change.

Still uncertainties involved when predicting flooding

Researchers did point out that the study had its limitations. Global climate models in themselves are not designed to provide exact numbers of the weather in a specific location or in a specific year.

As such, there are lots of uncertain elements involved when it comes to predicting hurricanes and sea level rise in New York City specifically. The four climate models’ predictions ranged from 23 years to 130 years, and a lot more needs to be done to improve these predictions.

Despite these catches, the “results of this analysis demonstrate how dramatically the frequency and magnitude of NYC’s extreme floods may increase over time, due to the compound effects of sea level rise and storm climatology change,” write the researchers.

“The grand answer is that things are going to get worse by 2100,” says researcher Benjamin Horton from Rutgers University. “If nothing changes with hurricanes, sea-level rise alone will increase the frequency of Sandy-like events by 2100.”

Photo by Ruanon