New estimates from the Pennsylvania State University (PSU) researchers suggest that New York City is at a much higher risk of flooding in the event of future hurricanes.

For their study, PSU researchers compared records of storm surge levels from before and after climate change. They used proxy sea level records of sediments and foraminifera, which are tiny ocean organisms, to better understand past sea level changes. Then they simulated tropical cyclone histories of past 1,000 years using climate and cyclone behavior models. After evaluating the data, researchers were finally able to develop a storm surge model.

"We wanted to look at the impact of climate change on sea level and storm characteristics to see how that has affected the storm surge on the Atlantic coast, specifically in New York City," Andra Reed, graduate student in meteorology at Penn State, said in a news release. "Hurricane Sandy was the motivating factor."

When Hurricane Sandy hit in 2012, many transportation tunnels in NYC flooded. Generally, hurricane-related flooding along coastal areas depends on the storm, tide and sea level. In the case of Sandy, it was the overall size of the hurricane that caused such a large storm surge.

"Actual storm surge records don't go back far enough to establish a pre-industrial baseline," Michael Mann, a meteorology professor at Penn State, said in the release. "So we used a combination of models and paleoclimate data to describe the longer-term storm surge history."

"Sea level is rising because of climate change," Mann said in a statement. "But climate change also appears to be leading to larger and more intense tropical storms."

Their study was recently published in the journal Proceedings of the National Academy of Sciences.

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