New York faces rising flood risk
Serious storms becoming much more frequent, climate study warns
It’s already bad and it’s getting worse.
A first-of-its-kind study warns that the risk of flooding along the New York City and New Jersey shorelines has increased significantly in the past 1,000 years and that under a changing climate, the risk is likely to grow even more.
Researchers used proxy sea-level records and climate models to compare sea-level rise rates and storm surge heights in prehistoric and modern eras in the North Atlantic basin.
They found that the combination of those two factors has greatly increased the possibility of major storms.
Storms that may have once occurred every 500 years could soon happen every 25 years or so, according to the study, which may have implications for other coastal regions.
Researchers also found that flood heights have increased 1.2 metres, mainly due to the rising sea level.
“Given that we are already committed to additional sea-level rise due to warming temperatures, we would expect that flood heights are likely to continue to climb in the future,” said Andra Reed, one of the researchers and a PhD candidate with the department of meteorology at Pennsylvania State University.
Flooding from tropical cyclones will likely continue to worsen, Reed said.
The findings were published in the journal Proceedings of the National Academy of Sciences on Monday by a team of researchers from five American universities, including well-known climate scientists Michael Mann of Pennsylvania State and Kerry Emanuel of the Massachusetts Institute of Technology.
Mann believes the study’s findings likely apply to other coastal regions — that’s what they want to pursue next.
“Given the significant interest in storm surges impacting New York City in the wake of (Hurricane) Sandy, it seemed appropriate to us to focus on this location first,” he said.
Sea-level rise is already having a huge impact, he said.
A one-foot (30-centimetre) rise along the mid-Atlantic coast over the past century caused havoc, he said, alluding to Hurricane Sandy in 2012. “Imagine what six feet of sea level rise — which we can’t rule out by the end of the century if we continue with business-as-usual fossil fuel burning — would do.”
What surprised the researchers is how man-made climate change is impacting the characteristics of tropical storms.
“Climate change has already likely increased both the intensity and the size of North Atlantic hurricanes. Both factors — increased intensity and size — lead to larger storm surges,” said Mann. (Two types of storms cause the most damage, scientists say: big, slow-moving ones and smaller, higher-intensity ones.)
The million-dollar question is what is the probability of a storm like Hurricane Sandy, which killed dozens, flooded streets to chest height and cost billions of dollars, descending on us again this century.
Data analysis indicates that Sandy-magnitude flooding used to be a onein-3,000-year event, something that would not be seen for generations at a time, said Reed.
Fast forward to now, and Reed said that “a person might very likely see (that kind of event) at least once in their lifetime.”