Climate change is increasing the risk of severe flooding in New York

Continuing development in New York and other coastal areas is also making the impact of such floods worse, similar to how water in a bathtub rises when displaced by a person entering the tub. According to a report from the Washington Post, a new study aims to change that by bringing things a little closer to home. Emmanuel and Lin released a separate study earlier this September outlining the risks faced by Tampa, FL from the same types of intensified coastal storms.

The research team attempted to make the best possible estimate of what hurricane records may have looked like from the years 850 to 1800 in the Atlantic Ocean.

The researchers discovered something important in their models.

“Sea level rise in increasing flood heights, and there’s the added fact that characteristics of tropical cyclones are being impacted by climate change”, said Andra Reed, lead author of the study. Storms varied widely over the last 1000 years on the Atlantic coast.

The result was that the storms and their consequences were pretty different across eras – most importantly, because sea levels have risen considerably since the year 850 A.D., with a particularly fast rate in the past 100 years or so.

This study showed that New York City was already seeing an increase in flood height & a risk of inundation at the coast because of climate change caused by humans.

Hurricane Sandy hit Manhattan on October 20th, 2012, and most of the city’s transportation tunnels were flooded in effect.

The chance of another storm like Sandy, with a 9-foot storm surge, is now about once every 130 years, compared to once every 3,000 years in the pre-anthropogenic era, Reed said.

“Actual storm surge records don’t go back far enough to establish a pre-industrial baseline”, said Michael Mann, distinguished professor of meteorology, Penn State.

Reed says it’s hard to generalise to other cities, because sea-level rise can vary a lot locally. You’re not even going to notice a meter less beach on your next visit to the shore, right?

The findings should serve as a wake up call for flood policies in the US and elsewhere, said Melanie Gall, a University of South Carolina professor who studies disaster risk and emergency management. They discovered that the combination of these two factors has greatly increased the possibility of major storms in the region. But it will become much worse if nothing is done. We all watched in 2012 as entire blocks of New York City were up to the trashcans in floodwater, subways closed, and cars floated aimlessly towards the sea as the streets drained. For New York, this could mean more damage from Sandy-like storms. The strong storm surge managed to breach the walls of the southern part of Manhattan, at Battery Park.

“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”, Reed said. The paper wrote, “The storm surge heights in the tails of the anthropogenic distributions are significantly greater than the storm surge heights in the tails of the pre-anthropogenic storm surge distributions”. Hurricane Sandy is an example.

“No matter what way you cut and slice the pie, with anthropogenic changes there is an increased risk for these sorts of severe events to occur”, said Greg Holland a climate and hurricane researcher at the National Center for Atmospheric Research in Boulder, Colo.