Some neighborhoods in the New York metro area will begin flooding once or twice every month, during full and new moons, as soon as the next few decades.
And a few could even go permanently underwater as soon as 80 years from now, if global carbon emissions aren't scaled back and protective measures for the city aren't undertaken soon.
That's the frightening conclusion of the New York City Panel on Climate Change, which announced its findings in a March 15 event at the New York Academy of Sciences in lower Manhattan.
And Stevens Institute of Technology research, which played a major role in that report, will continue to inform the collective response as that city — and others in the region — prepare for an uncertain future.
"Sea level rise is accelerating, including ice cap melting," explains Stevens ocean engineering professor Philip Orton, a co-author of the panel's 2019 report (also known as NPCC3) and a panel member since 2013. "The worst case, we found, is now a nearly ten-foot rise in the average sea level in the metro NYC in just 80 years.
"If that scenario came to pass, daily high tides would match Hurricane Sandy’s flooding."
Why the worst-case is now worse
Four years ago, the worst possible scenario was calculated as "only" a six-foot rise. Now it's worse.
"Here, due to concern about melting ice sheets, we included a new worst-case scenario," says Orton.
Even if a ten-foot rise doesn't come during this century, without global action to reduce atmospheric warming it will come eventually.
And since New York City isn't going anywhere in the meantime, something's going to have to give.
Stevens' resiliency researchers have determined that events like Sandy — previously once-in-a-generation occurrences — can, and very likely will, happen again to the metro New York region this century.
In fact, that process has already begun. In the New York-New Jersey region, the Atlantic Ocean has risen relative to the region's landforms by about 13 inches during the past century alone.
Orton's latest research, unveiled in the NPCC3 report, reveals that certain low-lying neighborhoods of the city can now expect to flood on a monthly basis by 2050.
Not worried yet? Well, even the average projection for sea level rise from NPCC3 calls for normal, non-storm water levels that are two to four feet higher by 2100 than they are now — and higher during storms, of course.
That may sound like a tiny amount. But for low-lying boroughs and a city mostly laid out one to two centuries ago, it would be potentially devastating.
"We're talking flooded streets, homes, high-traffic expressways and boulevards, subways," says Orton. "The infrastructure of the city was not engineered to factor in the sea rising and frequently flooding inland. And now that's going to become a problem."
The problem wasn't entirely predictable when the city’s present infrastructure was built, because we didn't have the methods nor the data to recognize the process that had already begun. The sudden warming of the Earth's atmosphere over the past century has been a real shock to the system, melting ice caps and sparking heat waves, wildfires and extreme weather.
The process is also nudging ocean levels gradually, dangerously higher.
It happens like this: As humans burn more fossil fuel, gases are produced and rise. But they don't leave the earth's atmosphere entirely. Instead, they linger very high above, like insulation.
The atmosphere begins to warm. That causes oceans to warm. The warmer water fuels stronger hurricanes. And those heavier storms and higher winds bring more flooding during storms, pushing higher, heavier tidal surges farther inland.
For low-lying coastal cities like Miami and New York, this means partial inundation is now all but inevitable.
"Coastal floods are becoming more common due to climate change," sums Orton. "That is absolutely known. This is where the indisputable effect of sea-level rise comes into play."
If protective measures are not undertaken, areas of Brooklyn, Queens and Staten Island will lose real estate and flood first and most often, Orton says. (Some communities, such as Broad Channel and Hamilton Beach, have already begun flooding several times per year.)
And hundreds of other coastal communities in the nation, once believed safely protected from the ocean's brute force by beaches, berms, seawalls or distance, will soon be under the gun as well.
Responding with a three-pronged attack
To support city, regional and federal officials as they ready new plans, warning systems and defenses to protect the Big Apple, Stevens researchers are simultaneously examining the issue of climate change from at least three different perspectives:
- The Davidson Laboratory is a national leader at forecasting — and warning of — sudden, storm-driven floods, which will likely become more frequent and intense in the city as the climate continues to warm.
- At the same time, Stevens researchers are working to get a handle on what the longer-term effects of climate change will be on homes, skyscrapers, barriers, beaches, business districts and almost everything else in the urban and suburban communities surrounding New York Harbor.
- And the university's experts are also helping design and engineer strong, lasting, cost-effective physical defenses that carefully balance the region's growth, cultural sensibilities and physical realities with changing climatic, meteorological and ocean conditions.
"All three of these areas are critically important," notes Davidson Lab director Muhammad Hajj. "It's critical to get the event-forecasting piece right, because this saves lives, reduces adverse economic impacts and provides officials with time to warn the public, evacuate if needed, move critical infrastructure and otherwise prepare for extreme-weather events."
Evolving models that forecast better than ever
Given the uncertainties of weather and water, how will Stevens' storm-surge models and forecasts help?
Science, plus a touch of art.
The secret sauce is the Stevens Estuarine and Coastal Ocean Model (sECOM), a "probabilistic" mathematical model developed at Stevens by researchers including former faculty members Nickitas Georgas and Alan Blumberg that's now considered among the best in the world at modeling urban-ocean environments.
sECOM forms the backbone of both NYHOPS and SFAS, the university's two primary forecast and visualization tools.
The team of researchers, which also includes Orton and Raju Datla, has continually tweaked the models' math to make those forecasts even more powerful and accurate, introducing both parallel computing and new assumptions to the algorithms that further simplify and speed those calculations.
"These forecasts were originally designed to focus on the effects of winter storms," explains Orton. "They didn't always perform optimally during very large storms such as Hurricanes Irene and Sandy."
Among other updates, the group improved the physics calculations within the model to account for the ways in which waves enhance a wind-driven storm surge — which sounds arcane, but is actually vitally important to the predictions generated.
The team also updated the system by expanding the model to cover a larger region of the Atlantic Ocean. That helped it cope with the very large storms, like Irene and Sandy, that have plagued the Eastern Seaboard over the past decade.
Fighting floods, street by street
Sandy's power, placement and timing combined to produce the highest floods and storm surges ever recorded in the city. The superstorm brought an 11-foot storm tide to New York Harbor, killed more than 200 people and caused approximately $70 billion in property damage to the Eastern Seaboard. Several years of work were required to rebuild beaches, homes and communities.
Determined not to be caught off guard again, state and federal officials immediately reached out to Stevens for support in Sandy's wake.
And they haven't stopped doing so since.
"Especially during extreme events, our predictions are sought by different entities for assessment of vulnerabilities, identification of potential impacts and development of preparedness plans throughout New Jersey and New York," notes Hajj.
One of the first relationships Stevens developed post-Sandy was an exclusive contract with the Port Authority of New York & New Jersey (PANYNJ), the interstate agency charged with managing the region's airports, bridges, tunnels and seaports.
For PANYNJ, the Davidson Lab team created street-by-street flood and storm-surge forecasting maps for New York City planners. Those maps and models will help build new warning systems to inform regional officials and residents sooner about specific surge and flood threats, as well as evacuation planning.
In addition to the contract work Stevens performs on behalf of agencies and planning authorities, local city officials access the university's daily public updates — and use them when preparing for storms.
"Most days, the Stevens Flood Advisory System is the first piece of information I check in the morning," says Caleb Stratton, Chief Resilience Officer for the city of Hoboken. "Accurate records and projections of surge allow us to escalate our emergency operations in real time, and make informed decisions about the resources and communications that need to be shared with the community."
In addition, Stevens built tools, models and warning systems that predict floods in Hoboken and the New Jersey Meadowlands under a contract with New Jersey Transit (NJT). The goal: to help NJT both reposition its train equipment to safer areas before high surges and warn commuters prior to predicted flood and surge events — a relief to those who remember flooded stations and stranded trains during Sandy.
Davidson Lab researchers have also produced visualizations of climate change-driven floods for the city of Philadelphia; dramatic modeling of the long-term effects over time of sea-level rise on Jamaica Bay (where much of the land surrounding JFK Airport would be swallowed up); and the Hudson River flood plain.
Engineering better resilience
Stevens' legacy in engineering also comes into play when preparing for stronger storms.
- Faculty and student researchers study, design and advise a range of proposals, plans and blueprints, from a solar-powered home that can withstand hurricane-force winds (and close its own shutters to resist rising flood waters) to gated barriers in the sea that could be locked shut during strong surges to reduce damage.
- Stevens faculty advised two of the finalist teams in the U.S. Department of Housing and Urban Development's (HUD) recent Rebuild by Design post-Hurricane Sandy resilience competition, including one winner: a "Living Breakwaters" proposal that incorporates a series of natural breakwaters just off the southeastern shore of vulnerable Staten Island.
- Stevens urban engineer Valentina Prigiobbe studies Hoboken's antiquated sewage system, modeling its capacity to handle both normal and extreme events.
- Researcher Elizabeth Fassman-Beck attacks the problem from a different angle: the air. Her experimental "green roofs" on the Stevens campus demonstrate a new means of filtering, slowing and channeling punishing rainwaters before they overwhelm sewer systems.
- Orton works with flood-prone local city neighborhoods such as Broad Channel and Hamilton Beach to help inform and engineer local defenses.
- And Orton has also advised Jersey City, New Jersey's second-largest city (population: 270,000), on engineering and landscaping plans that could direct flood waters around (rather than into) the city. Some of those plans have already been integrated into the city's official sustainability planning.
"We have a responsibility to provide and continually enhance our modeling ability," sums Hajj. "Communities and agencies urgently look to Stevens for this critical data in times of need.
"The university will continue to serve communities and the government by helping in the preparation for sudden extreme-weather events, as well as for the more gradual, but also devastating, effects of gradual sea-level rise."