Two studies out in recent days put New York City at a severe risk of climate change-enhanced flooding—and much sooner than previously thought.
2 Degrees, Surging Seas
The first is a comprehensive new review in the journal Science that shows that if the planet warms by 2 degrees Celsius (3.6°F), sea levels will rise about 20 feet. Obviously, this could have dramatic impacts on coastal cities across the globe—including our favorite coastal metropolis, New York City.
Entire neighborhoods in NYC would be submerged—the East and West Village, TriBeCa, Chelsea, Greenpoint, Williamsburg, Coney Island, Long Island City, and the Rockaways to name a few—and nearly 2 million people could be displaced.
The second study is written by James Hansen, NASA’s former lead climate scientist, along with 16 co-authors, and will soon be published in the peer-reviewed journal Atmospheric Physics and Chemistry. It posits that glaciers in Greenland and Antarctica will melt 10 times faster than previous estimates, which will result in sea level rise of at least 10 feet in as little as 50 years.
“a feedback loop in the ocean near Antarctica that results in cooler freshwater from melting glaciers forcing warmer, saltier water underneath the ice sheets, speeding up the melting rate.”
Hansen gives no specific timeline, but suggests the feedback loop is likely to occur this century—that is, by 2100.
If correct, Hansen’s findings mean that ice is melting and seas are rising much faster than expected. The Intergovernmental Panel on Climate Change has projected closer to 3 feet of sea level rise by the end of the century. Even that amount that would mean serious consequences for New York City residents, and would put runways of JFK, LaGuardia, and Newark airports underwater.
According to Hansen, this report requires “emergency cooperation among nations.” He continues:
“We conclude that continued high emissions will make multi-meter sea level rise practically unavoidable and likely to occur this century. Social disruption and economic consequences of such large sea level rise could be devastating. It is not difficult to imagine that conflicts arising from forced migrations and economic collapse might make the planet ungovernable, threatening the fabric of civilization.”
Over 400,000 New York City residents, an increase of 84% from the current 218,088, will soon be living in flood zones.
As we reported last Fall, the Federal Emergency Management Agency has updated maps that depict which parts of New York City are at risk from a 100-year-flood—meaning areas that have a one percent chance of flooding each year.
Finalized maps will be released next year.
Properties included in the expanded flood zones have jumped from 23,885 structures in 2010 to 84,596 in 2013—an increase of more than 60,000 buildings.
The number of buildings in flood zones more than doubled in all boroughs except the Bronx, but the largest spike came in Brooklyn: more than 42,000 structures are now identified as at-risk, compared to the previous 5,648.
If you own a home or residential building in a flood zone, you will be required to purchase flood insurance. Flood insurance premiums are projected to increase significantly, a problem which the City has been trying to address.
Check out our latest story, written by contributor Samar Khurshid, to learn more about rising flood insurance rates and what they mean for New York City.
Find out even more about New York City’s flood insurance issues here.
See the latest sea level rise projections for New York City here.
Overall, the news is grim: according to the report’s authors, annual temperatures are hot and getting hotter, extreme precipitation events are increasing in frequency, and the sea is rising faster than expected.
The report was produced by the New York City Panel on Climate Change, an independent body of academic and private sector experts that advises the city on climate risks and resiliency. The NPCC was convened by Mayor Michael Bloomberg in August 2008 as part of PlaNYC. This is their third report since that time and presents work from January 2013 to January 2015.
Sea Levels Are Rising, and Fast
Some of the most startling findings from today’s report revolve around sea level rise projections. Since 1900, New York City has seen sea levels rise around 12 inches—that’s nearly twice the observed global rate over a similar time period.
But it’s not going to stop there: this trend is expected to continue, and even accelerate, as the century progresses. According to the report, sea level could rise 11-21 inches by the 2050s, and 18-39 inches by the 2080s. By 2100, it could reach as high as six feet.
Low-lying and coastal areas of New York City will certainly feel the brunt of this inundation—and many have already begun to experience the impacts. The report suggests that just the current 12 inches of sea level rise may have expanded Hurricane Sandy’s flood area by approximately 25 square miles.
Of all the boroughs, Queens has the most land area at risk of future coastal flooding due to sea level rise, followed by Brooklyn, Staten Island, the Bronx, and Manhattan.
More Storms, More Problems
While continued sea level rise is all but certain, the specific frequency of future storms like hurricanes and nor’easters has proven harder to predict. However, the report’s authors note that it is “more likely than not” that there will be more intense storms, and they will bring extreme winds and intense precipitation.
Coupled with already high sea levels, these storms could cause serious flooding in parts of the City that are already struggling to cope with climate impacts. The report states that “under the high sea level rise estimate for the 2080s, the current 100-year flood (a flood with a 1 percent annual chance of occurrence) is projected to become an approximately once-in-eight year event.”
It’s going to get hotter in New York City—but it’s also going to get wetter and more extreme.
Since 1900, temperatures measured in Central Park have risen 3.4°F, mirroring an increase that’s been seen throughout the entire Northeast, in both rural and urban areas.
By the 2050s, the NPCC suggests that annual temperatures could increase by 4.1 to 5.7°F. By 2080, it could be closer to 8.8°F.
That may not seem like much, especially as we shiver through a snowy February. But keep in mind that these increases will occur in all months of the year. To put things in perspective, the NPCC offers this: “By the 2080s, New York City’s mean temperatures … may bear similarities to those of a city like Norfolk, Virginia, today.”
We can expect to see more days above 90°F, more days above 100°F, and more heat waves (three or more consecutive days above 90°F), too. The NPCC report suggests that by 2080, the number of heat waves could triple—up to six per year.
But the extremes won’t be limited to temperature. Since 1900, annual precipitation has increased a total of 8 inches (about 0.8 inches a decade); the report suggests this increase is likely to continue, but will probably come in the form of short, intense bursts—perfect for flash floods and combined sewage overflows.
The Time for Action is Now
While it is difficult to project individual weather events with any kind of certainty, the NPCC’s report is clear that climate change is a serious and imminent threat to New York City’s people, economy, infrastructure, and natural environment.
And while the City is taking dramatic steps to reduce its greenhouse gas emissions, it must also act now to protect against sea level rise, coastal flooding, and warming temperatures that are now inevitable.
“NPCC’s findings underscore the urgency of not only mitigating our contributions to climate change, but adapting our city to its risks,” said Mayor de Blasio. “The task at hand is daunting— and that is why we’re making an unprecedented commitment, with a sweeping plan to reduce emissions 80 percent by 2050, and a comprehensive, multi-layered resiliency plan that is already making neighborhoods safer.”
The City is also making progress on a number of key projects, including:
The launch of scoping and preliminary design work on the Lower East Side to implement a $335 million integrated, neighborhood-sensitive flood protection system to mitigate risk and help connect the community with the waterfront.
The Office of Recovery and Resiliency (ORR), partnering with the New York City Economic Development Corporation (NYCEDC), has launched the first-ever, comprehensive regional resiliency analysis of New York City’s food supply chain network.
To combat the urban heat island effect, as of the end of 2014, NYC Cool Roofs has coated over six million square feet of building roofs with reflective paint to address the climate change risks associated with urban heat. The City’s recent green buildings plan commits to coating at least one million square feet a year more to continue mitigating the urban heat island effect and provide energy savings in affordable housing, public buildings, and non-profit organizations.
ORR and NYCEDC have also launched an approximately $100 million shoreline investment program to protect the most vulnerable waterfront communities, including Coney Island Creek and Staten Island’s South Shore, and other low-lying parts of the city that will be evaluated as part of the first phase of work.
Future efforts include upgrading flood protection systems and coastal protection in at-risk areas, preparing NYCHA for heavy flooding, investments in the Staten Island Bluebelt and other storm water infrastructure, and the construction of levees in Midland Beach and on Staten Island’s East Shore.
Many other sustainability plans are outlined in PlaNYC; the mayor’s office will release a progress report for those initiatives in April 2015.