Extreme Heat Means Tough Choices for New York City Building Owners

When summertime rolls around in New York City in the year 2065, the living ain’t gonna be easy. 

On a perfectly average day in August, the mercury will climb to 91.6 degrees, rather than the historic average of 84.6, according to one future climate scenario calculated by the U.S. Green Building Council’s WeatherShift tool. That’s assuming the world’s population manages to reduce its greenhouse gas emissions fairly aggressively in the intervening decades. Under a business-as-usual scenario, the heat index on the hottest day of the year in 2065 will reach 126.7 and hit 143.6 by 2090, transforming the city into an inhospitable open-air sauna.

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Good urban planning can help New York City cool down to some degree. But given the dystopian possibilities bearing down within many of our lifetimes, real estate owners also need to prepare for a time when the indoors becomes the main human habitat for significant stretches of the summer.

“In a way, it’s not a mystery,” said Clinton Andrews, a professor of urban planning and policy development at Rutgers University who has spent a lot of time thinking about this issue. “Because billions of people live in warm climates, and they’ve built very successful cities.”

But from a structural standpoint, extreme heat can wreak all kinds of havoc, according to Andrews, especially when combined with humidity. And that poses risks for the city’s largest piece of infrastructure: its million buildings. 

The first thing that comes to mind for Andrews is thermal cracks, which form more readily in brickwork and other types of masonry after repeated expansion and contraction during temperature fluctuations. 

This barely perceptible phenomenon is a likely culprit behind the spider web of cracks that have formed in the Lasa marble heated floor of the Oculus transit hub in Lower Manhattan, designed by Santiago Calatrava and completed in 2016. “And related to that you’ll see gaps that start to develop between dissimilar materials because they expand and contract at different rates,” Andrews said.

For both of these reasons, New York City buildings will likely see an uptick in thermal cracking and weathering this century.

“Is there anything that the landlords ought to be doing? Or that the city fathers ought to be doing?” Andrews said.  

There certainly are. Starting with heating, ventilation and air conditioning systems.

An HVAC system typically comprises about 10 percent of the construction cost of new Class A office buildings under development today, according to Jaros, Baum & Bolles. Scott Frank, a managing partner at Jaros, Baum & Bolles who advises building owners on long-term decisions about cooling systems, generally recommends builders increase a system’s capacity 3 to 5 percent to prepare for intensifying heat decades hence. 

That means paying a premium of about 0.5 percent of the total project cost — a meaningful number, but not a fundamental change to the financial picture for most developers, according to Frank.

“This is somewhat of a moving target,” he said. “You’re taking the theoretical science and translating that into actual predictions about temperatures and durations. There are a lot of assumptions that go into it.”

Sometimes, Frank said, it’s easier just to tell clients they should prepare for New York’s future climate to resemble the current one in Washington, D.C.

Either way, “what that means for buildings in general — new or existing — to maintain comfortable conditions inside, the air-conditioning systems have to work harder,” Frank said. “They have to have more capacity.”

Perhaps the only thing developers hate more than being caught flat-footed in the face of new capital costs is uncertainty about how to avoid those costs. This is unpleasant for everyone, but for some people — particularly the elderly — the stakes are higher.

Today, Americans spend 90 percent of their lives indoors year-round, which will likely go up as triple-digit temperatures become an increasingly normal occurrence. New York Gov. Kathy Hochul’s official advice during this past July’s heat wave was to “stay inside in the air conditioning.” For those who aren’t able to do so, New York Mayor Eric Adams has repeatedly recommended visiting one of the city’s 492 cooling centers, most of which are public libraries that close at night.

“We’ve said it over and over again: Climate change is here and it’s real,” Adams told reporters July 15. “Our city is prepared, the entire apparatus is coordinating together.”

It didn’t inspire confidence when a cog in that apparatus — the Third Avenue Bridge — ceased functioning midafternoon on July 8 due to heat expansion, halting the flow of traffic between East Harlem and Mott Haven in the Bronx until the New York City Fire Department managed to cool it down with a jet of water suctioned from the Harlem River. The weather station at LaGuardia Airport recorded a high of merely 91 that day.

Weeks earlier, sagging overheated wires and a brush fire in Secaucus, N.J., temporarily shut down Amtrak and New Jersey Transit service into Midtown, causing a melee at Pennsylvania Station.

But the city’s largest piece of infrastructure is its approximately 1 million buildings whose thermal resilience is tied to myriad factors, including their building envelope and glazing materials, orientation toward the sun, window design, solar shading, air tightness and ventilation.

Aside from thermal cracks, a related focus for structural engineers are gaps between dissimilar materials that respond to heat differently. For both of these reasons, New York City buildings will likely see an uptick in thermal cracking and weathering this century, according to Rutgers’ Andrews.

But there’s good news for the city, which is that it’s built on a solid foundation of bedrock dating to the Pleistocene Epoch. At its thickest point, the schist underlying the city stretches 1,280 feet into the Earth, providing a safeguard against sinkholes and other changes that occur elsewhere in the United State, especially in clay-ridden subsoil.

And New York City builders are not  alone in preparing for the ravages of extreme heat.

There’s a growing awareness of the real estate industry’s role in reducing the urban heat island effect, which was first observed as far back as 1968 in  Manhattan by Robert Bornstein.

The hotbox effect of densely developed land also occurs in virtually every city across the globe and can be inferred from archeological evidence of ancient Rome, according to Joanna Frank, the founding president and CEO of the Center for Active Design (CfAD), a nonprofit think tank launched by former Mayor Michael Bloomberg in 2012.

In June, CfAD released its latest update to Fitwel, a certification system for buildings to comply with design standards that prioritize future public health and environmental needs.

“All of this is evidence-based,” Joanna Frank said. “What real estate owners can do is actually not rocket science.”

The recommendations include low-hanging fruit such as light-colored roofs, which New York City already requires for most buildings thanks to a 2011 local law. There are more sophisticated measures such as outfitting buildings with louvers that provide shade while also aligning with the direction of the wind. 

Trees, of course, play a pivotal role in cooling the city, and are also a burgeoning design trend in office towers that offer outdoor spaces like the logia terraces planned for Taconic Partners’ and Nuveen Real Estate’s One Grand. 

Joanna Frank pointed to Tishman Speyer’s Rockefeller Center as an example of how office landlords can incorporate CfAD’s design standards. The pale limestone façade of the Midtown towers deflects the summertime sun’s intensity, and the public courtyard in front of 1221 Sixth Avenue is brimming with trees and shrubs after a $50 million upgrade completed last year.

Some of these techniques are taken from cities that have developed them over the course of centuries.

“There are many parts of the world that have experienced extreme heat for millennia at this point,” Joanna Frank said. “So it’s not that we can’t create a built environment that works in extreme heat, and it isn’t that populations can’t thrive in that heat, because they can.” 

Yet New York City has four seasons, not just one, and that makes its challenges unique. 

“A place like Dubai doesn’t have cold winters,” Andrews said. “So, if you design for just a nice hot day in Dubai, your building probably won’t work very well in a New York winter.”

Indeed, heavy rain this spring tested Dubai’s infrastructure, collapsing roads and forcing residents to climb the stairs in some high-rise apartment buildings where the elevators broke down.

What’s now growing is the collective will and urgency to prepare for the heat waves of the future, and city agencies like New York’s Public Design Commission are getting involved in that. Joanna Frank sees the commission as a bright spot in a city where the construction trades are otherwise plagued by what she describes as high costs, red tape and endless approvals. Public design projects, no matter which city agency is leading them, are all channeled through the Public Design Commission, which “actually makes it very efficient to change policies and to change direction,” Frank said.

She has hope that New York will be nimble enough for developers to pick up on some of those ideas and make the changes necessary to keep the city habitable.

“To include the peoples’ perspective is what we’re talking about here,” Frank added. “How do you create a built environment and how do you create a city that is prioritizing the quality of life and the health of its people?”

Abigail Nehring can be reached at anehring@commercialobserver.com.