In the shadows of booming cities, a tension between sunlight and prosperity
In the shadows of booming cities, a tension between sunlight and prosperity
May 4th, 2015
By Emily Badger
Read More: http://www.washingtonpost.com/blogs/...nd-prosperity/
Quote:
“Billionaires' Row” is rising over midtown, a collection of glassy new pinnacles that promise the kind of condo views you can only get in Manhattan by building taller than everything else around. With its $95 million penthouse, 432 Park Avenue tops out just shy of 1,400 feet. It will remain the tallest residential building in the Western Hemisphere until the Nordstrom Tower — high-end shopping below, lavish apartments above — goes up four blocks away.
- These new buildings — a product of developer ingenuity, architectural advance and international wealth — are changing more than the city’s famous skyline, though. They will also transform New York far below, further darkening city streets and casting long shadows that will sweep across Central Park. --- Together, these towers, and new additions in neighborhoods undergoing a building boom from San Francisco to Toronto to even low-rise D.C., have revived a long-simmering urban tension: between light and growth, between the benefits of city living and its cost in shadows.
- For cities, shadows present both a technical challenge — one that can be modeled in 3-D and measured in “theoretical annual sunlight hours” lost — and an ethereal one. They change the feel of space and the value of property in ways that are hard to define. They’re a stark reminder that the new growth needed in healthy cities can come at the expense of people already living there. And in some ways, shadows even turn light into another medium of inequality — a resource that can be bought by the wealthy, eclipsed from the poor.
- These tensions are rising with the scale of new development in many cities. As New York's skyscrapers set height records, Mayor Bill de Blasio has also proposed building 80,000 units of affordable housing over the next 10 years, much of which the city would find room for by rezoning land to build higher. Boston wants to find space for an additional 53,000 units. Toronto in the last five years has built more than 67,000. All of which will inevitably mean more shadow — or even shadows cast upon shadow, creating places that are darker still.
- In New York, legislation was introduced in the city council this spring that would create a task force scrutinizing shadows on public parks. Lawmakers in Boston in the last few years have repeatedly proposed to ban new shadows on parkland, though they haven't succeeded. --- In San Francisco, the city has tightened guidance on a long-standing law regulating shadows in an era of increasingly contentious development fights. In Washington, where the conflict arises not from luxury skyscrapers but modest apartments and rowhouse pop-ups, the zoning commission voted in April on rules that would prohibit new shadows cast on neighboring solar panels.
- The stakes are highest in Manhattan, a crammed borough with few of the back yards, balconies, or even clear window views that city dwellers count on for light that doesn't come from a fluorescent bulb. --- "Parks have become the place where we go for this incredibly important experience of being in the sun," says Mark Levine, the New York councilman who introduced the bill that now awaits public hearings. "And if even parks lose the sunlight, then I think it diminishes the experience of living of here."
- New York City has been regulating shadows, if in an indirect way, for a century. When the 42-story Equitable Building was completed in Lower Manhattan in 1915 — rising from the sidewalk like the sheer face of a cliff for more than 500 feet — it cast a seven-acre shadow over the neighborhood. --- The outcry it caused helped prompt the city’s first comprehensive zoning law. Those rules didn’t require buildings to cast shadows of a certain size, but they influenced the shape of skyscrapers in ways that controlled how they loomed over the city below.
- Tall buildings required "setbacks" at higher floors. This is why the Empire State Building grows narrower as it rises, why New York’s skyline looks like a collection of wedding-cake toppers. This is also what creates space and light between buildings that might otherwise rise shoulder to shoulder. --- In Central Park today, the new generation of luxury towers on Billionaires' Row reach higher than many in the city ever envisioned. The developers behind them merged multiple building lots or purchased the “air rights” above adjacent properties to legally build taller than what would historically be allowed.
- As a result, multimillion-dollar apartments in the sky will darken parts of the park a mile away. Enjoyment of the park while actually in the park — a notably free activity in a high-cost city — will be dimmed a little to give millionaires and billionaires views of it from above. That picture is an apt symbol for the city’s widening inequality. But it’s also an example of a much broader conflict: New York, and many cities desperate for new housing, must find space to put it.
- Since 1984, San Francisco has had a “sunlight ordinance” that requires the parks commission to review any proposed building taller than 40 feet that might shadow public parks. Last year, the planning department wrote new guidance on how developers must measure their shadow impacts with tremendous precision to comply with it. --- First, they must hire shadow consultants to calculate how much theoretical sunlight, in square-foot-hours, a park would receive over a year if nothing were blocking it. The park is then modeled in 3-D with the buildings around it, taking into account how the sun moves over the course of the day and changes position over the year. "This software," Schuett says, "is literally like a calculus model."
- The software recognizes the intricate geometry of sunshine: that the sun isn’t as high at “high noon” in San Francisco as it is in Mexico City, that it casts shorter shadows when it’s overhead and long, gloomy ones when it’s low in the sky in winter. --- In a model like this, it's possible then to insert a new building and measure how the shadow load changes, maybe subtracting another few percentage points of theoretical sunlight. This is the number the parks commission in San Francisco then considers, alongside diagrams of where those shadows would fall.
- In entirely different contexts — Southern cities, the Middle East — shade is an essential resource in its own right, and shadows can add a dimension to open space that can be quite pleasant. It appears in the reflections of trees that cast shivering patterns on the sidewalk, in the stark lines between light and dark that give drama to our photos of cities, in the shadows that turn ornate buildings into two-dimensional cityscapes.
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Pedestrians in downtown D.C. make the early-morning commute in March 2014. (Astrid Riecken for The Washington Post )
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