The ribbon-cutting ceremony for Society Hill’s new Headhouse Plaza took place on the kind of searing June day that is sadly becoming more common in the Northeastern United States. Although the space features a pair of assertively designed, butterfly-wing canopies, their strange angles offered the crowd virtually no protection from the sun on that brutally hot morning. As people waited for Mayor Jim Kenney to arrive, a few began drifting across the street to take refuge in the shadows of buildings on Second Street. Pretty soon, everyone was huddled together in the same small pool of shade.

Well before the United Nations issued its code-red climate report this week, we knew that our world was rapidly becoming a hotter place. It’s been more than a decade since Philadelphia established an office of sustainability to grapple with the impact of rising temperatures, and there is widespread agreement that we need to incorporate a lot more shade into the urban core if we want city life to remain bearable. And yet, as the new Headhouse Plaza so visibly demonstrates, we keep designing our public spaces according to the same outmoded thinking.

The plaza was built by the South Street Headhouse District, the private manager that oversees the area’s commercial corridors, to replace a block-long traffic island in the middle of Second Street, just south of the historic New Market Headhouse. Yet the new version is little more than a glorified traffic island. There probably hasn’t been such an ill-conceived public space in Philadelphia since the original Independence Mall, another hardscape extravaganza. There is similarly little shade or graciousness at the new Headhouse Plaza. It offers no restrooms, no respite from the rumbling traffic, no water feature, no public art, nothing to delight our eyes.

What makes the results especially unfortunate is that the two blocks of Second Street between Pine and South are one of Philadelphia’s most iconic places, as well as the bridge between the quiet residential streets of Society Hill and the more raucous South Street. That stretch of Second Street is unusually wide because a food market — New Market — was built down the center median during colonial times to serve what was then a busy waterfront neighborhood.

The market continued to operate into the ’60s, when the city launched the federally funded makeover that would transform Society Hill into an upscale enclave. In keeping with the philosophy of the time, the venerable brick headhouse and canopy at the northern end was preserved, while the ramshackle wooden market sheds between Lombard and South were demolished. That long, narrow site was turned into a surface parking lot, primarily for shoppers and tourists driving in from elsewhere.

The lot was an eyesore from the very beginning, and several efforts were made over the years to improve it. At some point, a seating area and fountain were installed at Lombard Street. But it wasn’t until the South Street business district took on the project that the replacement effort gained traction. The group hired Ambit Architecture, a neighborhood firm specializing in private homes and small apartment buildings. In 2016, the business district dutifully held a series of community meetings.

The problem is that the South Street district always approached the project through the lens of business-district placemaking. It wasn’t interested in designing a great neighborhood park or greening a chunk of asphalt. Rather, its main aim was to create a multipurpose event space suitable for big visitor attractions, like — ironically enough — the Clear Air Council’s annual GreenFest Philly. It’s the same script the city followed at the equally function-driven LOVE Park, which was also conceived as a stage for events, like Christmas Village and this summer’s beer garden. The neighborhood did get a small seating area at the north end, with several trees that may someday provide shade. But it’s no accident that the seating is next to the Headhouse shambles, where visitors spill out from the popular farmers market on Sundays.

There’s no doubt that Philadelphia’s business improvement districts do important work. They have brought comatose shopping corridors back to life with regular street cleaning, safety patrols, organized marketing, and promotional events. But their interests do not always align with neighborhood interests. Too often the neighborhood is treated as a prop to help attract shoppers and diners. Because the South Street district’s mission is supporting businesses, it was reluctant to let go of the parking component when it redesigned the traffic island.

While the business district cut the number of spaces from 40 to 30, parking remains the plaza’s main function, just as it was back in the ’60s. Never mind that there are two parking garages across the street. Or that many of the plaza’s potential users are neighborhood residents who can easily walk there. Or that we, as a city, should be encouraging people to choose alternative means of transportation — transit, bikes, scooters — when they visit South Street.

Ambit Architecture has essentially designed a better traffic island. Pedestrians can now walk safely from South Street to the Headhouse along a brick path. The crosswalks have been improved, and the island’s corners have been squared off to slow traffic. But even though the city chipped in two-thirds of the $3 million budget — including $700,000 from the Water Department — fully half the space is still devoted to cars. And what remains for the non-driving public is hardly welcoming.

In the early designs for the plaza, Ambit showed a single large canopy whose shape mimicked the roofline of the Headhouse shambles. But as the budget tightened, the design was watered down. In the end, two anemic canopies were placed at each end of the plaza. They function more as gateway markers than as protection from the elements. Not only are the roofs covered with open slats, allowing the sun and rain to pour in, the main canopy at the north end, where the seating is, appears to be pitched in the wrong direction: Because the Abbotts Square apartments are tall enough to block the western sun in the afternoon, the roof should have been angled to the east, to deflect the morning rays.

The South Street district’s focus on creating a flexible platform for events isn’t the only reason for the design’s failings. This was really a job for a landscape architect. A designer attuned to the natural world would have been more likely to use greenery to shape the space and create a sense of enclosure. Even though Second Street is heavily trafficked, the Ambit design does nothing to buffer the plaza from the noise and exhaust.

Michael E. Harris, the district’s executive director, told me that the organization wanted such an open feeling because it envisioned the new plaza as a counterpoint to the shaded shambles. But can you really have too much shade in a place like Headhouse Square, which is lined with restaurants and is a magnet for yoga classes, rollerblading, and other activities? With the pace of climate change, everything we build needs to anticipate a hotter future.

A park could have been a perfect counterpoint to the shambles. Imagine an allée of trees that grew together to form a living canopy — nature’s yin to the architectural yang of the shambles. Or perhaps they could have erected an arbor and planted it with flowering vines, similar to what Paris did on the Promenade plantée.

It’s not unreasonable for the South Street district to want a flat surface for events, but who says it has to be a fixed space? What if the district marked off the intersection of Second and Lombard with paint and then closed it to traffic for events, a treatment sometimes called a “raised intersection”? We need to stop thinking of our streets as being the exclusive province of cars. It’s true that the Route 40 bus uses that intersection to turn, but that bus is frequently diverted to other streets.

Any number of other design options would have been preferable to this car-dominated plaza. At least, we can escape this overheated space to find refuge elsewhere. Unfortunately, we won’t be able to escape our overheated planet.