Is the new Barclay Center green roof really green or greenwash?

By Lloyd Alter - Source: http://www.treehugger.com
Photo © SHoP

Photo © SHoP

The Atlantic Yards, home of the Barclay Center, has been controversial from the start, sitting as it does so close to upscale Park Slope and its very active and political residents. It is now getting a very big green roof installed over the stadium. In a press release from developer Forest City Ratner and partner Greenland Group, they claim it’s all about the environmental benefits.

“Our original design for the arena had anticipated a green roof as part of our effort to achieve Silver LEED certification,” MaryAnne Gilmartin, FCRC President and CEO, said. “While we independently reached that goal, we always hoped to still create a green roof, further improving the environmental footprint of the arena and also making a more direct connection to the sedum covered transit entrance on the plaza. Thanks to Greenland, which shares our commitment to sustainable development, we now have the resources to make this dream a reality.”

The Chinese Partner continues:

Ifei Chang, CEO Greenland USA Holding Companies, said “Greenland is very excited about working with FCRC on what we believe will be one of the largest and most impressive green roofs in the City and perhaps the country. We are strongly committed the environmental benefits of green roofs.”

So what’s so green about a green roof?

Green roofs can have lots of environmental benefits as bird and insect habitats, for stormwater management, reducing heat island effects and capturing airborne pollutants, as well as absorbing CO2 and releasing oxygen. Except this is an extensive (lightweight) green roof being built over a white roof, and some studies have claimed that white roofs are greener. It is a lightweight prefab pre-planted sedum roof that will not contribute to stormwater management. In fact, according to an article in Scientific American, ” A roof planted with sedum is no greener, from the standpoint of sustainability, than is ordinary tar or asphalt.”

Sedum does not absorb water as efficiently as other plant species, according to Scott MacIvor, a PhD student in biology at York University in Toronto who studies bee and wasp habitats on green roofs…. “The problem is that sedum plants aren’t really performing on green roofs,” he notes. “They’re just there.” One of the plant’s biggest failings, it turns out, is that it does not encourage biodiversity of plant species on the roof. According to MacIvor’s research, green roofs provide the most benefit when they are planted with a diverse group of species that are adapted to local conditions.

Then there is the biggest issue, the giant steel elephant in the room: it’s not being installed on the actual roof. They are building a giant 130,000 square foot steel superstructure that spans the whole existing roof with an air gap of between four and ten feet, installed by three cranes over a period of six months. They are essentially building a bridge to hold up a “flocked” pattern of sedum trays. The carbon footprint and embodied energy of so much steel far outweighs the environmental benefits of any green roof, let alone this one. The whole thing, from start to finish is a multimillion dollar environmental negative.

Photo © SHoP

Photo © SHoP

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