Design Architecture No, Bill De Blasio Has Not Banned Glass and Steel Buildings in New York By Lloyd Alter Design Editor University of Toronto Lloyd Alter is Design Editor for Treehugger and teaches Sustainable Design at Ryerson University in Toronto. our editorial process Facebook Facebook Twitter Twitter Lloyd Alter Updated April 30, 2019 ©. TIMOTHY A. CLARY/AFP/Getty Images Share Twitter Pinterest Email Design Tiny Homes Architecture Interior Design Green Design Urban Design But maybe he should. The good news is that the Mayor of New York, Bill de Blasio, is going after buildings that are energy hogs. The bad news is that some of what is being said is nonsense. Or at leastthe New York Times is getting it wrong: De Blasio, a Democrat who is hinting at a presidential run, vowed this week to introduce a bill to ban glass and steel skyscrapers, saying those buildings are much less energy efficient than their brick and concrete counterparts and contribute more to global warming. World Trade Center/ Lloyd Alter/CC BY 2.0 I have written that All-glass buildings are an aesthetic, as well as a thermal crime, noting that the best glass is no better than a bad wall, but this is not the end of glass buildings, and that's not what the Mayor said. What he actually said was: We are going to introduce legislation to ban glass and steel skyscrapers that have contributed so much to global warming. They have no place in our city, or in our earth anymore. If a company wants to build a big skyscraper, they can use all the glass, if they do all the things needed to reduce the emissions. But putting up monuments to themselves that harm our earth and threaten our future. That will no longer be allowed in New York City. Hudson Yards from the High Line/ Lloyd Alter/CC BY 2.0 In another interview he said: “The kind of the glass and steel buildings of the past, and some bluntly were being built very recently, are just not going to be allowed any more.” De Blasio clarified again, saying he would be tightening the energy code, not banning glass. It’s literally going to be a much higher standard and the only way that kind of design would even be acceptable is with a whole host of other changes that were made to compensate, because those buildings were inherently very inefficient. We do not know what the standard is yet, as it has not been released, but the first thing the standard should include is a ban on demolition of the kind happening at 270 Park Avenue, where a perfectly good, energy-efficient building is being knocked down to replace with one twice the size. And Upfront Carbon Emissions, my preferred name for embodied carbon, should be part of any new code, because that's carbon we have to avoid emitting right now. Replacing glass and steel with brick and concrete might well make upfront carbon emissions worse. Combined with announcements made earlier about retrofitting existing buildings, the real estate industry is very unhappy. One owner of a lot of residential buildings pulled the poor seniors' excuse about his tenants: “Most are on a fixed income and I have to be very cognizant about anything that I do because I don’t want to put an undue burden on people that can’t afford it.” But really, this is all inevitable if we are serious about reducing our carbon emissions. That's another reason to put an upfront carbon emissions tax on building; perhaps that could go to help out the poor seniors. View from the South Bank of the Thames/ Lloyd Alter/CC BY 2.0 It is also going to spread; people in London are already talking about emulating this. Simon Sturgis, a consultant in London, tells the Architects Journal about the problems with all glass buildings: The first and most obvious is that glass buildings absorb huge amounts of heat which requires high levels of cooling to remove. Secondly the cladding of an all-glass building has a life of about 40 years, so replacing it on this cycle has significant embodied carbon costs over the life of the building. He suggests that market forces might make a difference. "I believe we are moving to a position where all glass buildings will be seen as environmentally irresponsible, will consequently have difficulty in attracting tenants and therefore be seen as an investment risk." Some are pushing back. Karen Cook of PLP Architecture tells AJ that, "There is a danger when the succinctness of political headlines undermines the objective. Glass is made from natural materials, lasts forever and is recyclable." Concrete is made from natural materials too. Glass curtain walls do not last forever; it is an assembly of many components that can fail, often relatively quickly. Glass is rarely recycled into windows because of contamination. But Cook is right about one thing: it is a complex issue and we need a lot more information.