The City of Vancouver is moving forward with plans to incorporate policies into rezoning applications that would require developers to limit embodied greenhouse gas (GHG) emissions associated with their building projects.
Embodied emissions are those associated with the production of a building, such as building materials and the transport of building products.
Despite Mayor Gregor Robertson’s Greenest City 2020 Action Plan, until now city planners have not taken into account embodied emissions, and instead have focused solely on operating GHGs.
Patrick Condon, the chair of the urban design program of the School of Architecture + Landscape Architecture at the University of British Columbia (UBC), who is seeking the Vancouver mayoral nomination for the Coalition of Progressive Electors (COPE), believes the omission was short sighted.
“That's just one example of how narrow their view of sustainability has been,” said Condon. “Certainly, when we're looking at 2020 -- which is only two years away now -- the consequences of a lot of [their] strategies have made our buildings not only damaging to the environment but too expensive for any of our people to afford. I think it's outrageous.”
Sean Pander, a Green Building Manager with the City of Vancouver, admits the city was pressured in previous years by academics at UBC and by environmental non-governmental organizations to include embodied emissions in rezoning policy requirements, but says accurate data was not available until recently.
“We've historically looked at and saw research that said embodied emissions are about 20 per cent and operating emissions are about 80 per cent, so we focused on operating [emissions]."
However, Pander said that in 2015 the City began talking to the Athena Sustainable Buildings Institute, a company that collects data on embodied and operational emissions from buildings. They found that embodied emissions actually make up 50 per cent of the total.
“They shared a couple of studies with us that were really eye opening that showed that the operation emissions after 60 years are only half of the emissions of the embodied emissions that are present as of day one.”
Pander added that the timing was right as they realized they could bring forward new policy and regulation with industry support. Currently developers only have to calculate, not limit, the embodied emissions associated with their projects for rezoning applications, a requirement that was mandatory as of May 2017. Pander said in the future the city will work with industry to look at how developers can set realistic targets to reduce embodied carbon, perhaps by offering incentives.
“Ultimately we're probably quite a number of years away from a regulation that works on embodied emissions but once we start getting the data back... again I think you'll start to see people looking at different construction approaches.”
Cement, the primary component of concrete used in high-rise buildings in the city, is the primary contributor to the embodied emissions of buildings and is responsible for five per cent of all GHGs worldwide due to its production process, where limestone, silica alumina, iron and other materials are heated in coal-powered kilns at temperatures of up to 1,650 degrees Celsius.
Currently, buildings in the province over six stories are required to be constructed from concrete due to building codes and most buildings under six stories incorporate a wood frame construction. Condon believes Vancouver should focus on six-storey buildings instead of approving so many high-rises, as wooden frame construction is not only cheaper than concrete but is much less carbon intensive.
“We really don't need towers to get densification in Vancouver. With six stories we could basically have an infinitely large population into the numbers of millions. So those who think we have to go to high-rises in order to get density are dead wrong.”
Pander accepts that high emissions are associated with the cement makeup of concrete high-rises but said the operating emissions of a high-rise building are significantly lower per square foot when compared to a low-rise, adding that when density is built up around shops and transit hubs, people don't drive as much which also contributes to lower emissions.
“I think there are a whole bunch of societal reasons that say we want to keep working on higher density living; it might be a bit radical to ban high density construction,” said Pander.
Tim Gray, executive director of the group Environmental Defence, said wood is preferable to concrete when it comes to limiting greenhouse gas emissions but that the concrete industry in Canada has been working on decreasing emissions by targeting a number of areas in the production process, with some success.
“They are working on new formulations for cement itself where they are able to capture carbon from the atmosphere and are able to reincorporate that into the cement,” explained Gray. “They're trying to replace some of the fossil fuels they've been burning in the cement kiln with other fuel sources, mainly garbage and stuff that they otherwise they can't recycle, like old tires or plastics.”
Gray said that regardless of whether concrete or wood is used, building codes should be moving towards requirements that buildings emit zero emissions both in production and use.
“Overall the design should come together in a way so that instead of being large energy consumers they're either neutral on energy or preferably net energy producers. And there's a place for concrete in that and for wood.”
Image: Cliff Hellis/Flickr
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