Greenhouse gas emissions from new buildings are on the decline, but that doesn’t necessarily mean their carbon footprints are smaller than their older counterparts.
In fact, new construction projects targeting low emissions standards often use more environmentally-taxing materials. This means a new tower with today’s most advanced operations system could have a larger carbon footprint than another building that is decades old.
Government agencies looking to curb the effects of global warming have started to consider this disparity when crafting policy and climate advocates are already beating the war drum against what is known as embodied carbon.
“The good news is we know how to build good, clean, environmentally-friendly buildings,” Bruce King, founder of the Ecological Building Network, said. “The bad news is we don’t, most of the time we build crap.”
King was one of several speakers at the Carbon Leadership Forum’s “Build Positive” symposium last week at Skanska’s Empire State Building office. Embodied carbon was the topic du jour.
A growing focal point for researchers and government regulators, embodied carbon is the term used for a project’s pre-construction emissions, those resulting from the extraction and processing of raw materials as well as the manufacture and transport of elements such as steel beams, concrete and glass.
Collectively, embodied emissions can make up more than half of a building’s lifetime carbon footprint before the first light is even switched on, according to the World Economic Forum, a Swiss non-profit.
And here’s the real rub: to meet more stringent operational emission standards, builders are increasing their embodied carbon, employing highly-processed materials and advanced technological systems, the likes of which require a lot of energy to produce.
“Sometimes, by creating net neutral buildings, we crank up the embodied emissions,” King said. “And that’s not good either.”
Take, for example, 270 Park Avenue, where JPMorgan Chase plans to demolish the current 52-story building and replace it with a taller, more modern replacement.
While the new 270 Park will, no doubt, achieve the latest industry efficiency standards, it will do so only after piling up hundreds of feet work of newly produced building materials. Portland cement, the most common concrete mixture in the world, is said to account for about six percent of the world’s annual carbon emissions.
Compare that to the Time-Life Building, 1271 Avenue of the Americas, which was built in the same era as 270 Park and stands nearly as tall. With its ongoing retrofit, it could have nearly the same operational efficiency as a modern office tower without creating new embodied carbon.
“Interestingly, the age of the building does not have a strong correlation with the efficiency of the building,” Jaxon Love, Shorenstein Properties’ sustainability program manager, said. “What correlates more strongly is the robustness of the operating program in place. We have properties, like our office here in San Francisco, which was built in 1927 and recently recertified as LEED Platinum.”
Over time, new buildings might have fewer tail-end emissions but unlike operational emissions, which can be recaptured or otherwise mitigated, embedded carbon has already been released into the atmosphere. What’s done is done.
This is especially problematic in the eyes of climate advocates who believe global warming is rapidly approaching a tipping point.
If global average temperatures reach 2 degrees Celsius (3.6 degrees Fahrenheit) above pre-industrial levels, the effects of climate change will become permanent, according to the science agreed upon in during the 2015 Paris climate talks. During the conference, the global average temperature was roughly 1 degree Celsius more than the pre-industrial average and on track to surpass 2 degrees by 2050.
To do this, the Intergovernmental Panel on Climate Change is calling for world governments to implement a hard cap on greenhouse gas emissions by 2020 and phase them out entirely by 2050. Erin McDade, program manager of Architecture 2030, a sustainability-focused non-profit, said this strategy would give the world an 85 percent chance of staying below that 2 degree Celsius threshold.
McDade, who also spoke during last week’s event, said buildings account for roughly 40 percent of greenhouse emissions, nearly double the output of transportation, which accounts for 22 percent. With two trillion s/f of global new construction planned for the next 32 years — a Manhattan’s worth every 35 days or so — current building practices could put a damper on the Paris Accord’s 2050 aspirations.
Long-term, much of that new construction will take place in developing countries in Africa and Asia, but for now, New York’s mantra is build, baby, build; between 2013 and 2017, city builders broke ground on 73 million s/f of commercial space, according to the New York Building Congress. During the past three years, the five boroughs have also seen close to 100,000 new apartments.
LEED, the industry standard for sustainability set by the U.S. Green Buildings Council, has included additional material considerations in its latest policy update but more with the goal of facilitating conversations between builders and manufacturers.
True zero or negative emission materials do exist but with front-runners being wood beams, straw insulation and low-impact concretes such as “hempcrete” or adobe, they are hardly suited for today’s commercial needs.
“You can’t build Manhattan out of clay,” King said. “I’m not stupid, I know that.”
Climate change is a growing concern for developers in New York and elsewhere, Joseph G. Nahas, Jr., chair of The Counselors of Real Estate, said, though primarily because of its end results rather than how they might be contributing to it.
Each year, The Counselors of Real Estate, an association of real estate advisers, puts together a list of the top 10 issues the industry is facing. Natural disasters and climate change ranked as the No. 3 long-term issue.
“We’ve heard our clients say look, these rising sea levels, these storms and now volcanoes are not going away,” Nahas said. “They’re starting to think about where they’re building or investing and how those locations are affected by weather or implications of climate change.
“If I’m a builder and I’m looking at property in Miami or Boston, places we know are more vulnerable to rising sea levels, I’m going to look at it a little differently,” he added.
However, Nahas said those concerns haven’t caused his clients to reflect on their own building methods.
Charles Copeland, president and CEO of the Manhattan-based engineering firm Goldman Copeland, said there are two main reasons why building owners are seeking to shrink their carbon footprint at all: government regulations and tenant demands.
However, when it comes time to decide between retrofitting an old building and ground-up construction, Copeland said the decision is driven by economics far more than environmental obligation.
“The decision on whether to tear a building down and put a new one up is essentially a financial decision,” he said. “They’re not going to make it based on energy, they’re going to do that based on the huge costs considerations for land and labor.”