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  • Writer's picturePeter Alspach

GETTING TO ZERO, Rethinking Carbon in the Built Environment

Editor’s Note: As we work with our clients to improve the health of people and the planet, addressing carbon emissions from the built environment is imperative. In this series, we focus on the ethics and economics of carbon-based decision-making, as well as actionable steps to reduce both embodied and operational carbon.

This post was co-authored by Peter Alspach, Margaret Montgomery and Megha Sinha It goes without saying that the conversation around climate change dominates news headlines. Seemingly every day, we read about extreme weather events, rising energy prices and dwindling resources. This year alone, the US has experienced eighteen separate extreme weather disasters costing up to $1 billion each.

Ethically, carbon-based decision-making is imperative. Six of the top 10 greenhouse gas emitters are developing countries, and the US and Canada emit more than double the global average per capita. The least developed countries emit the least carbon dioxide, but the effects of climate change are felt most strongly by these nations. And globally, climate change disproportionately impacts women and communities of color. For example, weather events fall harder on disadvantaged communities, who generally have fewer resources and take much longer to regain equilibrium.

So, how does the built environment come into play? According to a 2019 report by the World Green Building Council, the building and construction industries together are responsible for 39 percent of all carbon emissions in the world. Moreover, according to UN Habitat, cities consume 78 percent of the world’s energy and produce more than 60 percent of greenhouse gas emissions–yet they account for less than 2 percent of the Earth’s surface. The conversation about how to get to zero-carbon can feel daunting, but we believe that creative and world-changing solutions are within our reach. In this series, we will discuss the main considerations to achieve zero-carbon in our cities and the built environment, with the goal of counteracting the building industry’s growing impact on climate change.

Beyond the Building Footprint The scale of the challenge at hand necessitates that zero-carbon thinking start well before the building footprint—at urban, district and campus scales. It is at this scale that critical carbon reduction strategies and policies as they relate to energy infrastructure, transportation, land use, urban tree canopy preservation, existing and new building construction, and public-private partnerships must be made to create meaningful and long-lasting change.

Cities are leaders in the climate change movement in large part because city government—and mayors in particular—are more directly connected to their constituency than state or federal legislators. They also hold the majority of carbon emissions for most of their locations, and they have the authority to move more quickly than state, federal or national government.

For example, the City of Boston has introduced the Carbon Free Boston initiative, a comprehensive plan to become carbon neutral by 2050 by putting strategies in place to cut emissions from cars and buildings. Likewise, Denver recently became the eighth US jurisdiction to pass a building performance standard, and Seattle’s Mayor Durkan issued a Climate Executive Order during the COP26 Summit to accelerate efforts toward net-zero emission buildings.

Applying carbon-reduction strategies at the city level is important in mitigating the built environment’s carbon footprint. Tencent’s Net City, in China, prioritizes people and the environment, rather than automobiles, for a healthier experience.

A Shift in Thinking Zero-carbon buildings require a shift in thinking at the onset to meet the aggressive targets we need to achieve by 2030. Where a project is located, its height, massing, materiality and whether it needs to be built at all are considerations that can affect a building’s contribution to carbon emissions. On a recent high-rise office tower, our design team made the early decision to incorporate a steel, below-grade parking structure when concrete would be more conventional path. As a result of these and other design decisions, this project has a projected embodied carbon 10% below the ILFI Zero Carbon threshold of 500 kg/m2.

In addition, a project’s location touches issues from preservation of the natural environment to equity and accessibility. For example, building in an urban area accessible via low-carbon public transportation as opposed to a suburban or rural area where the automobile dominates affects emissions—and employee and community well-being. A client recently considered relocating a new headquarters from downtown to a suburban site and found that it would be detrimental to many of their employees who depended on local transit for commuting. Instead, they chose a site where transit access was more available.

Planning around low-carbon public transportation options such as subways or designated bike lanes not only impacts emissions, but also touches issues such as equity and accessibility. Amazon’s Seattle HQ features a two-way cycle track and a dedicated entrance for bicycle commuters, promoting health and ease of access.

The Economics and Benefits of Integrated Thinking The best approach to carbon-based decision-making is through integrated thinking early in the process. Often, we can leverage one design strategy to achieve multiple goals and amplify value. While sustainability measures may appear costly at a project’s onset, the overall energy savings throughout the lifecycle of the project are exponential. Integrated thinking at the onset enables successful zero-carbon buildings by avoiding the layering of costs further down the road. Embracing carbon-based decision-making as an economic opportunity allows us to build the building of 2050, today. Future retrofitting for sustainability requirements will be more costly, not to mention more environmentally damaging, than an up-front investment.

In addition, the costs associated with many sustainable solutions are changing rapidly, with solar and wind power now tracking lower in price for the grid than coal or gas power plants. Employing long-term thinking that recognizes the cost of energy over a building’s lifetime pays back in dividends. In Boston, the BERDO 2.0 city ordinance dictates that buildings over 35,000 square feet or those that have 35 units or more report their energy and water use to the City of Boston every year. Those buildings not meeting the city’s emissions standards must then pay a fee on any overages. And in Southern California, our team recently designed a net-zero energy hospital where the cost of on-site solar power was less than half ($0.05/kWh) of the typical utility rate, not counting demand reduction benefits.

Creative and innovative solutions to reduce the building industry’s carbon footprint are within our reach. Microsoft’s corporate campus expansion taps geothermal wells 550 feet underground to provide power and achieve the company’s goal of becoming carbon negative by 2030.

Now that we are aware of the implications of our decisions regarding climate change and carbon emissions, we are ethically bound to act responsibly. In the words of UNESCO in an article on the ethical principles of climate change, “Adapting to climate change and trying to mitigate its impacts are not just a matter of scientific knowledge and political will; it demands a broader view of a complex situation.”

In the next installment of our series on carbon-neutral buildings, we dig deeper into the subject of embodied carbon and the urgency of addressing it for the architecture, engineering and construction industry.

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