Materials matter in combating climate change
Tackling climate action in the building industry starts with making conscious decisions about the materials with which we build. Today, the production, maintenance and disposal of the materials used in building construction are responsible for 11% of global greenhouse gas emissions. This accounts for roughly a quarter of annual building sector emissions, a percentage which is growing.
By sourcing materials and products from local, regional or domestic sources, we could make serious inroads toward cutting down on the carbon emissions associated with the built environment. The lockdowns and quarantine orders in the first half of 2020 showed improved air quality measurements around the globe due to reduced transportation-related emissions — and sourcing locally could do the same.
This concept is not new. For millennia, cultures all over the world have relied on local materials to construct habitats. Rives Taylor, Gensler Design Resilience co-leader, notes, “Largely, these traditions are due to the materials being readily available, but those materials also enhance performance because they are well suited to local climate. Adobe, which has been used for centuries across the American Southwest, has a high thermal mass that keeps buildings cool in the region’s scorching heat. Since ancient times, structures in Japan have been composed of cypress because of its resistance to the mold and rot that can easily occur in the island nation’s wet, humid climate.”
But with our competitive global industries and complex supply chains, local sourcing can be a challenge especially when factoring into consideration other requirements for material selections (costs, availability, durability, etc.). Designers need to think holistically about the products we specify and the impact of those selections.
Local sourcing, as well as other sustainability attributes of materials, can have a significant impact to the greenhouse gas emissions of buildings. Currently, the building sector accounts for nearly 40% of annual emissions, and it is projected that by 2050 nearly half of this will be due to the embodied carbon of building materials — the carbon emissions due to extracting, manufacturing, shipping, installing, maintaining and disposing of construction materials. As we strive to reduce the carbon footprint of our building operations, it is equally important that we find ways to reduce the carbon footprint of the very materials with which we build. To quote Gensler’s Co-CEO Diane Hoskins, “We can no longer ignore that building materials account for half of a building’s total lifetime carbon footprint.”
Look for Low Carbon Alternatives
Today, an informed designer can research and select materials with a low carbon footprint. For some products, this information is readily available in documents called Environmental Product Declarations, or “EPDs.” In fact, there are plenty of low embodied carbon, and even carbon neutral, carpet options in the market for designers to choose from. One example is the Smart City carpet plank system by Mohawk Group, a product that Gensler helped develop as a product design consultant. It earned Living Product Petal Certification from the International Living Future Institute for its regenerative qualities.
Minimizing embodied carbon in a building, however, should start from the design concept by exploring alternative solutions to conventional designs. Reusing existing building components in lieu of installing new materials, for instance, reduces the carbon footprint of a project by simply not adding to the embodied carbon accounting of the project. More often than not, a building material is discarded before its usefulness runs out, and the longer that materials are used in buildings, the less carbon we expend to make more, newer materials. Furniture and interior finishes tend to be replaced every few years, while structural elements can last as long as the building itself. Even though structural elements are high embodied carbon materials, the repeated churn of interior projects and the replacement of their materials over the life span of a building can add up to an equal or greater share of the building’s overall carbon footprint.
So, when designing projects we should ask ourselves several key questions: Might we rethink the materiality of our built spaces? Can we engineer building materials in a way that allows them to be durable but also capable of disassembly and repurposing? And can we find unexpected sources of local materials and work with our manufacturing partners to improve the sustainability performance of these products?
Overall, this means a shift in focus toward lifecycle thinking for every design we create and every material, furniture and fixture we specify. And importantly, that means understanding not only the energy and carbon expended in the creation of an object or place, but what’s expended at the end of that lifecycle, too. That means planning for re-use of materials and buildings whenever possible — whether via refurbishment, recycling, or adaptive reuse — and seeing local resources for building products within the existing construction of our built environments.
Together, we have an opportunity to decrease embodied carbon levels throughout the built environment simply by making smart, forward-thinking choices about materials.
Kaley Blackstock, LEED AP, WELL AP, Fitwel Amb., CDT, is a sustainability specialist working to advance Gensler’s climate change goals and improve the built environment from an environmental, social and human health perspective. A trained architect, she has experience in certifying more than 40 LEED, WELL and Fitwel projects and has developed sustainability guidelines for key clients and institutions. She manages the firm’s Sustainable Materials Resource Group, a firmwide specifications liaison, and works to advance Gensler’s expertise in sustainable material specifications.