A tower made from mushrooms: Mushrooms can grow from organic waste and be used for building purposes, source: ARUP, The Urban BioLoop

Building materials are set to dominate the discussion and solution to climate change. There’s a good reason why. Not only does the global construction sector, one of the largest in the world, release the most process-related CO2 emissions, but it’s also consuming significant amounts of energy compared to other industries.

The industry accounts for over 34 percent of energy demand and at least 37 percent of the world’s CO2 emissions, according to the Global ABC report Building Materials and the Climate: Constructing a New Future. The $12 trillion-dollar construction industry is a top contributor to CO2 emissions, compared to other industries such as the transportation industry, which contributes 22 percent, according to the report.

“Until now, most of the progress in the sector has been made on reducing the “operational carbon” of a building — the emissions created from heating, cooling, and lighting, which are projected to decrease from 75 percent to 50 percent in the next few decades. However, reducing the “embodied” carbon emissions from the production and deployment of building materials such as cement, steel, and aluminum has lagged far behind,” according to the report.

The report is published by the Global Alliance for Buildings and Construction, UN Environment Programme, and Yale CEA, an academic collaboration between various disciplines at Yale including medicine, the environment, public health, and engineering. Design for Freedom by Grace Farms contributed to the report. Together, the report presents the escalation of the climate crisis, as well as the innovative solutions that are emerging such as the use of bio-based materials or organic materials that are often discarded as waste.

Bio-based materials represent the best hope for “radical decarbonization” through the responsible management of carbon cycles. The CO2 emissions from buildings has hit a new high, pushing the sector off track of its goal to decarbonize by 2050, the report says. The emerging use of bio-based building materials offers tangible ways to perhaps mitigate this crisis.

We need to remind ourselves that up until the mid-20th Century the “vast majority” of building materials were locally sourced, leaving a low-carbon footprint. With much better technology at the industry’s disposal, and a shift in mindsets to build more ethically and sustainably, bio-based materials could offer a viable alternative.

But by 2015, we’re in a march forward with ever-increasing reliance on non-renewable extractive minerals, said Anna Dyson (a member of the Design for Freedom’s Working Group), founding director of Yale’s CEA, and the Hines Professor of Architecture at the Yale Schools of Architecture and Environment, during a roundtable presentation discussion at Grace Farms’ Design for Freedom Summit held on March 30, 2023.

Dyson presented preliminary research that is included in the Global Report on Building Materials and the Climate that was publicly released on September 12, 2023, before Climate Week in New York City. The groundbreaking report published by the United Nations,Yale CEA, and Design for Freedom by Grace Farms, conveys the critical importance of the role the built environment plays in the climate crisis and will propose new pathways to radically accelerate the decarbonization of materials by 2050.

“If we’re going to get to the so-called onsite net zero, we have to think differently about how we consider the life-cycle of the building,” Dyson said at the Design for Freedom Summit at Grace Farms. “In theory, we have more data in the process, and we have an opportunity to potentially be more aware of the impacts of our decisions, all the way back. And then especially towards end of use.”

If we do believe that we can move with natural rhythms in our built environment systems, Dyson said, then by 2060 the industry should be able to supply about half of the materials with bio-based ones. The conversation isn’t just around using timber, including changing forestation methods, but the discussion also needs to include circularity (a model that follows reduce, reuse, and recycle)and the use of agricultural byproducts such as mycelia (fungi and mushrooms) and living biomass as materials, she added.

Global architect and design firm Arup, a member of Design for Freedom’s Working Group, has been involved in building projects where biodegradable alternative materials have been used in construction. In its 2017 report, The Urban Bio-loop, it examined and offered case studies on how organic material that usually ends up in landfills could be used as alternatives lower-CO2 building materials. For instance, banana fruit and leaves can be used to make rugged textiles such as carpets and fibers for composite applications, according to the report.

“These are based on a large variety of natural fibres such as those obtained from residue of bananas or pineapple harvesting, and other flexible, strong and lightweight fibres … To some extent natural fibres can be combined with biopolymers to obtain stiff end-products that can be employed for both interior and exterior applications.”

In addition, mushrooms bricks have been used to create the structure of three towers for an installation for the MoMa in New York City. “The mycelium, the base material for the bricks, is a microscopic, fibrous fungus that binds itself to its food source to create a strong, resilient matrix in any shape desired. The raw materials needed to produce them — mushrooms and corn stalks (waste material from farms) that the spores feed on — are as eco-friendly as they come.”

The report goes onto say that bricks can be grown in just five days, producing no waste or carbon emissions. Then when the structure is taken down the bricks can be turned into compost and fertilizer.

While the development of bio-based materials ­­in the construction industry offers a viable alternative “embodied” carbon emissions, it also addresses the need for transparency in the global supply chain. The lack of transparency has allowed the systemic reliance on forced labor around the world. Grace Farms’ Design for Freedom is leading the global movement to eliminate forced labor in the industry.

“The next step in architectural justice must include social equity, and ethical material transparency,” said Sharon Prince, CEO and Founder of Grace Farms Foundation.

Further resources:

Building Materials and the Climate: Constructing a New Future