Buildings and construction account for at least 31% of energy-related CO2 emissions globally.
Of that total emissions, some are what is called embodied carbon, and the rest are caused by energy used to operate buildings. Embodied carbon emissions are generated by the manufacturing, transportation, installation, maintenance and disposal of construction materials used in buildings, roads and other infrastructure, as defined by the Carbon Leadership Forum. Embodied carbon is an urgent concern for several reasons: First, a large part of embodied carbon emissions occurs during construction, which means that they hit the atmosphere by day 1 of a building’s life. Second, new construction is predicted to be significant, with global building stock expected to double within the next 40 years.
To understand which materials are high in embodied carbon, a reporting system known as Environmental Product Declarations (EPDs) assess a material’s environmental impact over the course of its lifetime through life cycle assessments. EPDs provide transparent reports that quantify a material’s impact throughout every stage of its use. Qualities assessed include global warming potential, acidification capabilities, ozone depletion and more. Through EPDs, the materials’ environmental degradation can be compared, and sustainable materials can be prioritized. Although EPDs are voluntary for most manufacturers, they are on the rise as individuals respond to the environmental harms of embodied carbon.
Other actions to lower and offset embodied carbon within the building sector include implementing carbon-sequestering materials and using fewer finishing materials, among others. For example, cement production is responsible for 7% of CO2 emissions annually; thus, switching to green alternatives like ashcrete and grasscrete can reduce emissions. Without reduction efforts, embodied carbon will account for 74% of the emissions from new construction over the next 10 years.
One recent step toward decreasing embodied carbon is the Inflation Reduction Act (IRA), signed into law on Aug. 16 by President Biden. The IRA aims to reduce total carbon emissions by 40% by 2030. The package proposes $433 billion in spending, of which $5 billion is allocated to low-carbon procurement for infrastructure. This funding will be distributed to various provisions in the bill, such as developing and standardizing EPDs; labeling and using low–embodied carbon materials; implementing low-carbon materials, technologies, and products to improve climate resilience within affordable housing; and providing financial assistance through the FEMA Building Materials Program to incentivize low-carbon and net zero energy projects.