Embodied Carbon: What Is It, and Why Does It Matter?
Across the globe, the realities of climate change are sobering. Deadly fires in Maui and Canada, devastating floods in Libya, and increased hurricane activity in recent years are all directly attributable to the warming of our planet.
During the past century, increased consumption of fossil fuels and associated emissions have resulted in a dramatic rise in the level of atmospheric carbon dioxide.
As the negative impacts of increased CO2 in the atmosphere have become well understood, individuals and companies are seeking ways to curb their emissions. Per-capita CO2 emissions in the United States are among the highest of any country—more than 15 metric tons per person each year. These emissions include fossils fuels burned to power and heat homes and buildings, and to supply food, transportation, and everything else that supports our existence. Fifteen metric tons of CO2 can be hard to comprehend, but it is roughly the equivalent carbon emissions from burning 1,500 gallons of gasoline, or filling the tank of the typical sedan 100 times.
Our built environment accounts for nearly 40% of global CO2 emissions. This includes construction and operation of buildings, bridges, homes, and all other built infrastructure. Building materials alone account for more than 11% of total CO2 emissions. Expanding the reuse of building materials can have a significant, positive impact on our environment.
You may have heard of the term embodied carbon, which refers to the total amount of CO2 generated from the manufacture, transportation, installation, maintenance, and disposal of an item. Embodied carbon can be calculated for any building material; understanding this metric can help guide our choices.
Wood, for example, contains about 50% carbon by dry weight. As long as the wood remains in the building, the carbon remains sequestered and not released into the atmosphere. If that wood is reused at the end of the building’s lifecycle, the carbon remains sequestered, and the environment benefits. If that wood is landfilled, the carbon will be released into the atmosphere as the wood decomposes, contributing to a warming climate.
In choices big and small, considering embodied carbon can help make a strong case for reuse. Ten linear feet of kitchen cabinetry and manufactured countertop contains approximately five metric tons of embodied carbon, or nearly one-third of a person’s carbon footprint for an entire year! The reuse of a typical vinyl window saves CO2 emissions equivalent to driving 200 miles, and the reuse of ten square feet of ceramic tile saves emissions equivalent to driving 25 miles.
Because building materials have an outsized impact on carbon emissions, even a few of our choices can significantly enlarge or shrink our personal footprint. Extending the life of useful building materials is one way to help keep the climate sustainable for the next generation.
