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| MYTH: Wood is more sustainable than steel because wood construction products store carbon. |
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REALITY: Carbon storage for construction products is temporary, only shifting impacts to future generations. Carbon is sequestered in the fibre of trees, but that does not mean that wood buildings become large reservoirs of carbon that is stored indefinitely. Upon harvesting, the unused root and leaf systems immediately return their CO2 to the atmosphere by decay. For wood products, the reality is that carbon storage is also temporary, and it is released back into the atmosphere at the end of the wood building’s life either by the demolition and subsequent decay of the wood or by incineration. As a result of wood waste and decomposition, the carbon stored long-term in harvested wood products may be a small proportion of that originally stored in the standing trees across North America, approximately 1% may remain in products in use, and 13% in landfills at 100 years post-harvest.
Wood is typically a single-use material. At the end of its life, a building’s wood frame is typically landfilled or incinerated. This returns any stored carbon dioxide back into the atmosphere as either carbon dioxide or methane, shifting greenhouse gas burdens to future generations. By comparison, steel is the world’s most recycled material. Steel construction products have a recycling rate of more than 90%, meaning that at the end of a steel building’s life, more than 90% of its steel is recycled into another steel product, using significantly less energy than was necessary to create the original product. A material that can be recycled continually over centuries with no loss in quality and that lowers the burden on future generations is the very definition of sustainability! |
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