A material revolution replacing cement and steel in urban construction by wood can have double benefits for climate stabilization, a new study shows. First, it can avoid greenhouse gas emissions from cement and steel production. Second, it can turn buildings into a carbon sink as they store the CO2 taken up from the air by trees that are harvested and used as engineered timber. 

“Urbanization and population growth will create a vast demand for the construction of new housing and commercial buildings, hence the production of cement and steel will remain a major source of greenhouse gas emissions unless appropriately addressed,” says the study’s lead-author Galina Churkina, who is affiliated with the Yale School of Forestry and Environmental Studies “Yet, this risk for the global climate system could be transformed into a powerful means to mitigate climate change by substantially increasing the use of engineered timber for construction worldwide. Our analysis reveals, that this potential can be realized under two conditions. First, the harvested forests are sustainably managed. Second, wood from demolished timber buildings is preserved on land in various forms.”

Four scenarios have been computed by the scientists for the next thirty years. Using more trees in construction could result in storing between 10 million tons of carbon per year in the lowest scenario and close to 700 million tons in the highest scenario. In addition, constructing timber buildings reduces cumulative emissions of greenhouse gases from steel and cement manufacturing at least by half. 

A five-story residential building structured in laminated timber can store up to 360 pounds of carbon per square yard, three times more than in the above ground biomass of natural forests with high carbon density.

“Trees offer us a technology of unparalleled perfection,” says Hans Joachim Schellnhuber, co-author of the study. “They take CO2 out of our atmosphere and smoothly transform it into oxygen for us to breathe and carbon in their trunks for us to use. Societies have made good use of wood for buildings for many centuries, yet now the challenge of climate stabilization calls for a very serious upscaling. If we engineer the wood into modern building materials and smartly manage harvest and construction, we humans can build ourselves a safe home on Earth.”