Rock, Paper, Scissors, as played by Concrete, Wood and Steel

This month, I’d like to have some fun with a serious topic. In the great sustainability measure of concrete, steel or wood specifications, rules of the childhood “Rock, Paper, Scissors” game transform to accommodate these heavyweight construction material contenders. Each wields strengths but also has its Achilles’ heel. Here’s how the matchup plays out:

Concrete smashes steel: Concrete is the heavyweight champion of resilience and sustainability. Made from abundant natural resources like rock and limestone, concrete is the product of an industry that has taken a critical look at its carbon footprint and is rapidly reducing it through material and production innovations. Its durability is unmatched, standing tall against fire, hurricanes, and tornadoes, acting like an unyielding fortress. Steel, while boasting recyclability, falters here. Recycled steel typically becomes rebar—an essential but limited-use product often playing a supporting role to concrete by reinforcing its strength and preventing cracks. In this round, concrete’s resource abundance and adaptability make it the undisputed victor.

Steel slices through wood: Steel, the sharp and shiny contender, brandishes its recycling badge proudly and shows its mettle compared to wood, which enters the ring armed with trees as a natural carbon sink. But there’s a twist: once those trees are cut and turned into construction materials, they lose their superpower. Wood can store carbon, but only for as long as it avoids the perils of fire, storms, or decay in landfills—all of which can release carbon dioxide back into the atmosphere. Steel takes the win here, slicing through wood’s weaknesses.

Concrete can’t be wrapped in wood: Wood, the renewable contender, steps into the sustainability game with its charm and promise of regeneration. But as we look to the future, the story becomes more complex. Concrete, once a heavyweight in CO2 emissions metrics, is undergoing a remarkable transformation. Innovations like LC3 (Limestone Calcined Clay Cement) can reduce CO2 emissions by up to 40 percent compared to traditional cement. Companies like Fortera, Sublime, Carbicrete, and Ecocem and many others are leading the charge, developing groundbreaking technologies to slash cement’s carbon footprint. Meanwhile, experimental carbon capture plants are being tested to collect and reuse CO2 from cement plants. These advancements are reshaping the landscape, making concrete not just resilient but increasingly the low carbon leader.

Meanwhile, wood faces a daunting challenge. Humanity’s construction needs are staggering, building the equivalent of one New York City every 30 days for 40 years (see www.architecture2030.org/why-the-built-environment/). Even with the vast softwood forests of regions like Canada, the renewable cycle of trees simply cannot keep pace with this demand. Interactive maps of global forest cover reveal the shrinking availability of softwood resources. As forests are harvested, the time required for regrowth far exceeds the speed at which we’re building. Wood’s trick of wrapping concrete is indeed clever, but it’s a small-scale solution in the face of large-scale urbanization. In short, wood’s little trick is, unfortunately, just that—little. In this future-focused round, concrete’s innovations and scalability outshine wood’s limitations. While its renewable nature is admirable, wood struggles to keep up with the relentless pace of global development, and with the strength and resilience of concrete.

And the winner: Concrete! As the sustainability game plays on, concrete secures its title with a combination of resilience, adaptability, boundless resources, and incomparable innovation. Unlike steel and wood, concrete is powering ahead with low-carbon innovations across the globe. This relentless march toward a greener future sets concrete apart as the leader in sustainable construction.

Chris Erickson is CEO and co-founder of Climate Earth, Point Richmond, Calif., www.climateearth.com, and welcomes comments on Carbon Smart, [email protected].