Making the Concrete and Steel We Need Doesn’t Have to Bake the Planet



Rebecca Dell | New York Times

You’ve probably spent a lot of time over the past year looking out the window while staying clear of the pandemic. If you’re a city dweller like me, no doubt you see mostly concrete, steel and maybe sky.

Roads and sidewalks, apartments and office buildings, overpasses and embankments, cars and buses, streetlights and even statues — they’re all made of concrete and steel. And there’s even more of it out of sight, in sewer mains, electricity transmission lines, foundations, ducts and girders.

It’s the stuff of modern life, and we use it in astonishing quantities. Last year, around the world, nearly two billion tons of steel was produced — more than 500 pounds for every person on earth. And at least 30 billion tons of concrete, or nearly 9,000 pounds for each of us. The scale can be hard to believe, until you look at a runway or a suspension bridge and contemplate what was required to build it.

But all the comfort, security and convenience provided by things made of steel and concrete comes at a cost. Making steel and cement — the main ingredient in concrete — generates about 15 percent of all global emissions of carbon dioxide, the gas most responsible for the climate crisis. In the United States, industrial sources like steel mills and cement kilns are also the leading source of some of the most damaging types of air pollution. We can’t solve climate or pollution problems if we don’t clean up these industries.

This is particularly urgent. In the coming years and decades, the United States will need a lot more steel and concrete. Roads are crumbling, mass transit is unavailable, many communities still don’t have access to high-speed internet, drinking water is contaminated, and a nasty winter storm left millions of Texans without power. Climate change is only going to increase the need for infrastructure, from wind turbines to flood control systems.

Last month, in an Oval Office meeting to discuss infrastructure and workers’ rights with the leaders of major unions, President Biden noted that the United States ranks “like 38th in the world in terms of infrastructure, everything from canals to highways to airports.” On Wednesday, the American Society of Civil Engineers gave American infrastructure a grade of C-, warning of “significant deficiencies.”

Both political parties want to turn that around.

But a single major infrastructure investment from Congress could increase U.S. carbon dioxide emissions by 200 million tons, or almost 4 percent of national annual emissions. For comparison, in the decade before 2019, the United States managed to decrease annual emissions by only some 220 million tons. We can’t afford to build in a way that emits huge amounts of climate-changing gases, adding to the climate problem at the same time we’re trying to fix it.

Fortunately, we don’t have to. Most infrastructure is paid for with tax dollars, so the public can insist that we build it in a cleaner way. This is the idea behind the Buy Clean campaign, an effort by a growing number of governments and corporations to change the way products are made by demanding low-carbon production and supply chains for what they purchase. This will hardly affect the cost to taxpayers, because steel and cement are a very small portion of the total cost of projects. For example, the eastern span of the bridge between San Francisco and Oakland, Calif., that was finished in 2013 cost California taxpayers more than $6 billion, but less than $25 million of that — less than one half of 1 percent of the cost — was spent on cement.

States are starting to experiment with this approach. California has a policy that sets a maximum level of greenhouse gas emissions per unit of material for some building materials. Lawmakers in New York and New Jersey are considering a plan that would award a credit to contractors for public construction projects that use cement and concrete produced with low greenhouse gas emissions.