The industry accounts for 10% of the global emissions of carbon dioxide

One way to cut the steel industry’s emissions is to recycle more iron and steel products than the world currently does.

 Knowledge of the basic chemical process to make iron is older than the periodic table: Iron ore + coal = iron + carbon dioxide. That last part — carbon dioxide — has put the iron and steel industry under the spotlight for its contribution to climate change.

Steel (an iron-carbon alloy) alone accounts for some 8% of annual global carbon dioxide emissions, and well over 10% if one includes the industry’s emissions from electricity generation and coal mining.

Fortunately, it is both technically possible and economically feasible to eliminate almost all the carbon dioxide from iron- and steel-making by midcentury. Getting there, however, will require a targeted policy push.

The key is first to identify the primary source of emissions. Over 80% result from the initial step: digging up iron ore, which is largely made up of iron and oxygen, and chemically separating the oxygen. The main ingredient used to achieve this “reduction” is coal, which of course generates massive amounts of carbon dioxide. At this point, turning iron into steel becomes a comparatively low-carbon process.

One way to cut the industry’s emissions, then, is to avoid that first step altogether by recycling more iron and steel products than we currently do. While the iron and steel recycling rate hovers around 80-90% in the United States, and over 80% globally, the fact remains that steel is 100% recyclable. To recycle all of it means pushing designers to make products that are easier to disassemble, to more easily remove copper wiring and other contaminants.

Another important factor is basic material efficiency: using less steel in the first place, with architects and structural engineers minimizing its use in their designs. Governments, the largest buyer of infrastructure, have an obvious role to play here. But so, too, do the architecture and engineering professions, as well as car manufacturers.

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