It’s been centuries since humanity invented the fiery first step behind almost all steelmaking.
The work begins by loading iron ore and processed coal into a blast furnace. Combustion heats the ingredients to temperatures near 1,600 degrees Celsius, creating the molten iron necessary to produce steel, the ubiquitous modern metal found in everything from skyscrapers to automobiles.
An unfortunate byproduct is a massive amount of climate-warming gas. Iron smelting, in fact, is the main reason steelmaking accounts for between 7 and 9 percent of humanity’s carbon dioxide emissions — more than the climate impact released by the entire European Union…