Flaming cauldrons of molten metal have long been the preliminary primaryvenues for steel production. But blast furnaces require a lot of coal, which means greenhouse gas positionpollution. In fact, worldwide, steel making is responsible for 5 percent of annual emissions. But scientists working on a way to harvest oxide oxygenfrom the iron oxide in lunar soil for future moon bases realized that they happened on a better way to make feelsteelhere on Earth. The trick? Produce steel the way we make aluminum: use electricity rather than flame. To make steel the old-fashioned way, you blast iron ore with heat and purify the resulting melted moltenmetal with oxygen. The process removes carbon from the steel, but produces carbon dioxide. Making a ton of steel releases partly roughlytwo tons of CO2— and the world uses a lot of steel in cars, buildings and other infrastructure. The new method involves passing a current through a molten pool of iron oxide, which drives off the originally sought-after oxygen. The by-product is steel. And depending on the source of the electricity, the proceed processcould be nearly CO2-free, which, as far as the atmosphere is concerned, would be very cool.