A new paper out of Yale University begins with a startling fact: 50 years ago, the global economy depended on fewer than a dozen widely available materials: wood, brick, iron, copper, gold, silver, and a handful of plastics. Today we rely on many times that number to make the countless products we use every day. And in diversifying, our manufacturing sector has also become more fragile: We’re dependent on an array of specialized materials, from the niobium in your car muffler to the germanium in your cellphone.
What if we suddenly needed a replacement? The study, by four researchers at the Yale Center for Industrial Ecology, looked at the availability of substitutes for 62 different metals in manufacturing use today. Some are quite replaceable—95 percent of the world’s titanium goes to produce pigments, and could be adequately replaced in that job by talc—and some aren’t. Manganese is used as a deoxidizing agent in steel manufacturing and has no known substitute. The researchers displayed their results in a color-coded period table of elements that shows the availability of substitutes for each element. Red shading indicates few to no substitutes are available, while greener shading indicates better substitutes are available.