porarily, restricted rare earth exports even though globally it supplies more than 90% of most of them. Still, mate- rial scientists note that there are at least as many non-rare earth materi- als that are or should be regarded as critical in the United States. Most industrial users’ time frames are a year or two, enough to satisfy cur- rent orders, but increasingly critical materials are incorporated into prod- ucts with far longer life spans. Take jet engines, for instance, in service for decades. Constructed with ever-more high-temperature superalloys, engine performance is on steroids, with jets traveling farther and on far less fuel. But when a turbine blade needs re- placing, it has to be with virtually an exact copy or risk throwing the engine out of balance, noted Thomas Graedel, a leading industrial ecologist at Yale. “It’s these longer-term considera- tions that are impor- tant and are not yet widely recognized,” he said, noting that mul- tiple industries are ramping up their use of critical materials. Satisfying Demand So far, any major dis- ruptions of critical materials have been dodged, but as time horizons stretch out over decades—as governments and multinationals need to consider —this should offer diminishing com- fort. Why? These wonder materi- als just might upset a long-standing tenet of resource economics—namely, that scarcity begets higher prices— enough to trigger more zealous ex- ploration, which in due course gets us more supply. And while this has worked in the past—and still could—Graedel cautions against complacency. First, mining is getting tougher. Most of what geol- ogists are looking for is a kilometer or so underground, so getting an accurate fix on the actual minable reserves for coming decades has real limitations. And just because deposits are located does not ensure access. Increasingly, nearby com- munities object on environmental or other grounds—and these concerns are not so easily pushed away any- more. They can also be combined with demand-side complications. Consider cobalt, used in significant amounts in
So the gen- eral idea that if we get short, we’ll find substitutes is an engaging idea but not one that in practice is going to be easy to pull off.
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