Toward Improved #Metalmiles Literacy.

Meeting many of the 17 sustainable development goals outlined by the United Nations will require improved soils literacy. A majority of this focus, however, has been on terrestrial carbon sequestration. Less attention has been paid to understanding connections between climate change and food choices; one approach that has gained attention recently within higher education has included robust approaches to estimating food miles, or the (primarily) transportation-driven annual carbon dioxide-equivalent emissions of food choices. In our view, improved metals literacy is an overlooked component of creative and integrated approaches to sustainable development. Here we define #metalmiles analogously to #foodmiles: five-year, metal-specific budgets are developed with a cradle-to-grave approach, with estimates of exploration-, mining-, smelting-, transportation-, and recycling-related emissions. We review results from a pilot study at Montana State University that sought to quantify the extent to which #metalmiles (including precious metals as well as rare earth elements) could be quantified as part of an upper level undergraduate course emphasizing holistic approaches to soil remediation. Our principal recommendation is the need for greater abstraction into the dominant metals (not an exhaustive inventory of all metals) that have replaced coal as essential metabolic ingredients of our modern civilization.