Footwear’s (carbon) footprint

Study finds the bulk of shoes' carbon footprint comes from manufacturing processes. A typical pair of running shoes generates 30 pounds of carbon dioxide emissions, equivalent to keeping a 100-watt light bulb on for one week, according to a new MIT-led lifecycle assessment. But what's surprising to researchers isn't the size of a shoe's carbon footprint, but where the majority of that footprint comes from. The researchers found that more than two-thirds of a running shoe's carbon impact can come from manufacturing processes, with a smaller percentage arising from acquiring or extracting raw materials. This breakdown is expected for more complex products such as electronics, where the energy that goes into manufacturing fine, integrated circuits can outweigh the energy expended in processing raw materials. But for "less-advanced" products - particularly those that don't require electronic components - the opposite is often the case. So why does a pair of sneakers, which may seem like a relatively simple product, emit so much more carbon dioxide in its manufacturing phase? A team led by Randolph Kirchain, principal research scientist in MIT's Materials Systems Laboratory, and research scientist Elsa Olivetti broke down the various steps involved in both materials extraction and manufacturing of one pair of running shoes to identify hotspots of greenhouse-gas emissions.