Three years after the market introduction of its recyclable running shoe Index.01, Salomon has presented a study by its footwear team that has researched the shoe’s environmental impact compared to a conventionally manufactured road running shoe.
Since 2019, shoes have been returned to Salomon by consumers to be recycled into ski boots. The lifecycle of the shoes has been compared with the impact during the life cycle of the Salomon Sonic 3 model. Evaluating the life cycle of a shoe enables shoe designers to assess the impact of each of the steps in terms of carbon emissions, consumption of natural resources, the eutrophication of water bodies by nitrates (caused by cooling of machinery and dyeing) and acidification of water bodies, as well as other aspects (17 in total). Overall, the impact of the Index.01 is 44 percent smaller than the Sonic 3’s, which is an equivalent of 4.9 kg of CO2 per pair.
In detail, the outcome is more differentiated:
- The Index.01 has +22 percent of emissions on its balance sheet for raw materials due to the heavier TPU sole material.
- The heavier weight also leads to +15 percent of emissions in logistics.
- In production, the study shows – 45 percent of emissions due to fewer materials, a minimalistic design and a new injection technology for the mid and outsole used for the shoe.
- Another 8 percent of emissions are saved by ditching the filling paper in the shoeboxes.
Most of the CO2 savings are achieved during the recycling process, as all emissions generated when the shoe is burned or landfilled are avoided: -2.1 kg. In the study, Salomon has attributed half of the emission reduction to the Index.01 and the other half to the MTN. ski boot for which the recycled running shoes are used.
