Why current assessments of ‘future efforts’ are no basis for establishing policies on material use—a response to research on ore grades

摘要: The concept of declining availability due to primary resource quality has been investigated for various categories try determine the effort needed in future either extract or treat it intended use. ‘future efforts’ is explored by Vieira et al. (2016, 2017). They suggest that a specific burden associated with production each material should be taken into account and this can done studying costs ore requirements projecting forward likely future. For purpose analysis, they employ mine cost data 2000–2013 reserve published US Geological Survey. We will argue below approach not correct and, comment, we wish make clear that—contrary what suggested much Life Cycle Assessment literature—the efforts an established rule natural extraction. mineral resources, quite impossible proceed extraction ordered way suggests because nobody comprehensive view entire resource. Secondly, there no evidence available support idea extracting today causes decrease tomorrow. On contrary, weight where declines grades have observed, are overwhelmingly technology development response high demand accompanied increased mining efficiency successive generations. Grade rather arbitrary measure since grade mined ultimately do relationship revenues. It only employed which matters but also how smartly applied. Thirdly, entirely overlooks potential materials from secondary (scrap) sources, sources expected become increasingly important supply Our conclusion discussion as humans able economically access ever-increasing amounts often lower lower-grade sources. What conclude environment longer contains any higher-grade In fact, all deposits still out there. remain critical optimists.