This document discusses perspectives on copper resource depletion from an economist, scientist, and geologist. The economist views resources as subject to inevitable decline due to higher costs and lower grades, but believes innovation can overcome this. The scientist sees resources as fixed stocks that will eventually be depleted. The geologist acknowledges declining grades but notes quality is uncertain and more discovery is needed. All agree sustainability is key and must consider social, economic, and environmental factors, not just resource life. Further research is needed to better target reserves for the future and enable sustainable development through continued exploration.