**6. Conclusions**

Japan is facing a number of challenges, among them, an aging shrinking population, and over-dependence on raw material imports from foreign nations. This study seeks to provide policy implications and recommendations for improving resource security in Japan, incorporating both recycling and indigenous deep ocean mining operations. Findings show that although deep ocean mining may have strong flow-on economic impacts, the overall quantity of copper extracted may not contribute strongly to Japan's resource security. On the other hand, I-O analysis of domestic copper production scenarios provides a new finding, that labor may be a constraint of realizing a recycling-centric society. Although producing copper by recycling eases environmental impacts, it requires significant manpower.

In order to overcome these shortcomings of individual resource security policies, this study provides three processes, complemented by economic, environmental and social analyses—considering employment, demographics and societal norms.

The analysis undertaken in this study enables a deeper understanding of the e ffect of demand increase for new industries under constant technological coe fficients. However, I-O table-based analysis has some limitations. Since the I-O table is a snapshot of a single year, the e ffect of investment over the long-term is not recognized. A model to analyze the e ffect of longer-term investments, such as recycling plant construction which takes longer than a single I-O period will allow for the further development of this research

**Author Contributions:** Conceptualization, R.M. and B.M.; methodology, R.M.; software, R.M.; validation, R.M., B.M; formal analysis, R.M.; investigation, R.M.; resources, R.M.; data curation, R.M.; writing—original draft preparation, R.M.; writing—review and editing, A.C., B.M. and T.T.; visualization, R.M.; supervision, A.C., B.M. and T.T.;

**Funding:** This research received no external funding.

**Conflicts of Interest:** The authors declare no conflict of interest.
