**8. Conclusions**

This article reviewed the essential concepts related to the development of Edge-AI G-IoT systems and their carbon footprint. In particular, the most relevant Edge-AI G-IoT communications architectures were analyzed together with their main subsystems. In addition, the most recent trends on the convergence of AI and edge computing were analyzed and a cross-analysis on the fusion of Edge-AI and G-IoT was provided. Furthermore, an Industry 5.0 application case was described and evaluated in order to illustrate the theoretical concepts described throughout the article. The obtained results show how CO2

emissions increase depending on the number of deployed Edge-AI G-IoT devices and on how greener is the energy generated by a country. Finally, the main open challenges for the development of the next generation of Edge-AI G-IoT systems were enumerated to guide future researchers.

**Author Contributions:** Conceptualization, P.F.-L., S.I.L., and T.M.F.-C.; methodology, P.F.-L., S.I.L., and T.M.F.-C.; investigation, P.F.-L., S.I.L., and T.M.F.-C.; writing—original draft preparation, P.F.-L., S.I.L., and T.M.F.-C.; writing—review and editing, P.F.-L., S.I.L., and T.M.F.-C.; supervision, T.M.F.-C.; project administration, T.M.F.-C.; funding acquisition, T.M.F.-C. All authors read and agreed to the published version of the manuscript.

**Funding:** This work has been supported through funds ED431G 2019/01 provided by Centro de Investigación de Galicia "CITIC" for a three-month research stay in Instituto Técnico de Viana do Castelo between 15 June and 15 September 2021. This work has also been funded by the Xunta de Galicia (by gran<sup>t</sup> ED431C 2020/15), the Agencia Estatal de Investigación of Spain (by grants RED2018-102668-T and PID2019-104958RB-C42) and ERDF funds of the EU (FEDER Galicia 2014– 2020 & AEI/FEDER Programs, UE).

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** Not applicable.

**Acknowledgments:** The authors would like to thank CITIC for its support for the research stay that led to this article. CITIC, as Research Center accredited by Galician University System, is funded by "Consellería de Cultura, Educación e Universidades from Xunta de Galicia", supported in an 80% through ERDF Funds, ERDF Operational Programme Galicia 2014-2020, and the remaining 20% by "Secretaría Xeral de Universidades" (Grant ED431G 2019/01).

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