Accounting of the consumption/needs -based GHG emissions requires systematic, transparent and interdisciplinary approaches to provide a consistent approach for users seeking to calculate their own carbon baseline and set carbon reduction targets. There are several prerequisites that must be fulfilled for a proper LCA and consumption/needs-based GHG emission accounting to be accomplished. This chapter describes the prerequisites or basics to GHG accounting system in terms of knowledge of the Paris Agreement, knowledge of study, interdisciplinary team and just transition, and knowledge management steps.