The differentiation of developed and developing countries is a critical challenge during operationalization of the Paris Agreement. The Agreement has been prepared and established under the clear guidance of the Conference of the Parties of the United Nations Framework Convention on Climate Change (UNFCCC). The motivation through constructing a new agreement is to include all countries for combatting climate change. Unlike the UNFCCC, the agreement is not referring to Annex-I, non-Annex or any specific country groups. Therefore, before the Agreement starts implementation in 2020, highlights as developed and developing countries in the agreement require a new definition and criteria. In this paper, we rank countries based on differentiation proposals for classification of developed and developing countries particularly on mitigation of greenhouse gas (GHG) emissions by using data from the world's top 50 emitters. The findings suggest that classifications based on the Annex system of the UNFCCC do not give a clear reference point to define developed and developing countries. (C) 2017 Elsevier Ltd. All rights reserved.