Common but differentiated responsibilities and respective capabilities. This is a more nuanced version of the CBDR principle mainly used by developed (Annex 1) countries, and "middle-ground" countries (e.g. the EIG and the LMDCs), pushing for the respective capabilities of countries to deal with climate change issues (see also CBDR). Since global realities are changing, including national circumstances, some also view the CBDR/RC principle "in the light of national circumstances". This new phrase was agreed on at COP20 in Lima, and has been promoted by countries like the US, Japan, Norway and the EU who wish to include developing countries whose economies are growing at fast rates (such as China, India, and Brazil) in more ambitious mitigation efforts along with the developed countries. Different understandings of concepts such as "historical responsibility" and "national circumstances" have caused widespread ambiguity and confusion regarding the principle. Different approaches and interpretations have also been used by developed and developing countries to make the principle serve in their advantage. 

Read more on:
www.theroadthroughparis.org (Common but Differentiated Responsibilities and Respective Capabilities (CBDR-RC))

ovalobserver.org (The Road from Rio to Paris: The Evolution of CBDR?)

post2015.org (The Principle of Common but Differentiated Responsibilities and the SDGs)