The 'Lima Call for Climate Action' decision marked the conclusion of the 20th session of the Conference of Parties (COP20) to the United Nations Framework Convention on Climate Change (UNFCCC). It expresses how the 196 UNFCCC Parties intend to negotiate the elements of a new agreement to be opened for signature in Paris at COP21. This 'Paris Agreement' would govern Parties starting in 2020, when the Kyoto Protocol's second commitment period ends. The new agreement would also move Parties beyond the Kyoto Protocol's focus on mitigation to include adaptation, finance, technology development and transfer, and capacity building requirements. At COP20, Party delegates struggled to find consensus on how to act on the UNFCCC's core principle of 'common but differentiated responsibilities and respective capacities' when drafting the Call for Climate Action. In this article, we provide a detailed account of the evolution of the COP20 decision, to show how both its overall structure and specific language shifted in each round of negotiation to reflect changing norms of equity and fairness. Tracing this progression is important to understanding the shifts that are occurring today, and to gain a vantage point for assessment of the eventual Paris Agreement. After analyzing how consensus was reached at COP20, we conclude that the 'softening' of differentiation over the last 20 years - perceived by some as a compromise on core environmental equity principles - is balanced by the 'democratized' negotiations witnessed in Lima.
