Also in this chapter:
Lead authors: Niklas Höhne, Chris Taylor
Contributing authors: Claudine Chen; Rob Dellink; Michel den Elzen; Jørgen Fenhann; Claudio Gesteira; Kelly Levin; Emanuele Massetti; Caspar Olausson; Murray Ward; Zhao Xiusheng
Nearly 140 countries have associated themselves with the Copenhagen Accord and over 80 countries, representing about 80 per cent of global emissions, have appended targets (Annex I countries) and/or mitigation actions (non-Annex I countries). The aim of this chapter is to assess the published analyses and to explore what these targets and actions (collectively referred to as “pledges”)36 are likely to lead to in terms of 2020 emissions37. Three appendices to this Chapter are available online. Appendix 1 provides detail on the differences between the four cases and the uncertainties around them. Appendix 2 provides a country-by-country analysis of the pledges of the largest emitting countries. Appendix 3 compares the modelling groups’ findings and details the adjustments made to their data to ensure consistent comparisons. Chapter 4 then goes on to combine these results with those of the previous chapter on emission pathways in order to assess the extent to which these pledges are consistent with a 2° C or 1.5° C pathway.
Estimating 2020 emissions, based on countries’ pledges or submissions to the Copenhagen Accord, is not a simple task. This Chapter explains in detail that it involves inter alia: information on the historical, current and future growth of countries’ emissions; interpretations in the cases in which countries have submitted a range of pledges; assumptions on the precise meaning of those pledges where countries have not been specific; and uncertainties in the underlying data used by modelling groups.
Therefore, we separate the emission estimates that are driven by distinct policy choices, either nationally or in the negotiations, from what is driven by different modelling assumptions. We first present the results of this analysis and then move on to explore the modelling uncertainties around them.