and ii) to transition towards a pathway in line with a leastcost trajectory after 2020. By making the shift in emissions less abrupt, enhanced pre-2020 and pre-2030 action reduces the so-called transitional challenges (see below). Furthermore, to keep the door open for limiting warming to below 1.5°C by 2100, enhanced early action seems essential. Previous reports (UNEP, 2012, 2013, 2014) provided detailed discussion of the trade-offs between early and late action. Three main areas of importance with respect to enhanced early action were highlighted in particular:1516 1. Economics and technology, where enhanced early action will: • mediate the requirement for very steep emission reductions in the medium term • facilitate mitigation in the medium to long term by reducing lock-in of carbon and energy intensive infrastructure in the energy system and society as a whole • spur near-term learning and development of technologies that will be essential in the long term • provide early policy signals which are needed for action in the following decades • reduce the overall costs and economic challenges during the transitional period, for example, in terms of upscaling of energy investments • reduce the dependence on unproven technologies such as negative emissions technologies17 and increase the options society can choose from to achieve stringent emission reductions. 2. Climate outcomes: enhanced early action will reduce climate risks, for example, by influencing the rate of temperature increase (Schaeffer et al., 2013; Ricke and Caldeira, 2014). 3. Co-benefits: enhanced early action will enable the realisation of near-term co-benefits of climate change mitigation, such as improved public health as a result of lower air pollution, improved energy security, and reduced crop yield losses18. The issue of lock-in is very important in a number of ways. Even with enhanced early action, it is projected that carbon intensive infrastructure, such as unabated coal-fired power plants, will have to be shut down before the end of their lifetime in some stringent mitigation scenarios, and delay exacerbates this (Rogelj et al., 2013; Johnson et al., 2015). Furthermore, delay also locks in energy intensive practices. Limiting energy demand is critical to keep stringent mitigation targets within reach (Clarke et al., 2014). Furthermore, the transition to a low energy-demand society is also inhibited by delays of action, as more energy intensive infrastructure continues to be built up. Infrastructure lock-in makes the transition to a low-carbon path harder. 15 16 17 Enhanced early action is important in reducing dependence on negative emissions in the long term for achieving stringent climate targets like 2°C. However, there are no scenarios available that return warming to below 1.5°C by 2100, without the use of bio-energy combined with capture and geological storage of CO2. 18 Note that the IPCC AR5 also identified adverse side-effects of climate change mitigation, which will have to be considered simultaneously.
Enhanced early action is thus important. As described above, overachievement of the 2020 pledges will improve the chances for the stringent emission reductions that are required post-2020 ( Rogelj et al., 2013; Clarke et al., 2014).
2.3 Progress towards the 2020 pledges: a closer look at major economies Section 2.2 underlined the importance of pre-2020 mitigation action to achieving consistency with the below 2°C by 2100 scenarios. It is critical that all countries, and particularly the highest-emitting economies, advance as far as possible towards achieving – and ideally exceeding – their Cancun pledges. This section takes a closer look at progress towards achieving these 2020 pledges, focusing on the parties that are members of the G2019. These economies collectively generate around three quarters of global GHG emissions20.
2.3.1 Assessment of G20 countries’ 2020 emissions under three cases
The section compares current emissions trajectories of G20 members with the trajectories associated with the achievement of these parties’ 2020 pledges. It should be read with three important caveats in mind. First, not all pledges demand the same level of effort to achieve. In other words, a country currently on track to achieve its pledge has not necessarily made a greater effort to mitigate emissions than a country not yet on track21. Secondly, these projections are subject to the uncertainty associated with macroeconomic trends, such as changes in gross domestic product (GDP), as well as the impact of policies. Thirdly, the emission trajectories analysed here do not quantify the potential impact of using offsets to achieve pledges. If offsets are traded internationally, and are counted towards the pledges of both buying and selling parties, the global impact of the pledges will be weakened. Most countries have not clarified their intentions concerning use of offsets to meet their 2020 pledges. Australia, Brazil, Canada, the European Union, and the United States have explicitly not excluded the possibility; others have not formally commented (CAIT WRI, 2015). Table 2.2 compares 2020 emissions under three cases: a pledge case, based on official data; a current policy trajectory case, based on official data; and a current policy trajectory case, based on independent analysis. These cases are described in Box 2.2.
19 The members of the G20 are Argentina, Australia, Brazil, Canada, China, France, Germany, India, Indonesia, Italy, Japan, Republic of Korea, Mexico, Russia, Saudi Arabia, South Africa, Turkey, the UK, the USA, and the EU. In our analysis, the EU including all its Member States (regardless of G20 status) is considered as a single Party, and EU Member States are not considered individually. In general, evaluating the pledges of other countries is limited by a lack of data. 20 In 2012, these parties accounted for 77 per cent of global emissions excluding LULUCF and 75 per cent of global GHG emissions including LULUCF (CAIT WRI, 2015). 21 See Appendix 2.D of the 2013 UNEP Emissions Gap Report (UNEP, 2013) for further discussion of this issue.
The Emissions Gap Report 2015 – The importance of pre-2020 action
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