Making or breaking climate targets: The AMPERE study on staged accession scenarios for climate policy

Abstract

International audienceThis study explores a situation of staged accession to a global climate policy regime from the current situation of regionally fragmented and moderate climate action. The analysis is based on scenarios in which a front runner coalition - the EU or the EU and China - embarks on immediate ambitious climate action while the rest of the world makes a transition to a global climate regime between 2030 and 2050. We assume that the ensuing regime involves strong mitigation efforts but does not require late joiners to compensate for their initially higher emissions. Thus, climate targets are relaxed, and although staged accession can achieve significant reductions of global warming, the resulting climate outcome is unlikely to be consistent with the goal of limiting global warming to 2 degrees. The addition of China to the front runner coalition can reduce pre-2050 excess emissions by 20-30%, increasing the likelihood of staying below 2 degrees. Not accounting for potential co-benefits, the cost of front runner action is found to be lower for the EU than for China. Regions that delay their accession to the climate regime face a trade-off between reduced short term costs and higher transitional requirements due to larger carbon lock-ins and more rapidly increasing carbon prices during the accession period

Economic tools to promote transparency and comparability in the Paris Agreement

“…These studies are limited to one model. Multi-model comparison projects (for example, EMF22 21 , LIMITS 22 and AMPERE 23 ) have primarily focused on long-term targets, although some research has considered national goals and used similar metrics 24 .…”

Post-2020 climate agreements in the major economies assessed in the light of global models

“…This review aims at synthetizing insights from the most comprehensive MIP on this subject, the LIMITS project 13,14,98 . Though other MIPs have explored the role of fragmented regional mitigation effort and staged accession to climate cooperation (EMF22 33 , AMPERE 34 , EMF27 1 ), globally delayed participation (RECIPE 35 , ROSE 36 , AMPERE 12 ), and burden-sharing schemes (RECIPE 37 ), none except of LIMITS has focused on potential outcomes of the Durban platform negotiations, i.e. a period of fragmented moderate climate policy followed by global cooperative 3 action under different assumptions about burden sharing regimes.…”

A new scenario framework for climate change research: the concept of shared climate policy assumptions

“…A key characteristic of mitigation policies is the number of countries that participate in an international climate policy regime over time and the stringency of their commitments and actions. IAM studies often distinguish a benchmark case of fully cooperative action starting immediately with more plausible policy scenarios that include regionally and sectorally fragmented climate policies, staged accession to a global climate regime, and non-participation (Clarke et al 2009;Blanford et al 2014;Kriegler et al 2014b;Luderer et al 2014). Thus, the SPA narrative should include information on the different timing of participation of regions and nations in emissions mitigation regimes, as well as being explicit whether mitigation stringency is globally uniform or differentiated across regions and countries.…”

“…For example, they will strongly influence (together with the choice of SSP) the global level of a carbon tax path that could be assumed instead of a target (Calvin et al 2012). Quantitative information that would be part of a reduced SPA, and thus would need to be complementary to information constrained by the RCPs can include, e.g., the allocation of emissions permits to different regions in terms of shares of global emissions , carbon price differentials between regions, sectors and land pools, a timetable for staged accession to a global climate policy regime (Clarke et al 2009), regional low carbon technology targets (Kriegler et al 2014b), and land use related policies such as forest protection and bioenergy constraints . Quantitative assumptions on adaptation policy can include, for example, adaptation targets such as protection against 100 year flood or drought events, timetables for implementing regional adaptation plans, and the size of an international adaptation fund that is set up to assist countries that are most affected by climate change.…”

“…And how should such policies be projected into the future in a policy reference case defined as continuation of current levels of ambition (Blanford et al 2014;Kriegler et al 2014b, Luderer et al 2014? These questions will need to be further addressed during the construction and testing of SSPs and SPAs, and their use in the development of socioeconomic scenarios.…”