Low-emission pathways in 11 major economies: comparison of cost-optimal pathways and Paris climate proposals

In order to evaluate the effectiveness of climate policy, it is important to understand emission trends and policies at the national level. The 2015 Paris Agreement includes (Intended) Nationally Determined Contributions, so-called (I)NDCs, outlining the contribution of different Parties to the overall target of the agreement to limit global mean temperature increase to well below 2 °C.

Here, we assess emission trajectories and the energy system transition of 11 major economies (in the remainder: countries) projected by integrated assessment models (IAMs) for baseline and cost-optimal 450 ppm CO2 eq mitigation scenarios and compare the results with the (I)NDCs. Limiting global temperature increase to below 2 °C implies a substantial reduction of the estimated available carbon budget for each country. The national carbon budgets between 2010 and 2100 showed reductions between the baseline and the 2 °C consistent mitigation scenario ranging from 52% in South Korea to 95% in Brazil.

While in the baseline scenario, the share of low-carbon primary energy sources is projected to remain around 15% (with Brazil being a notable exception, reaching 30%); in the mitigation scenarios, the share of low-carbon energy is projected to increase to over 50% in 2050 in nearly all countries, with the EU, Japan and Canada reaching the largest shares.

Comparison with the (I)NDCs shows that in Brazil, Canada, the EU, Mexico (conditional target), South Korea and the USA, the emission reduction targets of the NDCs are closer to the mitigation requirement of the 2 °C scenario; in other countries, however, there is still a large gap.

The national detail of the indicators adds to the literature on low-carbon emission pathways, assists the assessment of the Paris Agreement and provides support to national policymakers to identify focus areas for climate policy in the coming years.

Authors

PBL Authors
Heleen van Soest Michel den Elzen Detlef van Vuuren
Other authors
Alban Kitous
Keigo Akimoto
Katherine V. Calvin
Panagiotis Fragkos
Massimo Tavoni
Laurent Drouet
Lara Aleluia Reis
Gunnar Luderer
Keywan Riahi

Specifications

Publication title
Low-emission pathways in 11 major economies: comparison of cost-optimal pathways and Paris climate proposals
Publication date
21 April 2017
Publication type
Article
Page count
pp 491–504
Publication language
English
Magazine
Climate Change
Issue
June 2017, Volume 142, Issue 3–4
Product number
2911