A major question of international climate policy is which countries have to reduce their greenhouse gas emissions by how much. As ambitious global climate policy has been delayed for long, emissions now have to be reduced in all countries as fast as possible. Considerations whether the national emission pathway itself is in line with the responsibility and capability of that country moves more and more into the background. It is now more a question of who pays for the transition, not where it is happening. In this paper with Fraunhofer ISI, we argue that only the combination of assessments on "what is a fair contribution" and of "how much could emissions technically be reduced" can give sufficient guidance for national greenhouse gas emissions targets that are in line with the Paris Agreement. If the national potential is not large enough to represent a fair contribution (likely for most developed countries), these countries should support other countries to make the transition. If the highest possible ambition leads to faster reductions than the fair contribution (likely for many developing countries), these countries would receive financial support.
Five years after the adoption of the Paris Agreement, the need to reduce global greenhouse gas (GHG) emissions without further delay is more urgent than ever. Emission reduction rates never seen before are necessary to meet the long-term temperature goal of the Paris Agreement and to avoid the worst impacts from climate change. In the longer term, all sectors and countries will need to reach GHG neutrality and in particular, mitigate all avoidable energy- and process-related GHG emissions, in order to be in line with a Paris-compatible pathway. Given the agreement on the global challenge, the combination of equity-based assessments and domestic mitigation potential together can give guidance for exploring and setting national targets for greenhouse gas emissions that are in line with the goals of the Paris Agreement. While both methods yielded quite similar results only 10 years ago, they provide very different results today. The concept of a fair contribution applied only to domestic emissions may either stop the discussion before it started for developed countries (requiring net zero emissions within a decade) or suggesting that an increase in emissions is in line with the Paris Agreement for some developing countries for a longer period of time (while it is actually not). To make the stringent global mitigation pathways possible, emissions in all countries have to be reduced as fast as possible. Whether a national emission pathway itself is in line with the responsibility and capability of that country becomes less relevant. It is now more a question of who pays for the transition, not where it is happening. It is therefore fundamental that all countries explore their full mitigation potential, also considering global cost effectiveness or the “highest possible ambition“ as it is termed in the Paris Agreement. Until 2030 – most relevant for the updates of NDCs – substantial effort is needed in all sectors (energy supply, industry, buildings, transport), but speed of cost-efficient decarbonisation will be different across sectors and countries.
From the sectoral evaluation, we conclude that national sector targets will be required in addition to national economy-wide targets, to avoid lock-ins in the more difficult-to-decarbonize sectors. In particular, there is a strong need for ambitious sector-specific 2030 targets, best enshrined in national law. Complementing global model results with national bottom-up scenarios can provide valuable insights about national leeway in this regard. If the national potential is not substantial enough to represent a fair contribution (likely for most developed countries), these countries should support other countries to make the transition. If the highest possible ambition leads to faster reductions than the fair contribution (likely for many developing countries), these countries would receive financial support. Such support should not finance the cheapest reductions in developing countries as such reductions are to be implemented by the countries themselves in order to set and meet their stringent domestic emission targets. The financial support should, in particular, help to avoid sectoral lock-ins which usually require much higher efforts compared to current NDC pathways, most of which were designed to be in line with the now outdated below-2°C limit. The difference between cost-effective 2°C and 1.5°C pathways can help identify the difficult steps that could be supported, although some caution is required in the interpretation due to uncertainties about future cost developments. For instance, highly developed countries could support:
- In the energy supply sector: a “top up”, e.g. for each coal plant that the country replaces itself with renewables, developed countries offer to finance the replacement of an additional plant, especially when closing the plants is costly and requires significant societal change.
- In the industry sector: the switch to low- or zero-carbon industrial production processes.
- In the buildings sector: the transformation of building stocks based on the difference between globally best available technologies and a local building standard.
- In the transport sector: the development of infrastructure for low-carbon transport (electrification, public transport) that requires high upfront investments.
The support of highly developed countries to other countries to reach a 1.5°C pathway can be addressed through various instruments, e.g. international climate finance through multilateral or development banks, but also through international market mechanisms to be established under Article 6.4 of the Paris Agreement. In addition to financial support, instruments to overcome non-financial barriers, such as labour constraints, will be required. Both financial and non-financial instruments must be designed to support high-ambition activities in a coordinated manner.
Figure 1. Gap between fair share and mitigation potential illustratively for the EU and India for 1.5°C pathways.